summaryrefslogtreecommitdiffstats
path: root/mm/page_alloc.c
blob: 48eb0f1410d47c1622cf080331150b53c72ea2fa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
6623
6624
6625
6626
6627
6628
6629
6630
6631
6632
6633
6634
6635
6636
6637
6638
6639
6640
6641
6642
6643
6644
6645
6646
6647
6648
6649
6650
6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
6678
6679
6680
6681
6682
6683
6684
6685
6686
6687
6688
6689
6690
6691
6692
6693
6694
6695
6696
6697
6698
6699
6700
6701
6702
6703
6704
6705
6706
6707
6708
6709
6710
6711
6712
6713
6714
6715
6716
6717
6718
6719
6720
6721
6722
6723
6724
6725
6726
6727
6728
6729
6730
6731
6732
6733
6734
6735
6736
6737
6738
6739
6740
6741
6742
6743
6744
6745
6746
6747
6748
6749
6750
6751
6752
6753
6754
6755
6756
6757
6758
6759
6760
6761
6762
6763
6764
6765
6766
6767
6768
6769
6770
6771
6772
6773
6774
6775
6776
6777
6778
6779
6780
6781
6782
6783
6784
6785
6786
6787
6788
6789
6790
6791
6792
6793
6794
6795
6796
6797
6798
6799
6800
6801
6802
6803
6804
6805
6806
6807
6808
6809
6810
6811
6812
6813
6814
6815
6816
6817
6818
6819
6820
6821
6822
6823
6824
6825
6826
6827
6828
6829
6830
6831
6832
6833
6834
6835
6836
6837
6838
6839
6840
6841
6842
6843
6844
6845
6846
6847
6848
6849
6850
6851
6852
6853
6854
6855
6856
6857
6858
6859
6860
6861
6862
6863
6864
6865
6866
6867
6868
6869
6870
6871
6872
6873
6874
6875
6876
6877
6878
6879
6880
6881
6882
6883
6884
6885
6886
6887
6888
6889
6890
6891
6892
6893
6894
6895
6896
6897
6898
6899
6900
6901
6902
6903
6904
6905
6906
6907
6908
6909
6910
6911
6912
6913
6914
6915
6916
6917
6918
6919
6920
6921
6922
6923
6924
6925
6926
6927
6928
6929
6930
6931
6932
6933
6934
6935
6936
6937
6938
6939
6940
6941
6942
6943
6944
6945
6946
6947
6948
6949
6950
6951
6952
6953
6954
6955
6956
6957
6958
6959
6960
6961
6962
6963
6964
6965
6966
6967
6968
6969
6970
6971
6972
6973
6974
6975
6976
6977
6978
6979
6980
6981
6982
6983
6984
6985
6986
6987
6988
6989
6990
6991
6992
6993
6994
6995
6996
6997
6998
6999
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
7012
7013
7014
7015
7016
7017
7018
7019
7020
7021
7022
7023
7024
7025
7026
7027
7028
7029
7030
7031
7032
7033
7034
7035
7036
7037
7038
7039
7040
7041
7042
7043
7044
7045
7046
7047
7048
7049
7050
7051
7052
7053
7054
7055
7056
7057
7058
7059
7060
7061
7062
7063
7064
7065
7066
7067
7068
7069
7070
7071
7072
7073
7074
7075
7076
7077
7078
7079
7080
7081
7082
7083
7084
7085
7086
7087
7088
7089
7090
7091
7092
7093
7094
7095
7096
7097
7098
7099
7100
7101
7102
7103
7104
7105
7106
7107
7108
7109
7110
7111
7112
7113
7114
7115
7116
7117
7118
7119
7120
7121
7122
7123
7124
7125
7126
7127
7128
7129
7130
7131
7132
7133
7134
7135
7136
7137
7138
7139
7140
7141
7142
7143
7144
7145
7146
7147
7148
7149
7150
7151
7152
7153
7154
7155
7156
7157
7158
7159
7160
7161
7162
7163
7164
7165
7166
7167
7168
7169
7170
7171
7172
7173
7174
7175
7176
7177
7178
7179
7180
7181
7182
7183
7184
7185
7186
7187
7188
7189
7190
7191
7192
7193
7194
7195
7196
7197
7198
7199
7200
7201
7202
7203
7204
7205
7206
7207
7208
7209
7210
7211
7212
7213
7214
7215
7216
7217
7218
7219
7220
7221
7222
7223
7224
7225
7226
7227
7228
7229
7230
7231
7232
7233
7234
7235
7236
7237
7238
7239
7240
7241
7242
7243
7244
7245
7246
7247
7248
7249
7250
7251
7252
7253
7254
7255
7256
7257
7258
7259
7260
7261
7262
7263
7264
7265
7266
7267
7268
7269
7270
7271
7272
7273
7274
7275
7276
7277
7278
7279
7280
7281
7282
7283
7284
7285
7286
7287
7288
7289
7290
7291
7292
7293
7294
7295
7296
7297
7298
7299
7300
7301
7302
7303
7304
7305
7306
7307
7308
7309
7310
7311
7312
7313
7314
7315
7316
7317
7318
7319
7320
7321
7322
7323
7324
7325
7326
7327
7328
7329
7330
7331
7332
7333
7334
7335
7336
7337
7338
7339
7340
7341
7342
7343
7344
7345
7346
7347
7348
7349
7350
7351
7352
7353
7354
7355
7356
7357
7358
7359
7360
7361
7362
7363
7364
7365
7366
7367
7368
7369
7370
7371
7372
7373
7374
7375
7376
7377
7378
7379
7380
7381
7382
7383
7384
7385
7386
7387
7388
7389
7390
7391
7392
7393
7394
7395
7396
7397
7398
7399
7400
7401
7402
7403
7404
7405
7406
7407
7408
7409
7410
7411
7412
7413
7414
7415
7416
7417
7418
7419
7420
7421
7422
7423
7424
7425
7426
7427
7428
7429
7430
7431
7432
7433
7434
7435
7436
7437
7438
7439
7440
7441
7442
7443
7444
7445
7446
7447
7448
7449
7450
7451
7452
7453
7454
7455
7456
7457
7458
7459
7460
7461
7462
7463
7464
7465
7466
7467
7468
7469
7470
7471
7472
7473
7474
7475
7476
7477
7478
7479
7480
7481
7482
7483
7484
7485
7486
7487
7488
7489
7490
7491
7492
7493
7494
7495
7496
7497
7498
7499
7500
7501
7502
7503
7504
7505
7506
7507
7508
7509
7510
7511
7512
7513
7514
7515
7516
7517
7518
7519
7520
7521
7522
7523
7524
7525
7526
7527
7528
7529
7530
7531
7532
7533
7534
7535
7536
7537
7538
7539
7540
7541
7542
7543
7544
7545
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581
7582
7583
7584
7585
7586
7587
7588
7589
7590
7591
7592
7593
7594
7595
7596
7597
7598
7599
7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
7628
7629
7630
7631
7632
7633
7634
7635
7636
7637
7638
7639
7640
7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
7663
7664
7665
7666
7667
7668
7669
7670
7671
7672
7673
7674
7675
7676
7677
7678
7679
7680
7681
7682
7683
7684
7685
7686
7687
7688
7689
7690
7691
7692
7693
7694
7695
7696
7697
7698
7699
7700
7701
7702
7703
7704
7705
7706
7707
7708
7709
7710
7711
7712
7713
7714
7715
7716
7717
7718
7719
7720
7721
7722
7723
7724
7725
7726
7727
7728
7729
7730
7731
7732
7733
7734
7735
7736
7737
7738
7739
7740
7741
7742
7743
7744
7745
7746
7747
7748
7749
7750
7751
7752
7753
7754
7755
7756
7757
7758
7759
7760
7761
7762
7763
7764
7765
7766
7767
7768
7769
7770
7771
7772
7773
7774
7775
7776
7777
7778
7779
7780
7781
7782
7783
7784
7785
7786
7787
7788
7789
7790
7791
7792
7793
7794
7795
7796
7797
7798
7799
7800
7801
7802
7803
7804
7805
7806
7807
7808
7809
7810
7811
7812
7813
7814
7815
7816
7817
7818
7819
7820
7821
7822
7823
7824
7825
7826
7827
7828
7829
7830
7831
7832
7833
7834
7835
7836
7837
7838
7839
7840
7841
7842
7843
7844
7845
7846
7847
7848
7849
7850
7851
7852
7853
7854
7855
7856
7857
7858
7859
7860
7861
7862
7863
7864
7865
7866
7867
7868
7869
7870
7871
7872
7873
7874
7875
7876
7877
7878
7879
7880
7881
7882
7883
7884
7885
7886
7887
7888
7889
7890
7891
7892
7893
7894
7895
7896
7897
7898
7899
7900
7901
7902
7903
7904
7905
7906
7907
7908
7909
7910
7911
7912
7913
7914
7915
7916
7917
7918
7919
7920
7921
7922
7923
7924
7925
7926
7927
7928
7929
7930
7931
7932
7933
7934
7935
7936
7937
7938
7939
7940
7941
7942
7943
7944
7945
7946
7947
7948
7949
7950
7951
7952
7953
7954
7955
7956
7957
7958
7959
7960
7961
7962
7963
7964
7965
7966
7967
7968
7969
7970
7971
7972
7973
7974
7975
7976
7977
7978
7979
7980
7981
7982
7983
7984
7985
7986
7987
7988
7989
7990
7991
7992
7993
7994
7995
7996
7997
7998
7999
8000
8001
8002
8003
8004
8005
8006
8007
8008
8009
8010
8011
8012
8013
8014
8015
8016
8017
8018
8019
8020
8021
8022
8023
8024
8025
8026
8027
8028
8029
8030
8031
8032
8033
8034
8035
8036
8037
8038
8039
8040
8041
8042
8043
8044
8045
8046
8047
8048
8049
8050
8051
8052
8053
8054
8055
8056
8057
8058
8059
8060
8061
8062
8063
8064
8065
8066
8067
8068
8069
8070
8071
8072
8073
8074
8075
8076
8077
8078
8079
8080
8081
8082
8083
8084
8085
8086
8087
8088
8089
8090
8091
8092
8093
8094
8095
8096
8097
8098
8099
8100
8101
8102
8103
8104
8105
8106
8107
8108
8109
8110
8111
8112
8113
8114
8115
8116
8117
8118
8119
8120
8121
8122
8123
8124
8125
8126
8127
8128
8129
8130
8131
8132
8133
8134
8135
8136
8137
8138
8139
8140
8141
8142
8143
8144
8145
8146
8147
8148
8149
8150
8151
8152
8153
8154
8155
8156
8157
8158
8159
8160
8161
8162
8163
8164
8165
8166
8167
8168
8169
8170
8171
8172
8173
8174
8175
8176
8177
8178
8179
8180
8181
8182
8183
8184
8185
8186
8187
8188
8189
8190
8191
8192
8193
8194
8195
8196
8197
8198
8199
8200
8201
8202
8203
8204
8205
8206
8207
8208
8209
8210
8211
8212
8213
8214
8215
8216
8217
8218
8219
8220
8221
8222
8223
8224
8225
8226
8227
8228
8229
8230
8231
8232
8233
8234
8235
8236
8237
8238
8239
8240
8241
8242
8243
8244
8245
8246
8247
8248
8249
8250
8251
8252
8253
8254
8255
8256
8257
8258
8259
8260
8261
8262
8263
8264
8265
8266
8267
8268
8269
8270
8271
8272
8273
8274
8275
8276
8277
8278
8279
8280
8281
8282
8283
8284
8285
8286
8287
8288
8289
8290
8291
8292
8293
8294
8295
8296
8297
8298
8299
8300
8301
8302
8303
8304
8305
8306
8307
8308
8309
8310
8311
8312
8313
8314
8315
8316
8317
8318
8319
8320
8321
8322
8323
8324
8325
8326
8327
8328
8329
8330
8331
8332
8333
8334
8335
8336
8337
8338
8339
8340
8341
8342
8343
8344
8345
8346
8347
8348
8349
8350
8351
8352
8353
8354
8355
8356
8357
8358
8359
8360
8361
8362
8363
8364
8365
8366
8367
8368
8369
8370
8371
8372
8373
8374
8375
8376
8377
8378
8379
8380
8381
8382
8383
8384
8385
8386
8387
8388
8389
8390
8391
8392
8393
8394
8395
8396
8397
8398
8399
8400
8401
8402
8403
8404
8405
8406
8407
8408
8409
8410
8411
8412
8413
8414
8415
8416
8417
8418
8419
8420
8421
8422
8423
8424
8425
8426
8427
8428
8429
8430
8431
8432
8433
8434
8435
8436
8437
8438
8439
8440
8441
8442
8443
8444
8445
8446
8447
8448
8449
8450
8451
8452
8453
8454
8455
8456
8457
8458
8459
8460
8461
8462
8463
8464
8465
8466
8467
8468
8469
8470
8471
8472
8473
8474
8475
8476
8477
8478
8479
8480
8481
8482
8483
8484
8485
8486
8487
8488
8489
8490
8491
8492
8493
8494
8495
8496
8497
8498
8499
8500
8501
8502
8503
8504
8505
8506
8507
8508
8509
8510
8511
8512
8513
8514
8515
8516
8517
8518
8519
8520
8521
8522
8523
8524
8525
8526
8527
8528
8529
8530
8531
8532
8533
8534
8535
8536
8537
8538
8539
8540
8541
8542
8543
8544
8545
8546
8547
8548
8549
8550
8551
8552
8553
8554
8555
8556
8557
8558
8559
8560
8561
8562
8563
8564
8565
8566
8567
8568
8569
8570
8571
8572
8573
8574
8575
8576
8577
8578
8579
8580
8581
8582
8583
8584
8585
8586
8587
8588
8589
8590
8591
8592
8593
8594
8595
8596
8597
8598
8599
8600
8601
8602
8603
8604
8605
8606
8607
8608
8609
8610
8611
8612
8613
8614
8615
8616
8617
8618
8619
8620
8621
8622
8623
8624
8625
8626
8627
8628
8629
8630
8631
8632
8633
8634
8635
8636
8637
8638
8639
8640
8641
8642
8643
8644
8645
8646
8647
8648
8649
8650
8651
8652
8653
8654
8655
8656
8657
8658
8659
8660
8661
8662
8663
8664
8665
8666
8667
8668
8669
8670
8671
8672
8673
8674
8675
8676
8677
8678
8679
8680
8681
8682
8683
8684
8685
8686
8687
8688
8689
8690
8691
8692
8693
8694
8695
8696
8697
8698
8699
8700
8701
8702
8703
8704
8705
8706
8707
8708
8709
8710
8711
8712
8713
8714
8715
8716
8717
8718
8719
8720
8721
8722
8723
8724
8725
8726
8727
8728
8729
8730
8731
8732
8733
8734
8735
8736
8737
8738
8739
8740
8741
8742
8743
8744
8745
8746
8747
8748
8749
8750
8751
8752
8753
8754
8755
8756
8757
8758
8759
8760
8761
8762
8763
8764
8765
8766
8767
8768
8769
8770
8771
8772
8773
8774
8775
8776
8777
8778
8779
8780
8781
8782
8783
8784
8785
8786
8787
8788
8789
8790
8791
8792
8793
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/mm/page_alloc.c
 *
 *  Manages the free list, the system allocates free pages here.
 *  Note that kmalloc() lives in slab.c
 *
 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *  Swap reorganised 29.12.95, Stephen Tweedie
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
 *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
 *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
 *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
 *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
 */

#include <linux/stddef.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/jiffies.h>
#include <linux/memblock.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/kasan.h>
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/ratelimit.h>
#include <linux/oom.h>
#include <linux/topology.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/memory_hotplug.h>
#include <linux/nodemask.h>
#include <linux/vmalloc.h>
#include <linux/vmstat.h>
#include <linux/mempolicy.h>
#include <linux/memremap.h>
#include <linux/stop_machine.h>
#include <linux/random.h>
#include <linux/sort.h>
#include <linux/pfn.h>
#include <linux/backing-dev.h>
#include <linux/fault-inject.h>
#include <linux/page-isolation.h>
#include <linux/debugobjects.h>
#include <linux/kmemleak.h>
#include <linux/compaction.h>
#include <trace/events/kmem.h>
#include <trace/events/oom.h>
#include <linux/prefetch.h>
#include <linux/mm_inline.h>
#include <linux/migrate.h>
#include <linux/hugetlb.h>
#include <linux/sched/rt.h>
#include <linux/sched/mm.h>
#include <linux/page_owner.h>
#include <linux/kthread.h>
#include <linux/memcontrol.h>
#include <linux/ftrace.h>
#include <linux/lockdep.h>
#include <linux/nmi.h>
#include <linux/psi.h>
#include <linux/padata.h>

#include <asm/sections.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
#include "internal.h"
#include "shuffle.h"
#include "page_reporting.h"

/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
static DEFINE_MUTEX(pcp_batch_high_lock);
#define MIN_PERCPU_PAGELIST_FRACTION	(8)

#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
DEFINE_PER_CPU(int, numa_node);
EXPORT_PER_CPU_SYMBOL(numa_node);
#endif

DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key);

#ifdef CONFIG_HAVE_MEMORYLESS_NODES
/*
 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
 * defined in <linux/topology.h>.
 */
DEFINE_PER_CPU(int, _numa_mem_);		/* Kernel "local memory" node */
EXPORT_PER_CPU_SYMBOL(_numa_mem_);
#endif

/* work_structs for global per-cpu drains */
struct pcpu_drain {
	struct zone *zone;
	struct work_struct work;
};
static DEFINE_MUTEX(pcpu_drain_mutex);
static DEFINE_PER_CPU(struct pcpu_drain, pcpu_drain);

#ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
volatile unsigned long latent_entropy __latent_entropy;
EXPORT_SYMBOL(latent_entropy);
#endif

/*
 * Array of node states.
 */
nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
	[N_POSSIBLE] = NODE_MASK_ALL,
	[N_ONLINE] = { { [0] = 1UL } },
#ifndef CONFIG_NUMA
	[N_NORMAL_MEMORY] = { { [0] = 1UL } },
#ifdef CONFIG_HIGHMEM
	[N_HIGH_MEMORY] = { { [0] = 1UL } },
#endif
	[N_MEMORY] = { { [0] = 1UL } },
	[N_CPU] = { { [0] = 1UL } },
#endif	/* NUMA */
};
EXPORT_SYMBOL(node_states);

atomic_long_t _totalram_pages __read_mostly;
EXPORT_SYMBOL(_totalram_pages);
unsigned long totalreserve_pages __read_mostly;
unsigned long totalcma_pages __read_mostly;

int percpu_pagelist_fraction;
gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
#ifdef CONFIG_INIT_ON_ALLOC_DEFAULT_ON
DEFINE_STATIC_KEY_TRUE(init_on_alloc);
#else
DEFINE_STATIC_KEY_FALSE(init_on_alloc);
#endif
EXPORT_SYMBOL(init_on_alloc);

#ifdef CONFIG_INIT_ON_FREE_DEFAULT_ON
DEFINE_STATIC_KEY_TRUE(init_on_free);
#else
DEFINE_STATIC_KEY_FALSE(init_on_free);
#endif
EXPORT_SYMBOL(init_on_free);

static int __init early_init_on_alloc(char *buf)
{
	int ret;
	bool bool_result;

	if (!buf)
		return -EINVAL;
	ret = kstrtobool(buf, &bool_result);
	if (bool_result && page_poisoning_enabled())
		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_alloc\n");
	if (bool_result)
		static_branch_enable(&init_on_alloc);
	else
		static_branch_disable(&init_on_alloc);
	return ret;
}
early_param("init_on_alloc", early_init_on_alloc);

static int __init early_init_on_free(char *buf)
{
	int ret;
	bool bool_result;

	if (!buf)
		return -EINVAL;
	ret = kstrtobool(buf, &bool_result);
	if (bool_result && page_poisoning_enabled())
		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_free\n");
	if (bool_result)
		static_branch_enable(&init_on_free);
	else
		static_branch_disable(&init_on_free);
	return ret;
}
early_param("init_on_free", early_init_on_free);

/*
 * A cached value of the page's pageblock's migratetype, used when the page is
 * put on a pcplist. Used to avoid the pageblock migratetype lookup when
 * freeing from pcplists in most cases, at the cost of possibly becoming stale.
 * Also the migratetype set in the page does not necessarily match the pcplist
 * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
 * other index - this ensures that it will be put on the correct CMA freelist.
 */
static inline int get_pcppage_migratetype(struct page *page)
{
	return page->index;
}

static inline void set_pcppage_migratetype(struct page *page, int migratetype)
{
	page->index = migratetype;
}

#ifdef CONFIG_PM_SLEEP
/*
 * The following functions are used by the suspend/hibernate code to temporarily
 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
 * while devices are suspended.  To avoid races with the suspend/hibernate code,
 * they should always be called with system_transition_mutex held
 * (gfp_allowed_mask also should only be modified with system_transition_mutex
 * held, unless the suspend/hibernate code is guaranteed not to run in parallel
 * with that modification).
 */

static gfp_t saved_gfp_mask;

void pm_restore_gfp_mask(void)
{
	WARN_ON(!mutex_is_locked(&system_transition_mutex));
	if (saved_gfp_mask) {
		gfp_allowed_mask = saved_gfp_mask;
		saved_gfp_mask = 0;
	}
}

void pm_restrict_gfp_mask(void)
{
	WARN_ON(!mutex_is_locked(&system_transition_mutex));
	WARN_ON(saved_gfp_mask);
	saved_gfp_mask = gfp_allowed_mask;
	gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
}

bool pm_suspended_storage(void)
{
	if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
		return false;
	return true;
}
#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
unsigned int pageblock_order __read_mostly;
#endif

static void __free_pages_ok(struct page *page, unsigned int order);

/*
 * results with 256, 32 in the lowmem_reserve sysctl:
 *	1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
 *	1G machine -> (16M dma, 784M normal, 224M high)
 *	NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
 *	HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
 *	HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA
 *
 * TBD: should special case ZONE_DMA32 machines here - in those we normally
 * don't need any ZONE_NORMAL reservation
 */
int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = {
#ifdef CONFIG_ZONE_DMA
	[ZONE_DMA] = 256,
#endif
#ifdef CONFIG_ZONE_DMA32
	[ZONE_DMA32] = 256,
#endif
	[ZONE_NORMAL] = 32,
#ifdef CONFIG_HIGHMEM
	[ZONE_HIGHMEM] = 0,
#endif
	[ZONE_MOVABLE] = 0,
};

static char * const zone_names[MAX_NR_ZONES] = {
#ifdef CONFIG_ZONE_DMA
	 "DMA",
#endif
#ifdef CONFIG_ZONE_DMA32
	 "DMA32",
#endif
	 "Normal",
#ifdef CONFIG_HIGHMEM
	 "HighMem",
#endif
	 "Movable",
#ifdef CONFIG_ZONE_DEVICE
	 "Device",
#endif
};

const char * const migratetype_names[MIGRATE_TYPES] = {
	"Unmovable",
	"Movable",
	"Reclaimable",
	"HighAtomic",
#ifdef CONFIG_CMA
	"CMA",
#endif
#ifdef CONFIG_MEMORY_ISOLATION
	"Isolate",
#endif
};

compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = {
	[NULL_COMPOUND_DTOR] = NULL,
	[COMPOUND_PAGE_DTOR] = free_compound_page,
#ifdef CONFIG_HUGETLB_PAGE
	[HUGETLB_PAGE_DTOR] = free_huge_page,
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	[TRANSHUGE_PAGE_DTOR] = free_transhuge_page,
#endif
};

int min_free_kbytes = 1024;
int user_min_free_kbytes = -1;
#ifdef CONFIG_DISCONTIGMEM
/*
 * DiscontigMem defines memory ranges as separate pg_data_t even if the ranges
 * are not on separate NUMA nodes. Functionally this works but with
 * watermark_boost_factor, it can reclaim prematurely as the ranges can be
 * quite small. By default, do not boost watermarks on discontigmem as in
 * many cases very high-order allocations like THP are likely to be
 * unsupported and the premature reclaim offsets the advantage of long-term
 * fragmentation avoidance.
 */
int watermark_boost_factor __read_mostly;
#else
int watermark_boost_factor __read_mostly = 15000;
#endif
int watermark_scale_factor = 10;

static unsigned long nr_kernel_pages __initdata;
static unsigned long nr_all_pages __initdata;
static unsigned long dma_reserve __initdata;

static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata;
static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata;
static unsigned long required_kernelcore __initdata;
static unsigned long required_kernelcore_percent __initdata;
static unsigned long required_movablecore __initdata;
static unsigned long required_movablecore_percent __initdata;
static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
static bool mirrored_kernelcore __meminitdata;

/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
int movable_zone;
EXPORT_SYMBOL(movable_zone);

#if MAX_NUMNODES > 1
unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;
unsigned int nr_online_nodes __read_mostly = 1;
EXPORT_SYMBOL(nr_node_ids);
EXPORT_SYMBOL(nr_online_nodes);
#endif

int page_group_by_mobility_disabled __read_mostly;

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
/*
 * During boot we initialize deferred pages on-demand, as needed, but once
 * page_alloc_init_late() has finished, the deferred pages are all initialized,
 * and we can permanently disable that path.
 */
static DEFINE_STATIC_KEY_TRUE(deferred_pages);

/*
 * Calling kasan_free_pages() only after deferred memory initialization
 * has completed. Poisoning pages during deferred memory init will greatly
 * lengthen the process and cause problem in large memory systems as the
 * deferred pages initialization is done with interrupt disabled.
 *
 * Assuming that there will be no reference to those newly initialized
 * pages before they are ever allocated, this should have no effect on
 * KASAN memory tracking as the poison will be properly inserted at page
 * allocation time. The only corner case is when pages are allocated by
 * on-demand allocation and then freed again before the deferred pages
 * initialization is done, but this is not likely to happen.
 */
static inline void kasan_free_nondeferred_pages(struct page *page, int order)
{
	if (!static_branch_unlikely(&deferred_pages))
		kasan_free_pages(page, order);
}

/* Returns true if the struct page for the pfn is uninitialised */
static inline bool __meminit early_page_uninitialised(unsigned long pfn)
{
	int nid = early_pfn_to_nid(pfn);

	if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
		return true;

	return false;
}

/*
 * Returns true when the remaining initialisation should be deferred until
 * later in the boot cycle when it can be parallelised.
 */
static bool __meminit
defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
{
	static unsigned long prev_end_pfn, nr_initialised;

	/*
	 * prev_end_pfn static that contains the end of previous zone
	 * No need to protect because called very early in boot before smp_init.
	 */
	if (prev_end_pfn != end_pfn) {
		prev_end_pfn = end_pfn;
		nr_initialised = 0;
	}

	/* Always populate low zones for address-constrained allocations */
	if (end_pfn < pgdat_end_pfn(NODE_DATA(nid)))
		return false;

	/*
	 * We start only with one section of pages, more pages are added as
	 * needed until the rest of deferred pages are initialized.
	 */
	nr_initialised++;
	if ((nr_initialised > PAGES_PER_SECTION) &&
	    (pfn & (PAGES_PER_SECTION - 1)) == 0) {
		NODE_DATA(nid)->first_deferred_pfn = pfn;
		return true;
	}
	return false;
}
#else
#define kasan_free_nondeferred_pages(p, o)	kasan_free_pages(p, o)

static inline bool early_page_uninitialised(unsigned long pfn)
{
	return false;
}

static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
{
	return false;
}
#endif

/* Return a pointer to the bitmap storing bits affecting a block of pages */
static inline unsigned long *get_pageblock_bitmap(struct page *page,
							unsigned long pfn)
{
#ifdef CONFIG_SPARSEMEM
	return section_to_usemap(__pfn_to_section(pfn));
#else
	return page_zone(page)->pageblock_flags;
#endif /* CONFIG_SPARSEMEM */
}

static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
{
#ifdef CONFIG_SPARSEMEM
	pfn &= (PAGES_PER_SECTION-1);
	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
#else
	pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
#endif /* CONFIG_SPARSEMEM */
}

/**
 * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
 * @page: The page within the block of interest
 * @pfn: The target page frame number
 * @end_bitidx: The last bit of interest to retrieve
 * @mask: mask of bits that the caller is interested in
 *
 * Return: pageblock_bits flags
 */
static __always_inline unsigned long __get_pfnblock_flags_mask(struct page *page,
					unsigned long pfn,
					unsigned long end_bitidx,
					unsigned long mask)
{
	unsigned long *bitmap;
	unsigned long bitidx, word_bitidx;
	unsigned long word;

	bitmap = get_pageblock_bitmap(page, pfn);
	bitidx = pfn_to_bitidx(page, pfn);
	word_bitidx = bitidx / BITS_PER_LONG;
	bitidx &= (BITS_PER_LONG-1);

	word = bitmap[word_bitidx];
	bitidx += end_bitidx;
	return (word >> (BITS_PER_LONG - bitidx - 1)) & mask;
}

unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
					unsigned long end_bitidx,
					unsigned long mask)
{
	return __get_pfnblock_flags_mask(page, pfn, end_bitidx, mask);
}

static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
{
	return __get_pfnblock_flags_mask(page, pfn, PB_migrate_end, MIGRATETYPE_MASK);
}

/**
 * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
 * @page: The page within the block of interest
 * @flags: The flags to set
 * @pfn: The target page frame number
 * @end_bitidx: The last bit of interest
 * @mask: mask of bits that the caller is interested in
 */
void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
					unsigned long pfn,
					unsigned long end_bitidx,
					unsigned long mask)
{
	unsigned long *bitmap;
	unsigned long bitidx, word_bitidx;
	unsigned long old_word, word;

	BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
	BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));

	bitmap = get_pageblock_bitmap(page, pfn);
	bitidx = pfn_to_bitidx(page, pfn);
	word_bitidx = bitidx / BITS_PER_LONG;
	bitidx &= (BITS_PER_LONG-1);

	VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);

	bitidx += end_bitidx;
	mask <<= (BITS_PER_LONG - bitidx - 1);
	flags <<= (BITS_PER_LONG - bitidx - 1);

	word = READ_ONCE(bitmap[word_bitidx]);
	for (;;) {
		old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
		if (word == old_word)
			break;
		word = old_word;
	}
}

void set_pageblock_migratetype(struct page *page, int migratetype)
{
	if (unlikely(page_group_by_mobility_disabled &&
		     migratetype < MIGRATE_PCPTYPES))
		migratetype = MIGRATE_UNMOVABLE;

	set_pageblock_flags_group(page, (unsigned long)migratetype,
					PB_migrate, PB_migrate_end);
}

#ifdef CONFIG_DEBUG_VM
static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
{
	int ret = 0;
	unsigned seq;
	unsigned long pfn = page_to_pfn(page);
	unsigned long sp, start_pfn;

	do {
		seq = zone_span_seqbegin(zone);
		start_pfn = zone->zone_start_pfn;
		sp = zone->spanned_pages;
		if (!zone_spans_pfn(zone, pfn))
			ret = 1;
	} while (zone_span_seqretry(zone, seq));

	if (ret)
		pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
			pfn, zone_to_nid(zone), zone->name,
			start_pfn, start_pfn + sp);

	return ret;
}

static int page_is_consistent(struct zone *zone, struct page *page)
{
	if (!pfn_valid_within(page_to_pfn(page)))
		return 0;
	if (zone != page_zone(page))
		return 0;

	return 1;
}
/*
 * Temporary debugging check for pages not lying within a given zone.
 */
static int __maybe_unused bad_range(struct zone *zone, struct page *page)
{
	if (page_outside_zone_boundaries(zone, page))
		return 1;
	if (!page_is_consistent(zone, page))
		return 1;

	return 0;
}
#else
static inline int __maybe_unused bad_range(struct zone *zone, struct page *page)
{
	return 0;
}
#endif

static void bad_page(struct page *page, const char *reason)
{
	static unsigned long resume;
	static unsigned long nr_shown;
	static unsigned long nr_unshown;

	/*
	 * Allow a burst of 60 reports, then keep quiet for that minute;
	 * or allow a steady drip of one report per second.
	 */
	if (nr_shown == 60) {
		if (time_before(jiffies, resume)) {
			nr_unshown++;
			goto out;
		}
		if (nr_unshown) {
			pr_alert(
			      "BUG: Bad page state: %lu messages suppressed\n",
				nr_unshown);
			nr_unshown = 0;
		}
		nr_shown = 0;
	}
	if (nr_shown++ == 0)
		resume = jiffies + 60 * HZ;

	pr_alert("BUG: Bad page state in process %s  pfn:%05lx\n",
		current->comm, page_to_pfn(page));
	__dump_page(page, reason);
	dump_page_owner(page);

	print_modules();
	dump_stack();
out:
	/* Leave bad fields for debug, except PageBuddy could make trouble */
	page_mapcount_reset(page); /* remove PageBuddy */
	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
}

/*
 * Higher-order pages are called "compound pages".  They are structured thusly:
 *
 * The first PAGE_SIZE page is called the "head page" and have PG_head set.
 *
 * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
 * in bit 0 of page->compound_head. The rest of bits is pointer to head page.
 *
 * The first tail page's ->compound_dtor holds the offset in array of compound
 * page destructors. See compound_page_dtors.
 *
 * The first tail page's ->compound_order holds the order of allocation.
 * This usage means that zero-order pages may not be compound.
 */

void free_compound_page(struct page *page)
{
	mem_cgroup_uncharge(page);
	__free_pages_ok(page, compound_order(page));
}

void prep_compound_page(struct page *page, unsigned int order)
{
	int i;
	int nr_pages = 1 << order;

	set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
	set_compound_order(page, order);
	__SetPageHead(page);
	for (i = 1; i < nr_pages; i++) {
		struct page *p = page + i;
		set_page_count(p, 0);
		p->mapping = TAIL_MAPPING;
		set_compound_head(p, page);
	}
	atomic_set(compound_mapcount_ptr(page), -1);
	if (hpage_pincount_available(page))
		atomic_set(compound_pincount_ptr(page), 0);
}

#ifdef CONFIG_DEBUG_PAGEALLOC
unsigned int _debug_guardpage_minorder;

bool _debug_pagealloc_enabled_early __read_mostly
			= IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
EXPORT_SYMBOL(_debug_pagealloc_enabled_early);
DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
EXPORT_SYMBOL(_debug_pagealloc_enabled);

DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);

static int __init early_debug_pagealloc(char *buf)
{
	return kstrtobool(buf, &_debug_pagealloc_enabled_early);
}
early_param("debug_pagealloc", early_debug_pagealloc);

void init_debug_pagealloc(void)
{
	if (!debug_pagealloc_enabled())
		return;

	static_branch_enable(&_debug_pagealloc_enabled);

	if (!debug_guardpage_minorder())
		return;

	static_branch_enable(&_debug_guardpage_enabled);
}

static int __init debug_guardpage_minorder_setup(char *buf)
{
	unsigned long res;

	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
		pr_err("Bad debug_guardpage_minorder value\n");
		return 0;
	}
	_debug_guardpage_minorder = res;
	pr_info("Setting debug_guardpage_minorder to %lu\n", res);
	return 0;
}
early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);

static inline bool set_page_guard(struct zone *zone, struct page *page,
				unsigned int order, int migratetype)
{
	if (!debug_guardpage_enabled())
		return false;

	if (order >= debug_guardpage_minorder())
		return false;

	__SetPageGuard(page);
	INIT_LIST_HEAD(&page->lru);
	set_page_private(page, order);
	/* Guard pages are not available for any usage */
	__mod_zone_freepage_state(zone, -(1 << order), migratetype);

	return true;
}

static inline void clear_page_guard(struct zone *zone, struct page *page,
				unsigned int order, int migratetype)
{
	if (!debug_guardpage_enabled())
		return;

	__ClearPageGuard(page);

	set_page_private(page, 0);
	if (!is_migrate_isolate(migratetype))
		__mod_zone_freepage_state(zone, (1 << order), migratetype);
}
#else
static inline bool set_page_guard(struct zone *zone, struct page *page,
			unsigned int order, int migratetype) { return false; }
static inline void clear_page_guard(struct zone *zone, struct page *page,
				unsigned int order, int migratetype) {}
#endif

static inline void set_page_order(struct page *page, unsigned int order)
{
	set_page_private(page, order);
	__SetPageBuddy(page);
}

/*
 * This function checks whether a page is free && is the buddy
 * we can coalesce a page and its buddy if
 * (a) the buddy is not in a hole (check before calling!) &&
 * (b) the buddy is in the buddy system &&
 * (c) a page and its buddy have the same order &&
 * (d) a page and its buddy are in the same zone.
 *
 * For recording whether a page is in the buddy system, we set PageBuddy.
 * Setting, clearing, and testing PageBuddy is serialized by zone->lock.
 *
 * For recording page's order, we use page_private(page).
 */
static inline bool page_is_buddy(struct page *page, struct page *buddy,
							unsigned int order)
{
	if (!page_is_guard(buddy) && !PageBuddy(buddy))
		return false;

	if (page_order(buddy) != order)
		return false;

	/*
	 * zone check is done late to avoid uselessly calculating
	 * zone/node ids for pages that could never merge.
	 */
	if (page_zone_id(page) != page_zone_id(buddy))
		return false;

	VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);

	return true;
}

#ifdef CONFIG_COMPACTION
static inline struct capture_control *task_capc(struct zone *zone)
{
	struct capture_control *capc = current->capture_control;

	return capc &&
		!(current->flags & PF_KTHREAD) &&
		!capc->page &&
		capc->cc->zone == zone &&
		capc->cc->direct_compaction ? capc : NULL;
}

static inline bool
compaction_capture(struct capture_control *capc, struct page *page,
		   int order, int migratetype)
{
	if (!capc || order != capc->cc->order)
		return false;

	/* Do not accidentally pollute CMA or isolated regions*/
	if (is_migrate_cma(migratetype) ||
	    is_migrate_isolate(migratetype))
		return false;

	/*
	 * Do not let lower order allocations polluate a movable pageblock.
	 * This might let an unmovable request use a reclaimable pageblock
	 * and vice-versa but no more than normal fallback logic which can
	 * have trouble finding a high-order free page.
	 */
	if (order < pageblock_order && migratetype == MIGRATE_MOVABLE)
		return false;

	capc->page = page;
	return true;
}

#else
static inline struct capture_control *task_capc(struct zone *zone)
{
	return NULL;
}

static inline bool
compaction_capture(struct capture_control *capc, struct page *page,
		   int order, int migratetype)
{
	return false;
}
#endif /* CONFIG_COMPACTION */

/* Used for pages not on another list */
static inline void add_to_free_list(struct page *page, struct zone *zone,
				    unsigned int order, int migratetype)
{
	struct free_area *area = &zone->free_area[order];

	list_add(&page->lru, &area->free_list[migratetype]);
	area->nr_free++;
}

/* Used for pages not on another list */
static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
					 unsigned int order, int migratetype)
{
	struct free_area *area = &zone->free_area[order];

	list_add_tail(&page->lru, &area->free_list[migratetype]);
	area->nr_free++;
}

/* Used for pages which are on another list */
static inline void move_to_free_list(struct page *page, struct zone *zone,
				     unsigned int order, int migratetype)
{
	struct free_area *area = &zone->free_area[order];

	list_move(&page->lru, &area->free_list[migratetype]);
}

static inline void del_page_from_free_list(struct page *page, struct zone *zone,
					   unsigned int order)
{
	/* clear reported state and update reported page count */
	if (page_reported(page))
		__ClearPageReported(page);

	list_del(&page->lru);
	__ClearPageBuddy(page);
	set_page_private(page, 0);
	zone->free_area[order].nr_free--;
}

/*
 * If this is not the largest possible page, check if the buddy
 * of the next-highest order is free. If it is, it's possible
 * that pages are being freed that will coalesce soon. In case,
 * that is happening, add the free page to the tail of the list
 * so it's less likely to be used soon and more likely to be merged
 * as a higher order page
 */
static inline bool
buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn,
		   struct page *page, unsigned int order)
{
	struct page *higher_page, *higher_buddy;
	unsigned long combined_pfn;

	if (order >= MAX_ORDER - 2)
		return false;

	if (!pfn_valid_within(buddy_pfn))
		return false;

	combined_pfn = buddy_pfn & pfn;
	higher_page = page + (combined_pfn - pfn);
	buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1);
	higher_buddy = higher_page + (buddy_pfn - combined_pfn);

	return pfn_valid_within(buddy_pfn) &&
	       page_is_buddy(higher_page, higher_buddy, order + 1);
}

/*
 * Freeing function for a buddy system allocator.
 *
 * The concept of a buddy system is to maintain direct-mapped table
 * (containing bit values) for memory blocks of various "orders".
 * The bottom level table contains the map for the smallest allocatable
 * units of memory (here, pages), and each level above it describes
 * pairs of units from the levels below, hence, "buddies".
 * At a high level, all that happens here is marking the table entry
 * at the bottom level available, and propagating the changes upward
 * as necessary, plus some accounting needed to play nicely with other
 * parts of the VM system.
 * At each level, we keep a list of pages, which are heads of continuous
 * free pages of length of (1 << order) and marked with PageBuddy.
 * Page's order is recorded in page_private(page) field.
 * So when we are allocating or freeing one, we can derive the state of the
 * other.  That is, if we allocate a small block, and both were
 * free, the remainder of the region must be split into blocks.
 * If a block is freed, and its buddy is also free, then this
 * triggers coalescing into a block of larger size.
 *
 * -- nyc
 */

static inline void __free_one_page(struct page *page,
		unsigned long pfn,
		struct zone *zone, unsigned int order,
		int migratetype, bool report)
{
	struct capture_control *capc = task_capc(zone);
	unsigned long uninitialized_var(buddy_pfn);
	unsigned long combined_pfn;
	unsigned int max_order;
	struct page *buddy;
	bool to_tail;

	max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);

	VM_BUG_ON(!zone_is_initialized(zone));
	VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);

	VM_BUG_ON(migratetype == -1);
	if (likely(!is_migrate_isolate(migratetype)))
		__mod_zone_freepage_state(zone, 1 << order, migratetype);

	VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
	VM_BUG_ON_PAGE(bad_range(zone, page), page);

continue_merging:
	while (order < max_order - 1) {
		if (compaction_capture(capc, page, order, migratetype)) {
			__mod_zone_freepage_state(zone, -(1 << order),
								migratetype);
			return;
		}
		buddy_pfn = __find_buddy_pfn(pfn, order);
		buddy = page + (buddy_pfn - pfn);

		if (!pfn_valid_within(buddy_pfn))
			goto done_merging;
		if (!page_is_buddy(page, buddy, order))
			goto done_merging;
		/*
		 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
		 * merge with it and move up one order.
		 */
		if (page_is_guard(buddy))
			clear_page_guard(zone, buddy, order, migratetype);
		else
			del_page_from_free_list(buddy, zone, order);
		combined_pfn = buddy_pfn & pfn;
		page = page + (combined_pfn - pfn);
		pfn = combined_pfn;
		order++;
	}
	if (max_order < MAX_ORDER) {
		/* If we are here, it means order is >= pageblock_order.
		 * We want to prevent merge between freepages on isolate
		 * pageblock and normal pageblock. Without this, pageblock
		 * isolation could cause incorrect freepage or CMA accounting.
		 *
		 * We don't want to hit this code for the more frequent
		 * low-order merging.
		 */
		if (unlikely(has_isolate_pageblock(zone))) {
			int buddy_mt;

			buddy_pfn = __find_buddy_pfn(pfn, order);
			buddy = page + (buddy_pfn - pfn);
			buddy_mt = get_pageblock_migratetype(buddy);

			if (migratetype != buddy_mt
					&& (is_migrate_isolate(migratetype) ||
						is_migrate_isolate(buddy_mt)))
				goto done_merging;
		}
		max_order++;
		goto continue_merging;
	}

done_merging:
	set_page_order(page, order);

	if (is_shuffle_order(order))
		to_tail = shuffle_pick_tail();
	else
		to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order);

	if (to_tail)
		add_to_free_list_tail(page, zone, order, migratetype);
	else
		add_to_free_list(page, zone, order, migratetype);

	/* Notify page reporting subsystem of freed page */
	if (report)
		page_reporting_notify_free(order);
}

/*
 * A bad page could be due to a number of fields. Instead of multiple branches,
 * try and check multiple fields with one check. The caller must do a detailed
 * check if necessary.
 */
static inline bool page_expected_state(struct page *page,
					unsigned long check_flags)
{
	if (unlikely(atomic_read(&page->_mapcount) != -1))
		return false;

	if (unlikely((unsigned long)page->mapping |
			page_ref_count(page) |
#ifdef CONFIG_MEMCG
			(unsigned long)page->mem_cgroup |
#endif
			(page->flags & check_flags)))
		return false;

	return true;
}

static const char *page_bad_reason(struct page *page, unsigned long flags)
{
	const char *bad_reason = NULL;

	if (unlikely(atomic_read(&page->_mapcount) != -1))
		bad_reason = "nonzero mapcount";
	if (unlikely(page->mapping != NULL))
		bad_reason = "non-NULL mapping";
	if (unlikely(page_ref_count(page) != 0))
		bad_reason = "nonzero _refcount";
	if (unlikely(page->flags & flags)) {
		if (flags == PAGE_FLAGS_CHECK_AT_PREP)
			bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set";
		else
			bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
	}
#ifdef CONFIG_MEMCG
	if (unlikely(page->mem_cgroup))
		bad_reason = "page still charged to cgroup";
#endif
	return bad_reason;
}

static void check_free_page_bad(struct page *page)
{
	bad_page(page,
		 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE));
}

static inline int check_free_page(struct page *page)
{
	if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
		return 0;

	/* Something has gone sideways, find it */
	check_free_page_bad(page);
	return 1;
}

static int free_tail_pages_check(struct page *head_page, struct page *page)
{
	int ret = 1;

	/*
	 * We rely page->lru.next never has bit 0 set, unless the page
	 * is PageTail(). Let's make sure that's true even for poisoned ->lru.
	 */
	BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);

	if (!IS_ENABLED(CONFIG_DEBUG_VM)) {
		ret = 0;
		goto out;
	}
	switch (page - head_page) {
	case 1:
		/* the first tail page: ->mapping may be compound_mapcount() */
		if (unlikely(compound_mapcount(page))) {
			bad_page(page, "nonzero compound_mapcount");
			goto out;
		}
		break;
	case 2:
		/*
		 * the second tail page: ->mapping is
		 * deferred_list.next -- ignore value.
		 */
		break;
	default:
		if (page->mapping != TAIL_MAPPING) {
			bad_page(page, "corrupted mapping in tail page");
			goto out;
		}
		break;
	}
	if (unlikely(!PageTail(page))) {
		bad_page(page, "PageTail not set");
		goto out;
	}
	if (unlikely(compound_head(page) != head_page)) {
		bad_page(page, "compound_head not consistent");
		goto out;
	}
	ret = 0;
out:
	page->mapping = NULL;
	clear_compound_head(page);
	return ret;
}

static void kernel_init_free_pages(struct page *page, int numpages)
{
	int i;

	for (i = 0; i < numpages; i++)
		clear_highpage(page + i);
}

static __always_inline bool free_pages_prepare(struct page *page,
					unsigned int order, bool check_free)
{
	int bad = 0;

	VM_BUG_ON_PAGE(PageTail(page), page);

	trace_mm_page_free(page, order);

	/*
	 * Check tail pages before head page information is cleared to
	 * avoid checking PageCompound for order-0 pages.
	 */
	if (unlikely(order)) {
		bool compound = PageCompound(page);
		int i;

		VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);

		if (compound)
			ClearPageDoubleMap(page);
		for (i = 1; i < (1 << order); i++) {
			if (compound)
				bad += free_tail_pages_check(page, page + i);
			if (unlikely(check_free_page(page + i))) {
				bad++;
				continue;
			}
			(page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
		}
	}
	if (PageMappingFlags(page))
		page->mapping = NULL;
	if (memcg_kmem_enabled() && PageKmemcg(page))
		__memcg_kmem_uncharge_page(page, order);
	if (check_free)
		bad += check_free_page(page);
	if (bad)
		return false;

	page_cpupid_reset_last(page);
	page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
	reset_page_owner(page, order);

	if (!PageHighMem(page)) {
		debug_check_no_locks_freed(page_address(page),
					   PAGE_SIZE << order);
		debug_check_no_obj_freed(page_address(page),
					   PAGE_SIZE << order);
	}
	if (want_init_on_free())
		kernel_init_free_pages(page, 1 << order);

	kernel_poison_pages(page, 1 << order, 0);
	/*
	 * arch_free_page() can make the page's contents inaccessible.  s390
	 * does this.  So nothing which can access the page's contents should
	 * happen after this.
	 */
	arch_free_page(page, order);

	if (debug_pagealloc_enabled_static())
		kernel_map_pages(page, 1 << order, 0);

	kasan_free_nondeferred_pages(page, order);

	return true;
}

#ifdef CONFIG_DEBUG_VM
/*
 * With DEBUG_VM enabled, order-0 pages are checked immediately when being freed
 * to pcp lists. With debug_pagealloc also enabled, they are also rechecked when
 * moved from pcp lists to free lists.
 */
static bool free_pcp_prepare(struct page *page)
{
	return free_pages_prepare(page, 0, true);
}

static bool bulkfree_pcp_prepare(struct page *page)
{
	if (debug_pagealloc_enabled_static())
		return check_free_page(page);
	else
		return false;
}
#else
/*
 * With DEBUG_VM disabled, order-0 pages being freed are checked only when
 * moving from pcp lists to free list in order to reduce overhead. With
 * debug_pagealloc enabled, they are checked also immediately when being freed
 * to the pcp lists.
 */
static bool free_pcp_prepare(struct page *page)
{
	if (debug_pagealloc_enabled_static())
		return free_pages_prepare(page, 0, true);
	else
		return free_pages_prepare(page, 0, false);
}

static bool bulkfree_pcp_prepare(struct page *page)
{
	return check_free_page(page);
}
#endif /* CONFIG_DEBUG_VM */

static inline void prefetch_buddy(struct page *page)
{
	unsigned long pfn = page_to_pfn(page);
	unsigned long buddy_pfn = __find_buddy_pfn(pfn, 0);
	struct page *buddy = page + (buddy_pfn - pfn);

	prefetch(buddy);
}

/*
 * Frees a number of pages from the PCP lists
 * Assumes all pages on list are in same zone, and of same order.
 * count is the number of pages to free.
 *
 * If the zone was previously in an "all pages pinned" state then look to
 * see if this freeing clears that state.
 *
 * And clear the zone's pages_scanned counter, to hold off the "all pages are
 * pinned" detection logic.
 */
static void free_pcppages_bulk(struct zone *zone, int count,
					struct per_cpu_pages *pcp)
{
	int migratetype = 0;
	int batch_free = 0;
	int prefetch_nr = 0;
	bool isolated_pageblocks;
	struct page *page, *tmp;
	LIST_HEAD(head);

	while (count) {
		struct list_head *list;

		/*
		 * Remove pages from lists in a round-robin fashion. A
		 * batch_free count is maintained that is incremented when an
		 * empty list is encountered.  This is so more pages are freed
		 * off fuller lists instead of spinning excessively around empty
		 * lists
		 */
		do {
			batch_free++;
			if (++migratetype == MIGRATE_PCPTYPES)
				migratetype = 0;
			list = &pcp->lists[migratetype];
		} while (list_empty(list));

		/* This is the only non-empty list. Free them all. */
		if (batch_free == MIGRATE_PCPTYPES)
			batch_free = count;

		do {
			page = list_last_entry(list, struct page, lru);
			/* must delete to avoid corrupting pcp list */
			list_del(&page->lru);
			pcp->count--;

			if (bulkfree_pcp_prepare(page))
				continue;

			list_add_tail(&page->lru, &head);

			/*
			 * We are going to put the page back to the global
			 * pool, prefetch its buddy to speed up later access
			 * under zone->lock. It is believed the overhead of
			 * an additional test and calculating buddy_pfn here
			 * can be offset by reduced memory latency later. To
			 * avoid excessive prefetching due to large count, only
			 * prefetch buddy for the first pcp->batch nr of pages.
			 */
			if (prefetch_nr++ < pcp->batch)
				prefetch_buddy(page);
		} while (--count && --batch_free && !list_empty(list));
	}

	spin_lock(&zone->lock);
	isolated_pageblocks = has_isolate_pageblock(zone);

	/*
	 * Use safe version since after __free_one_page(),
	 * page->lru.next will not point to original list.
	 */
	list_for_each_entry_safe(page, tmp, &head, lru) {
		int mt = get_pcppage_migratetype(page);
		/* MIGRATE_ISOLATE page should not go to pcplists */
		VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
		/* Pageblock could have been isolated meanwhile */
		if (unlikely(isolated_pageblocks))
			mt = get_pageblock_migratetype(page);

		__free_one_page(page, page_to_pfn(page), zone, 0, mt, true);
		trace_mm_page_pcpu_drain(page, 0, mt);
	}
	spin_unlock(&zone->lock);
}

static void free_one_page(struct zone *zone,
				struct page *page, unsigned long pfn,
				unsigned int order,
				int migratetype)
{
	spin_lock(&zone->lock);
	if (unlikely(has_isolate_pageblock(zone) ||
		is_migrate_isolate(migratetype))) {
		migratetype = get_pfnblock_migratetype(page, pfn);
	}
	__free_one_page(page, pfn, zone, order, migratetype, true);
	spin_unlock(&zone->lock);
}

static void __meminit __init_single_page(struct page *page, unsigned long pfn,
				unsigned long zone, int nid)
{
	mm_zero_struct_page(page);
	set_page_links(page, zone, nid, pfn);
	init_page_count(page);
	page_mapcount_reset(page);
	page_cpupid_reset_last(page);
	page_kasan_tag_reset(page);

	INIT_LIST_HEAD(&page->lru);
#ifdef WANT_PAGE_VIRTUAL
	/* The shift won't overflow because ZONE_NORMAL is below 4G. */
	if (!is_highmem_idx(zone))
		set_page_address(page, __va(pfn << PAGE_SHIFT));
#endif
}

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
static void __meminit init_reserved_page(unsigned long pfn)
{
	pg_data_t *pgdat;
	int nid, zid;

	if (!early_page_uninitialised(pfn))
		return;

	nid = early_pfn_to_nid(pfn);
	pgdat = NODE_DATA(nid);

	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
		struct zone *zone = &pgdat->node_zones[zid];

		if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
			break;
	}
	__init_single_page(pfn_to_page(pfn), pfn, zid, nid);
}
#else
static inline void init_reserved_page(unsigned long pfn)
{
}
#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */

/*
 * Initialised pages do not have PageReserved set. This function is
 * called for each range allocated by the bootmem allocator and
 * marks the pages PageReserved. The remaining valid pages are later
 * sent to the buddy page allocator.
 */
void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
{
	unsigned long start_pfn = PFN_DOWN(start);
	unsigned long end_pfn = PFN_UP(end);

	for (; start_pfn < end_pfn; start_pfn++) {
		if (pfn_valid(start_pfn)) {
			struct page *page = pfn_to_page(start_pfn);

			init_reserved_page(start_pfn);

			/* Avoid false-positive PageTail() */
			INIT_LIST_HEAD(&page->lru);

			/*
			 * no need for atomic set_bit because the struct
			 * page is not visible yet so nobody should
			 * access it yet.
			 */
			__SetPageReserved(page);
		}
	}
}

static void __free_pages_ok(struct page *page, unsigned int order)
{
	unsigned long flags;
	int migratetype;
	unsigned long pfn = page_to_pfn(page);

	if (!free_pages_prepare(page, order, true))
		return;

	migratetype = get_pfnblock_migratetype(page, pfn);
	local_irq_save(flags);
	__count_vm_events(PGFREE, 1 << order);
	free_one_page(page_zone(page), page, pfn, order, migratetype);
	local_irq_restore(flags);
}

void __free_pages_core(struct page *page, unsigned int order)
{
	unsigned int nr_pages = 1 << order;
	struct page *p = page;
	unsigned int loop;

	prefetchw(p);
	for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
		prefetchw(p + 1);
		__ClearPageReserved(p);
		set_page_count(p, 0);
	}
	__ClearPageReserved(p);
	set_page_count(p, 0);

	atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
	set_page_refcounted(page);
	__free_pages(page, order);
}

#ifdef CONFIG_NEED_MULTIPLE_NODES

static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;

#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID

/*
 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
 */
int __meminit __early_pfn_to_nid(unsigned long pfn,
					struct mminit_pfnnid_cache *state)
{
	unsigned long start_pfn, end_pfn;
	int nid;

	if (state->last_start <= pfn && pfn < state->last_end)
		return state->last_nid;

	nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
	if (nid != NUMA_NO_NODE) {
		state->last_start = start_pfn;
		state->last_end = end_pfn;
		state->last_nid = nid;
	}

	return nid;
}
#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */

int __meminit early_pfn_to_nid(unsigned long pfn)
{
	static DEFINE_SPINLOCK(early_pfn_lock);
	int nid;

	spin_lock(&early_pfn_lock);
	nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
	if (nid < 0)
		nid = first_online_node;
	spin_unlock(&early_pfn_lock);

	return nid;
}
#endif /* CONFIG_NEED_MULTIPLE_NODES */

void __init memblock_free_pages(struct page *page, unsigned long pfn,
							unsigned int order)
{
	if (early_page_uninitialised(pfn))
		return;
	__free_pages_core(page, order);
}

/*
 * Check that the whole (or subset of) a pageblock given by the interval of
 * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
 * with the migration of free compaction scanner. The scanners then need to
 * use only pfn_valid_within() check for arches that allow holes within
 * pageblocks.
 *
 * Return struct page pointer of start_pfn, or NULL if checks were not passed.
 *
 * It's possible on some configurations to have a setup like node0 node1 node0
 * i.e. it's possible that all pages within a zones range of pages do not
 * belong to a single zone. We assume that a border between node0 and node1
 * can occur within a single pageblock, but not a node0 node1 node0
 * interleaving within a single pageblock. It is therefore sufficient to check
 * the first and last page of a pageblock and avoid checking each individual
 * page in a pageblock.
 */
struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
				     unsigned long end_pfn, struct zone *zone)
{
	struct page *start_page;
	struct page *end_page;

	/* end_pfn is one past the range we are checking */
	end_pfn--;

	if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
		return NULL;

	start_page = pfn_to_online_page(start_pfn);
	if (!start_page)
		return NULL;

	if (page_zone(start_page) != zone)
		return NULL;

	end_page = pfn_to_page(end_pfn);

	/* This gives a shorter code than deriving page_zone(end_page) */
	if (page_zone_id(start_page) != page_zone_id(end_page))
		return NULL;

	return start_page;
}

void set_zone_contiguous(struct zone *zone)
{
	unsigned long block_start_pfn = zone->zone_start_pfn;
	unsigned long block_end_pfn;

	block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
	for (; block_start_pfn < zone_end_pfn(zone);
			block_start_pfn = block_end_pfn,
			 block_end_pfn += pageblock_nr_pages) {

		block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));

		if (!__pageblock_pfn_to_page(block_start_pfn,
					     block_end_pfn, zone))
			return;
		cond_resched();
	}

	/* We confirm that there is no hole */
	zone->contiguous = true;
}

void clear_zone_contiguous(struct zone *zone)
{
	zone->contiguous = false;
}

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
static void __init deferred_free_range(unsigned long pfn,
				       unsigned long nr_pages)
{
	struct page *page;
	unsigned long i;

	if (!nr_pages)
		return;

	page = pfn_to_page(pfn);

	/* Free a large naturally-aligned chunk if possible */
	if (nr_pages == pageblock_nr_pages &&
	    (pfn & (pageblock_nr_pages - 1)) == 0) {
		set_pageblock_migratetype(page, MIGRATE_MOVABLE);
		__free_pages_core(page, pageblock_order);
		return;
	}

	for (i = 0; i < nr_pages; i++, page++, pfn++) {
		if ((pfn & (pageblock_nr_pages - 1)) == 0)
			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
		__free_pages_core(page, 0);
	}
}

/* Completion tracking for deferred_init_memmap() threads */
static atomic_t pgdat_init_n_undone __initdata;
static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);

static inline void __init pgdat_init_report_one_done(void)
{
	if (atomic_dec_and_test(&pgdat_init_n_undone))
		complete(&pgdat_init_all_done_comp);
}

/*
 * Returns true if page needs to be initialized or freed to buddy allocator.
 *
 * First we check if pfn is valid on architectures where it is possible to have
 * holes within pageblock_nr_pages. On systems where it is not possible, this
 * function is optimized out.
 *
 * Then, we check if a current large page is valid by only checking the validity
 * of the head pfn.
 */
static inline bool __init deferred_pfn_valid(unsigned long pfn)
{
	if (!pfn_valid_within(pfn))
		return false;
	if (!(pfn & (pageblock_nr_pages - 1)) && !pfn_valid(pfn))
		return false;
	return true;
}

/*
 * Free pages to buddy allocator. Try to free aligned pages in
 * pageblock_nr_pages sizes.
 */
static void __init deferred_free_pages(unsigned long pfn,
				       unsigned long end_pfn)
{
	unsigned long nr_pgmask = pageblock_nr_pages - 1;
	unsigned long nr_free = 0;

	for (; pfn < end_pfn; pfn++) {
		if (!deferred_pfn_valid(pfn)) {
			deferred_free_range(pfn - nr_free, nr_free);
			nr_free = 0;
		} else if (!(pfn & nr_pgmask)) {
			deferred_free_range(pfn - nr_free, nr_free);
			nr_free = 1;
		} else {
			nr_free++;
		}
	}
	/* Free the last block of pages to allocator */
	deferred_free_range(pfn - nr_free, nr_free);
}

/*
 * Initialize struct pages.  We minimize pfn page lookups and scheduler checks
 * by performing it only once every pageblock_nr_pages.
 * Return number of pages initialized.
 */
static unsigned long  __init deferred_init_pages(struct zone *zone,
						 unsigned long pfn,
						 unsigned long end_pfn)
{
	unsigned long nr_pgmask = pageblock_nr_pages - 1;
	int nid = zone_to_nid(zone);
	unsigned long nr_pages = 0;
	int zid = zone_idx(zone);
	struct page *page = NULL;

	for (; pfn < end_pfn; pfn++) {
		if (!deferred_pfn_valid(pfn)) {
			page = NULL;
			continue;
		} else if (!page || !(pfn & nr_pgmask)) {
			page = pfn_to_page(pfn);
		} else {
			page++;
		}
		__init_single_page(page, pfn, zid, nid);
		nr_pages++;
	}
	return (nr_pages);
}

/*
 * This function is meant to pre-load the iterator for the zone init.
 * Specifically it walks through the ranges until we are caught up to the
 * first_init_pfn value and exits there. If we never encounter the value we
 * return false indicating there are no valid ranges left.
 */
static bool __init
deferred_init_mem_pfn_range_in_zone(u64 *i, struct zone *zone,
				    unsigned long *spfn, unsigned long *epfn,
				    unsigned long first_init_pfn)
{
	u64 j;

	/*
	 * Start out by walking through the ranges in this zone that have
	 * already been initialized. We don't need to do anything with them
	 * so we just need to flush them out of the system.
	 */
	for_each_free_mem_pfn_range_in_zone(j, zone, spfn, epfn) {
		if (*epfn <= first_init_pfn)
			continue;
		if (*spfn < first_init_pfn)
			*spfn = first_init_pfn;
		*i = j;
		return true;
	}

	return false;
}

/*
 * Initialize and free pages. We do it in two loops: first we initialize
 * struct page, then free to buddy allocator, because while we are
 * freeing pages we can access pages that are ahead (computing buddy
 * page in __free_one_page()).
 *
 * In order to try and keep some memory in the cache we have the loop
 * broken along max page order boundaries. This way we will not cause
 * any issues with the buddy page computation.
 */
static unsigned long __init
deferred_init_maxorder(u64 *i, struct zone *zone, unsigned long *start_pfn,
		       unsigned long *end_pfn)
{
	unsigned long mo_pfn = ALIGN(*start_pfn + 1, MAX_ORDER_NR_PAGES);
	unsigned long spfn = *start_pfn, epfn = *end_pfn;
	unsigned long nr_pages = 0;
	u64 j = *i;

	/* First we loop through and initialize the page values */
	for_each_free_mem_pfn_range_in_zone_from(j, zone, start_pfn, end_pfn) {
		unsigned long t;

		if (mo_pfn <= *start_pfn)
			break;

		t = min(mo_pfn, *end_pfn);
		nr_pages += deferred_init_pages(zone, *start_pfn, t);

		if (mo_pfn < *end_pfn) {
			*start_pfn = mo_pfn;
			break;
		}
	}

	/* Reset values and now loop through freeing pages as needed */
	swap(j, *i);

	for_each_free_mem_pfn_range_in_zone_from(j, zone, &spfn, &epfn) {
		unsigned long t;

		if (mo_pfn <= spfn)
			break;

		t = min(mo_pfn, epfn);
		deferred_free_pages(spfn, t);

		if (mo_pfn <= epfn)
			break;
	}

	return nr_pages;
}

static void __init
deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn,
			   void *arg)
{
	unsigned long spfn, epfn;
	struct zone *zone = arg;
	u64 i;

	deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, start_pfn);

	/*
	 * Initialize and free pages in MAX_ORDER sized increments so that we
	 * can avoid introducing any issues with the buddy allocator.
	 */
	while (spfn < end_pfn) {
		deferred_init_maxorder(&i, zone, &spfn, &epfn);
		cond_resched();
	}
}

/* An arch may override for more concurrency. */
__weak int __init
deferred_page_init_max_threads(const struct cpumask *node_cpumask)
{
	return 1;
}

/* Initialise remaining memory on a node */
static int __init deferred_init_memmap(void *data)
{
	pg_data_t *pgdat = data;
	const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
	unsigned long spfn = 0, epfn = 0;
	unsigned long first_init_pfn, flags;
	unsigned long start = jiffies;
	struct zone *zone;
	int zid, max_threads;
	u64 i;

	/* Bind memory initialisation thread to a local node if possible */
	if (!cpumask_empty(cpumask))
		set_cpus_allowed_ptr(current, cpumask);

	pgdat_resize_lock(pgdat, &flags);
	first_init_pfn = pgdat->first_deferred_pfn;
	if (first_init_pfn == ULONG_MAX) {
		pgdat_resize_unlock(pgdat, &flags);
		pgdat_init_report_one_done();
		return 0;
	}

	/* Sanity check boundaries */
	BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn);
	BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat));
	pgdat->first_deferred_pfn = ULONG_MAX;

	/*
	 * Once we unlock here, the zone cannot be grown anymore, thus if an
	 * interrupt thread must allocate this early in boot, zone must be
	 * pre-grown prior to start of deferred page initialization.
	 */
	pgdat_resize_unlock(pgdat, &flags);

	/* Only the highest zone is deferred so find it */
	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
		zone = pgdat->node_zones + zid;
		if (first_init_pfn < zone_end_pfn(zone))
			break;
	}

	/* If the zone is empty somebody else may have cleared out the zone */
	if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
						 first_init_pfn))
		goto zone_empty;

	max_threads = deferred_page_init_max_threads(cpumask);

	while (spfn < epfn) {
		unsigned long epfn_align = ALIGN(epfn, PAGES_PER_SECTION);
		struct padata_mt_job job = {
			.thread_fn   = deferred_init_memmap_chunk,
			.fn_arg      = zone,
			.start       = spfn,
			.size        = epfn_align - spfn,
			.align       = PAGES_PER_SECTION,
			.min_chunk   = PAGES_PER_SECTION,
			.max_threads = max_threads,
		};

		padata_do_multithreaded(&job);
		deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
						    epfn_align);
	}
zone_empty:
	/* Sanity check that the next zone really is unpopulated */
	WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));

	pr_info("node %d deferred pages initialised in %ums\n",
		pgdat->node_id, jiffies_to_msecs(jiffies - start));

	pgdat_init_report_one_done();
	return 0;
}

/*
 * If this zone has deferred pages, try to grow it by initializing enough
 * deferred pages to satisfy the allocation specified by order, rounded up to
 * the nearest PAGES_PER_SECTION boundary.  So we're adding memory in increments
 * of SECTION_SIZE bytes by initializing struct pages in increments of
 * PAGES_PER_SECTION * sizeof(struct page) bytes.
 *
 * Return true when zone was grown, otherwise return false. We return true even
 * when we grow less than requested, to let the caller decide if there are
 * enough pages to satisfy the allocation.
 *
 * Note: We use noinline because this function is needed only during boot, and
 * it is called from a __ref function _deferred_grow_zone. This way we are
 * making sure that it is not inlined into permanent text section.
 */
static noinline bool __init
deferred_grow_zone(struct zone *zone, unsigned int order)
{
	unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);
	pg_data_t *pgdat = zone->zone_pgdat;
	unsigned long first_deferred_pfn = pgdat->first_deferred_pfn;
	unsigned long spfn, epfn, flags;
	unsigned long nr_pages = 0;
	u64 i;

	/* Only the last zone may have deferred pages */
	if (zone_end_pfn(zone) != pgdat_end_pfn(pgdat))
		return false;

	pgdat_resize_lock(pgdat, &flags);

	/*
	 * If someone grew this zone while we were waiting for spinlock, return
	 * true, as there might be enough pages already.
	 */
	if (first_deferred_pfn != pgdat->first_deferred_pfn) {
		pgdat_resize_unlock(pgdat, &flags);
		return true;
	}

	/* If the zone is empty somebody else may have cleared out the zone */
	if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
						 first_deferred_pfn)) {
		pgdat->first_deferred_pfn = ULONG_MAX;
		pgdat_resize_unlock(pgdat, &flags);
		/* Retry only once. */
		return first_deferred_pfn != ULONG_MAX;
	}

	/*
	 * Initialize and free pages in MAX_ORDER sized increments so
	 * that we can avoid introducing any issues with the buddy
	 * allocator.
	 */
	while (spfn < epfn) {
		/* update our first deferred PFN for this section */
		first_deferred_pfn = spfn;

		nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
		touch_nmi_watchdog();

		/* We should only stop along section boundaries */
		if ((first_deferred_pfn ^ spfn) < PAGES_PER_SECTION)
			continue;

		/* If our quota has been met we can stop here */
		if (nr_pages >= nr_pages_needed)
			break;
	}

	pgdat->first_deferred_pfn = spfn;
	pgdat_resize_unlock(pgdat, &flags);

	return nr_pages > 0;
}

/*
 * deferred_grow_zone() is __init, but it is called from
 * get_page_from_freelist() during early boot until deferred_pages permanently
 * disables this call. This is why we have refdata wrapper to avoid warning,
 * and to ensure that the function body gets unloaded.
 */
static bool __ref
_deferred_grow_zone(struct zone *zone, unsigned int order)
{
	return deferred_grow_zone(zone, order);
}

#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */

void __init page_alloc_init_late(void)
{
	struct zone *zone;
	int nid;

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT

	/* There will be num_node_state(N_MEMORY) threads */
	atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
	for_each_node_state(nid, N_MEMORY) {
		kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
	}

	/* Block until all are initialised */
	wait_for_completion(&pgdat_init_all_done_comp);

	/*
	 * The number of managed pages has changed due to the initialisation
	 * so the pcpu batch and high limits needs to be updated or the limits
	 * will be artificially small.
	 */
	for_each_populated_zone(zone)
		zone_pcp_update(zone);

	/*
	 * We initialized the rest of the deferred pages.  Permanently disable
	 * on-demand struct page initialization.
	 */
	static_branch_disable(&deferred_pages);

	/* Reinit limits that are based on free pages after the kernel is up */
	files_maxfiles_init();
#endif

	/* Discard memblock private memory */
	memblock_discard();

	for_each_node_state(nid, N_MEMORY)
		shuffle_free_memory(NODE_DATA(nid));

	for_each_populated_zone(zone)
		set_zone_contiguous(zone);
}

#ifdef CONFIG_CMA
/* Free whole pageblock and set its migration type to MIGRATE_CMA. */
void __init init_cma_reserved_pageblock(struct page *page)
{
	unsigned i = pageblock_nr_pages;
	struct page *p = page;

	do {
		__ClearPageReserved(p);
		set_page_count(p, 0);
	} while (++p, --i);

	set_pageblock_migratetype(page, MIGRATE_CMA);

	if (pageblock_order >= MAX_ORDER) {
		i = pageblock_nr_pages;
		p = page;
		do {
			set_page_refcounted(p);
			__free_pages(p, MAX_ORDER - 1);
			p += MAX_ORDER_NR_PAGES;
		} while (i -= MAX_ORDER_NR_PAGES);
	} else {
		set_page_refcounted(page);
		__free_pages(page, pageblock_order);
	}

	adjust_managed_page_count(page, pageblock_nr_pages);
}
#endif

/*
 * The order of subdivision here is critical for the IO subsystem.
 * Please do not alter this order without good reasons and regression
 * testing. Specifically, as large blocks of memory are subdivided,
 * the order in which smaller blocks are delivered depends on the order
 * they're subdivided in this function. This is the primary factor
 * influencing the order in which pages are delivered to the IO
 * subsystem according to empirical testing, and this is also justified
 * by considering the behavior of a buddy system containing a single
 * large block of memory acted on by a series of small allocations.
 * This behavior is a critical factor in sglist merging's success.
 *
 * -- nyc
 */
static inline void expand(struct zone *zone, struct page *page,
	int low, int high, int migratetype)
{
	unsigned long size = 1 << high;

	while (high > low) {
		high--;
		size >>= 1;
		VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);

		/*
		 * Mark as guard pages (or page), that will allow to
		 * merge back to allocator when buddy will be freed.
		 * Corresponding page table entries will not be touched,
		 * pages will stay not present in virtual address space
		 */
		if (set_page_guard(zone, &page[size], high, migratetype))
			continue;

		add_to_free_list(&page[size], zone, high, migratetype);
		set_page_order(&page[size], high);
	}
}

static void check_new_page_bad(struct page *page)
{
	if (unlikely(page->flags & __PG_HWPOISON)) {
		/* Don't complain about hwpoisoned pages */
		page_mapcount_reset(page); /* remove PageBuddy */
		return;
	}

	bad_page(page,
		 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP));
}

/*
 * This page is about to be returned from the page allocator
 */
static inline int check_new_page(struct page *page)
{
	if (likely(page_expected_state(page,
				PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
		return 0;

	check_new_page_bad(page);
	return 1;
}

static inline bool free_pages_prezeroed(void)
{
	return (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) &&
		page_poisoning_enabled()) || want_init_on_free();
}

#ifdef CONFIG_DEBUG_VM
/*
 * With DEBUG_VM enabled, order-0 pages are checked for expected state when
 * being allocated from pcp lists. With debug_pagealloc also enabled, they are
 * also checked when pcp lists are refilled from the free lists.
 */
static inline bool check_pcp_refill(struct page *page)
{
	if (debug_pagealloc_enabled_static())
		return check_new_page(page);
	else
		return false;
}

static inline bool check_new_pcp(struct page *page)
{
	return check_new_page(page);
}
#else
/*
 * With DEBUG_VM disabled, free order-0 pages are checked for expected state
 * when pcp lists are being refilled from the free lists. With debug_pagealloc
 * enabled, they are also checked when being allocated from the pcp lists.
 */
static inline bool check_pcp_refill(struct page *page)
{
	return check_new_page(page);
}
static inline bool check_new_pcp(struct page *page)
{
	if (debug_pagealloc_enabled_static())
		return check_new_page(page);
	else
		return false;
}
#endif /* CONFIG_DEBUG_VM */

static bool check_new_pages(struct page *page, unsigned int order)
{
	int i;
	for (i = 0; i < (1 << order); i++) {
		struct page *p = page + i;

		if (unlikely(check_new_page(p)))
			return true;
	}

	return false;
}

inline void post_alloc_hook(struct page *page, unsigned int order,
				gfp_t gfp_flags)
{
	set_page_private(page, 0);
	set_page_refcounted(page);

	arch_alloc_page(page, order);
	if (debug_pagealloc_enabled_static())
		kernel_map_pages(page, 1 << order, 1);
	kasan_alloc_pages(page, order);
	kernel_poison_pages(page, 1 << order, 1);
	set_page_owner(page, order, gfp_flags);
}

static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
							unsigned int alloc_flags)
{
	post_alloc_hook(page, order, gfp_flags);

	if (!free_pages_prezeroed() && want_init_on_alloc(gfp_flags))
		kernel_init_free_pages(page, 1 << order);

	if (order && (gfp_flags & __GFP_COMP))
		prep_compound_page(page, order);

	/*
	 * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
	 * allocate the page. The expectation is that the caller is taking
	 * steps that will free more memory. The caller should avoid the page
	 * being used for !PFMEMALLOC purposes.
	 */
	if (alloc_flags & ALLOC_NO_WATERMARKS)
		set_page_pfmemalloc(page);
	else
		clear_page_pfmemalloc(page);
}

/*
 * Go through the free lists for the given migratetype and remove
 * the smallest available page from the freelists
 */
static __always_inline
struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
						int migratetype)
{
	unsigned int current_order;
	struct free_area *area;
	struct page *page;

	/* Find a page of the appropriate size in the preferred list */
	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
		area = &(zone->free_area[current_order]);
		page = get_page_from_free_area(area, migratetype);
		if (!page)
			continue;
		del_page_from_free_list(page, zone, current_order);
		expand(zone, page, order, current_order, migratetype);
		set_pcppage_migratetype(page, migratetype);
		return page;
	}

	return NULL;
}


/*
 * This array describes the order lists are fallen back to when
 * the free lists for the desirable migrate type are depleted
 */
static int fallbacks[MIGRATE_TYPES][4] = {
	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_TYPES },
	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_TYPES },
#ifdef CONFIG_CMA
	[MIGRATE_CMA]         = { MIGRATE_TYPES }, /* Never used */
#endif
#ifdef CONFIG_MEMORY_ISOLATION
	[MIGRATE_ISOLATE]     = { MIGRATE_TYPES }, /* Never used */
#endif
};

#ifdef CONFIG_CMA
static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone,
					unsigned int order)
{
	return __rmqueue_smallest(zone, order, MIGRATE_CMA);
}
#else
static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
					unsigned int order) { return NULL; }
#endif

/*
 * Move the free pages in a range to the free lists of the requested type.
 * Note that start_page and end_pages are not aligned on a pageblock
 * boundary. If alignment is required, use move_freepages_block()
 */
static int move_freepages(struct zone *zone,
			  struct page *start_page, struct page *end_page,
			  int migratetype, int *num_movable)
{
	struct page *page;
	unsigned int order;
	int pages_moved = 0;

	for (page = start_page; page <= end_page;) {
		if (!pfn_valid_within(page_to_pfn(page))) {
			page++;
			continue;
		}

		if (!PageBuddy(page)) {
			/*
			 * We assume that pages that could be isolated for
			 * migration are movable. But we don't actually try
			 * isolating, as that would be expensive.
			 */
			if (num_movable &&
					(PageLRU(page) || __PageMovable(page)))
				(*num_movable)++;

			page++;
			continue;
		}

		/* Make sure we are not inadvertently changing nodes */
		VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
		VM_BUG_ON_PAGE(page_zone(page) != zone, page);

		order = page_order(page);
		move_to_free_list(page, zone, order, migratetype);
		page += 1 << order;
		pages_moved += 1 << order;
	}

	return pages_moved;
}

int move_freepages_block(struct zone *zone, struct page *page,
				int migratetype, int *num_movable)
{
	unsigned long start_pfn, end_pfn;
	struct page *start_page, *end_page;

	if (num_movable)
		*num_movable = 0;

	start_pfn = page_to_pfn(page);
	start_pfn = start_pfn & ~(pageblock_nr_pages-1);
	start_page = pfn_to_page(start_pfn);
	end_page = start_page + pageblock_nr_pages - 1;
	end_pfn = start_pfn + pageblock_nr_pages - 1;

	/* Do not cross zone boundaries */
	if (!zone_spans_pfn(zone, start_pfn))
		start_page = page;
	if (!zone_spans_pfn(zone, end_pfn))
		return 0;

	return move_freepages(zone, start_page, end_page, migratetype,
								num_movable);
}

static void change_pageblock_range(struct page *pageblock_page,
					int start_order, int migratetype)
{
	int nr_pageblocks = 1 << (start_order - pageblock_order);

	while (nr_pageblocks--) {
		set_pageblock_migratetype(pageblock_page, migratetype);
		pageblock_page += pageblock_nr_pages;
	}
}

/*
 * When we are falling back to another migratetype during allocation, try to
 * steal extra free pages from the same pageblocks to satisfy further
 * allocations, instead of polluting multiple pageblocks.
 *
 * If we are stealing a relatively large buddy page, it is likely there will
 * be more free pages in the pageblock, so try to steal them all. For
 * reclaimable and unmovable allocations, we steal regardless of page size,
 * as fragmentation caused by those allocations polluting movable pageblocks
 * is worse than movable allocations stealing from unmovable and reclaimable
 * pageblocks.
 */
static bool can_steal_fallback(unsigned int order, int start_mt)
{
	/*
	 * Leaving this order check is intended, although there is
	 * relaxed order check in next check. The reason is that
	 * we can actually steal whole pageblock if this condition met,
	 * but, below check doesn't guarantee it and that is just heuristic
	 * so could be changed anytime.
	 */
	if (order >= pageblock_order)
		return true;

	if (order >= pageblock_order / 2 ||
		start_mt == MIGRATE_RECLAIMABLE ||
		start_mt == MIGRATE_UNMOVABLE ||
		page_group_by_mobility_disabled)
		return true;

	return false;
}

static inline void boost_watermark(struct zone *zone)
{
	unsigned long max_boost;

	if (!watermark_boost_factor)
		return;
	/*
	 * Don't bother in zones that are unlikely to produce results.
	 * On small machines, including kdump capture kernels running
	 * in a small area, boosting the watermark can cause an out of
	 * memory situation immediately.
	 */
	if ((pageblock_nr_pages * 4) > zone_managed_pages(zone))
		return;

	max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
			watermark_boost_factor, 10000);

	/*
	 * high watermark may be uninitialised if fragmentation occurs
	 * very early in boot so do not boost. We do not fall
	 * through and boost by pageblock_nr_pages as failing
	 * allocations that early means that reclaim is not going
	 * to help and it may even be impossible to reclaim the
	 * boosted watermark resulting in a hang.
	 */
	if (!max_boost)
		return;

	max_boost = max(pageblock_nr_pages, max_boost);

	zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
		max_boost);
}

/*
 * This function implements actual steal behaviour. If order is large enough,
 * we can steal whole pageblock. If not, we first move freepages in this
 * pageblock to our migratetype and determine how many already-allocated pages
 * are there in the pageblock with a compatible migratetype. If at least half
 * of pages are free or compatible, we can change migratetype of the pageblock
 * itself, so pages freed in the future will be put on the correct free list.
 */
static void steal_suitable_fallback(struct zone *zone, struct page *page,
		unsigned int alloc_flags, int start_type, bool whole_block)
{
	unsigned int current_order = page_order(page);
	int free_pages, movable_pages, alike_pages;
	int old_block_type;

	old_block_type = get_pageblock_migratetype(page);

	/*
	 * This can happen due to races and we want to prevent broken
	 * highatomic accounting.
	 */
	if (is_migrate_highatomic(old_block_type))
		goto single_page;

	/* Take ownership for orders >= pageblock_order */
	if (current_order >= pageblock_order) {
		change_pageblock_range(page, current_order, start_type);
		goto single_page;
	}

	/*
	 * Boost watermarks to increase reclaim pressure to reduce the
	 * likelihood of future fallbacks. Wake kswapd now as the node
	 * may be balanced overall and kswapd will not wake naturally.
	 */
	boost_watermark(zone);
	if (alloc_flags & ALLOC_KSWAPD)
		set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);

	/* We are not allowed to try stealing from the whole block */
	if (!whole_block)
		goto single_page;

	free_pages = move_freepages_block(zone, page, start_type,
						&movable_pages);
	/*
	 * Determine how many pages are compatible with our allocation.
	 * For movable allocation, it's the number of movable pages which
	 * we just obtained. For other types it's a bit more tricky.
	 */
	if (start_type == MIGRATE_MOVABLE) {
		alike_pages = movable_pages;
	} else {
		/*
		 * If we are falling back a RECLAIMABLE or UNMOVABLE allocation
		 * to MOVABLE pageblock, consider all non-movable pages as
		 * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or
		 * vice versa, be conservative since we can't distinguish the
		 * exact migratetype of non-movable pages.
		 */
		if (old_block_type == MIGRATE_MOVABLE)
			alike_pages = pageblock_nr_pages
						- (free_pages + movable_pages);
		else
			alike_pages = 0;
	}

	/* moving whole block can fail due to zone boundary conditions */
	if (!free_pages)
		goto single_page;

	/*
	 * If a sufficient number of pages in the block are either free or of
	 * comparable migratability as our allocation, claim the whole block.
	 */
	if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
			page_group_by_mobility_disabled)
		set_pageblock_migratetype(page, start_type);

	return;

single_page:
	move_to_free_list(page, zone, current_order, start_type);
}

/*
 * Check whether there is a suitable fallback freepage with requested order.
 * If only_stealable is true, this function returns fallback_mt only if
 * we can steal other freepages all together. This would help to reduce
 * fragmentation due to mixed migratetype pages in one pageblock.
 */
int find_suitable_fallback(struct free_area *area, unsigned int order,
			int migratetype, bool only_stealable, bool *can_steal)
{
	int i;
	int fallback_mt;

	if (area->nr_free == 0)
		return -1;

	*can_steal = false;
	for (i = 0;; i++) {
		fallback_mt = fallbacks[migratetype][i];
		if (fallback_mt == MIGRATE_TYPES)
			break;

		if (free_area_empty(area, fallback_mt))
			continue;

		if (can_steal_fallback(order, migratetype))
			*can_steal = true;

		if (!only_stealable)
			return fallback_mt;

		if (*can_steal)
			return fallback_mt;
	}

	return -1;
}

/*
 * Reserve a pageblock for exclusive use of high-order atomic allocations if
 * there are no empty page blocks that contain a page with a suitable order
 */
static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
				unsigned int alloc_order)
{
	int mt;
	unsigned long max_managed, flags;

	/*
	 * Limit the number reserved to 1 pageblock or roughly 1% of a zone.
	 * Check is race-prone but harmless.
	 */
	max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages;
	if (zone->nr_reserved_highatomic >= max_managed)
		return;

	spin_lock_irqsave(&zone->lock, flags);

	/* Recheck the nr_reserved_highatomic limit under the lock */
	if (zone->nr_reserved_highatomic >= max_managed)
		goto out_unlock;

	/* Yoink! */
	mt = get_pageblock_migratetype(page);
	if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt)
	    && !is_migrate_cma(mt)) {
		zone->nr_reserved_highatomic += pageblock_nr_pages;
		set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
		move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
	}

out_unlock:
	spin_unlock_irqrestore(&zone->lock, flags);
}

/*
 * Used when an allocation is about to fail under memory pressure. This
 * potentially hurts the reliability of high-order allocations when under
 * intense memory pressure but failed atomic allocations should be easier
 * to recover from than an OOM.
 *
 * If @force is true, try to unreserve a pageblock even though highatomic
 * pageblock is exhausted.
 */
static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
						bool force)
{
	struct zonelist *zonelist = ac->zonelist;
	unsigned long flags;
	struct zoneref *z;
	struct zone *zone;
	struct page *page;
	int order;
	bool ret;

	for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->highest_zoneidx,
								ac->nodemask) {
		/*
		 * Preserve at least one pageblock unless memory pressure
		 * is really high.
		 */
		if (!force && zone->nr_reserved_highatomic <=
					pageblock_nr_pages)
			continue;

		spin_lock_irqsave(&zone->lock, flags);
		for (order = 0; order < MAX_ORDER; order++) {
			struct free_area *area = &(zone->free_area[order]);

			page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
			if (!page)
				continue;

			/*
			 * In page freeing path, migratetype change is racy so
			 * we can counter several free pages in a pageblock
			 * in this loop althoug we changed the pageblock type
			 * from highatomic to ac->migratetype. So we should
			 * adjust the count once.
			 */
			if (is_migrate_highatomic_page(page)) {
				/*
				 * It should never happen but changes to
				 * locking could inadvertently allow a per-cpu
				 * drain to add pages to MIGRATE_HIGHATOMIC
				 * while unreserving so be safe and watch for
				 * underflows.
				 */
				zone->nr_reserved_highatomic -= min(
						pageblock_nr_pages,
						zone->nr_reserved_highatomic);
			}

			/*
			 * Convert to ac->migratetype and avoid the normal
			 * pageblock stealing heuristics. Minimally, the caller
			 * is doing the work and needs the pages. More
			 * importantly, if the block was always converted to
			 * MIGRATE_UNMOVABLE or another type then the number
			 * of pageblocks that cannot be completely freed
			 * may increase.
			 */
			set_pageblock_migratetype(page, ac->migratetype);
			ret = move_freepages_block(zone, page, ac->migratetype,
									NULL);
			if (ret) {
				spin_unlock_irqrestore(&zone->lock, flags);
				return ret;
			}
		}
		spin_unlock_irqrestore(&zone->lock, flags);
	}

	return false;
}

/*
 * Try finding a free buddy page on the fallback list and put it on the free
 * list of requested migratetype, possibly along with other pages from the same
 * block, depending on fragmentation avoidance heuristics. Returns true if
 * fallback was found so that __rmqueue_smallest() can grab it.
 *
 * The use of signed ints for order and current_order is a deliberate
 * deviation from the rest of this file, to make the for loop
 * condition simpler.
 */
static __always_inline bool
__rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
						unsigned int alloc_flags)
{
	struct free_area *area;
	int current_order;
	int min_order = order;
	struct page *page;
	int fallback_mt;
	bool can_steal;

	/*
	 * Do not steal pages from freelists belonging to other pageblocks
	 * i.e. orders < pageblock_order. If there are no local zones free,
	 * the zonelists will be reiterated without ALLOC_NOFRAGMENT.
	 */
	if (alloc_flags & ALLOC_NOFRAGMENT)
		min_order = pageblock_order;

	/*
	 * Find the largest available free page in the other list. This roughly
	 * approximates finding the pageblock with the most free pages, which
	 * would be too costly to do exactly.
	 */
	for (current_order = MAX_ORDER - 1; current_order >= min_order;
				--current_order) {
		area = &(zone->free_area[current_order]);
		fallback_mt = find_suitable_fallback(area, current_order,
				start_migratetype, false, &can_steal);
		if (fallback_mt == -1)
			continue;

		/*
		 * We cannot steal all free pages from the pageblock and the
		 * requested migratetype is movable. In that case it's better to
		 * steal and split the smallest available page instead of the
		 * largest available page, because even if the next movable
		 * allocation falls back into a different pageblock than this
		 * one, it won't cause permanent fragmentation.
		 */
		if (!can_steal && start_migratetype == MIGRATE_MOVABLE
					&& current_order > order)
			goto find_smallest;

		goto do_steal;
	}

	return false;

find_smallest:
	for (current_order = order; current_order < MAX_ORDER;
							current_order++) {
		area = &(zone->free_area[current_order]);
		fallback_mt = find_suitable_fallback(area, current_order,
				start_migratetype, false, &can_steal);
		if (fallback_mt != -1)
			break;
	}

	/*
	 * This should not happen - we already found a suitable fallback
	 * when looking for the largest page.
	 */
	VM_BUG_ON(current_order == MAX_ORDER);

do_steal:
	page = get_page_from_free_area(area, fallback_mt);

	steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
								can_steal);

	trace_mm_page_alloc_extfrag(page, order, current_order,
		start_migratetype, fallback_mt);

	return true;

}

/*
 * Do the hard work of removing an element from the buddy allocator.
 * Call me with the zone->lock already held.
 */
static __always_inline struct page *
__rmqueue(struct zone *zone, unsigned int order, int migratetype,
						unsigned int alloc_flags)
{
	struct page *page;

#ifdef CONFIG_CMA
	/*
	 * Balance movable allocations between regular and CMA areas by
	 * allocating from CMA when over half of the zone's free memory
	 * is in the CMA area.
	 */
	if (migratetype == MIGRATE_MOVABLE &&
	    zone_page_state(zone, NR_FREE_CMA_PAGES) >
	    zone_page_state(zone, NR_FREE_PAGES) / 2) {
		page = __rmqueue_cma_fallback(zone, order);
		if (page)
			return page;
	}
#endif
retry:
	page = __rmqueue_smallest(zone, order, migratetype);
	if (unlikely(!page)) {
		if (migratetype == MIGRATE_MOVABLE)
			page = __rmqueue_cma_fallback(zone, order);

		if (!page && __rmqueue_fallback(zone, order, migratetype,
								alloc_flags))
			goto retry;
	}

	trace_mm_page_alloc_zone_locked(page, order, migratetype);
	return page;
}

/*
 * Obtain a specified number of elements from the buddy allocator, all under
 * a single hold of the lock, for efficiency.  Add them to the supplied list.
 * Returns the number of new pages which were placed at *list.
 */
static int rmqueue_bulk(struct zone *zone, unsigned int order,
			unsigned long count, struct list_head *list,
			int migratetype, unsigned int alloc_flags)
{
	int i, alloced = 0;

	spin_lock(&zone->lock);
	for (i = 0; i < count; ++i) {
		struct page *page = __rmqueue(zone, order, migratetype,
								alloc_flags);
		if (unlikely(page == NULL))
			break;

		if (unlikely(check_pcp_refill(page)))
			continue;

		/*
		 * Split buddy pages returned by expand() are received here in
		 * physical page order. The page is added to the tail of
		 * caller's list. From the callers perspective, the linked list
		 * is ordered by page number under some conditions. This is
		 * useful for IO devices that can forward direction from the
		 * head, thus also in the physical page order. This is useful
		 * for IO devices that can merge IO requests if the physical
		 * pages are ordered properly.
		 */
		list_add_tail(&page->lru, list);
		alloced++;
		if (is_migrate_cma(get_pcppage_migratetype(page)))
			__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
					      -(1 << order));
	}

	/*
	 * i pages were removed from the buddy list even if some leak due
	 * to check_pcp_refill failing so adjust NR_FREE_PAGES based
	 * on i. Do not confuse with 'alloced' which is the number of
	 * pages added to the pcp list.
	 */
	__mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
	spin_unlock(&zone->lock);
	return alloced;
}

#ifdef CONFIG_NUMA
/*
 * Called from the vmstat counter updater to drain pagesets of this
 * currently executing processor on remote nodes after they have
 * expired.
 *
 * Note that this function must be called with the thread pinned to
 * a single processor.
 */
void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
{
	unsigned long flags;
	int to_drain, batch;

	local_irq_save(flags);
	batch = READ_ONCE(pcp->batch);
	to_drain = min(pcp->count, batch);
	if (to_drain > 0)
		free_pcppages_bulk(zone, to_drain, pcp);
	local_irq_restore(flags);
}
#endif

/*
 * Drain pcplists of the indicated processor and zone.
 *
 * The processor must either be the current processor and the
 * thread pinned to the current processor or a processor that
 * is not online.
 */
static void drain_pages_zone(unsigned int cpu, struct zone *zone)
{
	unsigned long flags;
	struct per_cpu_pageset *pset;
	struct per_cpu_pages *pcp;

	local_irq_save(flags);
	pset = per_cpu_ptr(zone->pageset, cpu);

	pcp = &pset->pcp;
	if (pcp->count)
		free_pcppages_bulk(zone, pcp->count, pcp);
	local_irq_restore(flags);
}

/*
 * Drain pcplists of all zones on the indicated processor.
 *
 * The processor must either be the current processor and the
 * thread pinned to the current processor or a processor that
 * is not online.
 */
static void drain_pages(unsigned int cpu)
{
	struct zone *zone;

	for_each_populated_zone(zone) {
		drain_pages_zone(cpu, zone);
	}
}

/*
 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
 *
 * The CPU has to be pinned. When zone parameter is non-NULL, spill just
 * the single zone's pages.
 */
void drain_local_pages(struct zone *zone)
{
	int cpu = smp_processor_id();

	if (zone)
		drain_pages_zone(cpu, zone);
	else
		drain_pages(cpu);
}

static void drain_local_pages_wq(struct work_struct *work)
{
	struct pcpu_drain *drain;

	drain = container_of(work, struct pcpu_drain, work);

	/*
	 * drain_all_pages doesn't use proper cpu hotplug protection so
	 * we can race with cpu offline when the WQ can move this from
	 * a cpu pinned worker to an unbound one. We can operate on a different
	 * cpu which is allright but we also have to make sure to not move to
	 * a different one.
	 */
	preempt_disable();
	drain_local_pages(drain->zone);
	preempt_enable();
}

/*
 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
 *
 * When zone parameter is non-NULL, spill just the single zone's pages.
 *
 * Note that this can be extremely slow as the draining happens in a workqueue.
 */
void drain_all_pages(struct zone *zone)
{
	int cpu;

	/*
	 * Allocate in the BSS so we wont require allocation in
	 * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
	 */
	static cpumask_t cpus_with_pcps;

	/*
	 * Make sure nobody triggers this path before mm_percpu_wq is fully
	 * initialized.
	 */
	if (WARN_ON_ONCE(!mm_percpu_wq))
		return;

	/*
	 * Do not drain if one is already in progress unless it's specific to
	 * a zone. Such callers are primarily CMA and memory hotplug and need
	 * the drain to be complete when the call returns.
	 */
	if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) {
		if (!zone)
			return;
		mutex_lock(&pcpu_drain_mutex);
	}

	/*
	 * We don't care about racing with CPU hotplug event
	 * as offline notification will cause the notified
	 * cpu to drain that CPU pcps and on_each_cpu_mask
	 * disables preemption as part of its processing
	 */
	for_each_online_cpu(cpu) {
		struct per_cpu_pageset *pcp;
		struct zone *z;
		bool has_pcps = false;

		if (zone) {
			pcp = per_cpu_ptr(zone->pageset, cpu);
			if (pcp->pcp.count)
				has_pcps = true;
		} else {
			for_each_populated_zone(z) {
				pcp = per_cpu_ptr(z->pageset, cpu);
				if (pcp->pcp.count) {
					has_pcps = true;
					break;
				}
			}
		}

		if (has_pcps)
			cpumask_set_cpu(cpu, &cpus_with_pcps);
		else
			cpumask_clear_cpu(cpu, &cpus_with_pcps);
	}

	for_each_cpu(cpu, &cpus_with_pcps) {
		struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu);

		drain->zone = zone;
		INIT_WORK(&drain->work, drain_local_pages_wq);
		queue_work_on(cpu, mm_percpu_wq, &drain->work);
	}
	for_each_cpu(cpu, &cpus_with_pcps)
		flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work);

	mutex_unlock(&pcpu_drain_mutex);
}

#ifdef CONFIG_HIBERNATION

/*
 * Touch the watchdog for every WD_PAGE_COUNT pages.
 */
#define WD_PAGE_COUNT	(128*1024)

void mark_free_pages(struct zone *zone)
{
	unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
	unsigned long flags;
	unsigned int order, t;
	struct page *page;

	if (zone_is_empty(zone))
		return;

	spin_lock_irqsave(&zone->lock, flags);

	max_zone_pfn = zone_end_pfn(zone);
	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
		if (pfn_valid(pfn)) {
			page = pfn_to_page(pfn);

			if (!--page_count) {
				touch_nmi_watchdog();
				page_count = WD_PAGE_COUNT;
			}

			if (page_zone(page) != zone)
				continue;

			if (!swsusp_page_is_forbidden(page))
				swsusp_unset_page_free(page);
		}

	for_each_migratetype_order(order, t) {
		list_for_each_entry(page,
				&zone->free_area[order].free_list[t], lru) {
			unsigned long i;

			pfn = page_to_pfn(page);
			for (i = 0; i < (1UL << order); i++) {
				if (!--page_count) {
					touch_nmi_watchdog();
					page_count = WD_PAGE_COUNT;
				}
				swsusp_set_page_free(pfn_to_page(pfn + i));
			}
		}
	}
	spin_unlock_irqrestore(&zone->lock, flags);
}
#endif /* CONFIG_PM */

static bool free_unref_page_prepare(struct page *page, unsigned long pfn)
{
	int migratetype;

	if (!free_pcp_prepare(page))
		return false;

	migratetype = get_pfnblock_migratetype(page, pfn);
	set_pcppage_migratetype(page, migratetype);
	return true;
}

static void free_unref_page_commit(struct page *page, unsigned long pfn)
{
	struct zone *zone = page_zone(page);
	struct per_cpu_pages *pcp;
	int migratetype;

	migratetype = get_pcppage_migratetype(page);
	__count_vm_event(PGFREE);

	/*
	 * We only track unmovable, reclaimable and movable on pcp lists.
	 * Free ISOLATE pages back to the allocator because they are being
	 * offlined but treat HIGHATOMIC as movable pages so we can get those
	 * areas back if necessary. Otherwise, we may have to free
	 * excessively into the page allocator
	 */
	if (migratetype >= MIGRATE_PCPTYPES) {
		if (unlikely(is_migrate_isolate(migratetype))) {
			free_one_page(zone, page, pfn, 0, migratetype);
			return;
		}
		migratetype = MIGRATE_MOVABLE;
	}

	pcp = &this_cpu_ptr(zone->pageset)->pcp;
	list_add(&page->lru, &pcp->lists[migratetype]);
	pcp->count++;
	if (pcp->count >= pcp->high) {
		unsigned long batch = READ_ONCE(pcp->batch);
		free_pcppages_bulk(zone, batch, pcp);
	}
}

/*
 * Free a 0-order page
 */
void free_unref_page(struct page *page)
{
	unsigned long flags;
	unsigned long pfn = page_to_pfn(page);

	if (!free_unref_page_prepare(page, pfn))
		return;

	local_irq_save(flags);
	free_unref_page_commit(page, pfn);
	local_irq_restore(flags);
}

/*
 * Free a list of 0-order pages
 */
void free_unref_page_list(struct list_head *list)
{
	struct page *page, *next;
	unsigned long flags, pfn;
	int batch_count = 0;

	/* Prepare pages for freeing */
	list_for_each_entry_safe(page, next, list, lru) {
		pfn = page_to_pfn(page);
		if (!free_unref_page_prepare(page, pfn))
			list_del(&page->lru);
		set_page_private(page, pfn);
	}

	local_irq_save(flags);
	list_for_each_entry_safe(page, next, list, lru) {
		unsigned long pfn = page_private(page);

		set_page_private(page, 0);
		trace_mm_page_free_batched(page);
		free_unref_page_commit(page, pfn);

		/*
		 * Guard against excessive IRQ disabled times when we get
		 * a large list of pages to free.
		 */
		if (++batch_count == SWAP_CLUSTER_MAX) {
			local_irq_restore(flags);
			batch_count = 0;
			local_irq_save(flags);
		}
	}
	local_irq_restore(flags);
}

/*
 * split_page takes a non-compound higher-order page, and splits it into
 * n (1<<order) sub-pages: page[0..n]
 * Each sub-page must be freed individually.
 *
 * Note: this is probably too low level an operation for use in drivers.
 * Please consult with lkml before using this in your driver.
 */
void split_page(struct page *page, unsigned int order)
{
	int i;

	VM_BUG_ON_PAGE(PageCompound(page), page);
	VM_BUG_ON_PAGE(!page_count(page), page);

	for (i = 1; i < (1 << order); i++)
		set_page_refcounted(page + i);
	split_page_owner(page, order);
}
EXPORT_SYMBOL_GPL(split_page);

int __isolate_free_page(struct page *page, unsigned int order)
{
	unsigned long watermark;
	struct zone *zone;
	int mt;

	BUG_ON(!PageBuddy(page));

	zone = page_zone(page);
	mt = get_pageblock_migratetype(page);

	if (!is_migrate_isolate(mt)) {
		/*
		 * Obey watermarks as if the page was being allocated. We can
		 * emulate a high-order watermark check with a raised order-0
		 * watermark, because we already know our high-order page
		 * exists.
		 */
		watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
		if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
			return 0;

		__mod_zone_freepage_state(zone, -(1UL << order), mt);
	}

	/* Remove page from free list */

	del_page_from_free_list(page, zone, order);

	/*
	 * Set the pageblock if the isolated page is at least half of a
	 * pageblock
	 */
	if (order >= pageblock_order - 1) {
		struct page *endpage = page + (1 << order) - 1;
		for (; page < endpage; page += pageblock_nr_pages) {
			int mt = get_pageblock_migratetype(page);
			if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
			    && !is_migrate_highatomic(mt))
				set_pageblock_migratetype(page,
							  MIGRATE_MOVABLE);
		}
	}


	return 1UL << order;
}

/**
 * __putback_isolated_page - Return a now-isolated page back where we got it
 * @page: Page that was isolated
 * @order: Order of the isolated page
 * @mt: The page's pageblock's migratetype
 *
 * This function is meant to return a page pulled from the free lists via
 * __isolate_free_page back to the free lists they were pulled from.
 */
void __putback_isolated_page(struct page *page, unsigned int order, int mt)
{
	struct zone *zone = page_zone(page);

	/* zone lock should be held when this function is called */
	lockdep_assert_held(&zone->lock);

	/* Return isolated page to tail of freelist. */
	__free_one_page(page, page_to_pfn(page), zone, order, mt, false);
}

/*
 * Update NUMA hit/miss statistics
 *
 * Must be called with interrupts disabled.
 */
static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
{
#ifdef CONFIG_NUMA
	enum numa_stat_item local_stat = NUMA_LOCAL;

	/* skip numa counters update if numa stats is disabled */
	if (!static_branch_likely(&vm_numa_stat_key))
		return;

	if (zone_to_nid(z) != numa_node_id())
		local_stat = NUMA_OTHER;

	if (zone_to_nid(z) == zone_to_nid(preferred_zone))
		__inc_numa_state(z, NUMA_HIT);
	else {
		__inc_numa_state(z, NUMA_MISS);
		__inc_numa_state(preferred_zone, NUMA_FOREIGN);
	}
	__inc_numa_state(z, local_stat);
#endif
}

/* Remove page from the per-cpu list, caller must protect the list */
static struct page *__rmqueue_pcplist(struct zone *zone, int migratetype,
			unsigned int alloc_flags,
			struct per_cpu_pages *pcp,
			struct list_head *list)
{
	struct page *page;

	do {
		if (list_empty(list)) {
			pcp->count += rmqueue_bulk(zone, 0,
					pcp->batch, list,
					migratetype, alloc_flags);
			if (unlikely(list_empty(list)))
				return NULL;
		}

		page = list_first_entry(list, struct page, lru);
		list_del(&page->lru);
		pcp->count--;
	} while (check_new_pcp(page));

	return page;
}

/* Lock and remove page from the per-cpu list */
static struct page *rmqueue_pcplist(struct zone *preferred_zone,
			struct zone *zone, gfp_t gfp_flags,
			int migratetype, unsigned int alloc_flags)
{
	struct per_cpu_pages *pcp;
	struct list_head *list;
	struct page *page;
	unsigned long flags;

	local_irq_save(flags);
	pcp = &this_cpu_ptr(zone->pageset)->pcp;
	list = &pcp->lists[migratetype];
	page = __rmqueue_pcplist(zone,  migratetype, alloc_flags, pcp, list);
	if (page) {
		__count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
		zone_statistics(preferred_zone, zone);
	}
	local_irq_restore(flags);
	return page;
}

/*
 * Allocate a page from the given zone. Use pcplists for order-0 allocations.
 */
static inline
struct page *rmqueue(struct zone *preferred_zone,
			struct zone *zone, unsigned int order,
			gfp_t gfp_flags, unsigned int alloc_flags,
			int migratetype)
{
	unsigned long flags;
	struct page *page;

	if (likely(order == 0)) {
		page = rmqueue_pcplist(preferred_zone, zone, gfp_flags,
					migratetype, alloc_flags);
		goto out;
	}

	/*
	 * We most definitely don't want callers attempting to
	 * allocate greater than order-1 page units with __GFP_NOFAIL.
	 */
	WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
	spin_lock_irqsave(&zone->lock, flags);

	do {
		page = NULL;
		if (alloc_flags & ALLOC_HARDER) {
			page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
			if (page)
				trace_mm_page_alloc_zone_locked(page, order, migratetype);
		}
		if (!page)
			page = __rmqueue(zone, order, migratetype, alloc_flags);
	} while (page && check_new_pages(page, order));
	spin_unlock(&zone->lock);
	if (!page)
		goto failed;
	__mod_zone_freepage_state(zone, -(1 << order),
				  get_pcppage_migratetype(page));

	__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
	zone_statistics(preferred_zone, zone);
	local_irq_restore(flags);

out:
	/* Separate test+clear to avoid unnecessary atomics */
	if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) {
		clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
		wakeup_kswapd(zone, 0, 0, zone_idx(zone));
	}

	VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
	return page;

failed:
	local_irq_restore(flags);
	return NULL;
}

#ifdef CONFIG_FAIL_PAGE_ALLOC

static struct {
	struct fault_attr attr;

	bool ignore_gfp_highmem;
	bool ignore_gfp_reclaim;
	u32 min_order;
} fail_page_alloc = {
	.attr = FAULT_ATTR_INITIALIZER,
	.ignore_gfp_reclaim = true,
	.ignore_gfp_highmem = true,
	.min_order = 1,
};

static int __init setup_fail_page_alloc(char *str)
{
	return setup_fault_attr(&fail_page_alloc.attr, str);
}
__setup("fail_page_alloc=", setup_fail_page_alloc);

static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
	if (order < fail_page_alloc.min_order)
		return false;
	if (gfp_mask & __GFP_NOFAIL)
		return false;
	if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
		return false;
	if (fail_page_alloc.ignore_gfp_reclaim &&
			(gfp_mask & __GFP_DIRECT_RECLAIM))
		return false;

	return should_fail(&fail_page_alloc.attr, 1 << order);
}

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS

static int __init fail_page_alloc_debugfs(void)
{
	umode_t mode = S_IFREG | 0600;
	struct dentry *dir;

	dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
					&fail_page_alloc.attr);

	debugfs_create_bool("ignore-gfp-wait", mode, dir,
			    &fail_page_alloc.ignore_gfp_reclaim);
	debugfs_create_bool("ignore-gfp-highmem", mode, dir,
			    &fail_page_alloc.ignore_gfp_highmem);
	debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);

	return 0;
}

late_initcall(fail_page_alloc_debugfs);

#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

#else /* CONFIG_FAIL_PAGE_ALLOC */

static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
	return false;
}

#endif /* CONFIG_FAIL_PAGE_ALLOC */

static noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
	return __should_fail_alloc_page(gfp_mask, order);
}
ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);

/*
 * Return true if free base pages are above 'mark'. For high-order checks it
 * will return true of the order-0 watermark is reached and there is at least
 * one free page of a suitable size. Checking now avoids taking the zone lock
 * to check in the allocation paths if no pages are free.
 */
bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
			 int highest_zoneidx, unsigned int alloc_flags,
			 long free_pages)
{
	long min = mark;
	int o;
	const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));

	/* free_pages may go negative - that's OK */
	free_pages -= (1 << order) - 1;

	if (alloc_flags & ALLOC_HIGH)
		min -= min / 2;

	/*
	 * If the caller does not have rights to ALLOC_HARDER then subtract
	 * the high-atomic reserves. This will over-estimate the size of the
	 * atomic reserve but it avoids a search.
	 */
	if (likely(!alloc_harder)) {
		free_pages -= z->nr_reserved_highatomic;
	} else {
		/*
		 * OOM victims can try even harder than normal ALLOC_HARDER
		 * users on the grounds that it's definitely going to be in
		 * the exit path shortly and free memory. Any allocation it
		 * makes during the free path will be small and short-lived.
		 */
		if (alloc_flags & ALLOC_OOM)
			min -= min / 2;
		else
			min -= min / 4;
	}


#ifdef CONFIG_CMA
	/* If allocation can't use CMA areas don't use free CMA pages */
	if (!(alloc_flags & ALLOC_CMA))
		free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
#endif

	/*
	 * Check watermarks for an order-0 allocation request. If these
	 * are not met, then a high-order request also cannot go ahead
	 * even if a suitable page happened to be free.
	 */
	if (free_pages <= min + z->lowmem_reserve[highest_zoneidx])
		return false;

	/* If this is an order-0 request then the watermark is fine */
	if (!order)
		return true;

	/* For a high-order request, check at least one suitable page is free */
	for (o = order; o < MAX_ORDER; o++) {
		struct free_area *area = &z->free_area[o];
		int mt;

		if (!area->nr_free)
			continue;

		for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
			if (!free_area_empty(area, mt))
				return true;
		}

#ifdef CONFIG_CMA
		if ((alloc_flags & ALLOC_CMA) &&
		    !free_area_empty(area, MIGRATE_CMA)) {
			return true;
		}
#endif
		if (alloc_harder && !free_area_empty(area, MIGRATE_HIGHATOMIC))
			return true;
	}
	return false;
}

bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
		      int highest_zoneidx, unsigned int alloc_flags)
{
	return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
					zone_page_state(z, NR_FREE_PAGES));
}

static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
				unsigned long mark, int highest_zoneidx,
				unsigned int alloc_flags)
{
	long free_pages = zone_page_state(z, NR_FREE_PAGES);
	long cma_pages = 0;

#ifdef CONFIG_CMA
	/* If allocation can't use CMA areas don't use free CMA pages */
	if (!(alloc_flags & ALLOC_CMA))
		cma_pages = zone_page_state(z, NR_FREE_CMA_PAGES);
#endif

	/*
	 * Fast check for order-0 only. If this fails then the reserves
	 * need to be calculated. There is a corner case where the check
	 * passes but only the high-order atomic reserve are free. If
	 * the caller is !atomic then it'll uselessly search the free
	 * list. That corner case is then slower but it is harmless.
	 */
	if (!order && (free_pages - cma_pages) >
				mark + z->lowmem_reserve[highest_zoneidx])
		return true;

	return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
					free_pages);
}

bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
			unsigned long mark, int highest_zoneidx)
{
	long free_pages = zone_page_state(z, NR_FREE_PAGES);

	if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
		free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);

	return __zone_watermark_ok(z, order, mark, highest_zoneidx, 0,
								free_pages);
}

#ifdef CONFIG_NUMA
static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
{
	return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <=
				node_reclaim_distance;
}
#else	/* CONFIG_NUMA */
static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
{
	return true;
}
#endif	/* CONFIG_NUMA */

/*
 * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid
 * fragmentation is subtle. If the preferred zone was HIGHMEM then
 * premature use of a lower zone may cause lowmem pressure problems that
 * are worse than fragmentation. If the next zone is ZONE_DMA then it is
 * probably too small. It only makes sense to spread allocations to avoid
 * fragmentation between the Normal and DMA32 zones.
 */
static inline unsigned int
alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
{
	unsigned int alloc_flags;

	/*
	 * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
	 * to save a branch.
	 */
	alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM);

#ifdef CONFIG_ZONE_DMA32
	if (!zone)
		return alloc_flags;

	if (zone_idx(zone) != ZONE_NORMAL)
		return alloc_flags;

	/*
	 * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and
	 * the pointer is within zone->zone_pgdat->node_zones[]. Also assume
	 * on UMA that if Normal is populated then so is DMA32.
	 */
	BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1);
	if (nr_online_nodes > 1 && !populated_zone(--zone))
		return alloc_flags;

	alloc_flags |= ALLOC_NOFRAGMENT;
#endif /* CONFIG_ZONE_DMA32 */
	return alloc_flags;
}

/*
 * get_page_from_freelist goes through the zonelist trying to allocate
 * a page.
 */
static struct page *
get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
						const struct alloc_context *ac)
{
	struct zoneref *z;
	struct zone *zone;
	struct pglist_data *last_pgdat_dirty_limit = NULL;
	bool no_fallback;

retry:
	/*
	 * Scan zonelist, looking for a zone with enough free.
	 * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
	 */
	no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
	z = ac->preferred_zoneref;
	for_next_zone_zonelist_nodemask(zone, z, ac->zonelist,
					ac->highest_zoneidx, ac->nodemask) {
		struct page *page;
		unsigned long mark;

		if (cpusets_enabled() &&
			(alloc_flags & ALLOC_CPUSET) &&
			!__cpuset_zone_allowed(zone, gfp_mask))
				continue;
		/*
		 * When allocating a page cache page for writing, we
		 * want to get it from a node that is within its dirty
		 * limit, such that no single node holds more than its
		 * proportional share of globally allowed dirty pages.
		 * The dirty limits take into account the node's
		 * lowmem reserves and high watermark so that kswapd
		 * should be able to balance it without having to
		 * write pages from its LRU list.
		 *
		 * XXX: For now, allow allocations to potentially
		 * exceed the per-node dirty limit in the slowpath
		 * (spread_dirty_pages unset) before going into reclaim,
		 * which is important when on a NUMA setup the allowed
		 * nodes are together not big enough to reach the
		 * global limit.  The proper fix for these situations
		 * will require awareness of nodes in the
		 * dirty-throttling and the flusher threads.
		 */
		if (ac->spread_dirty_pages) {
			if (last_pgdat_dirty_limit == zone->zone_pgdat)
				continue;

			if (!node_dirty_ok(zone->zone_pgdat)) {
				last_pgdat_dirty_limit = zone->zone_pgdat;
				continue;
			}
		}

		if (no_fallback && nr_online_nodes > 1 &&
		    zone != ac->preferred_zoneref->zone) {
			int local_nid;

			/*
			 * If moving to a remote node, retry but allow
			 * fragmenting fallbacks. Locality is more important
			 * than fragmentation avoidance.
			 */
			local_nid = zone_to_nid(ac->preferred_zoneref->zone);
			if (zone_to_nid(zone) != local_nid) {
				alloc_flags &= ~ALLOC_NOFRAGMENT;
				goto retry;
			}
		}

		mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
		if (!zone_watermark_fast(zone, order, mark,
				       ac->highest_zoneidx, alloc_flags)) {
			int ret;

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
			/*
			 * Watermark failed for this zone, but see if we can
			 * grow this zone if it contains deferred pages.
			 */
			if (static_branch_unlikely(&deferred_pages)) {
				if (_deferred_grow_zone(zone, order))
					goto try_this_zone;
			}
#endif
			/* Checked here to keep the fast path fast */
			BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
			if (alloc_flags & ALLOC_NO_WATERMARKS)
				goto try_this_zone;

			if (node_reclaim_mode == 0 ||
			    !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
				continue;

			ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
			switch (ret) {
			case NODE_RECLAIM_NOSCAN:
				/* did not scan */
				continue;
			case NODE_RECLAIM_FULL:
				/* scanned but unreclaimable */
				continue;
			default:
				/* did we reclaim enough */
				if (zone_watermark_ok(zone, order, mark,
					ac->highest_zoneidx, alloc_flags))
					goto try_this_zone;

				continue;
			}
		}

try_this_zone:
		page = rmqueue(ac->preferred_zoneref->zone, zone, order,
				gfp_mask, alloc_flags, ac->migratetype);
		if (page) {
			prep_new_page(page, order, gfp_mask, alloc_flags);

			/*
			 * If this is a high-order atomic allocation then check
			 * if the pageblock should be reserved for the future
			 */
			if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
				reserve_highatomic_pageblock(page, zone, order);

			return page;
		} else {
#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
			/* Try again if zone has deferred pages */
			if (static_branch_unlikely(&deferred_pages)) {
				if (_deferred_grow_zone(zone, order))
					goto try_this_zone;
			}
#endif
		}
	}

	/*
	 * It's possible on a UMA machine to get through all zones that are
	 * fragmented. If avoiding fragmentation, reset and try again.
	 */
	if (no_fallback) {
		alloc_flags &= ~ALLOC_NOFRAGMENT;
		goto retry;
	}

	return NULL;
}

static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
{
	unsigned int filter = SHOW_MEM_FILTER_NODES;

	/*
	 * This documents exceptions given to allocations in certain
	 * contexts that are allowed to allocate outside current's set
	 * of allowed nodes.
	 */
	if (!(gfp_mask & __GFP_NOMEMALLOC))
		if (tsk_is_oom_victim(current) ||
		    (current->flags & (PF_MEMALLOC | PF_EXITING)))
			filter &= ~SHOW_MEM_FILTER_NODES;
	if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
		filter &= ~SHOW_MEM_FILTER_NODES;

	show_mem(filter, nodemask);
}

void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;
	static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1);

	if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs))
		return;

	va_start(args, fmt);
	vaf.fmt = fmt;
	vaf.va = &args;
	pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl",
			current->comm, &vaf, gfp_mask, &gfp_mask,
			nodemask_pr_args(nodemask));
	va_end(args);

	cpuset_print_current_mems_allowed();
	pr_cont("\n");
	dump_stack();
	warn_alloc_show_mem(gfp_mask, nodemask);
}

static inline struct page *
__alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order,
			      unsigned int alloc_flags,
			      const struct alloc_context *ac)
{
	struct page *page;

	page = get_page_from_freelist(gfp_mask, order,
			alloc_flags|ALLOC_CPUSET, ac);
	/*
	 * fallback to ignore cpuset restriction if our nodes
	 * are depleted
	 */
	if (!page)
		page = get_page_from_freelist(gfp_mask, order,
				alloc_flags, ac);

	return page;
}

static inline struct page *
__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
	const struct alloc_context *ac, unsigned long *did_some_progress)
{
	struct oom_control oc = {
		.zonelist = ac->zonelist,
		.nodemask = ac->nodemask,
		.memcg = NULL,
		.gfp_mask = gfp_mask,
		.order = order,
	};
	struct page *page;

	*did_some_progress = 0;

	/*
	 * Acquire the oom lock.  If that fails, somebody else is
	 * making progress for us.
	 */
	if (!mutex_trylock(&oom_lock)) {
		*did_some_progress = 1;
		schedule_timeout_uninterruptible(1);
		return NULL;
	}

	/*
	 * Go through the zonelist yet one more time, keep very high watermark
	 * here, this is only to catch a parallel oom killing, we must fail if
	 * we're still under heavy pressure. But make sure that this reclaim
	 * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY
	 * allocation which will never fail due to oom_lock already held.
	 */
	page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
				      ~__GFP_DIRECT_RECLAIM, order,
				      ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
	if (page)
		goto out;

	/* Coredumps can quickly deplete all memory reserves */
	if (current->flags & PF_DUMPCORE)
		goto out;
	/* The OOM killer will not help higher order allocs */
	if (order > PAGE_ALLOC_COSTLY_ORDER)
		goto out;
	/*
	 * We have already exhausted all our reclaim opportunities without any
	 * success so it is time to admit defeat. We will skip the OOM killer
	 * because it is very likely that the caller has a more reasonable
	 * fallback than shooting a random task.
	 */
	if (gfp_mask & __GFP_RETRY_MAYFAIL)
		goto out;
	/* The OOM killer does not needlessly kill tasks for lowmem */
	if (ac->highest_zoneidx < ZONE_NORMAL)
		goto out;
	if (pm_suspended_storage())
		goto out;
	/*
	 * XXX: GFP_NOFS allocations should rather fail than rely on
	 * other request to make a forward progress.
	 * We are in an unfortunate situation where out_of_memory cannot
	 * do much for this context but let's try it to at least get
	 * access to memory reserved if the current task is killed (see
	 * out_of_memory). Once filesystems are ready to handle allocation
	 * failures more gracefully we should just bail out here.
	 */

	/* The OOM killer may not free memory on a specific node */
	if (gfp_mask & __GFP_THISNODE)
		goto out;

	/* Exhausted what can be done so it's blame time */
	if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
		*did_some_progress = 1;

		/*
		 * Help non-failing allocations by giving them access to memory
		 * reserves
		 */
		if (gfp_mask & __GFP_NOFAIL)
			page = __alloc_pages_cpuset_fallback(gfp_mask, order,
					ALLOC_NO_WATERMARKS, ac);
	}
out:
	mutex_unlock(&oom_lock);
	return page;
}

/*
 * Maximum number of compaction retries wit a progress before OOM
 * killer is consider as the only way to move forward.
 */
#define MAX_COMPACT_RETRIES 16

#ifdef CONFIG_COMPACTION
/* Try memory compaction for high-order allocations before reclaim */
static struct page *
__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
		unsigned int alloc_flags, const struct alloc_context *ac,
		enum compact_priority prio, enum compact_result *compact_result)
{
	struct page *page = NULL;
	unsigned long pflags;
	unsigned int noreclaim_flag;

	if (!order)
		return NULL;

	psi_memstall_enter(&pflags);
	noreclaim_flag = memalloc_noreclaim_save();

	*compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
								prio, &page);

	memalloc_noreclaim_restore(noreclaim_flag);
	psi_memstall_leave(&pflags);

	/*
	 * At least in one zone compaction wasn't deferred or skipped, so let's
	 * count a compaction stall
	 */
	count_vm_event(COMPACTSTALL);

	/* Prep a captured page if available */
	if (page)
		prep_new_page(page, order, gfp_mask, alloc_flags);

	/* Try get a page from the freelist if available */
	if (!page)
		page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);

	if (page) {
		struct zone *zone = page_zone(page);

		zone->compact_blockskip_flush = false;
		compaction_defer_reset(zone, order, true);
		count_vm_event(COMPACTSUCCESS);
		return page;
	}

	/*
	 * It's bad if compaction run occurs and fails. The most likely reason
	 * is that pages exist, but not enough to satisfy watermarks.
	 */
	count_vm_event(COMPACTFAIL);

	cond_resched();

	return NULL;
}

static inline bool
should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
		     enum compact_result compact_result,
		     enum compact_priority *compact_priority,
		     int *compaction_retries)
{
	int max_retries = MAX_COMPACT_RETRIES;
	int min_priority;
	bool ret = false;
	int retries = *compaction_retries;
	enum compact_priority priority = *compact_priority;

	if (!order)
		return false;

	if (compaction_made_progress(compact_result))
		(*compaction_retries)++;

	/*
	 * compaction considers all the zone as desperately out of memory
	 * so it doesn't really make much sense to retry except when the
	 * failure could be caused by insufficient priority
	 */
	if (compaction_failed(compact_result))
		goto check_priority;

	/*
	 * compaction was skipped because there are not enough order-0 pages
	 * to work with, so we retry only if it looks like reclaim can help.
	 */
	if (compaction_needs_reclaim(compact_result)) {
		ret = compaction_zonelist_suitable(ac, order, alloc_flags);
		goto out;
	}

	/*
	 * make sure the compaction wasn't deferred or didn't bail out early
	 * due to locks contention before we declare that we should give up.
	 * But the next retry should use a higher priority if allowed, so
	 * we don't just keep bailing out endlessly.
	 */
	if (compaction_withdrawn(compact_result)) {
		goto check_priority;
	}

	/*
	 * !costly requests are much more important than __GFP_RETRY_MAYFAIL
	 * costly ones because they are de facto nofail and invoke OOM
	 * killer to move on while costly can fail and users are ready
	 * to cope with that. 1/4 retries is rather arbitrary but we
	 * would need much more detailed feedback from compaction to
	 * make a better decision.
	 */
	if (order > PAGE_ALLOC_COSTLY_ORDER)
		max_retries /= 4;
	if (*compaction_retries <= max_retries) {
		ret = true;
		goto out;
	}

	/*
	 * Make sure there are attempts at the highest priority if we exhausted
	 * all retries or failed at the lower priorities.
	 */
check_priority:
	min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
			MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;

	if (*compact_priority > min_priority) {
		(*compact_priority)--;
		*compaction_retries = 0;
		ret = true;
	}
out:
	trace_compact_retry(order, priority, compact_result, retries, max_retries, ret);
	return ret;
}
#else
static inline struct page *
__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
		unsigned int alloc_flags, const struct alloc_context *ac,
		enum compact_priority prio, enum compact_result *compact_result)
{
	*compact_result = COMPACT_SKIPPED;
	return NULL;
}

static inline bool
should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
		     enum compact_result compact_result,
		     enum compact_priority *compact_priority,
		     int *compaction_retries)
{
	struct zone *zone;
	struct zoneref *z;

	if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
		return false;

	/*
	 * There are setups with compaction disabled which would prefer to loop
	 * inside the allocator rather than hit the oom killer prematurely.
	 * Let's give them a good hope and keep retrying while the order-0
	 * watermarks are OK.
	 */
	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
				ac->highest_zoneidx, ac->nodemask) {
		if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
					ac->highest_zoneidx, alloc_flags))
			return true;
	}
	return false;
}
#endif /* CONFIG_COMPACTION */

#ifdef CONFIG_LOCKDEP
static struct lockdep_map __fs_reclaim_map =
	STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map);

static bool __need_fs_reclaim(gfp_t gfp_mask)
{
	gfp_mask = current_gfp_context(gfp_mask);

	/* no reclaim without waiting on it */
	if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
		return false;

	/* this guy won't enter reclaim */
	if (current->flags & PF_MEMALLOC)
		return false;

	/* We're only interested __GFP_FS allocations for now */
	if (!(gfp_mask & __GFP_FS))
		return false;

	if (gfp_mask & __GFP_NOLOCKDEP)
		return false;

	return true;
}

void __fs_reclaim_acquire(void)
{
	lock_map_acquire(&__fs_reclaim_map);
}

void __fs_reclaim_release(void)
{
	lock_map_release(&__fs_reclaim_map);
}

void fs_reclaim_acquire(gfp_t gfp_mask)
{
	if (__need_fs_reclaim(gfp_mask))
		__fs_reclaim_acquire();
}
EXPORT_SYMBOL_GPL(fs_reclaim_acquire);

void fs_reclaim_release(gfp_t gfp_mask)
{
	if (__need_fs_reclaim(gfp_mask))
		__fs_reclaim_release();
}
EXPORT_SYMBOL_GPL(fs_reclaim_release);
#endif

/* Perform direct synchronous page reclaim */
static int
__perform_reclaim(gfp_t gfp_mask, unsigned int order,
					const struct alloc_context *ac)
{
	int progress;
	unsigned int noreclaim_flag;
	unsigned long pflags;

	cond_resched();

	/* We now go into synchronous reclaim */
	cpuset_memory_pressure_bump();
	psi_memstall_enter(&pflags);
	fs_reclaim_acquire(gfp_mask);
	noreclaim_flag = memalloc_noreclaim_save();

	progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
								ac->nodemask);

	memalloc_noreclaim_restore(noreclaim_flag);
	fs_reclaim_release(gfp_mask);
	psi_memstall_leave(&pflags);

	cond_resched();

	return progress;
}

/* The really slow allocator path where we enter direct reclaim */
static inline struct page *
__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
		unsigned int alloc_flags, const struct alloc_context *ac,
		unsigned long *did_some_progress)
{
	struct page *page = NULL;
	bool drained = false;

	*did_some_progress = __perform_reclaim(gfp_mask, order, ac);
	if (unlikely(!(*did_some_progress)))
		return NULL;

retry:
	page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);

	/*
	 * If an allocation failed after direct reclaim, it could be because
	 * pages are pinned on the per-cpu lists or in high alloc reserves.
	 * Shrink them them and try again
	 */
	if (!page && !drained) {
		unreserve_highatomic_pageblock(ac, false);
		drain_all_pages(NULL);
		drained = true;
		goto retry;
	}

	return page;
}

static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
			     const struct alloc_context *ac)
{
	struct zoneref *z;
	struct zone *zone;
	pg_data_t *last_pgdat = NULL;
	enum zone_type highest_zoneidx = ac->highest_zoneidx;

	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx,
					ac->nodemask) {
		if (last_pgdat != zone->zone_pgdat)
			wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx);
		last_pgdat = zone->zone_pgdat;
	}
}

static inline unsigned int
gfp_to_alloc_flags(gfp_t gfp_mask)
{
	unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;

	/*
	 * __GFP_HIGH is assumed to be the same as ALLOC_HIGH
	 * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
	 * to save two branches.
	 */
	BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
	BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD);

	/*
	 * The caller may dip into page reserves a bit more if the caller
	 * cannot run direct reclaim, or if the caller has realtime scheduling
	 * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
	 * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
	 */
	alloc_flags |= (__force int)
		(gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM));

	if (gfp_mask & __GFP_ATOMIC) {
		/*
		 * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
		 * if it can't schedule.
		 */
		if (!(gfp_mask & __GFP_NOMEMALLOC))
			alloc_flags |= ALLOC_HARDER;
		/*
		 * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
		 * comment for __cpuset_node_allowed().
		 */
		alloc_flags &= ~ALLOC_CPUSET;
	} else if (unlikely(rt_task(current)) && !in_interrupt())
		alloc_flags |= ALLOC_HARDER;

#ifdef CONFIG_CMA
	if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE)
		alloc_flags |= ALLOC_CMA;
#endif
	return alloc_flags;
}

static bool oom_reserves_allowed(struct task_struct *tsk)
{
	if (!tsk_is_oom_victim(tsk))
		return false;

	/*
	 * !MMU doesn't have oom reaper so give access to memory reserves
	 * only to the thread with TIF_MEMDIE set
	 */
	if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE))
		return false;

	return true;
}

/*
 * Distinguish requests which really need access to full memory
 * reserves from oom victims which can live with a portion of it
 */
static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask)
{
	if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
		return 0;
	if (gfp_mask & __GFP_MEMALLOC)
		return ALLOC_NO_WATERMARKS;
	if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
		return ALLOC_NO_WATERMARKS;
	if (!in_interrupt()) {
		if (current->flags & PF_MEMALLOC)
			return ALLOC_NO_WATERMARKS;
		else if (oom_reserves_allowed(current))
			return ALLOC_OOM;
	}

	return 0;
}

bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
{
	return !!__gfp_pfmemalloc_flags(gfp_mask);
}

/*
 * Checks whether it makes sense to retry the reclaim to make a forward progress
 * for the given allocation request.
 *
 * We give up when we either have tried MAX_RECLAIM_RETRIES in a row
 * without success, or when we couldn't even meet the watermark if we
 * reclaimed all remaining pages on the LRU lists.
 *
 * Returns true if a retry is viable or false to enter the oom path.
 */
static inline bool
should_reclaim_retry(gfp_t gfp_mask, unsigned order,
		     struct alloc_context *ac, int alloc_flags,
		     bool did_some_progress, int *no_progress_loops)
{
	struct zone *zone;
	struct zoneref *z;
	bool ret = false;

	/*
	 * Costly allocations might have made a progress but this doesn't mean
	 * their order will become available due to high fragmentation so
	 * always increment the no progress counter for them
	 */
	if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
		*no_progress_loops = 0;
	else
		(*no_progress_loops)++;

	/*
	 * Make sure we converge to OOM if we cannot make any progress
	 * several times in the row.
	 */
	if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
		/* Before OOM, exhaust highatomic_reserve */
		return unreserve_highatomic_pageblock(ac, true);
	}

	/*
	 * Keep reclaiming pages while there is a chance this will lead
	 * somewhere.  If none of the target zones can satisfy our allocation
	 * request even if all reclaimable pages are considered then we are
	 * screwed and have to go OOM.
	 */
	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
				ac->highest_zoneidx, ac->nodemask) {
		unsigned long available;
		unsigned long reclaimable;
		unsigned long min_wmark = min_wmark_pages(zone);
		bool wmark;

		available = reclaimable = zone_reclaimable_pages(zone);
		available += zone_page_state_snapshot(zone, NR_FREE_PAGES);

		/*
		 * Would the allocation succeed if we reclaimed all
		 * reclaimable pages?
		 */
		wmark = __zone_watermark_ok(zone, order, min_wmark,
				ac->highest_zoneidx, alloc_flags, available);
		trace_reclaim_retry_zone(z, order, reclaimable,
				available, min_wmark, *no_progress_loops, wmark);
		if (wmark) {
			/*
			 * If we didn't make any progress and have a lot of
			 * dirty + writeback pages then we should wait for
			 * an IO to complete to slow down the reclaim and
			 * prevent from pre mature OOM
			 */
			if (!did_some_progress) {
				unsigned long write_pending;

				write_pending = zone_page_state_snapshot(zone,
							NR_ZONE_WRITE_PENDING);

				if (2 * write_pending > reclaimable) {
					congestion_wait(BLK_RW_ASYNC, HZ/10);
					return true;
				}
			}

			ret = true;
			goto out;
		}
	}

out:
	/*
	 * Memory allocation/reclaim might be called from a WQ context and the
	 * current implementation of the WQ concurrency control doesn't
	 * recognize that a particular WQ is congested if the worker thread is
	 * looping without ever sleeping. Therefore we have to do a short sleep
	 * here rather than calling cond_resched().
	 */
	if (current->flags & PF_WQ_WORKER)
		schedule_timeout_uninterruptible(1);
	else
		cond_resched();
	return ret;
}

static inline bool
check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac)
{
	/*
	 * It's possible that cpuset's mems_allowed and the nodemask from
	 * mempolicy don't intersect. This should be normally dealt with by
	 * policy_nodemask(), but it's possible to race with cpuset update in
	 * such a way the check therein was true, and then it became false
	 * before we got our cpuset_mems_cookie here.
	 * This assumes that for all allocations, ac->nodemask can come only
	 * from MPOL_BIND mempolicy (whose documented semantics is to be ignored
	 * when it does not intersect with the cpuset restrictions) or the
	 * caller can deal with a violated nodemask.
	 */
	if (cpusets_enabled() && ac->nodemask &&
			!cpuset_nodemask_valid_mems_allowed(ac->nodemask)) {
		ac->nodemask = NULL;
		return true;
	}

	/*
	 * When updating a task's mems_allowed or mempolicy nodemask, it is
	 * possible to race with parallel threads in such a way that our
	 * allocation can fail while the mask is being updated. If we are about
	 * to fail, check if the cpuset changed during allocation and if so,
	 * retry.
	 */
	if (read_mems_allowed_retry(cpuset_mems_cookie))
		return true;

	return false;
}

static inline struct page *
__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
						struct alloc_context *ac)
{
	bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
	const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER;
	struct page *page = NULL;
	unsigned int alloc_flags;
	unsigned long did_some_progress;
	enum compact_priority compact_priority;
	enum compact_result compact_result;
	int compaction_retries;
	int no_progress_loops;
	unsigned int cpuset_mems_cookie;
	int reserve_flags;

	/*
	 * We also sanity check to catch abuse of atomic reserves being used by
	 * callers that are not in atomic context.
	 */
	if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
				(__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
		gfp_mask &= ~__GFP_ATOMIC;

retry_cpuset:
	compaction_retries = 0;
	no_progress_loops = 0;
	compact_priority = DEF_COMPACT_PRIORITY;
	cpuset_mems_cookie = read_mems_allowed_begin();

	/*
	 * The fast path uses conservative alloc_flags to succeed only until
	 * kswapd needs to be woken up, and to avoid the cost of setting up
	 * alloc_flags precisely. So we do that now.
	 */
	alloc_flags = gfp_to_alloc_flags(gfp_mask);

	/*
	 * We need to recalculate the starting point for the zonelist iterator
	 * because we might have used different nodemask in the fast path, or
	 * there was a cpuset modification and we are retrying - otherwise we
	 * could end up iterating over non-eligible zones endlessly.
	 */
	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
					ac->highest_zoneidx, ac->nodemask);
	if (!ac->preferred_zoneref->zone)
		goto nopage;

	if (alloc_flags & ALLOC_KSWAPD)
		wake_all_kswapds(order, gfp_mask, ac);

	/*
	 * The adjusted alloc_flags might result in immediate success, so try
	 * that first
	 */
	page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
	if (page)
		goto got_pg;

	/*
	 * For costly allocations, try direct compaction first, as it's likely
	 * that we have enough base pages and don't need to reclaim. For non-
	 * movable high-order allocations, do that as well, as compaction will
	 * try prevent permanent fragmentation by migrating from blocks of the
	 * same migratetype.
	 * Don't try this for allocations that are allowed to ignore
	 * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen.
	 */
	if (can_direct_reclaim &&
			(costly_order ||
			   (order > 0 && ac->migratetype != MIGRATE_MOVABLE))
			&& !gfp_pfmemalloc_allowed(gfp_mask)) {
		page = __alloc_pages_direct_compact(gfp_mask, order,
						alloc_flags, ac,
						INIT_COMPACT_PRIORITY,
						&compact_result);
		if (page)
			goto got_pg;

		/*
		 * Checks for costly allocations with __GFP_NORETRY, which
		 * includes some THP page fault allocations
		 */
		if (costly_order && (gfp_mask & __GFP_NORETRY)) {
			/*
			 * If allocating entire pageblock(s) and compaction
			 * failed because all zones are below low watermarks
			 * or is prohibited because it recently failed at this
			 * order, fail immediately unless the allocator has
			 * requested compaction and reclaim retry.
			 *
			 * Reclaim is
			 *  - potentially very expensive because zones are far
			 *    below their low watermarks or this is part of very
			 *    bursty high order allocations,
			 *  - not guaranteed to help because isolate_freepages()
			 *    may not iterate over freed pages as part of its
			 *    linear scan, and
			 *  - unlikely to make entire pageblocks free on its
			 *    own.
			 */
			if (compact_result == COMPACT_SKIPPED ||
			    compact_result == COMPACT_DEFERRED)
				goto nopage;

			/*
			 * Looks like reclaim/compaction is worth trying, but
			 * sync compaction could be very expensive, so keep
			 * using async compaction.
			 */
			compact_priority = INIT_COMPACT_PRIORITY;
		}
	}

retry:
	/* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
	if (alloc_flags & ALLOC_KSWAPD)
		wake_all_kswapds(order, gfp_mask, ac);

	reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
	if (reserve_flags)
		alloc_flags = reserve_flags;

	/*
	 * Reset the nodemask and zonelist iterators if memory policies can be
	 * ignored. These allocations are high priority and system rather than
	 * user oriented.
	 */
	if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) {
		ac->nodemask = NULL;
		ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
					ac->highest_zoneidx, ac->nodemask);
	}

	/* Attempt with potentially adjusted zonelist and alloc_flags */
	page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
	if (page)
		goto got_pg;

	/* Caller is not willing to reclaim, we can't balance anything */
	if (!can_direct_reclaim)
		goto nopage;

	/* Avoid recursion of direct reclaim */
	if (current->flags & PF_MEMALLOC)
		goto nopage;

	/* Try direct reclaim and then allocating */
	page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
							&did_some_progress);
	if (page)
		goto got_pg;

	/* Try direct compaction and then allocating */
	page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
					compact_priority, &compact_result);
	if (page)
		goto got_pg;

	/* Do not loop if specifically requested */
	if (gfp_mask & __GFP_NORETRY)
		goto nopage;

	/*
	 * Do not retry costly high order allocations unless they are
	 * __GFP_RETRY_MAYFAIL
	 */
	if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL))
		goto nopage;

	if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
				 did_some_progress > 0, &no_progress_loops))
		goto retry;

	/*
	 * It doesn't make any sense to retry for the compaction if the order-0
	 * reclaim is not able to make any progress because the current
	 * implementation of the compaction depends on the sufficient amount
	 * of free memory (see __compaction_suitable)
	 */
	if (did_some_progress > 0 &&
			should_compact_retry(ac, order, alloc_flags,
				compact_result, &compact_priority,
				&compaction_retries))
		goto retry;


	/* Deal with possible cpuset update races before we start OOM killing */
	if (check_retry_cpuset(cpuset_mems_cookie, ac))
		goto retry_cpuset;

	/* Reclaim has failed us, start killing things */
	page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
	if (page)
		goto got_pg;

	/* Avoid allocations with no watermarks from looping endlessly */
	if (tsk_is_oom_victim(current) &&
	    (alloc_flags == ALLOC_OOM ||
	     (gfp_mask & __GFP_NOMEMALLOC)))
		goto nopage;

	/* Retry as long as the OOM killer is making progress */
	if (did_some_progress) {
		no_progress_loops = 0;
		goto retry;
	}

nopage:
	/* Deal with possible cpuset update races before we fail */
	if (check_retry_cpuset(cpuset_mems_cookie, ac))
		goto retry_cpuset;

	/*
	 * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
	 * we always retry
	 */
	if (gfp_mask & __GFP_NOFAIL) {
		/*
		 * All existing users of the __GFP_NOFAIL are blockable, so warn
		 * of any new users that actually require GFP_NOWAIT
		 */
		if (WARN_ON_ONCE(!can_direct_reclaim))
			goto fail;

		/*
		 * PF_MEMALLOC request from this context is rather bizarre
		 * because we cannot reclaim anything and only can loop waiting
		 * for somebody to do a work for us
		 */
		WARN_ON_ONCE(current->flags & PF_MEMALLOC);

		/*
		 * non failing costly orders are a hard requirement which we
		 * are not prepared for much so let's warn about these users
		 * so that we can identify them and convert them to something
		 * else.
		 */
		WARN_ON_ONCE(order > PAGE_ALLOC_COSTLY_ORDER);

		/*
		 * Help non-failing allocations by giving them access to memory
		 * reserves but do not use ALLOC_NO_WATERMARKS because this
		 * could deplete whole memory reserves which would just make
		 * the situation worse
		 */
		page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_HARDER, ac);
		if (page)
			goto got_pg;

		cond_resched();
		goto retry;
	}
fail:
	warn_alloc(gfp_mask, ac->nodemask,
			"page allocation failure: order:%u", order);
got_pg:
	return page;
}

static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
		int preferred_nid, nodemask_t *nodemask,
		struct alloc_context *ac, gfp_t *alloc_mask,
		unsigned int *alloc_flags)
{
	ac->highest_zoneidx = gfp_zone(gfp_mask);
	ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
	ac->nodemask = nodemask;
	ac->migratetype = gfp_migratetype(gfp_mask);

	if (cpusets_enabled()) {
		*alloc_mask |= __GFP_HARDWALL;
		if (!ac->nodemask)
			ac->nodemask = &cpuset_current_mems_allowed;
		else
			*alloc_flags |= ALLOC_CPUSET;
	}

	fs_reclaim_acquire(gfp_mask);
	fs_reclaim_release(gfp_mask);

	might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);

	if (should_fail_alloc_page(gfp_mask, order))
		return false;

	if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE)
		*alloc_flags |= ALLOC_CMA;

	return true;
}

/* Determine whether to spread dirty pages and what the first usable zone */
static inline void finalise_ac(gfp_t gfp_mask, struct alloc_context *ac)
{
	/* Dirty zone balancing only done in the fast path */
	ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);

	/*
	 * The preferred zone is used for statistics but crucially it is
	 * also used as the starting point for the zonelist iterator. It
	 * may get reset for allocations that ignore memory policies.
	 */
	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
					ac->highest_zoneidx, ac->nodemask);
}

/*
 * This is the 'heart' of the zoned buddy allocator.
 */
struct page *
__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
							nodemask_t *nodemask)
{
	struct page *page;
	unsigned int alloc_flags = ALLOC_WMARK_LOW;
	gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
	struct alloc_context ac = { };

	/*
	 * There are several places where we assume that the order value is sane
	 * so bail out early if the request is out of bound.
	 */
	if (unlikely(order >= MAX_ORDER)) {
		WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
		return NULL;
	}

	gfp_mask &= gfp_allowed_mask;
	alloc_mask = gfp_mask;
	if (!prepare_alloc_pages(gfp_mask, order, preferred_nid, nodemask, &ac, &alloc_mask, &alloc_flags))
		return NULL;

	finalise_ac(gfp_mask, &ac);

	/*
	 * Forbid the first pass from falling back to types that fragment
	 * memory until all local zones are considered.
	 */
	alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp_mask);

	/* First allocation attempt */
	page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
	if (likely(page))
		goto out;

	/*
	 * Apply scoped allocation constraints. This is mainly about GFP_NOFS
	 * resp. GFP_NOIO which has to be inherited for all allocation requests
	 * from a particular context which has been marked by
	 * memalloc_no{fs,io}_{save,restore}.
	 */
	alloc_mask = current_gfp_context(gfp_mask);
	ac.spread_dirty_pages = false;

	/*
	 * Restore the original nodemask if it was potentially replaced with
	 * &cpuset_current_mems_allowed to optimize the fast-path attempt.
	 */
	ac.nodemask = nodemask;

	page = __alloc_pages_slowpath(alloc_mask, order, &ac);

out:
	if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
	    unlikely(__memcg_kmem_charge_page(page, gfp_mask, order) != 0)) {
		__free_pages(page, order);
		page = NULL;
	}

	trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);

	return page;
}
EXPORT_SYMBOL(__alloc_pages_nodemask);

/*
 * Common helper functions. Never use with __GFP_HIGHMEM because the returned
 * address cannot represent highmem pages. Use alloc_pages and then kmap if
 * you need to access high mem.
 */
unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
{
	struct page *page;

	page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order);
	if (!page)
		return 0;
	return (unsigned long) page_address(page);
}
EXPORT_SYMBOL(__get_free_pages);

unsigned long get_zeroed_page(gfp_t gfp_mask)
{
	return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
}
EXPORT_SYMBOL(get_zeroed_page);

static inline void free_the_page(struct page *page, unsigned int order)
{
	if (order == 0)		/* Via pcp? */
		free_unref_page(page);
	else
		__free_pages_ok(page, order);
}

void __free_pages(struct page *page, unsigned int order)
{
	if (put_page_testzero(page))
		free_the_page(page, order);
}
EXPORT_SYMBOL(__free_pages);

void free_pages(unsigned long addr, unsigned int order)
{
	if (addr != 0) {
		VM_BUG_ON(!virt_addr_valid((void *)addr));
		__free_pages(virt_to_page((void *)addr), order);
	}
}

EXPORT_SYMBOL(free_pages);

/*
 * Page Fragment:
 *  An arbitrary-length arbitrary-offset area of memory which resides
 *  within a 0 or higher order page.  Multiple fragments within that page
 *  are individually refcounted, in the page's reference counter.
 *
 * The page_frag functions below provide a simple allocation framework for
 * page fragments.  This is used by the network stack and network device
 * drivers to provide a backing region of memory for use as either an
 * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
 */
static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
					     gfp_t gfp_mask)
{
	struct page *page = NULL;
	gfp_t gfp = gfp_mask;

#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
	gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
		    __GFP_NOMEMALLOC;
	page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
				PAGE_FRAG_CACHE_MAX_ORDER);
	nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
#endif
	if (unlikely(!page))
		page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);

	nc->va = page ? page_address(page) : NULL;

	return page;
}

void __page_frag_cache_drain(struct page *page, unsigned int count)
{
	VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);

	if (page_ref_sub_and_test(page, count))
		free_the_page(page, compound_order(page));
}
EXPORT_SYMBOL(__page_frag_cache_drain);

void *page_frag_alloc(struct page_frag_cache *nc,
		      unsigned int fragsz, gfp_t gfp_mask)
{
	unsigned int size = PAGE_SIZE;
	struct page *page;
	int offset;

	if (unlikely(!nc->va)) {
refill:
		page = __page_frag_cache_refill(nc, gfp_mask);
		if (!page)
			return NULL;

#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
		/* if size can vary use size else just use PAGE_SIZE */
		size = nc->size;
#endif
		/* Even if we own the page, we do not use atomic_set().
		 * This would break get_page_unless_zero() users.
		 */
		page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);

		/* reset page count bias and offset to start of new frag */
		nc->pfmemalloc = page_is_pfmemalloc(page);
		nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
		nc->offset = size;
	}

	offset = nc->offset - fragsz;
	if (unlikely(offset < 0)) {
		page = virt_to_page(nc->va);

		if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
			goto refill;

#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
		/* if size can vary use size else just use PAGE_SIZE */
		size = nc->size;
#endif
		/* OK, page count is 0, we can safely set it */
		set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);

		/* reset page count bias and offset to start of new frag */
		nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
		offset = size - fragsz;
	}

	nc->pagecnt_bias--;
	nc->offset = offset;

	return nc->va + offset;
}
EXPORT_SYMBOL(page_frag_alloc);

/*
 * Frees a page fragment allocated out of either a compound or order 0 page.
 */
void page_frag_free(void *addr)
{
	struct page *page = virt_to_head_page(addr);

	if (unlikely(put_page_testzero(page)))
		free_the_page(page, compound_order(page));
}
EXPORT_SYMBOL(page_frag_free);

static void *make_alloc_exact(unsigned long addr, unsigned int order,
		size_t size)
{
	if (addr) {
		unsigned long alloc_end = addr + (PAGE_SIZE << order);
		unsigned long used = addr + PAGE_ALIGN(size);

		split_page(virt_to_page((void *)addr), order);
		while (used < alloc_end) {
			free_page(used);
			used += PAGE_SIZE;
		}
	}
	return (void *)addr;
}

/**
 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
 * @size: the number of bytes to allocate
 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
 *
 * This function is similar to alloc_pages(), except that it allocates the
 * minimum number of pages to satisfy the request.  alloc_pages() can only
 * allocate memory in power-of-two pages.
 *
 * This function is also limited by MAX_ORDER.
 *
 * Memory allocated by this function must be released by free_pages_exact().
 *
 * Return: pointer to the allocated area or %NULL in case of error.
 */
void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
{
	unsigned int order = get_order(size);
	unsigned long addr;

	if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
		gfp_mask &= ~__GFP_COMP;

	addr = __get_free_pages(gfp_mask, order);
	return make_alloc_exact(addr, order, size);
}
EXPORT_SYMBOL(alloc_pages_exact);

/**
 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
 *			   pages on a node.
 * @nid: the preferred node ID where memory should be allocated
 * @size: the number of bytes to allocate
 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
 *
 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
 * back.
 *
 * Return: pointer to the allocated area or %NULL in case of error.
 */
void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
{
	unsigned int order = get_order(size);
	struct page *p;

	if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
		gfp_mask &= ~__GFP_COMP;

	p = alloc_pages_node(nid, gfp_mask, order);
	if (!p)
		return NULL;
	return make_alloc_exact((unsigned long)page_address(p), order, size);
}

/**
 * free_pages_exact - release memory allocated via alloc_pages_exact()
 * @virt: the value returned by alloc_pages_exact.
 * @size: size of allocation, same value as passed to alloc_pages_exact().
 *
 * Release the memory allocated by a previous call to alloc_pages_exact.
 */
void free_pages_exact(void *virt, size_t size)
{
	unsigned long addr = (unsigned long)virt;
	unsigned long end = addr + PAGE_ALIGN(size);

	while (addr < end) {
		free_page(addr);
		addr += PAGE_SIZE;
	}
}
EXPORT_SYMBOL(free_pages_exact);

/**
 * nr_free_zone_pages - count number of pages beyond high watermark
 * @offset: The zone index of the highest zone
 *
 * nr_free_zone_pages() counts the number of pages which are beyond the
 * high watermark within all zones at or below a given zone index.  For each
 * zone, the number of pages is calculated as:
 *
 *     nr_free_zone_pages = managed_pages - high_pages
 *
 * Return: number of pages beyond high watermark.
 */
static unsigned long nr_free_zone_pages(int offset)
{
	struct zoneref *z;
	struct zone *zone;

	/* Just pick one node, since fallback list is circular */
	unsigned long sum = 0;

	struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);

	for_each_zone_zonelist(zone, z, zonelist, offset) {
		unsigned long size = zone_managed_pages(zone);
		unsigned long high = high_wmark_pages(zone);
		if (size > high)
			sum += size - high;
	}

	return sum;
}

/**
 * nr_free_buffer_pages - count number of pages beyond high watermark
 *
 * nr_free_buffer_pages() counts the number of pages which are beyond the high
 * watermark within ZONE_DMA and ZONE_NORMAL.
 *
 * Return: number of pages beyond high watermark within ZONE_DMA and
 * ZONE_NORMAL.
 */
unsigned long nr_free_buffer_pages(void)
{
	return nr_free_zone_pages(gfp_zone(GFP_USER));
}
EXPORT_SYMBOL_GPL(nr_free_buffer_pages);

/**
 * nr_free_pagecache_pages - count number of pages beyond high watermark
 *
 * nr_free_pagecache_pages() counts the number of pages which are beyond the
 * high watermark within all zones.
 *
 * Return: number of pages beyond high watermark within all zones.
 */
unsigned long nr_free_pagecache_pages(void)
{
	return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
}

static inline void show_node(struct zone *zone)
{
	if (IS_ENABLED(CONFIG_NUMA))
		printk("Node %d ", zone_to_nid(zone));
}

long si_mem_available(void)
{
	long available;
	unsigned long pagecache;
	unsigned long wmark_low = 0;
	unsigned long pages[NR_LRU_LISTS];
	unsigned long reclaimable;
	struct zone *zone;
	int lru;

	for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);

	for_each_zone(zone)
		wmark_low += low_wmark_pages(zone);

	/*
	 * Estimate the amount of memory available for userspace allocations,
	 * without causing swapping.
	 */
	available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages;

	/*
	 * Not all the page cache can be freed, otherwise the system will
	 * start swapping. Assume at least half of the page cache, or the
	 * low watermark worth of cache, needs to stay.
	 */
	pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
	pagecache -= min(pagecache / 2, wmark_low);
	available += pagecache;

	/*
	 * Part of the reclaimable slab and other kernel memory consists of
	 * items that are in use, and cannot be freed. Cap this estimate at the
	 * low watermark.
	 */
	reclaimable = global_node_page_state(NR_SLAB_RECLAIMABLE) +
			global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
	available += reclaimable - min(reclaimable / 2, wmark_low);

	if (available < 0)
		available = 0;
	return available;
}
EXPORT_SYMBOL_GPL(si_mem_available);

void si_meminfo(struct sysinfo *val)
{
	val->totalram = totalram_pages();
	val->sharedram = global_node_page_state(NR_SHMEM);
	val->freeram = global_zone_page_state(NR_FREE_PAGES);
	val->bufferram = nr_blockdev_pages();
	val->totalhigh = totalhigh_pages();
	val->freehigh = nr_free_highpages();
	val->mem_unit = PAGE_SIZE;
}

EXPORT_SYMBOL(si_meminfo);

#ifdef CONFIG_NUMA
void si_meminfo_node(struct sysinfo *val, int nid)
{
	int zone_type;		/* needs to be signed */
	unsigned long managed_pages = 0;
	unsigned long managed_highpages = 0;
	unsigned long free_highpages = 0;
	pg_data_t *pgdat = NODE_DATA(nid);

	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
		managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
	val->totalram = managed_pages;
	val->sharedram = node_page_state(pgdat, NR_SHMEM);
	val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
#ifdef CONFIG_HIGHMEM
	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
		struct zone *zone = &pgdat->node_zones[zone_type];

		if (is_highmem(zone)) {
			managed_highpages += zone_managed_pages(zone);
			free_highpages += zone_page_state(zone, NR_FREE_PAGES);
		}
	}
	val->totalhigh = managed_highpages;
	val->freehigh = free_highpages;
#else
	val->totalhigh = managed_highpages;
	val->freehigh = free_highpages;
#endif
	val->mem_unit = PAGE_SIZE;
}
#endif

/*
 * Determine whether the node should be displayed or not, depending on whether
 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
 */
static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask)
{
	if (!(flags & SHOW_MEM_FILTER_NODES))
		return false;

	/*
	 * no node mask - aka implicit memory numa policy. Do not bother with
	 * the synchronization - read_mems_allowed_begin - because we do not
	 * have to be precise here.
	 */
	if (!nodemask)
		nodemask = &cpuset_current_mems_allowed;

	return !node_isset(nid, *nodemask);
}

#define K(x) ((x) << (PAGE_SHIFT-10))

static void show_migration_types(unsigned char type)
{
	static const char types[MIGRATE_TYPES] = {
		[MIGRATE_UNMOVABLE]	= 'U',
		[MIGRATE_MOVABLE]	= 'M',
		[MIGRATE_RECLAIMABLE]	= 'E',
		[MIGRATE_HIGHATOMIC]	= 'H',
#ifdef CONFIG_CMA
		[MIGRATE_CMA]		= 'C',
#endif
#ifdef CONFIG_MEMORY_ISOLATION
		[MIGRATE_ISOLATE]	= 'I',
#endif
	};
	char tmp[MIGRATE_TYPES + 1];
	char *p = tmp;
	int i;

	for (i = 0; i < MIGRATE_TYPES; i++) {
		if (type & (1 << i))
			*p++ = types[i];
	}

	*p = '\0';
	printk(KERN_CONT "(%s) ", tmp);
}

/*
 * Show free area list (used inside shift_scroll-lock stuff)
 * We also calculate the percentage fragmentation. We do this by counting the
 * memory on each free list with the exception of the first item on the list.
 *
 * Bits in @filter:
 * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
 *   cpuset.
 */
void show_free_areas(unsigned int filter, nodemask_t *nodemask)
{
	unsigned long free_pcp = 0;
	int cpu;
	struct zone *zone;
	pg_data_t *pgdat;

	for_each_populated_zone(zone) {
		if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
			continue;

		for_each_online_cpu(cpu)
			free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
	}

	printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
		" active_file:%lu inactive_file:%lu isolated_file:%lu\n"
		" unevictable:%lu dirty:%lu writeback:%lu\n"
		" slab_reclaimable:%lu slab_unreclaimable:%lu\n"
		" mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
		" free:%lu free_pcp:%lu free_cma:%lu\n",
		global_node_page_state(NR_ACTIVE_ANON),
		global_node_page_state(NR_INACTIVE_ANON),
		global_node_page_state(NR_ISOLATED_ANON),
		global_node_page_state(NR_ACTIVE_FILE),
		global_node_page_state(NR_INACTIVE_FILE),
		global_node_page_state(NR_ISOLATED_FILE),
		global_node_page_state(NR_UNEVICTABLE),
		global_node_page_state(NR_FILE_DIRTY),
		global_node_page_state(NR_WRITEBACK),
		global_node_page_state(NR_SLAB_RECLAIMABLE),
		global_node_page_state(NR_SLAB_UNRECLAIMABLE),
		global_node_page_state(NR_FILE_MAPPED),
		global_node_page_state(NR_SHMEM),
		global_zone_page_state(NR_PAGETABLE),
		global_zone_page_state(NR_BOUNCE),
		global_zone_page_state(NR_FREE_PAGES),
		free_pcp,
		global_zone_page_state(NR_FREE_CMA_PAGES));

	for_each_online_pgdat(pgdat) {
		if (show_mem_node_skip(filter, pgdat->node_id, nodemask))
			continue;

		printk("Node %d"
			" active_anon:%lukB"
			" inactive_anon:%lukB"
			" active_file:%lukB"
			" inactive_file:%lukB"
			" unevictable:%lukB"
			" isolated(anon):%lukB"
			" isolated(file):%lukB"
			" mapped:%lukB"
			" dirty:%lukB"
			" writeback:%lukB"
			" shmem:%lukB"
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
			" shmem_thp: %lukB"
			" shmem_pmdmapped: %lukB"
			" anon_thp: %lukB"
#endif
			" writeback_tmp:%lukB"
			" all_unreclaimable? %s"
			"\n",
			pgdat->node_id,
			K(node_page_state(pgdat, NR_ACTIVE_ANON)),
			K(node_page_state(pgdat, NR_INACTIVE_ANON)),
			K(node_page_state(pgdat, NR_ACTIVE_FILE)),
			K(node_page_state(pgdat, NR_INACTIVE_FILE)),
			K(node_page_state(pgdat, NR_UNEVICTABLE)),
			K(node_page_state(pgdat, NR_ISOLATED_ANON)),
			K(node_page_state(pgdat, NR_ISOLATED_FILE)),
			K(node_page_state(pgdat, NR_FILE_MAPPED)),
			K(node_page_state(pgdat, NR_FILE_DIRTY)),
			K(node_page_state(pgdat, NR_WRITEBACK)),
			K(node_page_state(pgdat, NR_SHMEM)),
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
			K(node_page_state(pgdat, NR_SHMEM_THPS) * HPAGE_PMD_NR),
			K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)
					* HPAGE_PMD_NR),
			K(node_page_state(pgdat, NR_ANON_THPS) * HPAGE_PMD_NR),
#endif
			K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
			pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ?
				"yes" : "no");
	}

	for_each_populated_zone(zone) {
		int i;

		if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
			continue;

		free_pcp = 0;
		for_each_online_cpu(cpu)
			free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;

		show_node(zone);
		printk(KERN_CONT
			"%s"
			" free:%lukB"
			" min:%lukB"
			" low:%lukB"
			" high:%lukB"
			" reserved_highatomic:%luKB"
			" active_anon:%lukB"
			" inactive_anon:%lukB"
			" active_file:%lukB"
			" inactive_file:%lukB"
			" unevictable:%lukB"
			" writepending:%lukB"
			" present:%lukB"
			" managed:%lukB"
			" mlocked:%lukB"
			" kernel_stack:%lukB"
#ifdef CONFIG_SHADOW_CALL_STACK
			" shadow_call_stack:%lukB"
#endif
			" pagetables:%lukB"
			" bounce:%lukB"
			" free_pcp:%lukB"
			" local_pcp:%ukB"
			" free_cma:%lukB"
			"\n",
			zone->name,
			K(zone_page_state(zone, NR_FREE_PAGES)),
			K(min_wmark_pages(zone)),
			K(low_wmark_pages(zone)),
			K(high_wmark_pages(zone)),
			K(zone->nr_reserved_highatomic),
			K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
			K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
			K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
			K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
			K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
			K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
			K(zone->present_pages),
			K(zone_managed_pages(zone)),
			K(zone_page_state(zone, NR_MLOCK)),
			zone_page_state(zone, NR_KERNEL_STACK_KB),
#ifdef CONFIG_SHADOW_CALL_STACK
			zone_page_state(zone, NR_KERNEL_SCS_KB),
#endif
			K(zone_page_state(zone, NR_PAGETABLE)),
			K(zone_page_state(zone, NR_BOUNCE)),
			K(free_pcp),
			K(this_cpu_read(zone->pageset->pcp.count)),
			K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
		printk("lowmem_reserve[]:");
		for (i = 0; i < MAX_NR_ZONES; i++)
			printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
		printk(KERN_CONT "\n");
	}

	for_each_populated_zone(zone) {
		unsigned int order;
		unsigned long nr[MAX_ORDER], flags, total = 0;
		unsigned char types[MAX_ORDER];

		if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
			continue;
		show_node(zone);
		printk(KERN_CONT "%s: ", zone->name);

		spin_lock_irqsave(&zone->lock, flags);
		for (order = 0; order < MAX_ORDER; order++) {
			struct free_area *area = &zone->free_area[order];
			int type;

			nr[order] = area->nr_free;
			total += nr[order] << order;

			types[order] = 0;
			for (type = 0; type < MIGRATE_TYPES; type++) {
				if (!free_area_empty(area, type))
					types[order] |= 1 << type;
			}
		}
		spin_unlock_irqrestore(&zone->lock, flags);
		for (order = 0; order < MAX_ORDER; order++) {
			printk(KERN_CONT "%lu*%lukB ",
			       nr[order], K(1UL) << order);
			if (nr[order])
				show_migration_types(types[order]);
		}
		printk(KERN_CONT "= %lukB\n", K(total));
	}

	hugetlb_show_meminfo();

	printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));

	show_swap_cache_info();
}

static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
{
	zoneref->zone = zone;
	zoneref->zone_idx = zone_idx(zone);
}

/*
 * Builds allocation fallback zone lists.
 *
 * Add all populated zones of a node to the zonelist.
 */
static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs)
{
	struct zone *zone;
	enum zone_type zone_type = MAX_NR_ZONES;
	int nr_zones = 0;

	do {
		zone_type--;
		zone = pgdat->node_zones + zone_type;
		if (managed_zone(zone)) {
			zoneref_set_zone(zone, &zonerefs[nr_zones++]);
			check_highest_zone(zone_type);
		}
	} while (zone_type);

	return nr_zones;
}

#ifdef CONFIG_NUMA

static int __parse_numa_zonelist_order(char *s)
{
	/*
	 * We used to support different zonlists modes but they turned
	 * out to be just not useful. Let's keep the warning in place
	 * if somebody still use the cmd line parameter so that we do
	 * not fail it silently
	 */
	if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) {
		pr_warn("Ignoring unsupported numa_zonelist_order value:  %s\n", s);
		return -EINVAL;
	}
	return 0;
}

char numa_zonelist_order[] = "Node";

/*
 * sysctl handler for numa_zonelist_order
 */
int numa_zonelist_order_handler(struct ctl_table *table, int write,
		void *buffer, size_t *length, loff_t *ppos)
{
	if (write)
		return __parse_numa_zonelist_order(buffer);
	return proc_dostring(table, write, buffer, length, ppos);
}


#define MAX_NODE_LOAD (nr_online_nodes)
static int node_load[MAX_NUMNODES];

/**
 * find_next_best_node - find the next node that should appear in a given node's fallback list
 * @node: node whose fallback list we're appending
 * @used_node_mask: nodemask_t of already used nodes
 *
 * We use a number of factors to determine which is the next node that should
 * appear on a given node's fallback list.  The node should not have appeared
 * already in @node's fallback list, and it should be the next closest node
 * according to the distance array (which contains arbitrary distance values
 * from each node to each node in the system), and should also prefer nodes
 * with no CPUs, since presumably they'll have very little allocation pressure
 * on them otherwise.
 *
 * Return: node id of the found node or %NUMA_NO_NODE if no node is found.
 */
static int find_next_best_node(int node, nodemask_t *used_node_mask)
{
	int n, val;
	int min_val = INT_MAX;
	int best_node = NUMA_NO_NODE;
	const struct cpumask *tmp = cpumask_of_node(0);

	/* Use the local node if we haven't already */
	if (!node_isset(node, *used_node_mask)) {
		node_set(node, *used_node_mask);
		return node;
	}

	for_each_node_state(n, N_MEMORY) {

		/* Don't want a node to appear more than once */
		if (node_isset(n, *used_node_mask))
			continue;

		/* Use the distance array to find the distance */
		val = node_distance(node, n);

		/* Penalize nodes under us ("prefer the next node") */
		val += (n < node);

		/* Give preference to headless and unused nodes */
		tmp = cpumask_of_node(n);
		if (!cpumask_empty(tmp))
			val += PENALTY_FOR_NODE_WITH_CPUS;

		/* Slight preference for less loaded node */
		val *= (MAX_NODE_LOAD*MAX_NUMNODES);
		val += node_load[n];

		if (val < min_val) {
			min_val = val;
			best_node = n;
		}
	}

	if (best_node >= 0)
		node_set(best_node, *used_node_mask);

	return best_node;
}


/*
 * Build zonelists ordered by node and zones within node.
 * This results in maximum locality--normal zone overflows into local
 * DMA zone, if any--but risks exhausting DMA zone.
 */
static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order,
		unsigned nr_nodes)
{
	struct zoneref *zonerefs;
	int i;

	zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;

	for (i = 0; i < nr_nodes; i++) {
		int nr_zones;

		pg_data_t *node = NODE_DATA(node_order[i]);

		nr_zones = build_zonerefs_node(node, zonerefs);
		zonerefs += nr_zones;
	}
	zonerefs->zone = NULL;
	zonerefs->zone_idx = 0;
}

/*
 * Build gfp_thisnode zonelists
 */
static void build_thisnode_zonelists(pg_data_t *pgdat)
{
	struct zoneref *zonerefs;
	int nr_zones;

	zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs;
	nr_zones = build_zonerefs_node(pgdat, zonerefs);
	zonerefs += nr_zones;
	zonerefs->zone = NULL;
	zonerefs->zone_idx = 0;
}

/*
 * Build zonelists ordered by zone and nodes within zones.
 * This results in conserving DMA zone[s] until all Normal memory is
 * exhausted, but results in overflowing to remote node while memory
 * may still exist in local DMA zone.
 */

static void build_zonelists(pg_data_t *pgdat)
{
	static int node_order[MAX_NUMNODES];
	int node, load, nr_nodes = 0;
	nodemask_t used_mask = NODE_MASK_NONE;
	int local_node, prev_node;

	/* NUMA-aware ordering of nodes */
	local_node = pgdat->node_id;
	load = nr_online_nodes;
	prev_node = local_node;

	memset(node_order, 0, sizeof(node_order));
	while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
		/*
		 * We don't want to pressure a particular node.
		 * So adding penalty to the first node in same
		 * distance group to make it round-robin.
		 */
		if (node_distance(local_node, node) !=
		    node_distance(local_node, prev_node))
			node_load[node] = load;

		node_order[nr_nodes++] = node;
		prev_node = node;
		load--;
	}

	build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
	build_thisnode_zonelists(pgdat);
}

#ifdef CONFIG_HAVE_MEMORYLESS_NODES
/*
 * Return node id of node used for "local" allocations.
 * I.e., first node id of first zone in arg node's generic zonelist.
 * Used for initializing percpu 'numa_mem', which is used primarily
 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
 */
int local_memory_node(int node)
{
	struct zoneref *z;

	z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
				   gfp_zone(GFP_KERNEL),
				   NULL);
	return zone_to_nid(z->zone);
}
#endif

static void setup_min_unmapped_ratio(void);
static void setup_min_slab_ratio(void);
#else	/* CONFIG_NUMA */

static void build_zonelists(pg_data_t *pgdat)
{
	int node, local_node;
	struct zoneref *zonerefs;
	int nr_zones;

	local_node = pgdat->node_id;

	zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
	nr_zones = build_zonerefs_node(pgdat, zonerefs);
	zonerefs += nr_zones;

	/*
	 * Now we build the zonelist so that it contains the zones
	 * of all the other nodes.
	 * We don't want to pressure a particular node, so when
	 * building the zones for node N, we make sure that the
	 * zones coming right after the local ones are those from
	 * node N+1 (modulo N)
	 */
	for (node = local_node + 1; node < MAX_NUMNODES; node++) {
		if (!node_online(node))
			continue;
		nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
		zonerefs += nr_zones;
	}
	for (node = 0; node < local_node; node++) {
		if (!node_online(node))
			continue;
		nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
		zonerefs += nr_zones;
	}

	zonerefs->zone = NULL;
	zonerefs->zone_idx = 0;
}

#endif	/* CONFIG_NUMA */

/*
 * Boot pageset table. One per cpu which is going to be used for all
 * zones and all nodes. The parameters will be set in such a way
 * that an item put on a list will immediately be handed over to
 * the buddy list. This is safe since pageset manipulation is done
 * with interrupts disabled.
 *
 * The boot_pagesets must be kept even after bootup is complete for
 * unused processors and/or zones. They do play a role for bootstrapping
 * hotplugged processors.
 *
 * zoneinfo_show() and maybe other functions do
 * not check if the processor is online before following the pageset pointer.
 * Other parts of the kernel may not check if the zone is available.
 */
static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);

static void __build_all_zonelists(void *data)
{
	int nid;
	int __maybe_unused cpu;
	pg_data_t *self = data;
	static DEFINE_SPINLOCK(lock);

	spin_lock(&lock);

#ifdef CONFIG_NUMA
	memset(node_load, 0, sizeof(node_load));
#endif

	/*
	 * This node is hotadded and no memory is yet present.   So just
	 * building zonelists is fine - no need to touch other nodes.
	 */
	if (self && !node_online(self->node_id)) {
		build_zonelists(self);
	} else {
		for_each_online_node(nid) {
			pg_data_t *pgdat = NODE_DATA(nid);

			build_zonelists(pgdat);
		}

#ifdef CONFIG_HAVE_MEMORYLESS_NODES
		/*
		 * We now know the "local memory node" for each node--
		 * i.e., the node of the first zone in the generic zonelist.
		 * Set up numa_mem percpu variable for on-line cpus.  During
		 * boot, only the boot cpu should be on-line;  we'll init the
		 * secondary cpus' numa_mem as they come on-line.  During
		 * node/memory hotplug, we'll fixup all on-line cpus.
		 */
		for_each_online_cpu(cpu)
			set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
#endif
	}

	spin_unlock(&lock);
}

static noinline void __init
build_all_zonelists_init(void)
{
	int cpu;

	__build_all_zonelists(NULL);

	/*
	 * Initialize the boot_pagesets that are going to be used
	 * for bootstrapping processors. The real pagesets for
	 * each zone will be allocated later when the per cpu
	 * allocator is available.
	 *
	 * boot_pagesets are used also for bootstrapping offline
	 * cpus if the system is already booted because the pagesets
	 * are needed to initialize allocators on a specific cpu too.
	 * F.e. the percpu allocator needs the page allocator which
	 * needs the percpu allocator in order to allocate its pagesets
	 * (a chicken-egg dilemma).
	 */
	for_each_possible_cpu(cpu)
		setup_pageset(&per_cpu(boot_pageset, cpu), 0);

	mminit_verify_zonelist();
	cpuset_init_current_mems_allowed();
}

/*
 * unless system_state == SYSTEM_BOOTING.
 *
 * __ref due to call of __init annotated helper build_all_zonelists_init
 * [protected by SYSTEM_BOOTING].
 */
void __ref build_all_zonelists(pg_data_t *pgdat)
{
	if (system_state == SYSTEM_BOOTING) {
		build_all_zonelists_init();
	} else {
		__build_all_zonelists(pgdat);
		/* cpuset refresh routine should be here */
	}
	vm_total_pages = nr_free_pagecache_pages();
	/*
	 * Disable grouping by mobility if the number of pages in the
	 * system is too low to allow the mechanism to work. It would be
	 * more accurate, but expensive to check per-zone. This check is
	 * made on memory-hotadd so a system can start with mobility
	 * disabled and enable it later
	 */
	if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
		page_group_by_mobility_disabled = 1;
	else
		page_group_by_mobility_disabled = 0;

	pr_info("Built %u zonelists, mobility grouping %s.  Total pages: %ld\n",
		nr_online_nodes,
		page_group_by_mobility_disabled ? "off" : "on",
		vm_total_pages);
#ifdef CONFIG_NUMA
	pr_info("Policy zone: %s\n", zone_names[policy_zone]);
#endif
}

/* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
static bool __meminit
overlap_memmap_init(unsigned long zone, unsigned long *pfn)
{
	static struct memblock_region *r;

	if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
		if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
			for_each_memblock(memory, r) {
				if (*pfn < memblock_region_memory_end_pfn(r))
					break;
			}
		}
		if (*pfn >= memblock_region_memory_base_pfn(r) &&
		    memblock_is_mirror(r)) {
			*pfn = memblock_region_memory_end_pfn(r);
			return true;
		}
	}
	return false;
}

/*
 * Initially all pages are reserved - free ones are freed
 * up by memblock_free_all() once the early boot process is
 * done. Non-atomic initialization, single-pass.
 */
void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
		unsigned long start_pfn, enum memmap_context context,
		struct vmem_altmap *altmap)
{
	unsigned long pfn, end_pfn = start_pfn + size;
	struct page *page;

	if (highest_memmap_pfn < end_pfn - 1)
		highest_memmap_pfn = end_pfn - 1;

#ifdef CONFIG_ZONE_DEVICE
	/*
	 * Honor reservation requested by the driver for this ZONE_DEVICE
	 * memory. We limit the total number of pages to initialize to just
	 * those that might contain the memory mapping. We will defer the
	 * ZONE_DEVICE page initialization until after we have released
	 * the hotplug lock.
	 */
	if (zone == ZONE_DEVICE) {
		if (!altmap)
			return;

		if (start_pfn == altmap->base_pfn)
			start_pfn += altmap->reserve;
		end_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
	}
#endif

	for (pfn = start_pfn; pfn < end_pfn; ) {
		/*
		 * There can be holes in boot-time mem_map[]s handed to this
		 * function.  They do not exist on hotplugged memory.
		 */
		if (context == MEMMAP_EARLY) {
			if (overlap_memmap_init(zone, &pfn))
				continue;
			if (defer_init(nid, pfn, end_pfn))
				break;
		}

		page = pfn_to_page(pfn);
		__init_single_page(page, pfn, zone, nid);
		if (context == MEMMAP_HOTPLUG)
			__SetPageReserved(page);

		/*
		 * Mark the block movable so that blocks are reserved for
		 * movable at startup. This will force kernel allocations
		 * to reserve their blocks rather than leaking throughout
		 * the address space during boot when many long-lived
		 * kernel allocations are made.
		 *
		 * bitmap is created for zone's valid pfn range. but memmap
		 * can be created for invalid pages (for alignment)
		 * check here not to call set_pageblock_migratetype() against
		 * pfn out of zone.
		 */
		if (!(pfn & (pageblock_nr_pages - 1))) {
			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
			cond_resched();
		}
		pfn++;
	}
}

#ifdef CONFIG_ZONE_DEVICE
void __ref memmap_init_zone_device(struct zone *zone,
				   unsigned long start_pfn,
				   unsigned long nr_pages,
				   struct dev_pagemap *pgmap)
{
	unsigned long pfn, end_pfn = start_pfn + nr_pages;
	struct pglist_data *pgdat = zone->zone_pgdat;
	struct vmem_altmap *altmap = pgmap_altmap(pgmap);
	unsigned long zone_idx = zone_idx(zone);
	unsigned long start = jiffies;
	int nid = pgdat->node_id;

	if (WARN_ON_ONCE(!pgmap || zone_idx(zone) != ZONE_DEVICE))
		return;

	/*
	 * The call to memmap_init_zone should have already taken care
	 * of the pages reserved for the memmap, so we can just jump to
	 * the end of that region and start processing the device pages.
	 */
	if (altmap) {
		start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
		nr_pages = end_pfn - start_pfn;
	}

	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
		struct page *page = pfn_to_page(pfn);

		__init_single_page(page, pfn, zone_idx, nid);

		/*
		 * Mark page reserved as it will need to wait for onlining
		 * phase for it to be fully associated with a zone.
		 *
		 * We can use the non-atomic __set_bit operation for setting
		 * the flag as we are still initializing the pages.
		 */
		__SetPageReserved(page);

		/*
		 * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
		 * and zone_device_data.  It is a bug if a ZONE_DEVICE page is
		 * ever freed or placed on a driver-private list.
		 */
		page->pgmap = pgmap;
		page->zone_device_data = NULL;

		/*
		 * Mark the block movable so that blocks are reserved for
		 * movable at startup. This will force kernel allocations
		 * to reserve their blocks rather than leaking throughout
		 * the address space during boot when many long-lived
		 * kernel allocations are made.
		 *
		 * bitmap is created for zone's valid pfn range. but memmap
		 * can be created for invalid pages (for alignment)
		 * check here not to call set_pageblock_migratetype() against
		 * pfn out of zone.
		 *
		 * Please note that MEMMAP_HOTPLUG path doesn't clear memmap
		 * because this is done early in section_activate()
		 */
		if (!(pfn & (pageblock_nr_pages - 1))) {
			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
			cond_resched();
		}
	}

	pr_info("%s initialised %lu pages in %ums\n", __func__,
		nr_pages, jiffies_to_msecs(jiffies - start));
}

#endif
static void __meminit zone_init_free_lists(struct zone *zone)
{
	unsigned int order, t;
	for_each_migratetype_order(order, t) {
		INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
		zone->free_area[order].nr_free = 0;
	}
}

void __meminit __weak memmap_init(unsigned long size, int nid,
				  unsigned long zone,
				  unsigned long range_start_pfn)
{
	unsigned long start_pfn, end_pfn;
	unsigned long range_end_pfn = range_start_pfn + size;
	int i;

	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
		start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
		end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);

		if (end_pfn > start_pfn) {
			size = end_pfn - start_pfn;
			memmap_init_zone(size, nid, zone, start_pfn,
					 MEMMAP_EARLY, NULL);
		}
	}
}

static int zone_batchsize(struct zone *zone)
{
#ifdef CONFIG_MMU
	int batch;

	/*
	 * The per-cpu-pages pools are set to around 1000th of the
	 * size of the zone.
	 */
	batch = zone_managed_pages(zone) / 1024;
	/* But no more than a meg. */
	if (batch * PAGE_SIZE > 1024 * 1024)
		batch = (1024 * 1024) / PAGE_SIZE;
	batch /= 4;		/* We effectively *= 4 below */
	if (batch < 1)
		batch = 1;

	/*
	 * Clamp the batch to a 2^n - 1 value. Having a power
	 * of 2 value was found to be more likely to have
	 * suboptimal cache aliasing properties in some cases.
	 *
	 * For example if 2 tasks are alternately allocating
	 * batches of pages, one task can end up with a lot
	 * of pages of one half of the possible page colors
	 * and the other with pages of the other colors.
	 */
	batch = rounddown_pow_of_two(batch + batch/2) - 1;

	return batch;

#else
	/* The deferral and batching of frees should be suppressed under NOMMU
	 * conditions.
	 *
	 * The problem is that NOMMU needs to be able to allocate large chunks
	 * of contiguous memory as there's no hardware page translation to
	 * assemble apparent contiguous memory from discontiguous pages.
	 *
	 * Queueing large contiguous runs of pages for batching, however,
	 * causes the pages to actually be freed in smaller chunks.  As there
	 * can be a significant delay between the individual batches being
	 * recycled, this leads to the once large chunks of space being
	 * fragmented and becoming unavailable for high-order allocations.
	 */
	return 0;
#endif
}

/*
 * pcp->high and pcp->batch values are related and dependent on one another:
 * ->batch must never be higher then ->high.
 * The following function updates them in a safe manner without read side
 * locking.
 *
 * Any new users of pcp->batch and pcp->high should ensure they can cope with
 * those fields changing asynchronously (acording the the above rule).
 *
 * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
 * outside of boot time (or some other assurance that no concurrent updaters
 * exist).
 */
static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
		unsigned long batch)
{
       /* start with a fail safe value for batch */
	pcp->batch = 1;
	smp_wmb();

       /* Update high, then batch, in order */
	pcp->high = high;
	smp_wmb();

	pcp->batch = batch;
}

/* a companion to pageset_set_high() */
static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
{
	pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
}

static void pageset_init(struct per_cpu_pageset *p)
{
	struct per_cpu_pages *pcp;
	int migratetype;

	memset(p, 0, sizeof(*p));

	pcp = &p->pcp;
	for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
		INIT_LIST_HEAD(&pcp->lists[migratetype]);
}

static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
{
	pageset_init(p);
	pageset_set_batch(p, batch);
}

/*
 * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
 * to the value high for the pageset p.
 */
static void pageset_set_high(struct per_cpu_pageset *p,
				unsigned long high)
{
	unsigned long batch = max(1UL, high / 4);
	if ((high / 4) > (PAGE_SHIFT * 8))
		batch = PAGE_SHIFT * 8;

	pageset_update(&p->pcp, high, batch);
}

static void pageset_set_high_and_batch(struct zone *zone,
				       struct per_cpu_pageset *pcp)
{
	if (percpu_pagelist_fraction)
		pageset_set_high(pcp,
			(zone_managed_pages(zone) /
				percpu_pagelist_fraction));
	else
		pageset_set_batch(pcp, zone_batchsize(zone));
}

static void __meminit zone_pageset_init(struct zone *zone, int cpu)
{
	struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);

	pageset_init(pcp);
	pageset_set_high_and_batch(zone, pcp);
}

void __meminit setup_zone_pageset(struct zone *zone)
{
	int cpu;
	zone->pageset = alloc_percpu(struct per_cpu_pageset);
	for_each_possible_cpu(cpu)
		zone_pageset_init(zone, cpu);
}

/*
 * Allocate per cpu pagesets and initialize them.
 * Before this call only boot pagesets were available.
 */
void __init setup_per_cpu_pageset(void)
{
	struct pglist_data *pgdat;
	struct zone *zone;
	int __maybe_unused cpu;

	for_each_populated_zone(zone)
		setup_zone_pageset(zone);

#ifdef CONFIG_NUMA
	/*
	 * Unpopulated zones continue using the boot pagesets.
	 * The numa stats for these pagesets need to be reset.
	 * Otherwise, they will end up skewing the stats of
	 * the nodes these zones are associated with.
	 */
	for_each_possible_cpu(cpu) {
		struct per_cpu_pageset *pcp = &per_cpu(boot_pageset, cpu);
		memset(pcp->vm_numa_stat_diff, 0,
		       sizeof(pcp->vm_numa_stat_diff));
	}
#endif

	for_each_online_pgdat(pgdat)
		pgdat->per_cpu_nodestats =
			alloc_percpu(struct per_cpu_nodestat);
}

static __meminit void zone_pcp_init(struct zone *zone)
{
	/*
	 * per cpu subsystem is not up at this point. The following code
	 * relies on the ability of the linker to provide the
	 * offset of a (static) per cpu variable into the per cpu area.
	 */
	zone->pageset = &boot_pageset;

	if (populated_zone(zone))
		printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
			zone->name, zone->present_pages,
					 zone_batchsize(zone));
}

void __meminit init_currently_empty_zone(struct zone *zone,
					unsigned long zone_start_pfn,
					unsigned long size)
{
	struct pglist_data *pgdat = zone->zone_pgdat;
	int zone_idx = zone_idx(zone) + 1;

	if (zone_idx > pgdat->nr_zones)
		pgdat->nr_zones = zone_idx;

	zone->zone_start_pfn = zone_start_pfn;

	mminit_dprintk(MMINIT_TRACE, "memmap_init",
			"Initialising map node %d zone %lu pfns %lu -> %lu\n",
			pgdat->node_id,
			(unsigned long)zone_idx(zone),
			zone_start_pfn, (zone_start_pfn + size));

	zone_init_free_lists(zone);
	zone->initialized = 1;
}

/**
 * sparse_memory_present_with_active_regions - Call memory_present for each active range
 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
 *
 * If an architecture guarantees that all ranges registered contain no holes and may
 * be freed, this function may be used instead of calling memory_present() manually.
 */
void __init sparse_memory_present_with_active_regions(int nid)
{
	unsigned long start_pfn, end_pfn;
	int i, this_nid;

	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
		memory_present(this_nid, start_pfn, end_pfn);
}

/**
 * get_pfn_range_for_nid - Return the start and end page frames for a node
 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
 *
 * It returns the start and end page frame of a node based on information
 * provided by memblock_set_node(). If called for a node
 * with no available memory, a warning is printed and the start and end
 * PFNs will be 0.
 */
void __init get_pfn_range_for_nid(unsigned int nid,
			unsigned long *start_pfn, unsigned long *end_pfn)
{
	unsigned long this_start_pfn, this_end_pfn;
	int i;

	*start_pfn = -1UL;
	*end_pfn = 0;

	for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
		*start_pfn = min(*start_pfn, this_start_pfn);
		*end_pfn = max(*end_pfn, this_end_pfn);
	}

	if (*start_pfn == -1UL)
		*start_pfn = 0;
}

/*
 * This finds a zone that can be used for ZONE_MOVABLE pages. The
 * assumption is made that zones within a node are ordered in monotonic
 * increasing memory addresses so that the "highest" populated zone is used
 */
static void __init find_usable_zone_for_movable(void)
{
	int zone_index;
	for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
		if (zone_index == ZONE_MOVABLE)
			continue;

		if (arch_zone_highest_possible_pfn[zone_index] >
				arch_zone_lowest_possible_pfn[zone_index])
			break;
	}

	VM_BUG_ON(zone_index == -1);
	movable_zone = zone_index;
}

/*
 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
 * because it is sized independent of architecture. Unlike the other zones,
 * the starting point for ZONE_MOVABLE is not fixed. It may be different
 * in each node depending on the size of each node and how evenly kernelcore
 * is distributed. This helper function adjusts the zone ranges
 * provided by the architecture for a given node by using the end of the
 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
 * zones within a node are in order of monotonic increases memory addresses
 */
static void __init adjust_zone_range_for_zone_movable(int nid,
					unsigned long zone_type,
					unsigned long node_start_pfn,
					unsigned long node_end_pfn,
					unsigned long *zone_start_pfn,
					unsigned long *zone_end_pfn)
{
	/* Only adjust if ZONE_MOVABLE is on this node */
	if (zone_movable_pfn[nid]) {
		/* Size ZONE_MOVABLE */
		if (zone_type == ZONE_MOVABLE) {
			*zone_start_pfn = zone_movable_pfn[nid];
			*zone_end_pfn = min(node_end_pfn,
				arch_zone_highest_possible_pfn[movable_zone]);

		/* Adjust for ZONE_MOVABLE starting within this range */
		} else if (!mirrored_kernelcore &&
			*zone_start_pfn < zone_movable_pfn[nid] &&
			*zone_end_pfn > zone_movable_pfn[nid]) {
			*zone_end_pfn = zone_movable_pfn[nid];

		/* Check if this whole range is within ZONE_MOVABLE */
		} else if (*zone_start_pfn >= zone_movable_pfn[nid])
			*zone_start_pfn = *zone_end_pfn;
	}
}

/*
 * Return the number of pages a zone spans in a node, including holes
 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
 */
static unsigned long __init zone_spanned_pages_in_node(int nid,
					unsigned long zone_type,
					unsigned long node_start_pfn,
					unsigned long node_end_pfn,
					unsigned long *zone_start_pfn,
					unsigned long *zone_end_pfn)
{
	unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
	unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
	/* When hotadd a new node from cpu_up(), the node should be empty */
	if (!node_start_pfn && !node_end_pfn)
		return 0;

	/* Get the start and end of the zone */
	*zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
	*zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
	adjust_zone_range_for_zone_movable(nid, zone_type,
				node_start_pfn, node_end_pfn,
				zone_start_pfn, zone_end_pfn);

	/* Check that this node has pages within the zone's required range */
	if (*zone_end_pfn < node_start_pfn || *zone_start_pfn > node_end_pfn)
		return 0;

	/* Move the zone boundaries inside the node if necessary */
	*zone_end_pfn = min(*zone_end_pfn, node_end_pfn);
	*zone_start_pfn = max(*zone_start_pfn, node_start_pfn);

	/* Return the spanned pages */
	return *zone_end_pfn - *zone_start_pfn;
}

/*
 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
 * then all holes in the requested range will be accounted for.
 */
unsigned long __init __absent_pages_in_range(int nid,
				unsigned long range_start_pfn,
				unsigned long range_end_pfn)
{
	unsigned long nr_absent = range_end_pfn - range_start_pfn;
	unsigned long start_pfn, end_pfn;
	int i;

	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
		start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
		end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
		nr_absent -= end_pfn - start_pfn;
	}
	return nr_absent;
}

/**
 * absent_pages_in_range - Return number of page frames in holes within a range
 * @start_pfn: The start PFN to start searching for holes
 * @end_pfn: The end PFN to stop searching for holes
 *
 * Return: the number of pages frames in memory holes within a range.
 */
unsigned long __init absent_pages_in_range(unsigned long start_pfn,
							unsigned long end_pfn)
{
	return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
}

/* Return the number of page frames in holes in a zone on a node */
static unsigned long __init zone_absent_pages_in_node(int nid,
					unsigned long zone_type,
					unsigned long node_start_pfn,
					unsigned long node_end_pfn)
{
	unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
	unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
	unsigned long zone_start_pfn, zone_end_pfn;
	unsigned long nr_absent;

	/* When hotadd a new node from cpu_up(), the node should be empty */
	if (!node_start_pfn && !node_end_pfn)
		return 0;

	zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
	zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);

	adjust_zone_range_for_zone_movable(nid, zone_type,
			node_start_pfn, node_end_pfn,
			&zone_start_pfn, &zone_end_pfn);
	nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);

	/*
	 * ZONE_MOVABLE handling.
	 * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
	 * and vice versa.
	 */
	if (mirrored_kernelcore && zone_movable_pfn[nid]) {
		unsigned long start_pfn, end_pfn;
		struct memblock_region *r;

		for_each_memblock(memory, r) {
			start_pfn = clamp(memblock_region_memory_base_pfn(r),
					  zone_start_pfn, zone_end_pfn);
			end_pfn = clamp(memblock_region_memory_end_pfn(r),
					zone_start_pfn, zone_end_pfn);

			if (zone_type == ZONE_MOVABLE &&
			    memblock_is_mirror(r))
				nr_absent += end_pfn - start_pfn;

			if (zone_type == ZONE_NORMAL &&
			    !memblock_is_mirror(r))
				nr_absent += end_pfn - start_pfn;
		}
	}

	return nr_absent;
}

static void __init calculate_node_totalpages(struct pglist_data *pgdat,
						unsigned long node_start_pfn,
						unsigned long node_end_pfn)
{
	unsigned long realtotalpages = 0, totalpages = 0;
	enum zone_type i;

	for (i = 0; i < MAX_NR_ZONES; i++) {
		struct zone *zone = pgdat->node_zones + i;
		unsigned long zone_start_pfn, zone_end_pfn;
		unsigned long spanned, absent;
		unsigned long size, real_size;

		spanned = zone_spanned_pages_in_node(pgdat->node_id, i,
						     node_start_pfn,
						     node_end_pfn,
						     &zone_start_pfn,
						     &zone_end_pfn);
		absent = zone_absent_pages_in_node(pgdat->node_id, i,
						   node_start_pfn,
						   node_end_pfn);

		size = spanned;
		real_size = size - absent;

		if (size)
			zone->zone_start_pfn = zone_start_pfn;
		else
			zone->zone_start_pfn = 0;
		zone->spanned_pages = size;
		zone->present_pages = real_size;

		totalpages += size;
		realtotalpages += real_size;
	}

	pgdat->node_spanned_pages = totalpages;
	pgdat->node_present_pages = realtotalpages;
	printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
							realtotalpages);
}

#ifndef CONFIG_SPARSEMEM
/*
 * Calculate the size of the zone->blockflags rounded to an unsigned long
 * Start by making sure zonesize is a multiple of pageblock_order by rounding
 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
 * round what is now in bits to nearest long in bits, then return it in
 * bytes.
 */
static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
{
	unsigned long usemapsize;

	zonesize += zone_start_pfn & (pageblock_nr_pages-1);
	usemapsize = roundup(zonesize, pageblock_nr_pages);
	usemapsize = usemapsize >> pageblock_order;
	usemapsize *= NR_PAGEBLOCK_BITS;
	usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));

	return usemapsize / 8;
}

static void __ref setup_usemap(struct pglist_data *pgdat,
				struct zone *zone,
				unsigned long zone_start_pfn,
				unsigned long zonesize)
{
	unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
	zone->pageblock_flags = NULL;
	if (usemapsize) {
		zone->pageblock_flags =
			memblock_alloc_node(usemapsize, SMP_CACHE_BYTES,
					    pgdat->node_id);
		if (!zone->pageblock_flags)
			panic("Failed to allocate %ld bytes for zone %s pageblock flags on node %d\n",
			      usemapsize, zone->name, pgdat->node_id);
	}
}
#else
static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
				unsigned long zone_start_pfn, unsigned long zonesize) {}
#endif /* CONFIG_SPARSEMEM */

#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE

/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
void __init set_pageblock_order(void)
{
	unsigned int order;

	/* Check that pageblock_nr_pages has not already been setup */
	if (pageblock_order)
		return;

	if (HPAGE_SHIFT > PAGE_SHIFT)
		order = HUGETLB_PAGE_ORDER;
	else
		order = MAX_ORDER - 1;

	/*
	 * Assume the largest contiguous order of interest is a huge page.
	 * This value may be variable depending on boot parameters on IA64 and
	 * powerpc.
	 */
	pageblock_order = order;
}
#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */

/*
 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
 * is unused as pageblock_order is set at compile-time. See
 * include/linux/pageblock-flags.h for the values of pageblock_order based on
 * the kernel config
 */
void __init set_pageblock_order(void)
{
}

#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */

static unsigned long __init calc_memmap_size(unsigned long spanned_pages,
						unsigned long present_pages)
{
	unsigned long pages = spanned_pages;

	/*
	 * Provide a more accurate estimation if there are holes within
	 * the zone and SPARSEMEM is in use. If there are holes within the
	 * zone, each populated memory region may cost us one or two extra
	 * memmap pages due to alignment because memmap pages for each
	 * populated regions may not be naturally aligned on page boundary.
	 * So the (present_pages >> 4) heuristic is a tradeoff for that.
	 */
	if (spanned_pages > present_pages + (present_pages >> 4) &&
	    IS_ENABLED(CONFIG_SPARSEMEM))
		pages = present_pages;

	return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void pgdat_init_split_queue(struct pglist_data *pgdat)
{
	struct deferred_split *ds_queue = &pgdat->deferred_split_queue;

	spin_lock_init(&ds_queue->split_queue_lock);
	INIT_LIST_HEAD(&ds_queue->split_queue);
	ds_queue->split_queue_len = 0;
}
#else
static void pgdat_init_split_queue(struct pglist_data *pgdat) {}
#endif

#ifdef CONFIG_COMPACTION
static void pgdat_init_kcompactd(struct pglist_data *pgdat)
{
	init_waitqueue_head(&pgdat->kcompactd_wait);
}
#else
static void pgdat_init_kcompactd(struct pglist_data *pgdat) {}
#endif

static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
{
	pgdat_resize_init(pgdat);

	pgdat_init_split_queue(pgdat);
	pgdat_init_kcompactd(pgdat);

	init_waitqueue_head(&pgdat->kswapd_wait);
	init_waitqueue_head(&pgdat->pfmemalloc_wait);

	pgdat_page_ext_init(pgdat);
	spin_lock_init(&pgdat->lru_lock);
	lruvec_init(&pgdat->__lruvec);
}

static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
							unsigned long remaining_pages)
{
	atomic_long_set(&zone->managed_pages, remaining_pages);
	zone_set_nid(zone, nid);
	zone->name = zone_names[idx];
	zone->zone_pgdat = NODE_DATA(nid);
	spin_lock_init(&zone->lock);
	zone_seqlock_init(zone);
	zone_pcp_init(zone);
}

/*
 * Set up the zone data structures
 * - init pgdat internals
 * - init all zones belonging to this node
 *
 * NOTE: this function is only called during memory hotplug
 */
#ifdef CONFIG_MEMORY_HOTPLUG
void __ref free_area_init_core_hotplug(int nid)
{
	enum zone_type z;
	pg_data_t *pgdat = NODE_DATA(nid);

	pgdat_init_internals(pgdat);
	for (z = 0; z < MAX_NR_ZONES; z++)
		zone_init_internals(&pgdat->node_zones[z], z, nid, 0);
}
#endif

/*
 * Set up the zone data structures:
 *   - mark all pages reserved
 *   - mark all memory queues empty
 *   - clear the memory bitmaps
 *
 * NOTE: pgdat should get zeroed by caller.
 * NOTE: this function is only called during early init.
 */
static void __init free_area_init_core(struct pglist_data *pgdat)
{
	enum zone_type j;
	int nid = pgdat->node_id;

	pgdat_init_internals(pgdat);
	pgdat->per_cpu_nodestats = &boot_nodestats;

	for (j = 0; j < MAX_NR_ZONES; j++) {
		struct zone *zone = pgdat->node_zones + j;
		unsigned long size, freesize, memmap_pages;
		unsigned long zone_start_pfn = zone->zone_start_pfn;

		size = zone->spanned_pages;
		freesize = zone->present_pages;

		/*
		 * Adjust freesize so that it accounts for how much memory
		 * is used by this zone for memmap. This affects the watermark
		 * and per-cpu initialisations
		 */
		memmap_pages = calc_memmap_size(size, freesize);
		if (!is_highmem_idx(j)) {
			if (freesize >= memmap_pages) {
				freesize -= memmap_pages;
				if (memmap_pages)
					printk(KERN_DEBUG
					       "  %s zone: %lu pages used for memmap\n",
					       zone_names[j], memmap_pages);
			} else
				pr_warn("  %s zone: %lu pages exceeds freesize %lu\n",
					zone_names[j], memmap_pages, freesize);
		}

		/* Account for reserved pages */
		if (j == 0 && freesize > dma_reserve) {
			freesize -= dma_reserve;
			printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
					zone_names[0], dma_reserve);
		}

		if (!is_highmem_idx(j))
			nr_kernel_pages += freesize;
		/* Charge for highmem memmap if there are enough kernel pages */
		else if (nr_kernel_pages > memmap_pages * 2)
			nr_kernel_pages -= memmap_pages;
		nr_all_pages += freesize;

		/*
		 * Set an approximate value for lowmem here, it will be adjusted
		 * when the bootmem allocator frees pages into the buddy system.
		 * And all highmem pages will be managed by the buddy system.
		 */
		zone_init_internals(zone, j, nid, freesize);

		if (!size)
			continue;

		set_pageblock_order();
		setup_usemap(pgdat, zone, zone_start_pfn, size);
		init_currently_empty_zone(zone, zone_start_pfn, size);
		memmap_init(size, nid, j, zone_start_pfn);
	}
}

#ifdef CONFIG_FLAT_NODE_MEM_MAP
static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
{
	unsigned long __maybe_unused start = 0;
	unsigned long __maybe_unused offset = 0;

	/* Skip empty nodes */
	if (!pgdat->node_spanned_pages)
		return;

	start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
	offset = pgdat->node_start_pfn - start;
	/* ia64 gets its own node_mem_map, before this, without bootmem */
	if (!pgdat->node_mem_map) {
		unsigned long size, end;
		struct page *map;

		/*
		 * The zone's endpoints aren't required to be MAX_ORDER
		 * aligned but the node_mem_map endpoints must be in order
		 * for the buddy allocator to function correctly.
		 */
		end = pgdat_end_pfn(pgdat);
		end = ALIGN(end, MAX_ORDER_NR_PAGES);
		size =  (end - start) * sizeof(struct page);
		map = memblock_alloc_node(size, SMP_CACHE_BYTES,
					  pgdat->node_id);
		if (!map)
			panic("Failed to allocate %ld bytes for node %d memory map\n",
			      size, pgdat->node_id);
		pgdat->node_mem_map = map + offset;
	}
	pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
				__func__, pgdat->node_id, (unsigned long)pgdat,
				(unsigned long)pgdat->node_mem_map);
#ifndef CONFIG_NEED_MULTIPLE_NODES
	/*
	 * With no DISCONTIG, the global mem_map is just set as node 0's
	 */
	if (pgdat == NODE_DATA(0)) {
		mem_map = NODE_DATA(0)->node_mem_map;
		if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
			mem_map -= offset;
	}
#endif
}
#else
static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { }
#endif /* CONFIG_FLAT_NODE_MEM_MAP */

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
{
	pgdat->first_deferred_pfn = ULONG_MAX;
}
#else
static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
#endif

static void __init free_area_init_node(int nid)
{
	pg_data_t *pgdat = NODE_DATA(nid);
	unsigned long start_pfn = 0;
	unsigned long end_pfn = 0;

	/* pg_data_t should be reset to zero when it's allocated */
	WARN_ON(pgdat->nr_zones || pgdat->kswapd_highest_zoneidx);

	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);

	pgdat->node_id = nid;
	pgdat->node_start_pfn = start_pfn;
	pgdat->per_cpu_nodestats = NULL;

	pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
		(u64)start_pfn << PAGE_SHIFT,
		end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
	calculate_node_totalpages(pgdat, start_pfn, end_pfn);

	alloc_node_mem_map(pgdat);
	pgdat_set_deferred_range(pgdat);

	free_area_init_core(pgdat);
}

void __init free_area_init_memoryless_node(int nid)
{
	free_area_init_node(nid);
}

#if !defined(CONFIG_FLAT_NODE_MEM_MAP)
/*
 * Initialize all valid struct pages in the range [spfn, epfn) and mark them
 * PageReserved(). Return the number of struct pages that were initialized.
 */
static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn)
{
	unsigned long pfn;
	u64 pgcnt = 0;

	for (pfn = spfn; pfn < epfn; pfn++) {
		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
			pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
				+ pageblock_nr_pages - 1;
			continue;
		}
		/*
		 * Use a fake node/zone (0) for now. Some of these pages
		 * (in memblock.reserved but not in memblock.memory) will
		 * get re-initialized via reserve_bootmem_region() later.
		 */
		__init_single_page(pfn_to_page(pfn), pfn, 0, 0);
		__SetPageReserved(pfn_to_page(pfn));
		pgcnt++;
	}

	return pgcnt;
}

/*
 * Only struct pages that are backed by physical memory are zeroed and
 * initialized by going through __init_single_page(). But, there are some
 * struct pages which are reserved in memblock allocator and their fields
 * may be accessed (for example page_to_pfn() on some configuration accesses
 * flags). We must explicitly initialize those struct pages.
 *
 * This function also addresses a similar issue where struct pages are left
 * uninitialized because the physical address range is not covered by
 * memblock.memory or memblock.reserved. That could happen when memblock
 * layout is manually configured via memmap=, or when the highest physical
 * address (max_pfn) does not end on a section boundary.
 */
static void __init init_unavailable_mem(void)
{
	phys_addr_t start, end;
	u64 i, pgcnt;
	phys_addr_t next = 0;

	/*
	 * Loop through unavailable ranges not covered by memblock.memory.
	 */
	pgcnt = 0;
	for_each_mem_range(i, &memblock.memory, NULL,
			NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) {
		if (next < start)
			pgcnt += init_unavailable_range(PFN_DOWN(next),
							PFN_UP(start));
		next = end;
	}

	/*
	 * Early sections always have a fully populated memmap for the whole
	 * section - see pfn_valid(). If the last section has holes at the
	 * end and that section is marked "online", the memmap will be
	 * considered initialized. Make sure that memmap has a well defined
	 * state.
	 */
	pgcnt += init_unavailable_range(PFN_DOWN(next),
					round_up(max_pfn, PAGES_PER_SECTION));

	/*
	 * Struct pages that do not have backing memory. This could be because
	 * firmware is using some of this memory, or for some other reasons.
	 */
	if (pgcnt)
		pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
}
#else
static inline void __init init_unavailable_mem(void)
{
}
#endif /* !CONFIG_FLAT_NODE_MEM_MAP */

#if MAX_NUMNODES > 1
/*
 * Figure out the number of possible node ids.
 */
void __init setup_nr_node_ids(void)
{
	unsigned int highest;

	highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
	nr_node_ids = highest + 1;
}
#endif

/**
 * node_map_pfn_alignment - determine the maximum internode alignment
 *
 * This function should be called after node map is populated and sorted.
 * It calculates the maximum power of two alignment which can distinguish
 * all the nodes.
 *
 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)).  If the
 * nodes are shifted by 256MiB, 256MiB.  Note that if only the last node is
 * shifted, 1GiB is enough and this function will indicate so.
 *
 * This is used to test whether pfn -> nid mapping of the chosen memory
 * model has fine enough granularity to avoid incorrect mapping for the
 * populated node map.
 *
 * Return: the determined alignment in pfn's.  0 if there is no alignment
 * requirement (single node).
 */
unsigned long __init node_map_pfn_alignment(void)
{
	unsigned long accl_mask = 0, last_end = 0;
	unsigned long start, end, mask;
	int last_nid = NUMA_NO_NODE;
	int i, nid;

	for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
		if (!start || last_nid < 0 || last_nid == nid) {
			last_nid = nid;
			last_end = end;
			continue;
		}

		/*
		 * Start with a mask granular enough to pin-point to the
		 * start pfn and tick off bits one-by-one until it becomes
		 * too coarse to separate the current node from the last.
		 */
		mask = ~((1 << __ffs(start)) - 1);
		while (mask && last_end <= (start & (mask << 1)))
			mask <<= 1;

		/* accumulate all internode masks */
		accl_mask |= mask;
	}

	/* convert mask to number of pages */
	return ~accl_mask + 1;
}

/**
 * find_min_pfn_with_active_regions - Find the minimum PFN registered
 *
 * Return: the minimum PFN based on information provided via
 * memblock_set_node().
 */
unsigned long __init find_min_pfn_with_active_regions(void)
{
	return PHYS_PFN(memblock_start_of_DRAM());
}

/*
 * early_calculate_totalpages()
 * Sum pages in active regions for movable zone.
 * Populate N_MEMORY for calculating usable_nodes.
 */
static unsigned long __init early_calculate_totalpages(void)
{
	unsigned long totalpages = 0;
	unsigned long start_pfn, end_pfn;
	int i, nid;

	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
		unsigned long pages = end_pfn - start_pfn;

		totalpages += pages;
		if (pages)
			node_set_state(nid, N_MEMORY);
	}
	return totalpages;
}

/*
 * Find the PFN the Movable zone begins in each node. Kernel memory
 * is spread evenly between nodes as long as the nodes have enough
 * memory. When they don't, some nodes will have more kernelcore than
 * others
 */
static void __init find_zone_movable_pfns_for_nodes(void)
{
	int i, nid;
	unsigned long usable_startpfn;
	unsigned long kernelcore_node, kernelcore_remaining;
	/* save the state before borrow the nodemask */
	nodemask_t saved_node_state = node_states[N_MEMORY];
	unsigned long totalpages = early_calculate_totalpages();
	int usable_nodes = nodes_weight(node_states[N_MEMORY]);
	struct memblock_region *r;

	/* Need to find movable_zone earlier when movable_node is specified. */
	find_usable_zone_for_movable();

	/*
	 * If movable_node is specified, ignore kernelcore and movablecore
	 * options.
	 */
	if (movable_node_is_enabled()) {
		for_each_memblock(memory, r) {
			if (!memblock_is_hotpluggable(r))
				continue;

			nid = memblock_get_region_node(r);

			usable_startpfn = PFN_DOWN(r->base);
			zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
				min(usable_startpfn, zone_movable_pfn[nid]) :
				usable_startpfn;
		}

		goto out2;
	}

	/*
	 * If kernelcore=mirror is specified, ignore movablecore option
	 */
	if (mirrored_kernelcore) {
		bool mem_below_4gb_not_mirrored = false;

		for_each_memblock(memory, r) {
			if (memblock_is_mirror(r))
				continue;

			nid = memblock_get_region_node(r);

			usable_startpfn = memblock_region_memory_base_pfn(r);

			if (usable_startpfn < 0x100000) {
				mem_below_4gb_not_mirrored = true;
				continue;
			}

			zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
				min(usable_startpfn, zone_movable_pfn[nid]) :
				usable_startpfn;
		}

		if (mem_below_4gb_not_mirrored)
			pr_warn("This configuration results in unmirrored kernel memory.\n");

		goto out2;
	}

	/*
	 * If kernelcore=nn% or movablecore=nn% was specified, calculate the
	 * amount of necessary memory.
	 */
	if (required_kernelcore_percent)
		required_kernelcore = (totalpages * 100 * required_kernelcore_percent) /
				       10000UL;
	if (required_movablecore_percent)
		required_movablecore = (totalpages * 100 * required_movablecore_percent) /
					10000UL;

	/*
	 * If movablecore= was specified, calculate what size of
	 * kernelcore that corresponds so that memory usable for
	 * any allocation type is evenly spread. If both kernelcore
	 * and movablecore are specified, then the value of kernelcore
	 * will be used for required_kernelcore if it's greater than
	 * what movablecore would have allowed.
	 */
	if (required_movablecore) {
		unsigned long corepages;

		/*
		 * Round-up so that ZONE_MOVABLE is at least as large as what
		 * was requested by the user
		 */
		required_movablecore =
			roundup(required_movablecore, MAX_ORDER_NR_PAGES);
		required_movablecore = min(totalpages, required_movablecore);
		corepages = totalpages - required_movablecore;

		required_kernelcore = max(required_kernelcore, corepages);
	}

	/*
	 * If kernelcore was not specified or kernelcore size is larger
	 * than totalpages, there is no ZONE_MOVABLE.
	 */
	if (!required_kernelcore || required_kernelcore >= totalpages)
		goto out;

	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
	usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];

restart:
	/* Spread kernelcore memory as evenly as possible throughout nodes */
	kernelcore_node = required_kernelcore / usable_nodes;
	for_each_node_state(nid, N_MEMORY) {
		unsigned long start_pfn, end_pfn;

		/*
		 * Recalculate kernelcore_node if the division per node
		 * now exceeds what is necessary to satisfy the requested
		 * amount of memory for the kernel
		 */
		if (required_kernelcore < kernelcore_node)
			kernelcore_node = required_kernelcore / usable_nodes;

		/*
		 * As the map is walked, we track how much memory is usable
		 * by the kernel using kernelcore_remaining. When it is
		 * 0, the rest of the node is usable by ZONE_MOVABLE
		 */
		kernelcore_remaining = kernelcore_node;

		/* Go through each range of PFNs within this node */
		for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
			unsigned long size_pages;

			start_pfn = max(start_pfn, zone_movable_pfn[nid]);
			if (start_pfn >= end_pfn)
				continue;

			/* Account for what is only usable for kernelcore */
			if (start_pfn < usable_startpfn) {
				unsigned long kernel_pages;
				kernel_pages = min(end_pfn, usable_startpfn)
								- start_pfn;

				kernelcore_remaining -= min(kernel_pages,
							kernelcore_remaining);
				required_kernelcore -= min(kernel_pages,
							required_kernelcore);

				/* Continue if range is now fully accounted */
				if (end_pfn <= usable_startpfn) {

					/*
					 * Push zone_movable_pfn to the end so
					 * that if we have to rebalance
					 * kernelcore across nodes, we will
					 * not double account here
					 */
					zone_movable_pfn[nid] = end_pfn;
					continue;
				}
				start_pfn = usable_startpfn;
			}

			/*
			 * The usable PFN range for ZONE_MOVABLE is from
			 * start_pfn->end_pfn. Calculate size_pages as the
			 * number of pages used as kernelcore
			 */
			size_pages = end_pfn - start_pfn;
			if (size_pages > kernelcore_remaining)
				size_pages = kernelcore_remaining;
			zone_movable_pfn[nid] = start_pfn + size_pages;

			/*
			 * Some kernelcore has been met, update counts and
			 * break if the kernelcore for this node has been
			 * satisfied
			 */
			required_kernelcore -= min(required_kernelcore,
								size_pages);
			kernelcore_remaining -= size_pages;
			if (!kernelcore_remaining)
				break;
		}
	}

	/*
	 * If there is still required_kernelcore, we do another pass with one
	 * less node in the count. This will push zone_movable_pfn[nid] further
	 * along on the nodes that still have memory until kernelcore is
	 * satisfied
	 */
	usable_nodes--;
	if (usable_nodes && required_kernelcore > usable_nodes)
		goto restart;

out2:
	/* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
	for (nid = 0; nid < MAX_NUMNODES; nid++)
		zone_movable_pfn[nid] =
			roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);

out:
	/* restore the node_state */
	node_states[N_MEMORY] = saved_node_state;
}

/* Any regular or high memory on that node ? */
static void check_for_memory(pg_data_t *pgdat, int nid)
{
	enum zone_type zone_type;

	for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
		struct zone *zone = &pgdat->node_zones[zone_type];
		if (populated_zone(zone)) {
			if (IS_ENABLED(CONFIG_HIGHMEM))
				node_set_state(nid, N_HIGH_MEMORY);
			if (zone_type <= ZONE_NORMAL)
				node_set_state(nid, N_NORMAL_MEMORY);
			break;
		}
	}
}

/*
 * Some architecturs, e.g. ARC may have ZONE_HIGHMEM below ZONE_NORMAL. For
 * such cases we allow max_zone_pfn sorted in the descending order
 */
bool __weak arch_has_descending_max_zone_pfns(void)
{
	return false;
}

/**
 * free_area_init - Initialise all pg_data_t and zone data
 * @max_zone_pfn: an array of max PFNs for each zone
 *
 * This will call free_area_init_node() for each active node in the system.
 * Using the page ranges provided by memblock_set_node(), the size of each
 * zone in each node and their holes is calculated. If the maximum PFN
 * between two adjacent zones match, it is assumed that the zone is empty.
 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
 * starts where the previous one ended. For example, ZONE_DMA32 starts
 * at arch_max_dma_pfn.
 */
void __init free_area_init(unsigned long *max_zone_pfn)
{
	unsigned long start_pfn, end_pfn;
	int i, nid, zone;
	bool descending;

	/* Record where the zone boundaries are */
	memset(arch_zone_lowest_possible_pfn, 0,
				sizeof(arch_zone_lowest_possible_pfn));
	memset(arch_zone_highest_possible_pfn, 0,
				sizeof(arch_zone_highest_possible_pfn));

	start_pfn = find_min_pfn_with_active_regions();
	descending = arch_has_descending_max_zone_pfns();

	for (i = 0; i < MAX_NR_ZONES; i++) {
		if (descending)
			zone = MAX_NR_ZONES - i - 1;
		else
			zone = i;

		if (zone == ZONE_MOVABLE)
			continue;

		end_pfn = max(max_zone_pfn[zone], start_pfn);
		arch_zone_lowest_possible_pfn[zone] = start_pfn;
		arch_zone_highest_possible_pfn[zone] = end_pfn;

		start_pfn = end_pfn;
	}

	/* Find the PFNs that ZONE_MOVABLE begins at in each node */
	memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
	find_zone_movable_pfns_for_nodes();

	/* Print out the zone ranges */
	pr_info("Zone ranges:\n");
	for (i = 0; i < MAX_NR_ZONES; i++) {
		if (i == ZONE_MOVABLE)
			continue;
		pr_info("  %-8s ", zone_names[i]);
		if (arch_zone_lowest_possible_pfn[i] ==
				arch_zone_highest_possible_pfn[i])
			pr_cont("empty\n");
		else
			pr_cont("[mem %#018Lx-%#018Lx]\n",
				(u64)arch_zone_lowest_possible_pfn[i]
					<< PAGE_SHIFT,
				((u64)arch_zone_highest_possible_pfn[i]
					<< PAGE_SHIFT) - 1);
	}

	/* Print out the PFNs ZONE_MOVABLE begins at in each node */
	pr_info("Movable zone start for each node\n");
	for (i = 0; i < MAX_NUMNODES; i++) {
		if (zone_movable_pfn[i])
			pr_info("  Node %d: %#018Lx\n", i,
			       (u64)zone_movable_pfn[i] << PAGE_SHIFT);
	}

	/*
	 * Print out the early node map, and initialize the
	 * subsection-map relative to active online memory ranges to
	 * enable future "sub-section" extensions of the memory map.
	 */
	pr_info("Early memory node ranges\n");
	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
		pr_info("  node %3d: [mem %#018Lx-%#018Lx]\n", nid,
			(u64)start_pfn << PAGE_SHIFT,
			((u64)end_pfn << PAGE_SHIFT) - 1);
		subsection_map_init(start_pfn, end_pfn - start_pfn);
	}

	/* Initialise every node */
	mminit_verify_pageflags_layout();
	setup_nr_node_ids();
	init_unavailable_mem();
	for_each_online_node(nid) {
		pg_data_t *pgdat = NODE_DATA(nid);
		free_area_init_node(nid);

		/* Any memory on that node */
		if (pgdat->node_present_pages)
			node_set_state(nid, N_MEMORY);
		check_for_memory(pgdat, nid);
	}
}

static int __init cmdline_parse_core(char *p, unsigned long *core,
				     unsigned long *percent)
{
	unsigned long long coremem;
	char *endptr;

	if (!p)
		return -EINVAL;

	/* Value may be a percentage of total memory, otherwise bytes */
	coremem = simple_strtoull(p, &endptr, 0);
	if (*endptr == '%') {
		/* Paranoid check for percent values greater than 100 */
		WARN_ON(coremem > 100);

		*percent = coremem;
	} else {
		coremem = memparse(p, &p);
		/* Paranoid check that UL is enough for the coremem value */
		WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);

		*core = coremem >> PAGE_SHIFT;
		*percent = 0UL;
	}
	return 0;
}

/*
 * kernelcore=size sets the amount of memory for use for allocations that
 * cannot be reclaimed or migrated.
 */
static int __init cmdline_parse_kernelcore(char *p)
{
	/* parse kernelcore=mirror */
	if (parse_option_str(p, "mirror")) {
		mirrored_kernelcore = true;
		return 0;
	}

	return cmdline_parse_core(p, &required_kernelcore,
				  &required_kernelcore_percent);
}

/*
 * movablecore=size sets the amount of memory for use for allocations that
 * can be reclaimed or migrated.
 */
static int __init cmdline_parse_movablecore(char *p)
{
	return cmdline_parse_core(p, &required_movablecore,
				  &required_movablecore_percent);
}

early_param("kernelcore", cmdline_parse_kernelcore);
early_param("movablecore", cmdline_parse_movablecore);

void adjust_managed_page_count(struct page *page, long count)
{
	atomic_long_add(count, &page_zone(page)->managed_pages);
	totalram_pages_add(count);
#ifdef CONFIG_HIGHMEM
	if (PageHighMem(page))
		totalhigh_pages_add(count);
#endif
}
EXPORT_SYMBOL(adjust_managed_page_count);

unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
{
	void *pos;
	unsigned long pages = 0;

	start = (void *)PAGE_ALIGN((unsigned long)start);
	end = (void *)((unsigned long)end & PAGE_MASK);
	for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
		struct page *page = virt_to_page(pos);
		void *direct_map_addr;

		/*
		 * 'direct_map_addr' might be different from 'pos'
		 * because some architectures' virt_to_page()
		 * work with aliases.  Getting the direct map
		 * address ensures that we get a _writeable_
		 * alias for the memset().
		 */
		direct_map_addr = page_address(page);
		if ((unsigned int)poison <= 0xFF)
			memset(direct_map_addr, poison, PAGE_SIZE);

		free_reserved_page(page);
	}

	if (pages && s)
		pr_info("Freeing %s memory: %ldK\n",
			s, pages << (PAGE_SHIFT - 10));

	return pages;
}

#ifdef	CONFIG_HIGHMEM
void free_highmem_page(struct page *page)
{
	__free_reserved_page(page);
	totalram_pages_inc();
	atomic_long_inc(&page_zone(page)->managed_pages);
	totalhigh_pages_inc();
}
#endif


void __init mem_init_print_info(const char *str)
{
	unsigned long physpages, codesize, datasize, rosize, bss_size;
	unsigned long init_code_size, init_data_size;

	physpages = get_num_physpages();
	codesize = _etext - _stext;
	datasize = _edata - _sdata;
	rosize = __end_rodata - __start_rodata;
	bss_size = __bss_stop - __bss_start;
	init_data_size = __init_end - __init_begin;
	init_code_size = _einittext - _sinittext;

	/*
	 * Detect special cases and adjust section sizes accordingly:
	 * 1) .init.* may be embedded into .data sections
	 * 2) .init.text.* may be out of [__init_begin, __init_end],
	 *    please refer to arch/tile/kernel/vmlinux.lds.S.
	 * 3) .rodata.* may be embedded into .text or .data sections.
	 */
#define adj_init_size(start, end, size, pos, adj) \
	do { \
		if (start <= pos && pos < end && size > adj) \
			size -= adj; \
	} while (0)

	adj_init_size(__init_begin, __init_end, init_data_size,
		     _sinittext, init_code_size);
	adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
	adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
	adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
	adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);

#undef	adj_init_size

	pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
#ifdef	CONFIG_HIGHMEM
		", %luK highmem"
#endif
		"%s%s)\n",
		nr_free_pages() << (PAGE_SHIFT - 10),
		physpages << (PAGE_SHIFT - 10),
		codesize >> 10, datasize >> 10, rosize >> 10,
		(init_data_size + init_code_size) >> 10, bss_size >> 10,
		(physpages - totalram_pages() - totalcma_pages) << (PAGE_SHIFT - 10),
		totalcma_pages << (PAGE_SHIFT - 10),
#ifdef	CONFIG_HIGHMEM
		totalhigh_pages() << (PAGE_SHIFT - 10),
#endif
		str ? ", " : "", str ? str : "");
}

/**
 * set_dma_reserve - set the specified number of pages reserved in the first zone
 * @new_dma_reserve: The number of pages to mark reserved
 *
 * The per-cpu batchsize and zone watermarks are determined by managed_pages.
 * In the DMA zone, a significant percentage may be consumed by kernel image
 * and other unfreeable allocations which can skew the watermarks badly. This
 * function may optionally be used to account for unfreeable pages in the
 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
 * smaller per-cpu batchsize.
 */
void __init set_dma_reserve(unsigned long new_dma_reserve)
{
	dma_reserve = new_dma_reserve;
}

static int page_alloc_cpu_dead(unsigned int cpu)
{

	lru_add_drain_cpu(cpu);
	drain_pages(cpu);

	/*
	 * Spill the event counters of the dead processor
	 * into the current processors event counters.
	 * This artificially elevates the count of the current
	 * processor.
	 */
	vm_events_fold_cpu(cpu);

	/*
	 * Zero the differential counters of the dead processor
	 * so that the vm statistics are consistent.
	 *
	 * This is only okay since the processor is dead and cannot
	 * race with what we are doing.
	 */
	cpu_vm_stats_fold(cpu);
	return 0;
}

#ifdef CONFIG_NUMA
int hashdist = HASHDIST_DEFAULT;

static int __init set_hashdist(char *str)
{
	if (!str)
		return 0;
	hashdist = simple_strtoul(str, &str, 0);
	return 1;
}
__setup("hashdist=", set_hashdist);
#endif

void __init page_alloc_init(void)
{
	int ret;

#ifdef CONFIG_NUMA
	if (num_node_state(N_MEMORY) == 1)
		hashdist = 0;
#endif

	ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC_DEAD,
					"mm/page_alloc:dead", NULL,
					page_alloc_cpu_dead);
	WARN_ON(ret < 0);
}

/*
 * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio
 *	or min_free_kbytes changes.
 */
static void calculate_totalreserve_pages(void)
{
	struct pglist_data *pgdat;
	unsigned long reserve_pages = 0;
	enum zone_type i, j;

	for_each_online_pgdat(pgdat) {

		pgdat->totalreserve_pages = 0;

		for (i = 0; i < MAX_NR_ZONES; i++) {
			struct zone *zone = pgdat->node_zones + i;
			long max = 0;
			unsigned long managed_pages = zone_managed_pages(zone);

			/* Find valid and maximum lowmem_reserve in the zone */
			for (j = i; j < MAX_NR_ZONES; j++) {
				if (zone->lowmem_reserve[j] > max)
					max = zone->lowmem_reserve[j];
			}

			/* we treat the high watermark as reserved pages. */
			max += high_wmark_pages(zone);

			if (max > managed_pages)
				max = managed_pages;

			pgdat->totalreserve_pages += max;

			reserve_pages += max;
		}
	}
	totalreserve_pages = reserve_pages;
}

/*
 * setup_per_zone_lowmem_reserve - called whenever
 *	sysctl_lowmem_reserve_ratio changes.  Ensures that each zone
 *	has a correct pages reserved value, so an adequate number of
 *	pages are left in the zone after a successful __alloc_pages().
 */
static void setup_per_zone_lowmem_reserve(void)
{
	struct pglist_data *pgdat;
	enum zone_type j, idx;

	for_each_online_pgdat(pgdat) {
		for (j = 0; j < MAX_NR_ZONES; j++) {
			struct zone *zone = pgdat->node_zones + j;
			unsigned long managed_pages = zone_managed_pages(zone);

			zone->lowmem_reserve[j] = 0;

			idx = j;
			while (idx) {
				struct zone *lower_zone;

				idx--;
				lower_zone = pgdat->node_zones + idx;

				if (!sysctl_lowmem_reserve_ratio[idx] ||
				    !zone_managed_pages(lower_zone)) {
					lower_zone->lowmem_reserve[j] = 0;
					continue;
				} else {
					lower_zone->lowmem_reserve[j] =
						managed_pages / sysctl_lowmem_reserve_ratio[idx];
				}
				managed_pages += zone_managed_pages(lower_zone);
			}
		}
	}

	/* update totalreserve_pages */
	calculate_totalreserve_pages();
}

static void __setup_per_zone_wmarks(void)
{
	unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
	unsigned long lowmem_pages = 0;
	struct zone *zone;
	unsigned long flags;

	/* Calculate total number of !ZONE_HIGHMEM pages */
	for_each_zone(zone) {
		if (!is_highmem(zone))
			lowmem_pages += zone_managed_pages(zone);
	}

	for_each_zone(zone) {
		u64 tmp;

		spin_lock_irqsave(&zone->lock, flags);
		tmp = (u64)pages_min * zone_managed_pages(zone);
		do_div(tmp, lowmem_pages);
		if (is_highmem(zone)) {
			/*
			 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
			 * need highmem pages, so cap pages_min to a small
			 * value here.
			 *
			 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
			 * deltas control async page reclaim, and so should
			 * not be capped for highmem.
			 */
			unsigned long min_pages;

			min_pages = zone_managed_pages(zone) / 1024;
			min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
			zone->_watermark[WMARK_MIN] = min_pages;
		} else {
			/*
			 * If it's a lowmem zone, reserve a number of pages
			 * proportionate to the zone's size.
			 */
			zone->_watermark[WMARK_MIN] = tmp;
		}

		/*
		 * Set the kswapd watermarks distance according to the
		 * scale factor in proportion to available memory, but
		 * ensure a minimum size on small systems.
		 */
		tmp = max_t(u64, tmp >> 2,
			    mult_frac(zone_managed_pages(zone),
				      watermark_scale_factor, 10000));

		zone->watermark_boost = 0;
		zone->_watermark[WMARK_LOW]  = min_wmark_pages(zone) + tmp;
		zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;

		spin_unlock_irqrestore(&zone->lock, flags);
	}

	/* update totalreserve_pages */
	calculate_totalreserve_pages();
}

/**
 * setup_per_zone_wmarks - called when min_free_kbytes changes
 * or when memory is hot-{added|removed}
 *
 * Ensures that the watermark[min,low,high] values for each zone are set
 * correctly with respect to min_free_kbytes.
 */
void setup_per_zone_wmarks(void)
{
	static DEFINE_SPINLOCK(lock);

	spin_lock(&lock);
	__setup_per_zone_wmarks();
	spin_unlock(&lock);
}

/*
 * Initialise min_free_kbytes.
 *
 * For small machines we want it small (128k min).  For large machines
 * we want it large (64MB max).  But it is not linear, because network
 * bandwidth does not increase linearly with machine size.  We use
 *
 *	min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
 *	min_free_kbytes = sqrt(lowmem_kbytes * 16)
 *
 * which yields
 *
 * 16MB:	512k
 * 32MB:	724k
 * 64MB:	1024k
 * 128MB:	1448k
 * 256MB:	2048k
 * 512MB:	2896k
 * 1024MB:	4096k
 * 2048MB:	5792k
 * 4096MB:	8192k
 * 8192MB:	11584k
 * 16384MB:	16384k
 */
int __meminit init_per_zone_wmark_min(void)
{
	unsigned long lowmem_kbytes;
	int new_min_free_kbytes;

	lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
	new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);

	if (new_min_free_kbytes > user_min_free_kbytes) {
		min_free_kbytes = new_min_free_kbytes;
		if (min_free_kbytes < 128)
			min_free_kbytes = 128;
		if (min_free_kbytes > 262144)
			min_free_kbytes = 262144;
	} else {
		pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
				new_min_free_kbytes, user_min_free_kbytes);
	}
	setup_per_zone_wmarks();
	refresh_zone_stat_thresholds();
	setup_per_zone_lowmem_reserve();

#ifdef CONFIG_NUMA
	setup_min_unmapped_ratio();
	setup_min_slab_ratio();
#endif

	return 0;
}
core_initcall(init_per_zone_wmark_min)

/*
 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
 *	that we can call two helper functions whenever min_free_kbytes
 *	changes.
 */
int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
		void *buffer, size_t *length, loff_t *ppos)
{
	int rc;

	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
	if (rc)
		return rc;

	if (write) {
		user_min_free_kbytes = min_free_kbytes;
		setup_per_zone_wmarks();
	}
	return 0;
}

int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
		void *buffer, size_t *length, loff_t *ppos)
{
	int rc;

	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
	if (rc)
		return rc;

	if (write)
		setup_per_zone_wmarks();

	return 0;
}

#ifdef CONFIG_NUMA
static void setup_min_unmapped_ratio(void)
{
	pg_data_t *pgdat;
	struct zone *zone;

	for_each_online_pgdat(pgdat)
		pgdat->min_unmapped_pages = 0;

	for_each_zone(zone)
		zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) *
						         sysctl_min_unmapped_ratio) / 100;
}


int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
		void *buffer, size_t *length, loff_t *ppos)
{
	int rc;

	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
	if (rc)
		return rc;

	setup_min_unmapped_ratio();

	return 0;
}

static void setup_min_slab_ratio(void)
{
	pg_data_t *pgdat;
	struct zone *zone;

	for_each_online_pgdat(pgdat)
		pgdat->min_slab_pages = 0;

	for_each_zone(zone)
		zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) *
						     sysctl_min_slab_ratio) / 100;
}

int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
		void *buffer, size_t *length, loff_t *ppos)
{
	int rc;

	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
	if (rc)
		return rc;

	setup_min_slab_ratio();

	return 0;
}
#endif

/*
 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
 *	proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
 *	whenever sysctl_lowmem_reserve_ratio changes.
 *
 * The reserve ratio obviously has absolutely no relation with the
 * minimum watermarks. The lowmem reserve ratio can only make sense
 * if in function of the boot time zone sizes.
 */
int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
		void *buffer, size_t *length, loff_t *ppos)
{
	int i;

	proc_dointvec_minmax(table, write, buffer, length, ppos);

	for (i = 0; i < MAX_NR_ZONES; i++) {
		if (sysctl_lowmem_reserve_ratio[i] < 1)
			sysctl_lowmem_reserve_ratio[i] = 0;
	}

	setup_per_zone_lowmem_reserve();
	return 0;
}

static void __zone_pcp_update(struct zone *zone)
{
	unsigned int cpu;

	for_each_possible_cpu(cpu)
		pageset_set_high_and_batch(zone,
				per_cpu_ptr(zone->pageset, cpu));
}

/*
 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
 * cpu.  It is the fraction of total pages in each zone that a hot per cpu
 * pagelist can have before it gets flushed back to buddy allocator.
 */
int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
		void *buffer, size_t *length, loff_t *ppos)
{
	struct zone *zone;
	int old_percpu_pagelist_fraction;
	int ret;

	mutex_lock(&pcp_batch_high_lock);
	old_percpu_pagelist_fraction = percpu_pagelist_fraction;

	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
	if (!write || ret < 0)
		goto out;

	/* Sanity checking to avoid pcp imbalance */
	if (percpu_pagelist_fraction &&
	    percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) {
		percpu_pagelist_fraction = old_percpu_pagelist_fraction;
		ret = -EINVAL;
		goto out;
	}

	/* No change? */
	if (percpu_pagelist_fraction == old_percpu_pagelist_fraction)
		goto out;

	for_each_populated_zone(zone)
		__zone_pcp_update(zone);
out:
	mutex_unlock(&pcp_batch_high_lock);
	return ret;
}

#ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES
/*
 * Returns the number of pages that arch has reserved but
 * is not known to alloc_large_system_hash().
 */
static unsigned long __init arch_reserved_kernel_pages(void)
{
	return 0;
}
#endif

/*
 * Adaptive scale is meant to reduce sizes of hash tables on large memory
 * machines. As memory size is increased the scale is also increased but at
 * slower pace.  Starting from ADAPT_SCALE_BASE (64G), every time memory
 * quadruples the scale is increased by one, which means the size of hash table
 * only doubles, instead of quadrupling as well.
 * Because 32-bit systems cannot have large physical memory, where this scaling
 * makes sense, it is disabled on such platforms.
 */
#if __BITS_PER_LONG > 32
#define ADAPT_SCALE_BASE	(64ul << 30)
#define ADAPT_SCALE_SHIFT	2
#define ADAPT_SCALE_NPAGES	(ADAPT_SCALE_BASE >> PAGE_SHIFT)
#endif

/*
 * allocate a large system hash table from bootmem
 * - it is assumed that the hash table must contain an exact power-of-2
 *   quantity of entries
 * - limit is the number of hash buckets, not the total allocation size
 */
void *__init alloc_large_system_hash(const char *tablename,
				     unsigned long bucketsize,
				     unsigned long numentries,
				     int scale,
				     int flags,
				     unsigned int *_hash_shift,
				     unsigned int *_hash_mask,
				     unsigned long low_limit,
				     unsigned long high_limit)
{
	unsigned long long max = high_limit;
	unsigned long log2qty, size;
	void *table = NULL;
	gfp_t gfp_flags;
	bool virt;

	/* allow the kernel cmdline to have a say */
	if (!numentries) {
		/* round applicable memory size up to nearest megabyte */
		numentries = nr_kernel_pages;
		numentries -= arch_reserved_kernel_pages();

		/* It isn't necessary when PAGE_SIZE >= 1MB */
		if (PAGE_SHIFT < 20)
			numentries = round_up(numentries, (1<<20)/PAGE_SIZE);

#if __BITS_PER_LONG > 32
		if (!high_limit) {
			unsigned long adapt;

			for (adapt = ADAPT_SCALE_NPAGES; adapt < numentries;
			     adapt <<= ADAPT_SCALE_SHIFT)
				scale++;
		}
#endif

		/* limit to 1 bucket per 2^scale bytes of low memory */
		if (scale > PAGE_SHIFT)
			numentries >>= (scale - PAGE_SHIFT);
		else
			numentries <<= (PAGE_SHIFT - scale);

		/* Make sure we've got at least a 0-order allocation.. */
		if (unlikely(flags & HASH_SMALL)) {
			/* Makes no sense without HASH_EARLY */
			WARN_ON(!(flags & HASH_EARLY));
			if (!(numentries >> *_hash_shift)) {
				numentries = 1UL << *_hash_shift;
				BUG_ON(!numentries);
			}
		} else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
			numentries = PAGE_SIZE / bucketsize;
	}
	numentries = roundup_pow_of_two(numentries);

	/* limit allocation size to 1/16 total memory by default */
	if (max == 0) {
		max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
		do_div(max, bucketsize);
	}
	max = min(max, 0x80000000ULL);

	if (numentries < low_limit)
		numentries = low_limit;
	if (numentries > max)
		numentries = max;

	log2qty = ilog2(numentries);

	gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC;
	do {
		virt = false;
		size = bucketsize << log2qty;
		if (flags & HASH_EARLY) {
			if (flags & HASH_ZERO)
				table = memblock_alloc(size, SMP_CACHE_BYTES);
			else
				table = memblock_alloc_raw(size,
							   SMP_CACHE_BYTES);
		} else if (get_order(size) >= MAX_ORDER || hashdist) {
			table = __vmalloc(size, gfp_flags);
			virt = true;
		} else {
			/*
			 * If bucketsize is not a power-of-two, we may free
			 * some pages at the end of hash table which
			 * alloc_pages_exact() automatically does
			 */
			table = alloc_pages_exact(size, gfp_flags);
			kmemleak_alloc(table, size, 1, gfp_flags);
		}
	} while (!table && size > PAGE_SIZE && --log2qty);

	if (!table)
		panic("Failed to allocate %s hash table\n", tablename);

	pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
		tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
		virt ? "vmalloc" : "linear");

	if (_hash_shift)
		*_hash_shift = log2qty;
	if (_hash_mask)
		*_hash_mask = (1 << log2qty) - 1;

	return table;
}

/*
 * This function checks whether pageblock includes unmovable pages or not.
 *
 * PageLRU check without isolation or lru_lock could race so that
 * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
 * check without lock_page also may miss some movable non-lru pages at
 * race condition. So you can't expect this function should be exact.
 *
 * Returns a page without holding a reference. If the caller wants to
 * dereference that page (e.g., dumping), it has to make sure that that it
 * cannot get removed (e.g., via memory unplug) concurrently.
 *
 */
struct page *has_unmovable_pages(struct zone *zone, struct page *page,
				 int migratetype, int flags)
{
	unsigned long iter = 0;
	unsigned long pfn = page_to_pfn(page);

	/*
	 * TODO we could make this much more efficient by not checking every
	 * page in the range if we know all of them are in MOVABLE_ZONE and
	 * that the movable zone guarantees that pages are migratable but
	 * the later is not the case right now unfortunatelly. E.g. movablecore
	 * can still lead to having bootmem allocations in zone_movable.
	 */

	if (is_migrate_cma_page(page)) {
		/*
		 * CMA allocations (alloc_contig_range) really need to mark
		 * isolate CMA pageblocks even when they are not movable in fact
		 * so consider them movable here.
		 */
		if (is_migrate_cma(migratetype))
			return NULL;

		return page;
	}

	for (; iter < pageblock_nr_pages; iter++) {
		if (!pfn_valid_within(pfn + iter))
			continue;

		page = pfn_to_page(pfn + iter);

		if (PageReserved(page))
			return page;

		/*
		 * If the zone is movable and we have ruled out all reserved
		 * pages then it should be reasonably safe to assume the rest
		 * is movable.
		 */
		if (zone_idx(zone) == ZONE_MOVABLE)
			continue;

		/*
		 * Hugepages are not in LRU lists, but they're movable.
		 * THPs are on the LRU, but need to be counted as #small pages.
		 * We need not scan over tail pages because we don't
		 * handle each tail page individually in migration.
		 */
		if (PageHuge(page) || PageTransCompound(page)) {
			struct page *head = compound_head(page);
			unsigned int skip_pages;

			if (PageHuge(page)) {
				if (!hugepage_migration_supported(page_hstate(head)))
					return page;
			} else if (!PageLRU(head) && !__PageMovable(head)) {
				return page;
			}

			skip_pages = compound_nr(head) - (page - head);
			iter += skip_pages - 1;
			continue;
		}

		/*
		 * We can't use page_count without pin a page
		 * because another CPU can free compound page.
		 * This check already skips compound tails of THP
		 * because their page->_refcount is zero at all time.
		 */
		if (!page_ref_count(page)) {
			if (PageBuddy(page))
				iter += (1 << page_order(page)) - 1;
			continue;
		}

		/*
		 * The HWPoisoned page may be not in buddy system, and
		 * page_count() is not 0.
		 */
		if ((flags & MEMORY_OFFLINE) && PageHWPoison(page))
			continue;

		/*
		 * We treat all PageOffline() pages as movable when offlining
		 * to give drivers a chance to decrement their reference count
		 * in MEM_GOING_OFFLINE in order to indicate that these pages
		 * can be offlined as there are no direct references anymore.
		 * For actually unmovable PageOffline() where the driver does
		 * not support this, we will fail later when trying to actually
		 * move these pages that still have a reference count > 0.
		 * (false negatives in this function only)
		 */
		if ((flags & MEMORY_OFFLINE) && PageOffline(page))
			continue;

		if (__PageMovable(page) || PageLRU(page))
			continue;

		/*
		 * If there are RECLAIMABLE pages, we need to check
		 * it.  But now, memory offline itself doesn't call
		 * shrink_node_slabs() and it still to be fixed.
		 */
		/*
		 * If the page is not RAM, page_count()should be 0.
		 * we don't need more check. This is an _used_ not-movable page.
		 *
		 * The problematic thing here is PG_reserved pages. PG_reserved
		 * is set to both of a memory hole page and a _used_ kernel
		 * page at boot.
		 */
		return page;
	}
	return NULL;
}

#ifdef CONFIG_CONTIG_ALLOC
static unsigned long pfn_max_align_down(unsigned long pfn)
{
	return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
			     pageblock_nr_pages) - 1);
}

static unsigned long pfn_max_align_up(unsigned long pfn)
{
	return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
				pageblock_nr_pages));
}

/* [start, end) must belong to a single zone. */
static int __alloc_contig_migrate_range(struct compact_control *cc,
					unsigned long start, unsigned long end)
{
	/* This function is based on compact_zone() from compaction.c. */
	unsigned int nr_reclaimed;
	unsigned long pfn = start;
	unsigned int tries = 0;
	int ret = 0;

	migrate_prep();

	while (pfn < end || !list_empty(&cc->migratepages)) {
		if (fatal_signal_pending(current)) {
			ret = -EINTR;
			break;
		}

		if (list_empty(&cc->migratepages)) {
			cc->nr_migratepages = 0;
			pfn = isolate_migratepages_range(cc, pfn, end);
			if (!pfn) {
				ret = -EINTR;
				break;
			}
			tries = 0;
		} else if (++tries == 5) {
			ret = ret < 0 ? ret : -EBUSY;
			break;
		}

		nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
							&cc->migratepages);
		cc->nr_migratepages -= nr_reclaimed;

		ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
				    NULL, 0, cc->mode, MR_CONTIG_RANGE);
	}
	if (ret < 0) {
		putback_movable_pages(&cc->migratepages);
		return ret;
	}
	return 0;
}

/**
 * alloc_contig_range() -- tries to allocate given range of pages
 * @start:	start PFN to allocate
 * @end:	one-past-the-last PFN to allocate
 * @migratetype:	migratetype of the underlaying pageblocks (either
 *			#MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
 *			in range must have the same migratetype and it must
 *			be either of the two.
 * @gfp_mask:	GFP mask to use during compaction
 *
 * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
 * aligned.  The PFN range must belong to a single zone.
 *
 * The first thing this routine does is attempt to MIGRATE_ISOLATE all
 * pageblocks in the range.  Once isolated, the pageblocks should not
 * be modified by others.
 *
 * Return: zero on success or negative error code.  On success all
 * pages which PFN is in [start, end) are allocated for the caller and
 * need to be freed with free_contig_range().
 */
int alloc_contig_range(unsigned long start, unsigned long end,
		       unsigned migratetype, gfp_t gfp_mask)
{
	unsigned long outer_start, outer_end;
	unsigned int order;
	int ret = 0;

	struct compact_control cc = {
		.nr_migratepages = 0,
		.order = -1,
		.zone = page_zone(pfn_to_page(start)),
		.mode = MIGRATE_SYNC,
		.ignore_skip_hint = true,
		.no_set_skip_hint = true,
		.gfp_mask = current_gfp_context(gfp_mask),
		.alloc_contig = true,
	};
	INIT_LIST_HEAD(&cc.migratepages);

	/*
	 * What we do here is we mark all pageblocks in range as
	 * MIGRATE_ISOLATE.  Because pageblock and max order pages may
	 * have different sizes, and due to the way page allocator
	 * work, we align the range to biggest of the two pages so
	 * that page allocator won't try to merge buddies from
	 * different pageblocks and change MIGRATE_ISOLATE to some
	 * other migration type.
	 *
	 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
	 * migrate the pages from an unaligned range (ie. pages that
	 * we are interested in).  This will put all the pages in
	 * range back to page allocator as MIGRATE_ISOLATE.
	 *
	 * When this is done, we take the pages in range from page
	 * allocator removing them from the buddy system.  This way
	 * page allocator will never consider using them.
	 *
	 * This lets us mark the pageblocks back as
	 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
	 * aligned range but not in the unaligned, original range are
	 * put back to page allocator so that buddy can use them.
	 */

	ret = start_isolate_page_range(pfn_max_align_down(start),
				       pfn_max_align_up(end), migratetype, 0);
	if (ret < 0)
		return ret;

	/*
	 * In case of -EBUSY, we'd like to know which page causes problem.
	 * So, just fall through. test_pages_isolated() has a tracepoint
	 * which will report the busy page.
	 *
	 * It is possible that busy pages could become available before
	 * the call to test_pages_isolated, and the range will actually be
	 * allocated.  So, if we fall through be sure to clear ret so that
	 * -EBUSY is not accidentally used or returned to caller.
	 */
	ret = __alloc_contig_migrate_range(&cc, start, end);
	if (ret && ret != -EBUSY)
		goto done;
	ret =0;

	/*
	 * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
	 * aligned blocks that are marked as MIGRATE_ISOLATE.  What's
	 * more, all pages in [start, end) are free in page allocator.
	 * What we are going to do is to allocate all pages from
	 * [start, end) (that is remove them from page allocator).
	 *
	 * The only problem is that pages at the beginning and at the
	 * end of interesting range may be not aligned with pages that
	 * page allocator holds, ie. they can be part of higher order
	 * pages.  Because of this, we reserve the bigger range and
	 * once this is done free the pages we are not interested in.
	 *
	 * We don't have to hold zone->lock here because the pages are
	 * isolated thus they won't get removed from buddy.
	 */

	lru_add_drain_all();

	order = 0;
	outer_start = start;
	while (!PageBuddy(pfn_to_page(outer_start))) {
		if (++order >= MAX_ORDER) {
			outer_start = start;
			break;
		}
		outer_start &= ~0UL << order;
	}

	if (outer_start != start) {
		order = page_order(pfn_to_page(outer_start));

		/*
		 * outer_start page could be small order buddy page and
		 * it doesn't include start page. Adjust outer_start
		 * in this case to report failed page properly
		 * on tracepoint in test_pages_isolated()
		 */
		if (outer_start + (1UL << order) <= start)
			outer_start = start;
	}

	/* Make sure the range is really isolated. */
	if (test_pages_isolated(outer_start, end, 0)) {
		pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n",
			__func__, outer_start, end);
		ret = -EBUSY;
		goto done;
	}

	/* Grab isolated pages from freelists. */
	outer_end = isolate_freepages_range(&cc, outer_start, end);
	if (!outer_end) {
		ret = -EBUSY;
		goto done;
	}

	/* Free head and tail (if any) */
	if (start != outer_start)
		free_contig_range(outer_start, start - outer_start);
	if (end != outer_end)
		free_contig_range(end, outer_end - end);

done:
	undo_isolate_page_range(pfn_max_align_down(start),
				pfn_max_align_up(end), migratetype);
	return ret;
}
EXPORT_SYMBOL(alloc_contig_range);

static int __alloc_contig_pages(unsigned long start_pfn,
				unsigned long nr_pages, gfp_t gfp_mask)
{
	unsigned long end_pfn = start_pfn + nr_pages;

	return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
				  gfp_mask);
}

static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
				   unsigned long nr_pages)
{
	unsigned long i, end_pfn = start_pfn + nr_pages;
	struct page *page;

	for (i = start_pfn; i < end_pfn; i++) {
		page = pfn_to_online_page(i);
		if (!page)
			return false;

		if (page_zone(page) != z)
			return false;

		if (PageReserved(page))
			return false;

		if (page_count(page) > 0)
			return false;

		if (PageHuge(page))
			return false;
	}
	return true;
}

static bool zone_spans_last_pfn(const struct zone *zone,
				unsigned long start_pfn, unsigned long nr_pages)
{
	unsigned long last_pfn = start_pfn + nr_pages - 1;

	return zone_spans_pfn(zone, last_pfn);
}

/**
 * alloc_contig_pages() -- tries to find and allocate contiguous range of pages
 * @nr_pages:	Number of contiguous pages to allocate
 * @gfp_mask:	GFP mask to limit search and used during compaction
 * @nid:	Target node
 * @nodemask:	Mask for other possible nodes
 *
 * This routine is a wrapper around alloc_contig_range(). It scans over zones
 * on an applicable zonelist to find a contiguous pfn range which can then be
 * tried for allocation with alloc_contig_range(). This routine is intended
 * for allocation requests which can not be fulfilled with the buddy allocator.
 *
 * The allocated memory is always aligned to a page boundary. If nr_pages is a
 * power of two then the alignment is guaranteed to be to the given nr_pages
 * (e.g. 1GB request would be aligned to 1GB).
 *
 * Allocated pages can be freed with free_contig_range() or by manually calling
 * __free_page() on each allocated page.
 *
 * Return: pointer to contiguous pages on success, or NULL if not successful.
 */
struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask,
				int nid, nodemask_t *nodemask)
{
	unsigned long ret, pfn, flags;
	struct zonelist *zonelist;
	struct zone *zone;
	struct zoneref *z;

	zonelist = node_zonelist(nid, gfp_mask);
	for_each_zone_zonelist_nodemask(zone, z, zonelist,
					gfp_zone(gfp_mask), nodemask) {
		spin_lock_irqsave(&zone->lock, flags);

		pfn = ALIGN(zone->zone_start_pfn, nr_pages);
		while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
			if (pfn_range_valid_contig(zone, pfn, nr_pages)) {
				/*
				 * We release the zone lock here because
				 * alloc_contig_range() will also lock the zone
				 * at some point. If there's an allocation
				 * spinning on this lock, it may win the race
				 * and cause alloc_contig_range() to fail...
				 */
				spin_unlock_irqrestore(&zone->lock, flags);
				ret = __alloc_contig_pages(pfn, nr_pages,
							gfp_mask);
				if (!ret)
					return pfn_to_page(pfn);
				spin_lock_irqsave(&zone->lock, flags);
			}
			pfn += nr_pages;
		}
		spin_unlock_irqrestore(&zone->lock, flags);
	}
	return NULL;
}
#endif /* CONFIG_CONTIG_ALLOC */

void free_contig_range(unsigned long pfn, unsigned int nr_pages)
{
	unsigned int count = 0;

	for (; nr_pages--; pfn++) {
		struct page *page = pfn_to_page(pfn);

		count += page_count(page) != 1;
		__free_page(page);
	}
	WARN(count != 0, "%d pages are still in use!\n", count);
}
EXPORT_SYMBOL(free_contig_range);

/*
 * The zone indicated has a new number of managed_pages; batch sizes and percpu
 * page high values need to be recalulated.
 */
void __meminit zone_pcp_update(struct zone *zone)
{
	mutex_lock(&pcp_batch_high_lock);
	__zone_pcp_update(zone);
	mutex_unlock(&pcp_batch_high_lock);
}

void zone_pcp_reset(struct zone *zone)
{
	unsigned long flags;
	int cpu;
	struct per_cpu_pageset *pset;

	/* avoid races with drain_pages()  */
	local_irq_save(flags);
	if (zone->pageset != &boot_pageset) {
		for_each_online_cpu(cpu) {
			pset = per_cpu_ptr(zone->pageset, cpu);
			drain_zonestat(zone, pset);
		}
		free_percpu(zone->pageset);
		zone->pageset = &boot_pageset;
	}
	local_irq_restore(flags);
}

#ifdef CONFIG_MEMORY_HOTREMOVE
/*
 * All pages in the range must be in a single zone and isolated
 * before calling this.
 */
unsigned long
__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
{
	struct page *page;
	struct zone *zone;
	unsigned int order;
	unsigned long pfn;
	unsigned long flags;
	unsigned long offlined_pages = 0;

	/* find the first valid pfn */
	for (pfn = start_pfn; pfn < end_pfn; pfn++)
		if (pfn_valid(pfn))
			break;
	if (pfn == end_pfn)
		return offlined_pages;

	offline_mem_sections(pfn, end_pfn);
	zone = page_zone(pfn_to_page(pfn));
	spin_lock_irqsave(&zone->lock, flags);
	pfn = start_pfn;
	while (pfn < end_pfn) {
		if (!pfn_valid(pfn)) {
			pfn++;
			continue;
		}
		page = pfn_to_page(pfn);
		/*
		 * The HWPoisoned page may be not in buddy system, and
		 * page_count() is not 0.
		 */
		if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
			pfn++;
			offlined_pages++;
			continue;
		}
		/*
		 * At this point all remaining PageOffline() pages have a
		 * reference count of 0 and can simply be skipped.
		 */
		if (PageOffline(page)) {
			BUG_ON(page_count(page));
			BUG_ON(PageBuddy(page));
			pfn++;
			offlined_pages++;
			continue;
		}

		BUG_ON(page_count(page));
		BUG_ON(!PageBuddy(page));
		order = page_order(page);
		offlined_pages += 1 << order;
		del_page_from_free_list(page, zone, order);
		pfn += (1 << order);
	}
	spin_unlock_irqrestore(&zone->lock, flags);

	return offlined_pages;
}
#endif

bool is_free_buddy_page(struct page *page)
{
	struct zone *zone = page_zone(page);
	unsigned long pfn = page_to_pfn(page);
	unsigned long flags;
	unsigned int order;

	spin_lock_irqsave(&zone->lock, flags);
	for (order = 0; order < MAX_ORDER; order++) {
		struct page *page_head = page - (pfn & ((1 << order) - 1));

		if (PageBuddy(page_head) && page_order(page_head) >= order)
			break;
	}
	spin_unlock_irqrestore(&zone->lock, flags);

	return order < MAX_ORDER;
}

#ifdef CONFIG_MEMORY_FAILURE
/*
 * Set PG_hwpoison flag if a given page is confirmed to be a free page.  This
 * test is performed under the zone lock to prevent a race against page
 * allocation.
 */
bool set_hwpoison_free_buddy_page(struct page *page)
{
	struct zone *zone = page_zone(page);
	unsigned long pfn = page_to_pfn(page);
	unsigned long flags;
	unsigned int order;
	bool hwpoisoned = false;

	spin_lock_irqsave(&zone->lock, flags);
	for (order = 0; order < MAX_ORDER; order++) {
		struct page *page_head = page - (pfn & ((1 << order) - 1));

		if (PageBuddy(page_head) && page_order(page_head) >= order) {
			if (!TestSetPageHWPoison(page))
				hwpoisoned = true;
			break;
		}
	}
	spin_unlock_irqrestore(&zone->lock, flags);

	return hwpoisoned;
}
#endif