summaryrefslogtreecommitdiffstats
path: root/drivers/lightnvm/pblk-gc.c
blob: f811e4ca63f4dcab21c468d7a798b2ec2fdc0779 (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
/*
 * Copyright (C) 2016 CNEX Labs
 * Initial release: Javier Gonzalez <javier@cnexlabs.com>
 *                  Matias Bjorling <matias@cnexlabs.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * pblk-gc.c - pblk's garbage collector
 */

#include "pblk.h"
#include <linux/delay.h>

static void pblk_gc_free_gc_rq(struct pblk_gc_rq *gc_rq)
{
	kfree(gc_rq->data);
	kfree(gc_rq->lba_list);
	kfree(gc_rq);
}

static int pblk_gc_write(struct pblk *pblk)
{
	struct pblk_gc *gc = &pblk->gc;
	struct pblk_gc_rq *gc_rq, *tgc_rq;
	LIST_HEAD(w_list);

	spin_lock(&gc->w_lock);
	if (list_empty(&gc->w_list)) {
		spin_unlock(&gc->w_lock);
		return 1;
	}

	list_for_each_entry_safe(gc_rq, tgc_rq, &gc->w_list, list) {
		list_move_tail(&gc_rq->list, &w_list);
		gc->w_entries--;
	}
	spin_unlock(&gc->w_lock);

	list_for_each_entry_safe(gc_rq, tgc_rq, &w_list, list) {
		pblk_write_gc_to_cache(pblk, gc_rq->data, gc_rq->lba_list,
				gc_rq->nr_secs, gc_rq->secs_to_gc,
				gc_rq->line, PBLK_IOTYPE_GC);

		kref_put(&gc_rq->line->ref, pblk_line_put);

		list_del(&gc_rq->list);
		pblk_gc_free_gc_rq(gc_rq);
	}

	return 0;
}

static void pblk_gc_writer_kick(struct pblk_gc *gc)
{
	wake_up_process(gc->gc_writer_ts);
}

/*
 * Responsible for managing all memory related to a gc request. Also in case of
 * failure
 */
static int pblk_gc_move_valid_secs(struct pblk *pblk, struct pblk_line *line,
				   u64 *lba_list, unsigned int nr_secs)
{
	struct nvm_tgt_dev *dev = pblk->dev;
	struct nvm_geo *geo = &dev->geo;
	struct pblk_gc *gc = &pblk->gc;
	struct pblk_gc_rq *gc_rq;
	void *data;
	unsigned int secs_to_gc;
	int ret = NVM_IO_OK;

	data = kmalloc(nr_secs * geo->sec_size, GFP_KERNEL);
	if (!data) {
		ret = NVM_IO_ERR;
		goto free_lba_list;
	}

	/* Read from GC victim block */
	if (pblk_submit_read_gc(pblk, lba_list, data, nr_secs,
							&secs_to_gc, line)) {
		ret = NVM_IO_ERR;
		goto free_data;
	}

	if (!secs_to_gc)
		goto free_data;

	gc_rq = kmalloc(sizeof(struct pblk_gc_rq), GFP_KERNEL);
	if (!gc_rq) {
		ret = NVM_IO_ERR;
		goto free_data;
	}

	gc_rq->line = line;
	gc_rq->data = data;
	gc_rq->lba_list = lba_list;
	gc_rq->nr_secs = nr_secs;
	gc_rq->secs_to_gc = secs_to_gc;

	kref_get(&line->ref);

retry:
	spin_lock(&gc->w_lock);
	if (gc->w_entries > 256) {
		spin_unlock(&gc->w_lock);
		usleep_range(256, 1024);
		goto retry;
	}
	gc->w_entries++;
	list_add_tail(&gc_rq->list, &gc->w_list);
	spin_unlock(&gc->w_lock);

	pblk_gc_writer_kick(&pblk->gc);

	return NVM_IO_OK;

free_data:
	kfree(data);
free_lba_list:
	kfree(lba_list);

	return ret;
}

static void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
{
	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
	struct list_head *move_list;

	spin_lock(&line->lock);
	WARN_ON(line->state != PBLK_LINESTATE_GC);
	line->state = PBLK_LINESTATE_CLOSED;
	move_list = pblk_line_gc_list(pblk, line);
	spin_unlock(&line->lock);

	if (move_list) {
		spin_lock(&l_mg->gc_lock);
		list_add_tail(&line->list, move_list);
		spin_unlock(&l_mg->gc_lock);
	}
}

static void pblk_gc_line_ws(struct work_struct *work)
{
	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
									ws);
	struct pblk *pblk = line_ws->pblk;
	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
	struct pblk_line *line = line_ws->line;
	struct pblk_line_meta *lm = &pblk->lm;
	struct line_emeta *emeta_buf = line_ws->priv;
	__le64 *lba_list;
	u64 *gc_list;
	int sec_left;
	int nr_ppas, bit;
	int put_line = 1;

	pr_debug("pblk: line '%d' being reclaimed for GC\n", line->id);

	/* If this read fails, it means that emeta is corrupted. For now, leave
	 * the line untouched. TODO: Implement a recovery routine that scans and
	 * moves all sectors on the line.
	 */
	lba_list = pblk_recov_get_lba_list(pblk, emeta_buf);
	if (!lba_list) {
		pr_err("pblk: could not interpret emeta (line %d)\n", line->id);
		goto out;
	}

	spin_lock(&line->lock);
	sec_left = le32_to_cpu(*line->vsc);
	if (!sec_left) {
		/* Lines are erased before being used (l_mg->data_/log_next) */
		spin_unlock(&line->lock);
		goto out;
	}
	spin_unlock(&line->lock);

	if (sec_left < 0) {
		pr_err("pblk: corrupted GC line (%d)\n", line->id);
		put_line = 0;
		pblk_put_line_back(pblk, line);
		goto out;
	}

	bit = -1;
next_rq:
	gc_list = kmalloc_array(pblk->max_write_pgs, sizeof(u64), GFP_KERNEL);
	if (!gc_list) {
		put_line = 0;
		pblk_put_line_back(pblk, line);
		goto out;
	}

	nr_ppas = 0;
	do {
		bit = find_next_zero_bit(line->invalid_bitmap, lm->sec_per_line,
								bit + 1);
		if (bit > line->emeta_ssec)
			break;

		gc_list[nr_ppas++] = le64_to_cpu(lba_list[bit]);
	} while (nr_ppas < pblk->max_write_pgs);

	if (unlikely(!nr_ppas)) {
		kfree(gc_list);
		goto out;
	}

	if (pblk_gc_move_valid_secs(pblk, line, gc_list, nr_ppas)) {
		pr_err("pblk: could not GC all sectors: line:%d (%d/%d/%d)\n",
						line->id, *line->vsc,
						nr_ppas, nr_ppas);
		put_line = 0;
		pblk_put_line_back(pblk, line);
		goto out;
	}

	sec_left -= nr_ppas;
	if (sec_left > 0)
		goto next_rq;

out:
	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
	mempool_free(line_ws, pblk->line_ws_pool);
	atomic_dec(&pblk->gc.inflight_gc);
	if (put_line)
		kref_put(&line->ref, pblk_line_put);
}

static int pblk_gc_line(struct pblk *pblk, struct pblk_line *line)
{
	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
	struct pblk_line_meta *lm = &pblk->lm;
	struct line_emeta *emeta_buf;
	struct pblk_line_ws *line_ws;
	int ret;

	line_ws = mempool_alloc(pblk->line_ws_pool, GFP_KERNEL);
	emeta_buf = pblk_malloc(lm->emeta_len[0], l_mg->emeta_alloc_type,
								GFP_KERNEL);
	if (!emeta_buf) {
		pr_err("pblk: cannot use GC emeta\n");
		goto fail_free_ws;
	}

	ret = pblk_line_read_emeta(pblk, line, emeta_buf);
	if (ret) {
		pr_err("pblk: line %d read emeta failed (%d)\n", line->id, ret);
		goto fail_free_emeta;
	}

	line_ws->pblk = pblk;
	line_ws->line = line;
	line_ws->priv = emeta_buf;

	INIT_WORK(&line_ws->ws, pblk_gc_line_ws);
	queue_work(pblk->gc.gc_reader_wq, &line_ws->ws);

	return 0;

fail_free_emeta:
	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
fail_free_ws:
	mempool_free(line_ws, pblk->line_ws_pool);
	pblk_put_line_back(pblk, line);

	return 1;
}

static void pblk_gc_lines(struct pblk *pblk, struct list_head *gc_list)
{
	struct pblk_line *line, *tline;

	list_for_each_entry_safe(line, tline, gc_list, list) {
		if (pblk_gc_line(pblk, line))
			pr_err("pblk: failed to GC line %d\n", line->id);
		list_del(&line->list);
	}
}

static struct pblk_line *pblk_gc_get_victim_line(struct pblk *pblk,
						 struct list_head *group_list)
{
	struct pblk_line *line, *victim;

	victim = list_first_entry(group_list, struct pblk_line, list);
	list_for_each_entry(line, group_list, list) {
		if (*line->vsc < *victim->vsc)
			victim = line;
	}

	return victim;
}

/*
 * Lines with no valid sectors will be returned to the free list immediately. If
 * GC is activated - either because the free block count is under the determined
 * threshold, or because it is being forced from user space - only lines with a
 * high count of invalid sectors will be recycled.
 */
static void pblk_gc_run(struct pblk *pblk)
{
	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
	struct pblk_gc *gc = &pblk->gc;
	struct pblk_line *line, *tline;
	unsigned int nr_blocks_free, nr_blocks_need;
	struct list_head *group_list;
	int run_gc, gc_group = 0;
	int prev_gc = 0;
	int inflight_gc = atomic_read(&gc->inflight_gc);
	LIST_HEAD(gc_list);

	spin_lock(&l_mg->gc_lock);
	list_for_each_entry_safe(line, tline, &l_mg->gc_full_list, list) {
		spin_lock(&line->lock);
		WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
		line->state = PBLK_LINESTATE_GC;
		spin_unlock(&line->lock);

		list_del(&line->list);
		kref_put(&line->ref, pblk_line_put);
	}
	spin_unlock(&l_mg->gc_lock);

	nr_blocks_need = pblk_rl_gc_thrs(&pblk->rl);
	nr_blocks_free = pblk_rl_nr_free_blks(&pblk->rl);
	run_gc = (nr_blocks_need > nr_blocks_free || gc->gc_forced);

next_gc_group:
	group_list = l_mg->gc_lists[gc_group++];
	spin_lock(&l_mg->gc_lock);
	while (run_gc && !list_empty(group_list)) {
		/* No need to queue up more GC lines than we can handle */
		if (!run_gc || inflight_gc > gc->gc_jobs_active) {
			spin_unlock(&l_mg->gc_lock);
			pblk_gc_lines(pblk, &gc_list);
			return;
		}

		line = pblk_gc_get_victim_line(pblk, group_list);
		nr_blocks_free += atomic_read(&line->blk_in_line);

		spin_lock(&line->lock);
		WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
		line->state = PBLK_LINESTATE_GC;
		list_move_tail(&line->list, &gc_list);
		atomic_inc(&gc->inflight_gc);
		inflight_gc++;
		spin_unlock(&line->lock);

		prev_gc = 1;
		run_gc = (nr_blocks_need > nr_blocks_free || gc->gc_forced);
	}
	spin_unlock(&l_mg->gc_lock);

	pblk_gc_lines(pblk, &gc_list);

	if (!prev_gc && pblk->rl.rb_state > gc_group &&
						gc_group < PBLK_NR_GC_LISTS)
		goto next_gc_group;
}


static void pblk_gc_kick(struct pblk *pblk)
{
	struct pblk_gc *gc = &pblk->gc;

	wake_up_process(gc->gc_ts);
	pblk_gc_writer_kick(gc);
	mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
}

static void pblk_gc_timer(unsigned long data)
{
	struct pblk *pblk = (struct pblk *)data;

	pblk_gc_kick(pblk);
}

static int pblk_gc_ts(void *data)
{
	struct pblk *pblk = data;

	while (!kthread_should_stop()) {
		pblk_gc_run(pblk);
		set_current_state(TASK_INTERRUPTIBLE);
		io_schedule();
	}

	return 0;
}

static int pblk_gc_writer_ts(void *data)
{
	struct pblk *pblk = data;

	while (!kthread_should_stop()) {
		if (!pblk_gc_write(pblk))
			continue;
		set_current_state(TASK_INTERRUPTIBLE);
		io_schedule();
	}

	return 0;
}

static void pblk_gc_start(struct pblk *pblk)
{
	pblk->gc.gc_active = 1;

	pr_debug("pblk: gc start\n");
}

int pblk_gc_status(struct pblk *pblk)
{
	struct pblk_gc *gc = &pblk->gc;
	int ret;

	spin_lock(&gc->lock);
	ret = gc->gc_active;
	spin_unlock(&gc->lock);

	return ret;
}

static void __pblk_gc_should_start(struct pblk *pblk)
{
	struct pblk_gc *gc = &pblk->gc;

	lockdep_assert_held(&gc->lock);

	if (gc->gc_enabled && !gc->gc_active)
		pblk_gc_start(pblk);
}

void pblk_gc_should_start(struct pblk *pblk)
{
	struct pblk_gc *gc = &pblk->gc;

	spin_lock(&gc->lock);
	__pblk_gc_should_start(pblk);
	spin_unlock(&gc->lock);
}

/*
 * If flush_wq == 1 then no lock should be held by the caller since
 * flush_workqueue can sleep
 */
static void pblk_gc_stop(struct pblk *pblk, int flush_wq)
{
	spin_lock(&pblk->gc.lock);
	pblk->gc.gc_active = 0;
	spin_unlock(&pblk->gc.lock);

	pr_debug("pblk: gc stop\n");
}

void pblk_gc_should_stop(struct pblk *pblk)
{
	struct pblk_gc *gc = &pblk->gc;

	if (gc->gc_active && !gc->gc_forced)
		pblk_gc_stop(pblk, 0);
}

void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
			      int *gc_active)
{
	struct pblk_gc *gc = &pblk->gc;

	spin_lock(&gc->lock);
	*gc_enabled = gc->gc_enabled;
	*gc_active = gc->gc_active;
	spin_unlock(&gc->lock);
}

void pblk_gc_sysfs_force(struct pblk *pblk, int force)
{
	struct pblk_gc *gc = &pblk->gc;
	int rsv = 0;

	spin_lock(&gc->lock);
	if (force) {
		gc->gc_enabled = 1;
		rsv = 64;
	}
	pblk_rl_set_gc_rsc(&pblk->rl, rsv);
	gc->gc_forced = force;
	__pblk_gc_should_start(pblk);
	spin_unlock(&gc->lock);
}

int pblk_gc_init(struct pblk *pblk)
{
	struct pblk_gc *gc = &pblk->gc;
	int ret;

	gc->gc_ts = kthread_create(pblk_gc_ts, pblk, "pblk-gc-ts");
	if (IS_ERR(gc->gc_ts)) {
		pr_err("pblk: could not allocate GC main kthread\n");
		return PTR_ERR(gc->gc_ts);
	}

	gc->gc_writer_ts = kthread_create(pblk_gc_writer_ts, pblk,
							"pblk-gc-writer-ts");
	if (IS_ERR(gc->gc_writer_ts)) {
		pr_err("pblk: could not allocate GC writer kthread\n");
		ret = PTR_ERR(gc->gc_writer_ts);
		goto fail_free_main_kthread;
	}

	setup_timer(&gc->gc_timer, pblk_gc_timer, (unsigned long)pblk);
	mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));

	gc->gc_active = 0;
	gc->gc_forced = 0;
	gc->gc_enabled = 1;
	gc->gc_jobs_active = 8;
	gc->w_entries = 0;
	atomic_set(&gc->inflight_gc, 0);

	gc->gc_reader_wq = alloc_workqueue("pblk-gc-reader-wq",
			WQ_MEM_RECLAIM | WQ_UNBOUND, gc->gc_jobs_active);
	if (!gc->gc_reader_wq) {
		pr_err("pblk: could not allocate GC reader workqueue\n");
		ret = -ENOMEM;
		goto fail_free_writer_kthread;
	}

	spin_lock_init(&gc->lock);
	spin_lock_init(&gc->w_lock);
	INIT_LIST_HEAD(&gc->w_list);

	return 0;

fail_free_writer_kthread:
	kthread_stop(gc->gc_writer_ts);
fail_free_main_kthread:
	kthread_stop(gc->gc_ts);

	return ret;
}

void pblk_gc_exit(struct pblk *pblk)
{
	struct pblk_gc *gc = &pblk->gc;

	flush_workqueue(gc->gc_reader_wq);

	del_timer(&gc->gc_timer);
	pblk_gc_stop(pblk, 1);

	if (gc->gc_ts)
		kthread_stop(gc->gc_ts);

	if (pblk->gc.gc_reader_wq)
		destroy_workqueue(pblk->gc.gc_reader_wq);

	if (gc->gc_writer_ts)
		kthread_stop(gc->gc_writer_ts);
}