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2019-03-05mm,mremap: bail out earlier in mremap_to under map pressureOscar Salvador1-0/+17
When using mremap() syscall in addition to MREMAP_FIXED flag, mremap() calls mremap_to() which does the following: 1) unmaps the destination region where we are going to move the map 2) If the new region is going to be smaller, we unmap the last part of the old region Then, we will eventually call move_vma() to do the actual move. move_vma() checks whether we are at least 4 maps below max_map_count before going further, otherwise it bails out with -ENOMEM. The problem is that we might have already unmapped the vma's in steps 1) and 2), so it is not possible for userspace to figure out the state of the vmas after it gets -ENOMEM, and it gets tricky for userspace to clean up properly on error path. While it is true that we can return -ENOMEM for more reasons (e.g: see may_expand_vm() or move_page_tables()), I think that we can avoid this scenario if we check early in mremap_to() if the operation has high chances to succeed map-wise. Should that not be the case, we can bail out before we even try to unmap anything, so we make sure the vma's are left untouched in case we are likely to be short of maps. The thumb-rule now is to rely on the worst-scenario case we can have. That is when both vma's (old region and new region) are going to be split in 3, so we get two more maps to the ones we already hold (one per each). If current map count + 2 maps still leads us to 4 maps below the threshold, we are going to pass the check in move_vma(). Of course, this is not free, as it might generate false positives when it is true that we are tight map-wise, but the unmap operation can release several vma's leading us to a good state. Another approach was also investigated [1], but it may be too much hassle for what it brings. [1] https://lore.kernel.org/lkml/20190219155320.tkfkwvqk53tfdojt@d104.suse.de/ Link: http://lkml.kernel.org/r/20190226091314.18446-1-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Cyril Hrubis <chrubis@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/sparse: fix a bad comparisonQian Cai1-1/+1
next_present_section_nr() could only return an unsigned number -1, so just check it specifically where compilers will convert -1 to unsigned if needed. mm/sparse.c: In function 'sparse_init_nid': mm/sparse.c:200:20: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] ((section_nr >= 0) && \ ^~ mm/sparse.c:478:2: note: in expansion of macro 'for_each_present_section_nr' for_each_present_section_nr(pnum_begin, pnum) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/sparse.c:200:20: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] ((section_nr >= 0) && \ ^~ mm/sparse.c:497:2: note: in expansion of macro 'for_each_present_section_nr' for_each_present_section_nr(pnum_begin, pnum) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/sparse.c: In function 'sparse_init': mm/sparse.c:200:20: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] ((section_nr >= 0) && \ ^~ mm/sparse.c:520:2: note: in expansion of macro 'for_each_present_section_nr' for_each_present_section_nr(pnum_begin + 1, pnum_end) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~ Link: http://lkml.kernel.org/r/20190228181839.86504-1-cai@lca.pw Fixes: c4e1be9ec113 ("mm, sparsemem: break out of loops early") Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/memory.c: do_fault: avoid usage of stale vm_area_structJan Stancek1-1/+4
LTP testcase mtest06 [1] can trigger a crash on s390x running 5.0.0-rc8. This is a stress test, where one thread mmaps/writes/munmaps memory area and other thread is trying to read from it: CPU: 0 PID: 2611 Comm: mmap1 Not tainted 5.0.0-rc8+ #51 Hardware name: IBM 2964 N63 400 (z/VM 6.4.0) Krnl PSW : 0404e00180000000 00000000001ac8d8 (__lock_acquire+0x7/0x7a8) Call Trace: ([<0000000000000000>] (null)) [<00000000001adae4>] lock_acquire+0xec/0x258 [<000000000080d1ac>] _raw_spin_lock_bh+0x5c/0x98 [<000000000012a780>] page_table_free+0x48/0x1a8 [<00000000002f6e54>] do_fault+0xdc/0x670 [<00000000002fadae>] __handle_mm_fault+0x416/0x5f0 [<00000000002fb138>] handle_mm_fault+0x1b0/0x320 [<00000000001248cc>] do_dat_exception+0x19c/0x2c8 [<000000000080e5ee>] pgm_check_handler+0x19e/0x200 page_table_free() is called with NULL mm parameter, but because "0" is a valid address on s390 (see S390_lowcore), it keeps going until it eventually crashes in lockdep's lock_acquire. This crash is reproducible at least since 4.14. Problem is that "vmf->vma" used in do_fault() can become stale. Because mmap_sem may be released, other threads can come in, call munmap() and cause "vma" be returned to kmem cache, and get zeroed/re-initialized and re-used: handle_mm_fault | __handle_mm_fault | do_fault | vma = vmf->vma | do_read_fault | __do_fault | vma->vm_ops->fault(vmf); | mmap_sem is released | | | do_munmap() | remove_vma_list() | remove_vma() | vm_area_free() | # vma is released | ... | # same vma is allocated | # from kmem cache | do_mmap() | vm_area_alloc() | memset(vma, 0, ...) | pte_free(vma->vm_mm, ...); | page_table_free | spin_lock_bh(&mm->context.lock);| <crash> | Cache mm_struct to avoid using potentially stale "vma". [1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/mtest06/mmap1.c Link: http://lkml.kernel.org/r/5b3fdf19e2a5be460a384b936f5b56e13733f1b8.1551595137.git.jstancek@redhat.com Signed-off-by: Jan Stancek <jstancek@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Rafael Aquini <aquini@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@surriel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/huge_memory.c: fix "orig_pud" set but not usedQian Cai1-3/+1
Commit a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent hugepages") introduced pudp_huge_get_and_clear_full() but no one uses its return code. In order to not diverge from pmdp_huge_get_and_clear_full(), just change zap_huge_pud() to not assign the return value from pudp_huge_get_and_clear_full(). mm/huge_memory.c: In function 'zap_huge_pud': mm/huge_memory.c:1982:8: warning: variable 'orig_pud' set but not used [-Wunused-but-set-variable] pud_t orig_pud; ^~~~~~~~ Link: http://lkml.kernel.org/r/20190301221956.97493-1-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/hotplug: fix an imbalance with DEBUG_PAGEALLOCQian Cai1-0/+1
When onlining a memory block with DEBUG_PAGEALLOC, it unmaps the pages in the block from kernel, However, it does not map those pages while offlining at the beginning. As the result, it triggers a panic below while onlining on ppc64le as it checks if the pages are mapped before unmapping. However, the imbalance exists for all arches where double-unmappings could happen. Therefore, let kernel map those pages in generic_online_page() before they have being freed into the page allocator for the first time where it will set the page count to one. On the other hand, it works fine during the boot, because at least for IBM POWER8, it does, early_setup early_init_mmu harsh__early_init_mmu htab_initialize [1] htab_bolt_mapping [2] where it effectively map all memblock regions just like kernel_map_linear_page(), so later mem_init() -> memblock_free_all() will unmap them just fine without any imbalance. On other arches without this imbalance checking, it still unmap them once at the most. [1] for_each_memblock(memory, reg) { base = (unsigned long)__va(reg->base); size = reg->size; DBG("creating mapping for region: %lx..%lx (prot: %lx)\n", base, size, prot); BUG_ON(htab_bolt_mapping(base, base + size, __pa(base), prot, mmu_linear_psize, mmu_kernel_ssize)); } [2] linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80; kernel BUG at arch/powerpc/mm/hash_utils_64.c:1815! Oops: Exception in kernel mode, sig: 5 [#1] LE SMP NR_CPUS=256 DEBUG_PAGEALLOC NUMA pSeries CPU: 2 PID: 4298 Comm: bash Not tainted 5.0.0-rc7+ #15 NIP: c000000000062670 LR: c00000000006265c CTR: 0000000000000000 REGS: c0000005bf8a75b0 TRAP: 0700 Not tainted (5.0.0-rc7+) MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 28422842 XER: 00000000 CFAR: c000000000804f44 IRQMASK: 1 NIP [c000000000062670] __kernel_map_pages+0x2e0/0x4f0 LR [c00000000006265c] __kernel_map_pages+0x2cc/0x4f0 Call Trace: __kernel_map_pages+0x2cc/0x4f0 free_unref_page_prepare+0x2f0/0x4d0 free_unref_page+0x44/0x90 __online_page_free+0x84/0x110 online_pages_range+0xc0/0x150 walk_system_ram_range+0xc8/0x120 online_pages+0x280/0x5a0 memory_subsys_online+0x1b4/0x270 device_online+0xc0/0xf0 state_store+0xc0/0x180 dev_attr_store+0x3c/0x60 sysfs_kf_write+0x70/0xb0 kernfs_fop_write+0x10c/0x250 __vfs_write+0x48/0x240 vfs_write+0xd8/0x210 ksys_write+0x70/0x120 system_call+0x5c/0x70 Link: http://lkml.kernel.org/r/20190301220814.97339-1-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: Michal Hocko <mhocko@kernel.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/memcontrol.c: fix bad line in commentQian Cai1-1/+1
Commit 230671533d64 ("mm: memory.low hierarchical behavior") missed an asterisk in one of the comments. mm/memcontrol.c:5774: warning: bad line: | 0, otherwise. Link: http://lkml.kernel.org/r/20190301143734.94393-1-cai@lca.pw Acked-by: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/cma.c: cma_declare_contiguous: correct err handlingPeng Fan1-1/+3
In case cma_init_reserved_mem failed, need to free the memblock allocated by memblock_reserve or memblock_alloc_range. Quote Catalin's comments: https://lkml.org/lkml/2019/2/26/482 Kmemleak is supposed to work with the memblock_{alloc,free} pair and it ignores the memblock_reserve() as a memblock_alloc() implementation detail. It is, however, tolerant to memblock_free() being called on a sub-range or just a different range from a previous memblock_alloc(). So the original patch looks fine to me. FWIW: Link: http://lkml.kernel.org/r/20190227144631.16708-1-peng.fan@nxp.com Signed-off-by: Peng Fan <peng.fan@nxp.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/page_ext.c: fix an imbalance with kmemleakQian Cai1-0/+1
After offlining a memory block, kmemleak scan will trigger a crash, as it encounters a page ext address that has already been freed during memory offlining. At the beginning in alloc_page_ext(), it calls kmemleak_alloc(), but it does not call kmemleak_free() in free_page_ext(). BUG: unable to handle kernel paging request at ffff888453d00000 PGD 128a01067 P4D 128a01067 PUD 128a04067 PMD 47e09e067 PTE 800ffffbac2ff060 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI CPU: 1 PID: 1594 Comm: bash Not tainted 5.0.0-rc8+ #15 Hardware name: HP ProLiant DL180 Gen9/ProLiant DL180 Gen9, BIOS U20 10/25/2017 RIP: 0010:scan_block+0xb5/0x290 Code: 85 6e 01 00 00 48 b8 00 00 30 f5 81 88 ff ff 48 39 c3 0f 84 5b 01 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 0f 85 87 01 00 00 <4c> 8b 3b e8 f3 0c fa ff 4c 39 3d 0c 6b 4c 01 0f 87 08 01 00 00 4c RSP: 0018:ffff8881ec57f8e0 EFLAGS: 00010082 RAX: 0000000000000000 RBX: ffff888453d00000 RCX: ffffffffa61e5a54 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888453d00000 RBP: ffff8881ec57f920 R08: fffffbfff4ed588d R09: fffffbfff4ed588c R10: fffffbfff4ed588c R11: ffffffffa76ac463 R12: dffffc0000000000 R13: ffff888453d00ff9 R14: ffff8881f80cef48 R15: ffff8881f80cef48 FS: 00007f6c0e3f8740(0000) GS:ffff8881f7680000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888453d00000 CR3: 00000001c4244003 CR4: 00000000001606a0 Call Trace: scan_gray_list+0x269/0x430 kmemleak_scan+0x5a8/0x10f0 kmemleak_write+0x541/0x6ca full_proxy_write+0xf8/0x190 __vfs_write+0xeb/0x980 vfs_write+0x15a/0x4f0 ksys_write+0xd2/0x1b0 __x64_sys_write+0x73/0xb0 do_syscall_64+0xeb/0xaaa entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f6c0dad73b8 Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 65 63 2d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55 RSP: 002b:00007ffd5b863cb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f6c0dad73b8 RDX: 0000000000000005 RSI: 000055a9216e1710 RDI: 0000000000000001 RBP: 000055a9216e1710 R08: 000000000000000a R09: 00007ffd5b863840 R10: 000000000000000a R11: 0000000000000246 R12: 00007f6c0dda9780 R13: 0000000000000005 R14: 00007f6c0dda4740 R15: 0000000000000005 Modules linked in: nls_iso8859_1 nls_cp437 vfat fat kvm_intel kvm irqbypass efivars ip_tables x_tables xfs sd_mod ahci libahci igb i2c_algo_bit libata i2c_core dm_mirror dm_region_hash dm_log dm_mod efivarfs CR2: ffff888453d00000 ---[ end trace ccf646c7456717c5 ]--- Kernel panic - not syncing: Fatal exception Shutting down cpus with NMI Kernel Offset: 0x24c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception ]--- Link: http://lkml.kernel.org/r/20190227173147.75650-1-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/compaction: pass pgdat to too_many_isolated() instead of zoneAndrey Ryabinin1-10/+9
too_many_isolated() in mm/compaction.c looks only at node state, so it makes more sense to change argument to pgdat instead of zone. Link: http://lkml.kernel.org/r/20190228083329.31892-3-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Rik van Riel <riel@surriel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: William Kucharski <william.kucharski@oracle.com> Cc: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: remove zone_lru_lock() function, access ->lru_lock directlyAndrey Ryabinin9-49/+50
We have common pattern to access lru_lock from a page pointer: zone_lru_lock(page_zone(page)) Which is silly, because it unfolds to this: &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)]->zone_pgdat->lru_lock while we can simply do &NODE_DATA(page_to_nid(page))->lru_lock Remove zone_lru_lock() function, since it's only complicate things. Use 'page_pgdat(page)->lru_lock' pattern instead. [aryabinin@virtuozzo.com: a slightly better version of __split_huge_page()] Link: http://lkml.kernel.org/r/20190301121651.7741-1-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/20190228083329.31892-2-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/workingset: remove unused @mapping argument in workingset_eviction()Andrey Ryabinin2-4/+3
workingset_eviction() doesn't use and never did use the @mapping argument. Remove it. Link: http://lkml.kernel.org/r/20190228083329.31892-1-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Rik van Riel <riel@surriel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: William Kucharski <william.kucharski@oracle.com> Cc: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/swapfile.c: use struct_size() in kvzalloc()Gustavo A. R. Silva1-2/+1
One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; struct boo entry[]; }; size = sizeof(struct foo) + count * sizeof(struct boo); instance = kvzalloc(size, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kvzalloc(struct_size(instance, entry, count), GFP_KERNEL); Notice that, in this case, variable size is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Link: http://lkml.kernel.org/r/20190221154622.GA19599@embeddedor Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/cma_debug.c: remove static scoped cma_debugfs_rootYue Hu1-5/+4
Currently cma_debugfs_root is static storage. That is unnecessary since it will be only used by next cma_debugfs_add_one(). We can just pass it to following calling to save thisspace. Also remove useless idx parameter. Link: http://lkml.kernel.org/r/20190221040130.8940-1-zbestahu@gmail.com Signed-off-by: Yue Hu <huyue2@yulong.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/shmem: make find_get_pages_range() work for huge pageYu Zhao1-2/+2
find_get_pages_range() and find_get_pages_range_tag() already correctly increment reference count on head when seeing compound page, but they may still use page index from tail. Page index from tail is always zero, so these functions don't work on huge shmem. This hasn't been a problem because, AFAIK, nobody calls these functions on (huge) shmem. Fix them anyway just in case. Link: http://lkml.kernel.org/r/20190110030838.84446-1-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Dave Chinner <david@fromorbit.com> Cc: "Darrick J . Wong" <darrick.wong@oracle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: unexport free_reserved_areaChristoph Hellwig1-1/+0
This function is only used by built-in code, which makes perfect sense given the purpose of it. Link: http://lkml.kernel.org/r/20190213174621.29297-2-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm,memory_hotplug: explicitly pass the head to isolate_huge_pageOscar Salvador1-2/+2
isolate_huge_page() expects we pass the head of hugetlb page to it: bool isolate_huge_page(...) { ... VM_BUG_ON_PAGE(!PageHead(page), page); ... } While I really cannot think of any situation where we end up with a non-head page between hands in do_migrate_range(), let us make sure the code is as sane as possible by explicitly passing the Head. Since we already got the pointer, it does not take us extra effort. Link: http://lkml.kernel.org/r/20190208090604.975-1-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Anthony Yznaga <anthony.yznaga@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/migrate.c: cleanup expected_page_refs()Jan Kara1-4/+4
Andrea has noted that page migration code propagates page_mapping(page) through the whole migration stack down to migrate_page() function so it seems stupid to then use page_mapping(page) in expected_page_refs() instead of passed down 'mapping' argument. I agree so let's make expected_page_refs() more in line with the rest of the migration stack. Link: http://lkml.kernel.org/r/20190207112314.24872-1-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Suggested-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05docs/core-api/mm: fix return value descriptions in mm/Mike Rapoport12-59/+221
Many kernel-doc comments in mm/ have the return value descriptions either misformatted or omitted at all which makes kernel-doc script unhappy: $ make V=1 htmldocs ... ./mm/util.c:36: info: Scanning doc for kstrdup ./mm/util.c:41: warning: No description found for return value of 'kstrdup' ./mm/util.c:57: info: Scanning doc for kstrdup_const ./mm/util.c:66: warning: No description found for return value of 'kstrdup_const' ./mm/util.c:75: info: Scanning doc for kstrndup ./mm/util.c:83: warning: No description found for return value of 'kstrndup' ... Fixing the formatting and adding the missing return value descriptions eliminates ~100 such warnings. Link: http://lkml.kernel.org/r/1549549644-4903-4-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05docs/mm: vmalloc: re-indent kernel-doc comemntsMike Rapoport1-185/+182
Some kernel-doc comments in mm/vmalloc.c have leading tab in indentation. This leads to excessive indentation in the generated HTML and to the inconsistency of its layout ([1] vs [2]). Besides, multi-line Note: sections are not handled properly with extra indentation. [1] https://www.kernel.org/doc/html/v4.20/core-api/mm-api.html?#c.vm_map_ram [2] https://www.kernel.org/doc/html/v4.20/core-api/mm-api.html?#c.vfree Link: http://lkml.kernel.org/r/1549549644-4903-2-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05numa: make "nr_online_nodes" unsigned intAlexey Dobriyan1-2/+2
Number of online NUMA nodes can't be negative as well. This doesn't save space as the variable is used only in 32-bit context, but do it anyway for consistency. Link: http://lkml.kernel.org/r/20190201223151.GB15820@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05numa: make "nr_node_ids" unsigned intAlexey Dobriyan7-9/+7
Number of NUMA nodes can't be negative. This saves a few bytes on x86_64: add/remove: 0/0 grow/shrink: 4/21 up/down: 27/-265 (-238) Function old new delta hv_synic_alloc.cold 88 110 +22 prealloc_shrinker 260 262 +2 bootstrap 249 251 +2 sched_init_numa 1566 1567 +1 show_slab_objects 778 777 -1 s_show 1201 1200 -1 kmem_cache_init 346 345 -1 __alloc_workqueue_key 1146 1145 -1 mem_cgroup_css_alloc 1614 1612 -2 __do_sys_swapon 4702 4699 -3 __list_lru_init 655 651 -4 nic_probe 2379 2374 -5 store_user_store 118 111 -7 red_zone_store 106 99 -7 poison_store 106 99 -7 wq_numa_init 348 338 -10 __kmem_cache_empty 75 65 -10 task_numa_free 186 173 -13 merge_across_nodes_store 351 336 -15 irq_create_affinity_masks 1261 1246 -15 do_numa_crng_init 343 321 -22 task_numa_fault 4760 4737 -23 swapfile_init 179 156 -23 hv_synic_alloc 536 492 -44 apply_wqattrs_prepare 746 695 -51 Link: http://lkml.kernel.org/r/20190201223029.GA15820@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm,oom: don't kill global init via memory.oom.groupTetsuo Handa1-1/+2
Since setting global init process to some memory cgroup is technically possible, oom_kill_memcg_member() must check it. Tasks in /test1 are going to be killed due to memory.oom.group set Memory cgroup out of memory: Killed process 1 (systemd) total-vm:43400kB, anon-rss:1228kB, file-rss:3992kB, shmem-rss:0kB oom_reaper: reaped process 1 (systemd), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000008b #include <stdio.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> int main(int argc, char *argv[]) { static char buffer[10485760]; static int pipe_fd[2] = { EOF, EOF }; unsigned int i; int fd; char buf[64] = { }; if (pipe(pipe_fd)) return 1; if (chdir("/sys/fs/cgroup/")) return 1; fd = open("cgroup.subtree_control", O_WRONLY); write(fd, "+memory", 7); close(fd); mkdir("test1", 0755); fd = open("test1/memory.oom.group", O_WRONLY); write(fd, "1", 1); close(fd); fd = open("test1/cgroup.procs", O_WRONLY); write(fd, "1", 1); snprintf(buf, sizeof(buf) - 1, "%d", getpid()); write(fd, buf, strlen(buf)); close(fd); snprintf(buf, sizeof(buf) - 1, "%lu", sizeof(buffer) * 5); fd = open("test1/memory.max", O_WRONLY); write(fd, buf, strlen(buf)); close(fd); for (i = 0; i < 10; i++) if (fork() == 0) { char c; close(pipe_fd[1]); read(pipe_fd[0], &c, 1); memset(buffer, 0, sizeof(buffer)); sleep(3); _exit(0); } close(pipe_fd[0]); close(pipe_fd[1]); sleep(3); return 0; } [ 37.052923][ T9185] a.out invoked oom-killer: gfp_mask=0xcc0(GFP_KERNEL), order=0, oom_score_adj=0 [ 37.056169][ T9185] CPU: 4 PID: 9185 Comm: a.out Kdump: loaded Not tainted 5.0.0-rc4-next-20190131 #280 [ 37.059205][ T9185] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 37.062954][ T9185] Call Trace: [ 37.063976][ T9185] dump_stack+0x67/0x95 [ 37.065263][ T9185] dump_header+0x51/0x570 [ 37.066619][ T9185] ? trace_hardirqs_on+0x3f/0x110 [ 37.068171][ T9185] ? _raw_spin_unlock_irqrestore+0x3d/0x70 [ 37.069967][ T9185] oom_kill_process+0x18d/0x210 [ 37.071515][ T9185] out_of_memory+0x11b/0x380 [ 37.072936][ T9185] mem_cgroup_out_of_memory+0xb6/0xd0 [ 37.074601][ T9185] try_charge+0x790/0x820 [ 37.076021][ T9185] mem_cgroup_try_charge+0x42/0x1d0 [ 37.077629][ T9185] mem_cgroup_try_charge_delay+0x11/0x30 [ 37.079370][ T9185] do_anonymous_page+0x105/0x5e0 [ 37.080939][ T9185] __handle_mm_fault+0x9cb/0x1070 [ 37.082485][ T9185] handle_mm_fault+0x1b2/0x3a0 [ 37.083819][ T9185] ? handle_mm_fault+0x47/0x3a0 [ 37.085181][ T9185] __do_page_fault+0x255/0x4c0 [ 37.086529][ T9185] do_page_fault+0x28/0x260 [ 37.087788][ T9185] ? page_fault+0x8/0x30 [ 37.088978][ T9185] page_fault+0x1e/0x30 [ 37.090142][ T9185] RIP: 0033:0x7f8b183aefe0 [ 37.091433][ T9185] Code: 20 f3 44 0f 7f 44 17 d0 f3 44 0f 7f 47 30 f3 44 0f 7f 44 17 c0 48 01 fa 48 83 e2 c0 48 39 d1 74 a3 66 0f 1f 84 00 00 00 00 00 <66> 44 0f 7f 01 66 44 0f 7f 41 10 66 44 0f 7f 41 20 66 44 0f 7f 41 [ 37.096917][ T9185] RSP: 002b:00007fffc5d329e8 EFLAGS: 00010206 [ 37.098615][ T9185] RAX: 00000000006010e0 RBX: 0000000000000008 RCX: 0000000000c30000 [ 37.100905][ T9185] RDX: 00000000010010c0 RSI: 0000000000000000 RDI: 00000000006010e0 [ 37.103349][ T9185] RBP: 0000000000000000 R08: 00007f8b188f4740 R09: 0000000000000000 [ 37.105797][ T9185] R10: 00007fffc5d32420 R11: 00007f8b183aef40 R12: 0000000000000005 [ 37.108228][ T9185] R13: 0000000000000000 R14: ffffffffffffffff R15: 0000000000000000 [ 37.110840][ T9185] memory: usage 51200kB, limit 51200kB, failcnt 125 [ 37.113045][ T9185] memory+swap: usage 0kB, limit 9007199254740988kB, failcnt 0 [ 37.115808][ T9185] kmem: usage 0kB, limit 9007199254740988kB, failcnt 0 [ 37.117660][ T9185] Memory cgroup stats for /test1: cache:0KB rss:49484KB rss_huge:30720KB shmem:0KB mapped_file:0KB dirty:0KB writeback:0KB inactive_anon:0KB active_anon:49700KB inactive_file:0KB active_file:0KB unevictable:0KB [ 37.123371][ T9185] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,oom_memcg=/test1,task_memcg=/test1,task=a.out,pid=9188,uid=0 [ 37.128158][ T9185] Memory cgroup out of memory: Killed process 9188 (a.out) total-vm:14456kB, anon-rss:10324kB, file-rss:504kB, shmem-rss:0kB [ 37.132710][ T9185] Tasks in /test1 are going to be killed due to memory.oom.group set [ 37.132833][ T54] oom_reaper: reaped process 9188 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [ 37.135498][ T9185] Memory cgroup out of memory: Killed process 1 (systemd) total-vm:43400kB, anon-rss:1228kB, file-rss:3992kB, shmem-rss:0kB [ 37.143434][ T9185] Memory cgroup out of memory: Killed process 9182 (a.out) total-vm:14456kB, anon-rss:76kB, file-rss:588kB, shmem-rss:0kB [ 37.144328][ T54] oom_reaper: reaped process 1 (systemd), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [ 37.147585][ T9185] Memory cgroup out of memory: Killed process 9183 (a.out) total-vm:14456kB, anon-rss:6228kB, file-rss:512kB, shmem-rss:0kB [ 37.157222][ T9185] Memory cgroup out of memory: Killed process 9184 (a.out) total-vm:14456kB, anon-rss:6228kB, file-rss:508kB, shmem-rss:0kB [ 37.157259][ T9185] Memory cgroup out of memory: Killed process 9185 (a.out) total-vm:14456kB, anon-rss:6228kB, file-rss:512kB, shmem-rss:0kB [ 37.157291][ T9185] Memory cgroup out of memory: Killed process 9186 (a.out) total-vm:14456kB, anon-rss:4180kB, file-rss:508kB, shmem-rss:0kB [ 37.157306][ T54] oom_reaper: reaped process 9183 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [ 37.157328][ T9185] Memory cgroup out of memory: Killed process 9187 (a.out) total-vm:14456kB, anon-rss:4180kB, file-rss:512kB, shmem-rss:0kB [ 37.157452][ T9185] Memory cgroup out of memory: Killed process 9189 (a.out) total-vm:14456kB, anon-rss:6228kB, file-rss:512kB, shmem-rss:0kB [ 37.158733][ T9185] Memory cgroup out of memory: Killed process 9190 (a.out) total-vm:14456kB, anon-rss:552kB, file-rss:512kB, shmem-rss:0kB [ 37.160083][ T54] oom_reaper: reaped process 9186 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [ 37.160187][ T54] oom_reaper: reaped process 9189 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [ 37.206941][ T54] oom_reaper: reaped process 9185 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [ 37.212300][ T9185] Memory cgroup out of memory: Killed process 9191 (a.out) total-vm:14456kB, anon-rss:4180kB, file-rss:512kB, shmem-rss:0kB [ 37.212317][ T54] oom_reaper: reaped process 9190 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [ 37.218860][ T9185] Memory cgroup out of memory: Killed process 9192 (a.out) total-vm:14456kB, anon-rss:1080kB, file-rss:512kB, shmem-rss:0kB [ 37.227667][ T54] oom_reaper: reaped process 9192 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [ 37.292323][ T9193] abrt-hook-ccpp (9193) used greatest stack depth: 10480 bytes left [ 37.351843][ T1] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000008b [ 37.354833][ T1] CPU: 7 PID: 1 Comm: systemd Kdump: loaded Not tainted 5.0.0-rc4-next-20190131 #280 [ 37.357876][ T1] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 37.361685][ T1] Call Trace: [ 37.363239][ T1] dump_stack+0x67/0x95 [ 37.365010][ T1] panic+0xfc/0x2b0 [ 37.366853][ T1] do_exit+0xd55/0xd60 [ 37.368595][ T1] do_group_exit+0x47/0xc0 [ 37.370415][ T1] get_signal+0x32a/0x920 [ 37.372449][ T1] ? _raw_spin_unlock_irqrestore+0x3d/0x70 [ 37.374596][ T1] do_signal+0x32/0x6e0 [ 37.376430][ T1] ? exit_to_usermode_loop+0x26/0x9b [ 37.378418][ T1] ? prepare_exit_to_usermode+0xa8/0xd0 [ 37.380571][ T1] exit_to_usermode_loop+0x3e/0x9b [ 37.382588][ T1] prepare_exit_to_usermode+0xa8/0xd0 [ 37.384594][ T1] ? page_fault+0x8/0x30 [ 37.386453][ T1] retint_user+0x8/0x18 [ 37.388160][ T1] RIP: 0033:0x7f42c06974a8 [ 37.389922][ T1] Code: Bad RIP value. [ 37.391788][ T1] RSP: 002b:00007ffc3effd388 EFLAGS: 00010213 [ 37.394075][ T1] RAX: 000000000000000e RBX: 00007ffc3effd390 RCX: 0000000000000000 [ 37.396963][ T1] RDX: 000000000000002a RSI: 00007ffc3effd390 RDI: 0000000000000004 [ 37.399550][ T1] RBP: 00007ffc3effd680 R08: 0000000000000000 R09: 0000000000000000 [ 37.402334][ T1] R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000001 [ 37.404890][ T1] R13: ffffffffffffffff R14: 0000000000000884 R15: 000056460b1ac3b0 Link: http://lkml.kernel.org/r/201902010336.x113a4EO027170@www262.sakura.ne.jp Fixes: 3d8b38eb81cac813 ("mm, oom: introduce memory.oom.group") Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <guro@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm, swap: bounds check swap_info array accesses to avoid NULL derefsDaniel Jordan1-22/+29
Dan Carpenter reports a potential NULL dereference in get_swap_page_of_type: Smatch complains that the NULL checks on "si" aren't consistent. This seems like a real bug because we have not ensured that the type is valid and so "si" can be NULL. Add the missing check for NULL, taking care to use a read barrier to ensure CPU1 observes CPU0's updates in the correct order: CPU0 CPU1 alloc_swap_info() if (type >= nr_swapfiles) swap_info[type] = p /* handle invalid entry */ smp_wmb() smp_rmb() ++nr_swapfiles p = swap_info[type] Without smp_rmb, CPU1 might observe CPU0's write to nr_swapfiles before CPU0's write to swap_info[type] and read NULL from swap_info[type]. Ying Huang noticed other places in swapfile.c don't order these reads properly. Introduce swap_type_to_swap_info to encourage correct usage. Use READ_ONCE and WRITE_ONCE to follow the Linux Kernel Memory Model (see tools/memory-model/Documentation/explanation.txt). This ordering need not be enforced in places where swap_lock is held (e.g. si_swapinfo) because swap_lock serializes updates to nr_swapfiles and the swap_info array. Link: http://lkml.kernel.org/r/20190131024410.29859-1-daniel.m.jordan@oracle.com Fixes: ec8acf20afb8 ("swap: add per-partition lock for swapfile") Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Suggested-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Shaohua Li <shli@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tejun Heo <tj@kernel.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/vmscan.c: do not allocate duplicate stack variables in shrink_page_list()Kirill Tkhai1-30/+14
On path shrink_inactive_list() ---> shrink_page_list() we allocate stack variables for the statistics twice. This is completely useless, and this just consumes stack much more, then we really need. The patch kills duplicate stack variables from shrink_page_list(), and this reduce stack usage and object file size significantly: Stack usage: Before: vmscan.c:1122:22:shrink_page_list 648 static After: vmscan.c:1122:22:shrink_page_list 616 static Size of vmscan.o: text data bss dec hex filename Before: 56866 4720 128 61714 f112 mm/vmscan.o After: 56770 4720 128 61618 f0b2 mm/vmscan.o Link: http://lkml.kernel.org/r/154894900030.5211.12104993874109647641.stgit@localhost.localdomain Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: ksm: do not block on page lock when searching stable treeYang Shi1-10/+35
ksmd needs to search the stable tree to look for the suitable KSM page, but the KSM page might be locked for a while due to i.e. KSM page rmap walk. Basically it is not a big deal since commit 2c653d0ee2ae ("ksm: introduce ksm_max_page_sharing per page deduplication limit"), since max_page_sharing limits the number of shared KSM pages. But it still sounds not worth waiting for the lock, the page can be skip, then try to merge it in the next scan to avoid potential stall if its content is still intact. Introduce trylock mode to get_ksm_page() to not block on page lock, like what try_to_merge_one_page() does. And, define three possible operations (nolock, lock and trylock) as enum type to avoid stacking up bools and make the code more readable. Return -EBUSY if trylock fails, since NULL means not find suitable KSM page, which is a valid case. With the default max_page_sharing setting (256), there is almost no observed change comparing lock vs trylock. However, with ksm02 of LTP, the reduced ksmd full scan time can be observed, which has set max_page_sharing to 786432. With lock version, ksmd may tak 10s - 11s to run two full scans, with trylock version ksmd may take 8s - 11s to run two full scans. And, the number of pages_sharing and pages_to_scan keep same. Basically, this change has no harm. [hughd@google.com: fix BUG_ON()] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1902182122280.6914@eggly.anvils Link: http://lkml.kernel.org/r/1548793753-62377-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Hugh Dickins <hughd@google.com> Suggested-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: memcontrol: expose THP events on a per-memcg basisChris Down3-0/+20
Currently THP allocation events data is fairly opaque, since you can only get it system-wide. This patch makes it easier to reason about transparent hugepage behaviour on a per-memcg basis. For anonymous THP-backed pages, we already have MEMCG_RSS_HUGE in v1, which is used for v1's rss_huge [sic]. This is reused here as it's fairly involved to untangle NR_ANON_THPS right now to make it per-memcg, since right now some of this is delegated to rmap before we have any memcg actually assigned to the page. It's a good idea to rework that, but let's leave untangling THP allocation for a future patch. [akpm@linux-foundation.org: fix build] [chris@chrisdown.name: fix memcontrol build when THP is disabled] Link: http://lkml.kernel.org/r/20190131160802.GA5777@chrisdown.name Link: http://lkml.kernel.org/r/20190129205852.GA7310@chrisdown.name Signed-off-by: Chris Down <chris@chrisdown.name> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: vmscan: do not iterate all mem cgroups for global direct reclaimYang Shi1-4/+3
In current implementation, both kswapd and direct reclaim has to iterate all mem cgroups. It is not a problem before offline mem cgroups could be iterated. But, currently with iterating offline mem cgroups, it could be very time consuming. In our workloads, we saw over 400K mem cgroups accumulated in some cases, only a few hundred are online memcgs. Although kswapd could help out to reduce the number of memcgs, direct reclaim still get hit with iterating a number of offline memcgs in some cases. We experienced the responsiveness problems due to this occassionally. A simple test with pref shows it may take around 220ms to iterate 8K memcgs in direct reclaim: dd 13873 [011] 578.542919: vmscan:mm_vmscan_direct_reclaim_begin dd 13873 [011] 578.758689: vmscan:mm_vmscan_direct_reclaim_end So for 400K, it may take around 11 seconds to iterate all memcgs. Here just break the iteration once it reclaims enough pages as what memcg direct reclaim does. This may hurt the fairness among memcgs. But the cached iterator cookie could help to achieve the fairness more or less. Link: http://lkml.kernel.org/r/1548799877-10949-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfdJoel Fernandes (Google)2-4/+24
Android uses ashmem for sharing memory regions. We are looking forward to migrating all usecases of ashmem to memfd so that we can possibly remove the ashmem driver in the future from staging while also benefiting from using memfd and contributing to it. Note staging drivers are also not ABI and generally can be removed at anytime. One of the main usecases Android has is the ability to create a region and mmap it as writeable, then add protection against making any "future" writes while keeping the existing already mmap'ed writeable-region active. This allows us to implement a usecase where receivers of the shared memory buffer can get a read-only view, while the sender continues to write to the buffer. See CursorWindow documentation in Android for more details: https://developer.android.com/reference/android/database/CursorWindow This usecase cannot be implemented with the existing F_SEAL_WRITE seal. To support the usecase, this patch adds a new F_SEAL_FUTURE_WRITE seal which prevents any future mmap and write syscalls from succeeding while keeping the existing mmap active. A better way to do F_SEAL_FUTURE_WRITE seal was discussed [1] last week where we don't need to modify core VFS structures to get the same behavior of the seal. This solves several side-effects pointed by Andy. self-tests are provided in later patch to verify the expected semantics. [1] https://lore.kernel.org/lkml/20181111173650.GA256781@google.com/ Thanks a lot to Andy for suggestions to improve code. Link: http://lkml.kernel.org/r/20190112203816.85534-2-joel@joelfernandes.org Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: J. Bruce Fields <bfields@fieldses.org> Cc: Jeff Layton <jlayton@kernel.org> Cc: Marc-Andr Lureau <marcandre.lureau@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: update get_user_pages_longterm to migrate pages allocated from CMA regionAneesh Kumar K.V2-26/+178
This patch updates get_user_pages_longterm to migrate pages allocated out of CMA region. This makes sure that we don't keep non-movable pages (due to page reference count) in the CMA area. This will be used by ppc64 in a later patch to avoid pinning pages in the CMA region. ppc64 uses CMA region for allocation of the hardware page table (hash page table) and not able to migrate pages out of CMA region results in page table allocation failures. One case where we hit this easy is when a guest using a VFIO passthrough device. VFIO locks all the guest's memory and if the guest memory is backed by CMA region, it becomes unmovable resulting in fragmenting the CMA and possibly preventing other guests from allocation a large enough hash page table. NOTE: We allocate the new page without using __GFP_THISNODE Link: http://lkml.kernel.org/r/20190114095438.32470-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: rid swapoff of quadratic complexityVineeth Remanan Pillai2-390/+310
This patch was initially posted by Kelley Nielsen. Reposting the patch with all review comments addressed and with minor modifications and optimizations. Also, folding in the fixes offered by Hugh Dickins and Huang Ying. Tests were rerun and commit message updated with new results. try_to_unuse() is of quadratic complexity, with a lot of wasted effort. It unuses swap entries one by one, potentially iterating over all the page tables for all the processes in the system for each one. This new proposed implementation of try_to_unuse simplifies its complexity to linear. It iterates over the system's mms once, unusing all the affected entries as it walks each set of page tables. It also makes similar changes to shmem_unuse. Improvement swapoff was called on a swap partition containing about 6G of data, in a VM(8cpu, 16G RAM), and calls to unuse_pte_range() were counted. Present implementation....about 1200M calls(8min, avg 80% cpu util). Prototype.................about 9.0K calls(3min, avg 5% cpu util). Details In shmem_unuse(), iterate over the shmem_swaplist and, for each shmem_inode_info that contains a swap entry, pass it to shmem_unuse_inode(), along with the swap type. In shmem_unuse_inode(), iterate over its associated xarray, and store the index and value of each swap entry in an array for passing to shmem_swapin_page() outside of the RCU critical section. In try_to_unuse(), instead of iterating over the entries in the type and unusing them one by one, perhaps walking all the page tables for all the processes for each one, iterate over the mmlist, making one pass. Pass each mm to unuse_mm() to begin its page table walk, and during the walk, unuse all the ptes that have backing store in the swap type received by try_to_unuse(). After the walk, check the type for orphaned swap entries with find_next_to_unuse(), and remove them from the swap cache. If find_next_to_unuse() starts over at the beginning of the type, repeat the check of the shmem_swaplist and the walk a maximum of three times. Change unuse_mm() and the intervening walk functions down to unuse_pte_range() to take the type as a parameter, and to iterate over their entire range, calling the next function down on every iteration. In unuse_pte_range(), make a swap entry from each pte in the range using the passed in type. If it has backing store in the type, call swapin_readahead() to retrieve the page and pass it to unuse_pte(). Pass the count of pages_to_unuse down the page table walks in try_to_unuse(), and return from the walk when the desired number of pages has been swapped back in. Link: http://lkml.kernel.org/r/20190114153129.4852-2-vpillai@digitalocean.com Signed-off-by: Vineeth Remanan Pillai <vpillai@digitalocean.com> Signed-off-by: Kelley Nielsen <kelleynnn@gmail.com> Signed-off-by: Huang Ying <ying.huang@intel.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: refactor swap-in logic out of shmem_getpage_gfpVineeth Remanan Pillai1-205/+244
swapin logic can be reused independently without rest of the logic in shmem_getpage_gfp. So lets refactor it out as an independent function. Link: http://lkml.kernel.org/r/20190114153129.4852-1-vpillai@digitalocean.com Signed-off-by: Vineeth Remanan Pillai <vpillai@digitalocean.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kelley Nielsen <kelleynnn@gmail.com> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/vmscan.c: remove 7th argument of isolate_lru_pages()Kirill Tkhai1-11/+4
We may simply check for sc->may_unmap in isolate_lru_pages() instead of doing that in both of its callers. Link: http://lkml.kernel.org/r/154748280735.29962.15867846875217618569.stgit@localhost.localdomain Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm, mempolicy: fix uninit memory accessVlastimil Babka1-1/+1
Syzbot with KMSAN reports (excerpt): ================================================================== BUG: KMSAN: uninit-value in mpol_rebind_policy mm/mempolicy.c:353 [inline] BUG: KMSAN: uninit-value in mpol_rebind_mm+0x249/0x370 mm/mempolicy.c:384 CPU: 1 PID: 17420 Comm: syz-executor4 Not tainted 4.20.0-rc7+ #15 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x173/0x1d0 lib/dump_stack.c:113 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613 __msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:295 mpol_rebind_policy mm/mempolicy.c:353 [inline] mpol_rebind_mm+0x249/0x370 mm/mempolicy.c:384 update_tasks_nodemask+0x608/0xca0 kernel/cgroup/cpuset.c:1120 update_nodemasks_hier kernel/cgroup/cpuset.c:1185 [inline] update_nodemask kernel/cgroup/cpuset.c:1253 [inline] cpuset_write_resmask+0x2a98/0x34b0 kernel/cgroup/cpuset.c:1728 ... Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:204 [inline] kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:158 kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176 kmem_cache_alloc+0x572/0xb90 mm/slub.c:2777 mpol_new mm/mempolicy.c:276 [inline] do_mbind mm/mempolicy.c:1180 [inline] kernel_mbind+0x8a7/0x31a0 mm/mempolicy.c:1347 __do_sys_mbind mm/mempolicy.c:1354 [inline] As it's difficult to report where exactly the uninit value resides in the mempolicy object, we have to guess a bit. mm/mempolicy.c:353 contains this part of mpol_rebind_policy(): if (!mpol_store_user_nodemask(pol) && nodes_equal(pol->w.cpuset_mems_allowed, *newmask)) "mpol_store_user_nodemask(pol)" is testing pol->flags, which I couldn't ever see being uninitialized after leaving mpol_new(). So I'll guess it's actually about accessing pol->w.cpuset_mems_allowed on line 354, but still part of statement starting on line 353. For w.cpuset_mems_allowed to be not initialized, and the nodes_equal() reachable for a mempolicy where mpol_set_nodemask() is called in do_mbind(), it seems the only possibility is a MPOL_PREFERRED policy with empty set of nodes, i.e. MPOL_LOCAL equivalent, with MPOL_F_LOCAL flag. Let's exclude such policies from the nodes_equal() check. Note the uninit access should be benign anyway, as rebinding this kind of policy is always a no-op. Therefore no actual need for stable inclusion. Link: http://lkml.kernel.org/r/a71997c3-e8ae-a787-d5ce-3db05768b27c@suse.cz Link: http://lkml.kernel.org/r/73da3e9c-cc84-509e-17d9-0c434bb9967d@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: syzbot+b19c2dc2c990ea657a71@syzkaller.appspotmail.com Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Yisheng Xie <xieyisheng1@huawei.com> Cc: zhong jiang <zhongjiang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05memcg: killed threads should not invoke memcg OOM killerTetsuo Handa1-5/+14
If a memory cgroup contains a single process with many threads (including different process group sharing the mm) then it is possible to trigger a race when the oom killer complains that there are no oom elible tasks and complain into the log which is both annoying and confusing because there is no actual problem. The race looks as follows: P1 oom_reaper P2 try_charge try_charge mem_cgroup_out_of_memory mutex_lock(oom_lock) out_of_memory oom_kill_process(P1,P2) wake_oom_reaper mutex_unlock(oom_lock) oom_reap_task mutex_lock(oom_lock) select_bad_process # no victim The problem is more visible with many threads. Fix this by checking for fatal_signal_pending from mem_cgroup_out_of_memory when the oom_lock is already held. The oom bypass is safe because we do the same early in the try_charge path already. The situation migh have changed in the mean time. It should be safe to check for fatal_signal_pending and tsk_is_oom_victim but for a better code readability abstract the current charge bypass condition into should_force_charge and reuse it from that path. " Link: http://lkml.kernel.org/r/01370f70-e1f6-ebe4-b95e-0df21a0bc15e@i-love.sakura.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/page_alloc.c: check return value of memblock_alloc_node_nopanic()Mike Rapoport1-1/+8
There are two early memory allocations that use memblock_alloc_node_nopanic() and do not check its return value. While this happens very early during boot and chances that the allocation will fail are diminishing, it is still worth to have proper checks for the allocation errors. Link: http://lkml.kernel.org/r/1547734941-944-1-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/hugetlb: add prot_modify_start/commit sequence for hugetlb updateAneesh Kumar K.V1-3/+5
Architectures like ppc64 require to do a conditional tlb flush based on the old and new value of pte. Follow the regular pte change protection sequence for hugetlb too. This allows the architectures to override the update sequence. Link: http://lkml.kernel.org/r/20190116085035.29729-5-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: update ptep_modify_prot_commit to take old pte value as argAneesh Kumar K.V2-7/+7
Architectures like ppc64 require to do a conditional tlb flush based on the old and new value of pte. Enable that by passing old pte value as the arg. Link: http://lkml.kernel.org/r/20190116085035.29729-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: update ptep_modify_prot_start/commit to take vm_area_struct as argAneesh Kumar K.V2-4/+4
Patch series "NestMMU pte upgrade workaround for mprotect", v5. We can upgrade pte access (R -> RW transition) via mprotect. We need to make sure we follow the recommended pte update sequence as outlined in commit bd5050e38aec ("powerpc/mm/radix: Change pte relax sequence to handle nest MMU hang") for such updates. This patch series does that. This patch (of 5): Some architectures may want to call flush_tlb_range from these helpers. Link: http://lkml.kernel.org/r/20190116085035.29729-2-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: fix some typos in mm directoryWei Yang5-9/+9
No functional change. Link: http://lkml.kernel.org/r/20190118235123.27843-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/page_owner: move config option to mm/Kconfig.debugChangbin Du1-0/+17
Move the PAGE_OWNER option from submenu "Compile-time checks and compiler options" to dedicated submenu "Memory Debugging". Link: http://lkml.kernel.org/r/20190120024254.6270-1-changbin.du@gmail.com Signed-off-by: Changbin Du <changbin.du@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/mmap.c: remove some redundancy in arch_get_unmapped_area_topdown()Yang Fan1-4/+3
The variable 'addr' is redundant in arch_get_unmapped_area_topdown(), just use parameter 'addr0' directly. Then remove the const qualifier of the parameter, and change its name to 'addr'. And in according with other functions, remove the const qualifier of all other no-pointer parameters in function arch_get_unmapped_area_topdown(). Link: http://lkml.kernel.org/r/20190127041112.25599-1-nullptr.cpp@gmail.com Signed-off-by: Yang Fan <nullptr.cpp@gmail.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Cc: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm, oom: remove 'prefer children over parent' heuristicShakeel Butt1-60/+18
Since the start of the git history of Linux, the kernel after selecting the worst process to be oom-killed, prefer to kill its child (if the child does not share mm with the parent). Later it was changed to prefer to kill a child who is worst. If the parent is still the worst then the parent will be killed. This heuristic assumes that the children did less work than their parent and by killing one of them, the work lost will be less. However this is very workload dependent. If there is a workload which can benefit from this heuristic, can use oom_score_adj to prefer children to be killed before the parent. The select_bad_process() has already selected the worst process in the system/memcg. There is no need to recheck the badness of its children and hoping to find a worse candidate. That's a lot of unneeded racy work. Also the heuristic is dangerous because it make fork bomb like workloads to recover much later because we constantly pick and kill processes which are not memory hogs. So, let's remove this whole heuristic. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20190121215850.221745-2-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: no need to check return value of debugfs_create functionsGreg Kroah-Hartman9-64/+24
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Link: http://lkml.kernel.org/r/20190122152151.16139-14-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Laura Abbott <labbott@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/memory.c: prevent mapping typed pages to userspaceMatthew Wilcox1-1/+1
Pages which use page_type must never be mapped to userspace as it would destroy their page type. Add an explicit check for this instead of assuming that kernel drivers always get this right. Link: http://lkml.kernel.org/r/20190129053830.3749-1-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: prevent mapping slab pages to userspaceMatthew Wilcox1-1/+1
It's never appropriate to map a page allocated by SLAB into userspace. A buggy device driver might try this, or an attacker might be able to find a way to make it happen. Christoph said: : Let's just fail the code. Currently this may work with SLUB. But SLAB : and SLOB overlay fields with mapcount. So you would have a corrupted page : struct if you mapped a slab page to user space. Link: http://lkml.kernel.org/r/20190125173827.2658-1-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/vmalloc.c: fix kernel BUG at mm/vmalloc.c:512!Uladzislau Rezki (Sony)1-1/+5
One of the vmalloc stress test case triggers the kernel BUG(): <snip> [60.562151] ------------[ cut here ]------------ [60.562154] kernel BUG at mm/vmalloc.c:512! [60.562206] invalid opcode: 0000 [#1] PREEMPT SMP PTI [60.562247] CPU: 0 PID: 430 Comm: vmalloc_test/0 Not tainted 4.20.0+ #161 [60.562293] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [60.562351] RIP: 0010:alloc_vmap_area+0x36f/0x390 <snip> it can happen due to big align request resulting in overflowing of calculated address, i.e. it becomes 0 after ALIGN()'s fixup. Fix it by checking if calculated address is within vstart/vend range. Link: http://lkml.kernel.org/r/20190124115648.9433-2-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Joel Fernandes <joelaf@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm, memcg: extract memcg maxable seq_file logic to seq_show_memcg_tunableChris Down1-45/+19
memcg has a significant number of files exposed to kernfs where their value is either exposed directly or is "max" in the case of PAGE_COUNTER_MAX. This patch makes this generic by providing a single function to do this work. In combination with the previous patch adding mem_cgroup_from_seq, this makes all of the seq_show feeder functions significantly more simple. Link: http://lkml.kernel.org/r/20190124194100.GA31425@chrisdown.name Signed-off-by: Chris Down <chris@chrisdown.name> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm, memcg: create mem_cgroup_from_seqChris Down2-15/+15
This is the start of a series of patches similar to my earlier DEFINE_MEMCG_MAX_OR_VAL work, but with less Macro Magic(tm). There are a bunch of places we go from seq_file to mem_cgroup, which currently requires manually getting the css, then getting the mem_cgroup from the css. It's in enough places now that having mem_cgroup_from_seq makes sense (and also makes the next patch a bit nicer). Link: http://lkml.kernel.org/r/20190124194050.GA31341@chrisdown.name Signed-off-by: Chris Down <chris@chrisdown.name> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm, compaction: capture a page under direct compactionMel Gorman3-11/+102
Compaction is inherently race-prone as a suitable page freed during compaction can be allocated by any parallel task. This patch uses a capture_control structure to isolate a page immediately when it is freed by a direct compactor in the slow path of the page allocator. The intent is to avoid redundant scanning. 5.0.0-rc1 5.0.0-rc1 selective-v3r17 capture-v3r19 Amean fault-both-1 0.00 ( 0.00%) 0.00 * 0.00%* Amean fault-both-3 2582.11 ( 0.00%) 2563.68 ( 0.71%) Amean fault-both-5 4500.26 ( 0.00%) 4233.52 ( 5.93%) Amean fault-both-7 5819.53 ( 0.00%) 6333.65 ( -8.83%) Amean fault-both-12 9321.18 ( 0.00%) 9759.38 ( -4.70%) Amean fault-both-18 9782.76 ( 0.00%) 10338.76 ( -5.68%) Amean fault-both-24 15272.81 ( 0.00%) 13379.55 * 12.40%* Amean fault-both-30 15121.34 ( 0.00%) 16158.25 ( -6.86%) Amean fault-both-32 18466.67 ( 0.00%) 18971.21 ( -2.73%) Latency is only moderately affected but the devil is in the details. A closer examination indicates that base page fault latency is reduced but latency of huge pages is increased as it takes creater care to succeed. Part of the "problem" is that allocation success rates are close to 100% even when under pressure and compaction gets harder 5.0.0-rc1 5.0.0-rc1 selective-v3r17 capture-v3r19 Percentage huge-3 96.70 ( 0.00%) 98.23 ( 1.58%) Percentage huge-5 96.99 ( 0.00%) 95.30 ( -1.75%) Percentage huge-7 94.19 ( 0.00%) 97.24 ( 3.24%) Percentage huge-12 94.95 ( 0.00%) 97.35 ( 2.53%) Percentage huge-18 96.74 ( 0.00%) 97.30 ( 0.58%) Percentage huge-24 97.07 ( 0.00%) 97.55 ( 0.50%) Percentage huge-30 95.69 ( 0.00%) 98.50 ( 2.95%) Percentage huge-32 96.70 ( 0.00%) 99.27 ( 2.65%) And scan rates are reduced as expected by 6% for the migration scanner and 29% for the free scanner indicating that there is less redundant work. Compaction migrate scanned 20815362 19573286 Compaction free scanned 16352612 11510663 [mgorman@techsingularity.net: remove redundant check] Link: http://lkml.kernel.org/r/20190201143853.GH9565@techsingularity.net Link: http://lkml.kernel.org/r/20190118175136.31341-23-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm, compaction: be selective about what pageblocks to clear skip hintsMel Gorman1-18/+106
Pageblock hints are cleared when compaction restarts or kswapd makes enough progress that it can sleep but it's over-eager in that the bit is cleared for migration sources with no LRU pages and migration targets with no free pages. As pageblock skip hint flushes are relatively rare and out-of-band with respect to kswapd, this patch makes a few more expensive checks to see if it's appropriate to even clear the bit. Every pageblock that is not cleared will avoid 512 pages being scanned unnecessarily on x86-64. The impact is variable with different workloads showing small differences in latency, success rates and scan rates. This is expected as clearing the hints is not that common but doing a small amount of work out-of-band to avoid a large amount of work in-band later is generally a good thing. Link: http://lkml.kernel.org/r/20190118175136.31341-22-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Qian Cai <cai@lca.pw> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: YueHaibing <yuehaibing@huawei.com> [cai@lca.pw: no stuck in __reset_isolation_pfn()] Link: http://lkml.kernel.org/r/20190206034732.75687-1-cai@lca.pw Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>