linux/mm
Chunxin Zang 069c411de4 mm/vmscan: fix infinite loop in drop_slab_node
We have observed that drop_caches can take a considerable amount of
time (<put data here>).  Especially when there are many memcgs involved
because they are adding an additional overhead.

It is quite unfortunate that the operation cannot be interrupted by a
signal currently.  Add a check for fatal signals into the main loop so
that userspace can control early bailout.

There are two reasons:

1. We have too many memcgs, even though one object freed in one memcg,
   the sum of object is bigger than 10.

2. We spend a lot of time in traverse memcg once.  So, the memcg who
   traversed at the first have been freed many objects.  Traverse memcg
   next time, the freed count bigger than 10 again.

We can get the following info through 'ps':

  root:~# ps -aux | grep drop
  root  357956 ... R    Aug25 21119854:55 echo 3 > /proc/sys/vm/drop_caches
  root 1771385 ... R    Aug16 21146421:17 echo 3 > /proc/sys/vm/drop_caches
  root 1986319 ... R    18:56 117:27 echo 3 > /proc/sys/vm/drop_caches
  root 2002148 ... R    Aug24 5720:39 echo 3 > /proc/sys/vm/drop_caches
  root 2564666 ... R    18:59 113:58 echo 3 > /proc/sys/vm/drop_caches
  root 2639347 ... R    Sep03 2383:39 echo 3 > /proc/sys/vm/drop_caches
  root 3904747 ... R    03:35 993:31 echo 3 > /proc/sys/vm/drop_caches
  root 4016780 ... R    Aug21 7882:18 echo 3 > /proc/sys/vm/drop_caches

Use bpftrace follow 'freed' value in drop_slab_node:

  root:~# bpftrace -e 'kprobe:drop_slab_node+70 {@ret=hist(reg("bp")); }'
  Attaching 1 probe...
  ^B^C

  @ret:
  [64, 128)        1 |                                                    |
  [128, 256)      28 |                                                    |
  [256, 512)     107 |@                                                   |
  [512, 1K)      298 |@@@                                                 |
  [1K, 2K)       613 |@@@@@@@                                             |
  [2K, 4K)      4435 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
  [4K, 8K)       442 |@@@@@                                               |
  [8K, 16K)      299 |@@@                                                 |
  [16K, 32K)     100 |@                                                   |
  [32K, 64K)     139 |@                                                   |
  [64K, 128K)     56 |                                                    |
  [128K, 256K)    26 |                                                    |
  [256K, 512K)     2 |                                                    |

In the while loop, we can check whether the TASK_KILLABLE signal is set,
if so, we should break the loop.

Signed-off-by: Chunxin Zang <zangchunxin@bytedance.com>
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Link: https://lkml.kernel.org/r/20200909152047.27905-1-zangchunxin@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-13 18:38:34 -07:00
..
kasan mm: kasan: do not panic if both panic_on_warn and kasan_multishot set 2020-10-13 18:38:32 -07:00
backing-dev.c bdi: replace BDI_CAP_NO_{WRITEBACK,ACCT_DIRTY} with a single flag 2020-09-24 13:43:39 -06:00
balloon_compaction.c mm/balloon_compaction: suppress allocation warnings 2019-09-04 07:42:01 -04:00
cleancache.c Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
cma_debug.c debugfs: make sure we can remove u32_array files cleanly 2020-07-10 13:54:00 -07:00
cma.c cma: don't quit at first error when activating reserved areas 2020-08-12 10:57:57 -07:00
cma.h mm: cma: fix the name of CMA areas 2020-08-12 10:57:57 -07:00
compaction.c mm: replace hpage_nr_pages with thp_nr_pages 2020-08-14 19:56:56 -07:00
debug_page_ref.c
debug_vm_pgtable.c Documentation/mm: add descriptions for arch page table helpers 2020-08-07 11:33:23 -07:00
debug.c mm, dump_page: rename head_mapcount() --> head_compound_mapcount() 2020-10-13 18:38:29 -07:00
dmapool.c mm/dmapool.c: replace hard coded function name with __func__ 2020-10-13 18:38:32 -07:00
early_ioremap.c mm/early_ioremap.c: use %pa to print resource_size_t variables 2020-01-31 10:30:38 -08:00
fadvise.c mm, fadvise: improve the expensive remote LRU cache draining after FADV_DONTNEED 2020-10-13 18:38:29 -07:00
failslab.c mm/failslab.c: by default, do not fail allocations with direct reclaim only 2019-07-12 11:05:43 -07:00
filemap.c mm/filemap: fix filemap_map_pages for THP 2020-10-13 18:38:29 -07:00
frame_vector.c mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
frontswap.c mm/frontswap: mark various intentional data races 2020-08-14 19:56:56 -07:00
gup_benchmark.c mm/gup_benchmark: use pin_user_pages for FOLL_LONGTERM flag 2020-10-13 18:38:29 -07:00
gup.c mm/gup: protect unpin_user_pages() against npages==-ERRNO 2020-10-13 18:38:29 -07:00
highmem.c mm, x86/mm: Untangle address space layout definitions from basic pgtable type definitions 2019-12-10 10:12:55 +01:00
hmm.c mm: do page fault accounting in handle_mm_fault 2020-08-12 10:58:02 -07:00
huge_memory.c mm/mmap: leave adjust_next as virtual address instead of page frame number 2020-10-13 18:38:31 -07:00
hugetlb_cgroup.c hugetlb_cgroup: convert comma to semicolon 2020-08-21 09:52:52 -07:00
hugetlb.c hugetlb: add lockdep check for i_mmap_rwsem held in huge_pmd_share 2020-10-13 18:38:34 -07:00
hwpoison-inject.c mm/hwpoison-inject: use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs fops 2019-12-01 12:59:09 -08:00
init-mm.c mmap locking API: add MMAP_LOCK_INITIALIZER 2020-06-09 09:39:14 -07:00
internal.h i915: use find_lock_page instead of find_lock_entry 2020-10-13 18:38:29 -07:00
interval_tree.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 248 2019-06-19 17:09:08 +02:00
ioremap.c mm: move p?d_alloc_track to separate header file 2020-08-07 11:33:26 -07:00
Kconfig mm/gup_benchmark: update the documentation in Kconfig 2020-10-13 18:38:29 -07:00
Kconfig.debug treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
khugepaged.c mm: khugepaged: recalculate min_free_kbytes after memory hotplug as expected by khugepaged 2020-10-11 10:31:11 -07:00
kmemleak.c mm/kmemleak: rely on rcu for task stack scanning 2020-10-13 18:38:27 -07:00
ksm.c ksm: reinstate memcg charge on copied pages 2020-09-19 13:13:38 -07:00
list_lru.c mm/list_lru: fix a data race in list_lru_count_one 2020-08-14 19:56:57 -07:00
maccess.c uaccess: add force_uaccess_{begin,end} helpers 2020-08-12 10:57:59 -07:00
madvise.c mm: optimise madvise WILLNEED 2020-10-13 18:38:29 -07:00
Makefile mm,kmemleak-test.c: move kmemleak-test.c to samples dir 2020-10-13 18:38:27 -07:00
mapping_dirty_helpers.c mm/mapping_dirty_helpers: update huge page-table entry callbacks 2020-04-02 09:35:29 -07:00
memblock.c mm/memblock: expose only miminal interface to add/walk physmem 2020-07-10 15:08:09 +02:00
memcontrol.c mm/memcg: fix device private memcg accounting 2020-10-13 18:38:31 -07:00
memfd.c mm: page cache: store only head pages in i_pages 2019-09-24 15:54:08 -07:00
memory_hotplug.c mm/memory_hotplug: introduce default phys_to_target_node() implementation 2020-10-13 18:38:27 -07:00
memory-failure.c mm/memory-failure.c: remove unused macro `writeback' 2020-10-13 18:38:32 -07:00
memory.c mm: remove src/dst mm parameter in copy_page_range() 2020-10-13 18:38:32 -07:00
mempolicy.c mm: replace hpage_nr_pages with thp_nr_pages 2020-08-14 19:56:56 -07:00
mempool.c mm/mempool: fix a data race in mempool_free() 2020-08-14 19:56:57 -07:00
memremap.c mm/memremap.c: convert devmap static branch to {inc,dec} 2020-10-13 18:38:30 -07:00
memtest.c
migrate.c block-5.10-2020-10-12 2020-10-13 12:12:44 -07:00
mincore.c mm: factor find_get_incore_page out of mincore_page 2020-10-13 18:38:29 -07:00
mlock.c mlock: fix unevictable_pgs event counts on THP 2020-09-19 13:13:38 -07:00
mm_init.c mm: adjust vm_committed_as_batch according to vm overcommit policy 2020-08-07 11:33:26 -07:00
mmap.c mm/mmap.c: replace do_brk with do_brk_flags in comment of insert_vm_struct() 2020-10-13 18:38:32 -07:00
mmu_gather.c mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
mmu_notifier.c mm: mmu_notifier: fix and extend kerneldoc 2020-08-12 10:57:57 -07:00
mmzone.c
mprotect.c mm: Introduce arch_validate_flags() 2020-09-04 12:46:07 +01:00
mremap.c mm/mremap: start addresses are properly aligned 2020-08-07 11:33:27 -07:00
msync.c mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
nommu.c Fix references to nommu-mmap.rst 2020-09-24 11:03:40 -06:00
oom_kill.c mm, oom: show process exiting information in __oom_kill_process() 2020-08-12 10:57:56 -07:00
page_alloc.c mm/page_alloc.c: fix freeing non-compound pages 2020-10-13 18:38:33 -07:00
page_counter.c mm/page_counter: correct the obsolete func name in the comment of page_counter_try_charge() 2020-10-13 18:38:30 -07:00
page_ext.c mm/page_ext.c: drop pfn_present() check when onlining 2020-04-07 10:43:40 -07:00
page_idle.c mm/page_idle.c: skip offline pages 2020-06-08 11:05:55 -07:00
page_io.c mm/page_io.c: remove useless out label in __swap_writepage() 2020-10-13 18:38:30 -07:00
page_isolation.c mm/page_isolation: cleanup set_migratetype_isolate() 2020-10-13 18:38:33 -07:00
page_owner.c mm: rename gfpflags_to_migratetype to gfp_migratetype for same convention 2020-06-03 20:09:45 -07:00
page_poison.c mm/page_poison.c: fix a typo in a comment 2019-09-24 15:54:08 -07:00
page_reporting.c mm/page_reporting: add budget limit on how many pages can be reported per pass 2020-04-07 10:43:39 -07:00
page_reporting.h mm: introduce include/linux/pgtable.h 2020-06-09 09:39:13 -07:00
page_vma_mapped.c mm: replace hpage_nr_pages with thp_nr_pages 2020-08-14 19:56:56 -07:00
page-writeback.c bdi: replace BDI_CAP_NO_{WRITEBACK,ACCT_DIRTY} with a single flag 2020-09-24 13:43:39 -06:00
pagewalk.c mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
percpu-internal.h mm: memcg/percpu: account percpu memory to memory cgroups 2020-08-12 10:57:55 -07:00
percpu-km.c mm: memcg/percpu: account percpu memory to memory cgroups 2020-08-12 10:57:55 -07:00
percpu-stats.c mm: memcg/percpu: account percpu memory to memory cgroups 2020-08-12 10:57:55 -07:00
percpu-vm.c mm: memcg/percpu: account percpu memory to memory cgroups 2020-08-12 10:57:55 -07:00
percpu.c percpu: fix first chunk size calculation for populated bitmap 2020-09-17 17:34:39 +00:00
pgalloc-track.h mm: move p?d_alloc_track to separate header file 2020-08-07 11:33:26 -07:00
pgtable-generic.c mm: introduce include/linux/pgtable.h 2020-06-09 09:39:13 -07:00
process_vm_access.c mm: remove compat_process_vm_{readv,writev} 2020-10-03 00:02:15 -04:00
ptdump.c mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
readahead.c mm: use memalloc_nofs_save in readahead path 2020-06-02 10:59:07 -07:00
rmap.c mm/rmap: fixup copying of soft dirty and uffd ptes 2020-09-05 12:14:30 -07:00
rodata_test.c mm/rodata_test.c: fix missing function declaration 2020-08-21 09:52:53 -07:00
shmem.c mm/shmem: return head page from find_lock_entry 2020-10-13 18:38:29 -07:00
shuffle.c mm/shuffle: remove dynamic reconfiguration 2020-08-07 11:33:29 -07:00
shuffle.h mm/shuffle: remove dynamic reconfiguration 2020-08-07 11:33:29 -07:00
slab_common.c mm/slab_common.c: delete duplicated word 2020-08-12 10:57:58 -07:00
slab.c mm: memcg/slab: uncharge during kmem_cache_free_bulk() 2020-10-13 18:38:31 -07:00
slab.h mm: memcg/slab: uncharge during kmem_cache_free_bulk() 2020-10-13 18:38:31 -07:00
slob.c mm: memcg: convert vmstat slab counters to bytes 2020-08-07 11:33:24 -07:00
slub.c mm: memcg/slab: uncharge during kmem_cache_free_bulk() 2020-10-13 18:38:31 -07:00
sparse-vmemmap.c mm/sparse: only sub-section aligned range would be populated 2020-08-07 11:33:27 -07:00
sparse.c mm/sparse: cleanup the code surrounding memory_present() 2020-08-07 11:33:27 -07:00
swap_cgroup.c mm: memcontrol: make swap tracking an integral part of memory control 2020-06-03 20:09:48 -07:00
swap_slots.c mm/swap_slots.c: remove always zero and unused return value of enable_swap_slots_cache() 2020-10-13 18:38:30 -07:00
swap_state.c swap: rename SWP_FS to SWAP_FS_OPS to avoid ambiguity 2020-10-13 18:38:29 -07:00
swap.c mm: move call to compound_head() in release_pages() 2020-10-13 18:38:33 -07:00
swapfile.c mm/swapfile.c: fix potential memory leak in sys_swapon 2020-10-13 18:38:30 -07:00
truncate.c mm, fadvise: improve the expensive remote LRU cache draining after FADV_DONTNEED 2020-10-13 18:38:29 -07:00
usercopy.c mm/usercopy.c: delete duplicated word 2020-08-12 10:57:58 -07:00
userfaultfd.c mm/vmscan: protect the workingset on anonymous LRU 2020-08-12 10:57:55 -07:00
util.c arm64: mte: Tags-aware aware memcmp_pages() implementation 2020-09-04 12:46:07 +01:00
vmacache.c kernel: better document the use_mm/unuse_mm API contract 2020-06-10 19:14:18 -07:00
vmalloc.c mm/vmalloc.c: fix the comment of find_vm_area 2020-10-13 18:38:32 -07:00
vmpressure.c mm: vmpressure: use mem_cgroup_is_root API 2020-04-02 09:35:31 -07:00
vmscan.c mm/vmscan: fix infinite loop in drop_slab_node 2020-10-13 18:38:34 -07:00
vmstat.c Merge branch 'simplify-do_wp_page' 2020-09-04 09:31:54 -07:00
workingset.c mm: replace hpage_nr_pages with thp_nr_pages 2020-08-14 19:56:56 -07:00
z3fold.c mm/z3fold: silence kmemleak false positives of slots 2020-05-28 11:35:40 -07:00
zbud.c mm: use false for bool variable 2020-06-04 19:06:24 -07:00
zpool.c mm/zpool.c: delete duplicated word and fix grammar 2020-08-12 10:57:58 -07:00
zsmalloc.c mm/zsmalloc.c: fix duplicated words 2020-08-12 10:57:58 -07:00
zswap.c mm/zswap: allow setting default status, compressor and allocator in Kconfig 2020-04-07 10:43:41 -07:00