linux/mm
Michal Hocko bd041733c9 mm, vmscan: add cond_resched() into shrink_node_memcg()
Boris Zhmurov has reported RCU stalls during the kswapd reclaim:

  INFO: rcu_sched detected stalls on CPUs/tasks:
   23-...: (22 ticks this GP) idle=92f/140000000000000/0 softirq=2638404/2638404 fqs=23
   (detected by 4, t=6389 jiffies, g=786259, c=786258, q=42115)
  Task dump for CPU 23:
  kswapd1         R  running task        0   148      2 0x00000008
  Call Trace:
    shrink_node+0xd2/0x2f0
    kswapd+0x2cb/0x6a0
    mem_cgroup_shrink_node+0x160/0x160
    kthread+0xbd/0xe0
    __switch_to+0x1fa/0x5c0
    ret_from_fork+0x1f/0x40
    kthread_create_on_node+0x180/0x180

a closer code inspection has shown that we might indeed miss all the
scheduling points in the reclaim path if no pages can be isolated from
the LRU list.  This is a pathological case but other reports from Donald
Buczek have shown that we might indeed hit such a path:

        clusterd-989   [009] .... 118023.654491: mm_vmscan_direct_reclaim_end: nr_reclaimed=193
         kswapd1-86    [001] dN.. 118023.987475: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239830 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118024.320968: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239844 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118024.654375: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239858 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118024.987036: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239872 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118025.319651: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239886 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118025.652248: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239900 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118025.984870: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239914 nr_taken=0 file=1
  [...]
         kswapd1-86    [001] dN.. 118084.274403: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4241133 nr_taken=0 file=1

this is minute long snapshot which didn't take a single page from the
LRU.  It is not entirely clear why only 1303 pages have been scanned
during that time (maybe there was a heavy IRQ activity interfering).

In any case it looks like we can really hit long periods without
scheduling on non preemptive kernels so an explicit cond_resched() in
shrink_node_memcg which is independent on the reclaim operation is due.

Link: http://lkml.kernel.org/r/20161202095841.16648-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Boris Zhmurov <bb@kernelpanic.ru>
Tested-by: Boris Zhmurov <bb@kernelpanic.ru>
Reported-by: Donald Buczek <buczek@molgen.mpg.de>
Reported-by: "Christopher S. Aker" <caker@theshore.net>
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-02 18:48:03 -08:00
..
kasan kasan: support use-after-scope detection 2016-11-30 16:32:52 -08:00
backing-dev.c block: fix bdi vs gendisk lifetime mismatch 2016-08-04 14:19:16 -06:00
balloon_compaction.c
bootmem.c mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping 2016-10-11 15:06:33 -07:00
cleancache.c
cma_debug.c
cma.c mm/cma.c: check the max limit for cma allocation 2016-11-11 08:12:37 -08:00
cma.h
compaction.c mm, compaction: restrict fragindex to costly orders 2016-10-07 18:46:29 -07:00
debug_page_ref.c
debug.c mm: clarify why we avoid page_mapcount() for slab pages in dump_page() 2016-10-07 18:46:29 -07:00
dmapool.c
early_ioremap.c
fadvise.c
failslab.c
filemap.c mm/filemap: don't allow partially uptodate page for pipes 2016-11-11 08:12:37 -08:00
frame_vector.c mm: replace get_vaddr_frames() write/force parameters with gup_flags 2016-10-19 08:11:24 -07:00
frontswap.c
gup.c mm: unexport __get_user_pages() 2016-10-24 19:13:20 -07:00
highmem.c
huge_memory.c mremap: move_ptes: check pte dirty after its removal 2016-11-29 08:20:24 -08:00
hugetlb_cgroup.c
hugetlb.c mm/hugetlb: fix huge page reservation leak in private mapping error paths 2016-11-11 08:12:37 -08:00
hwpoison-inject.c
init-mm.c
internal.h mm, compaction: make full priority ignore pageblock suitability 2016-10-07 18:46:29 -07:00
interval_tree.c
Kconfig Allow KASAN and HOTPLUG_MEMORY to co-exist when doing build testing 2016-10-27 16:23:01 -07:00
Kconfig.debug PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO 2016-09-13 02:35:27 +02:00
khugepaged.c mm, thp: propagation of conditional compilation in khugepaged.c 2016-11-30 16:32:52 -08:00
kmemcheck.c
kmemleak-test.c
kmemleak.c mm: kmemleak: scan .data.ro_after_init 2016-11-11 08:12:37 -08:00
ksm.c mm,ksm: add __GFP_HIGH to the allocation in alloc_stable_node() 2016-10-07 18:46:29 -07:00
list_lru.c mm/list_lru.c: avoid error-path NULL pointer deref 2016-10-27 18:43:42 -07:00
maccess.c
madvise.c
Makefile Disable the __builtin_return_address() warning globally after all 2016-10-12 10:23:41 -07:00
memblock.c mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping 2016-10-11 15:06:33 -07:00
memcontrol.c mm: memcontrol: do not recurse in direct reclaim 2016-10-27 18:43:43 -07:00
memory_hotplug.c mm: remove unused variable in memory hotplug 2016-10-27 15:49:12 -07:00
memory-failure.c mm: hwpoison: fix thp split handling in memory_failure() 2016-11-11 08:12:37 -08:00
memory.c mm: replace access_process_vm() write parameter with gup_flags 2016-10-19 08:31:25 -07:00
mempolicy.c mm: replace get_user_pages() write/force parameters with gup_flags 2016-10-19 08:11:43 -07:00
mempool.c Revert "mm, mempool: only set __GFP_NOMEMALLOC if there are free elements" 2016-07-28 16:07:41 -07:00
memtest.c
migrate.c mm: vm_page_prot: update with WRITE_ONCE/READ_ONCE 2016-10-07 18:46:29 -07:00
mincore.c mm, swap: use offset of swap entry as key of swap cache 2016-10-07 18:46:28 -07:00
mlock.c thp: fix corner case of munlock() of PTE-mapped THPs 2016-11-30 16:32:52 -08:00
mm_init.c
mmap.c mm: vma_merge: correct false positive from __vma_unlink->validate_mm_rb 2016-10-07 18:46:29 -07:00
mmu_context.c
mmu_notifier.c
mmzone.c
mprotect.c mm/numa: Remove duplicated include from mprotect.c 2016-10-19 17:28:48 +02:00
mremap.c mremap: move_ptes: check pte dirty after its removal 2016-11-29 08:20:24 -08:00
msync.c
nobootmem.c mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping 2016-10-11 15:06:33 -07:00
nommu.c mm: unexport __get_user_pages() 2016-10-24 19:13:20 -07:00
oom_kill.c oom: print nodemask in the oom report 2016-10-07 18:46:29 -07:00
page_alloc.c mm: remove extra newline from allocation stall warning 2016-11-11 08:12:37 -08:00
page_counter.c
page_ext.c mm/page_ext: support extra space allocation by page_ext user 2016-10-07 18:46:27 -07:00
page_idle.c
page_io.c mm/page_io.c: replace some BUG_ON()s with VM_BUG_ON_PAGE() 2016-10-07 18:46:29 -07:00
page_isolation.c mm/page_isolation: fix typo: "paes" -> "pages" 2016-10-07 18:46:29 -07:00
page_owner.c mm/page_owner: don't define fields on struct page_ext by hard-coding 2016-10-07 18:46:27 -07:00
page_poison.c
page-writeback.c mm: don't use radix tree writeback tags for pages in swap cache 2016-10-07 18:46:28 -07:00
pagewalk.c
percpu-km.c
percpu-vm.c
percpu.c mm/percpu.c: fix potential memory leakage for pcpu_embed_first_chunk() 2016-10-05 11:52:55 -04:00
pgtable-generic.c
process_vm_access.c mm: remove write/force parameters from __get_user_pages_unlocked() 2016-10-18 14:13:37 -07:00
quicklist.c
readahead.c mm: silently skip readahead for DAX inodes 2016-08-26 17:39:35 -07:00
rmap.c rmap: fix compound check logic in page_remove_file_rmap 2016-08-10 16:40:56 -07:00
shmem.c shmem: fix pageflags after swapping DMA32 object 2016-11-11 08:12:37 -08:00
slab_common.c memcg: prevent memcg caches to be both OFF_SLAB & OBJFREELIST_SLAB 2016-11-11 08:12:37 -08:00
slab.c mm/slab: improve performance of gathering slabinfo stats 2016-10-27 18:43:43 -07:00
slab.h mm/slab: improve performance of gathering slabinfo stats 2016-10-27 18:43:43 -07:00
slob.c
slub.c slub: Convert to hotplug state machine 2016-09-06 18:30:20 +02:00
sparse-vmemmap.c treewide: replace obsolete _refok by __ref 2016-08-02 17:31:41 -04:00
sparse.c treewide: replace obsolete _refok by __ref 2016-08-02 17:31:41 -04:00
swap_cgroup.c
swap_state.c mm, swap: use offset of swap entry as key of swap cache 2016-10-07 18:46:28 -07:00
swap.c thp: reduce usage of huge zero page's atomic counter 2016-10-07 18:46:28 -07:00
swapfile.c swapfile: fix memory corruption via malformed swapfile 2016-11-11 08:12:37 -08:00
truncate.c mm: fix false-positive WARN_ON() in truncate/invalidate for hugetlb 2016-11-30 16:32:52 -08:00
usercopy.c mm: usercopy: Check for module addresses 2016-09-20 16:07:39 -07:00
userfaultfd.c
util.c Merge branch 'mm-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-10-22 09:39:10 -07:00
vmacache.c mm: unrig VMA cache hit ratio 2016-10-07 18:46:27 -07:00
vmalloc.c mm: consolidate warn_alloc_failed users 2016-10-07 18:46:29 -07:00
vmpressure.c
vmscan.c mm, vmscan: add cond_resched() into shrink_node_memcg() 2016-12-02 18:48:03 -08:00
vmstat.c seq/proc: modify seq_put_decimal_[u]ll to take a const char *, not char 2016-10-07 18:46:30 -07:00
workingset.c mm: workingset: fix NULL ptr in count_shadow_nodes 2016-12-02 18:48:03 -08:00
z3fold.c
zbud.c
zpool.c
zsmalloc.c zsmalloc: Delete an unnecessary check before the function call "iput" 2016-07-28 16:07:41 -07:00
zswap.c