The patch titled
memcg: check under limit at shrink_usage
has been added to the -mm tree. Its filename is
memcg-check-under-limit-at-shrink_usage.patch
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------------------------------------------------------
Subject: memcg: check under limit at shrink_usage
From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Current memory cgroup(both in mainline and -mm) doesn't account swap
caches as memory(swap cache support is dropped temporarily now).
So try_to_free_mem_cgroup_pages doesn't reflect the count of pages that
have been moved to swap cache.
But this makes mem_cgroup_shrink_usage fail easily if most of the pages
are anon/shmem, and then shmem_getpage returns -ENOMEM and the process
will be killed.
This patch adds res_counter_check_under_limit to avoid these cases.
BTW, even if swap cache support is enabled again, if a process is moved to
another cgroup, which has been just made, between precharge and
shrink_usage in shmem_getpage, shrink_usage may fail just because there is
no pages to reclaim.
So this change would make sense anyway.
Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 1 +
1 file changed, 1 insertion(+)
diff -puN mm/memcontrol.c~memcg-check-under-limit-at-shrink_usage mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-check-under-limit-at-shrink_usage
+++ a/mm/memcontrol.c
@@ -806,6 +806,7 @@ int mem_cgroup_shrink_usage(struct mm_st
do {
progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
+ progress += res_counter_check_under_limit(&mem->res);
} while (!progress && --retry);
css_put(&mem->css);
_
Patches currently in -mm which might be from nishimura@xxxxxxxxxxxxxxxxx are
memcg-check-under-limit-at-shrink_usage.patch
mm-owner-fix-race-between-swap-and-exit-fix-fix.patch
vmscan-split-lru-lists-into-anon-file-sets-memcg-fix-handling-of-shmem-migrationv2.patch
unevictable-lru-infrastructure.patch
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