diff options
| author | Yang Shi <[email protected]> | 2019-08-02 21:48:44 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2019-08-03 07:02:00 -0700 |
| commit | fa1e512fac717f34e7c12d7a384c46e90a647392 (patch) | |
| tree | be1f6e39f770aaeb27c6eb68e3e0d2ed2650a111 | |
| parent | 7bc36e3ce91471b6377c8eadc0a2f220a2280083 (diff) | |
mm: vmscan: check if mem cgroup is disabled or not before calling memcg slab shrinker
Shakeel Butt reported premature oom on kernel with
"cgroup_disable=memory" since mem_cgroup_is_root() returns false even
though memcg is actually NULL. The drop_caches is also broken.
It is because commit aeed1d325d42 ("mm/vmscan.c: generalize
shrink_slab() calls in shrink_node()") removed the !memcg check before
!mem_cgroup_is_root(). And, surprisingly root memcg is allocated even
though memory cgroup is disabled by kernel boot parameter.
Add mem_cgroup_disabled() check to make reclaimer work as expected.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: aeed1d325d42 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()")
Signed-off-by: Yang Shi <[email protected]>
Reported-by: Shakeel Butt <[email protected]>
Reviewed-by: Shakeel Butt <[email protected]>
Reviewed-by: Kirill Tkhai <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Jan Hadrava <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Qian Cai <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: <[email protected]> [4.19+]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | mm/vmscan.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 44df66a98f2a..dbdc46a84f63 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -699,7 +699,14 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, unsigned long ret, freed = 0; struct shrinker *shrinker; - if (!mem_cgroup_is_root(memcg)) + /* + * The root memcg might be allocated even though memcg is disabled + * via "cgroup_disable=memory" boot parameter. This could make + * mem_cgroup_is_root() return false, then just run memcg slab + * shrink, but skip global shrink. This may result in premature + * oom. + */ + if (!mem_cgroup_disabled() && !mem_cgroup_is_root(memcg)) return shrink_slab_memcg(gfp_mask, nid, memcg, priority); if (!down_read_trylock(&shrinker_rwsem)) |