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authorJohannes Weiner <hannes@cmpxchg.org>2021-08-20 05:04:21 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-08-20 21:31:42 +0300
commitf56ce412a59d7d938b81de8878faef128812482c (patch)
treeb2b5546c8c06aadf6f9193dd175e1f05d11b7854 /include
parent91ed3ed0f79884f66581e2162cc5ae91ce82b4fb (diff)
downloadlinux-f56ce412a59d7d938b81de8878faef128812482c.tar.xz
mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaim
We've noticed occasional OOM killing when memory.low settings are in effect for cgroups. This is unexpected and undesirable as memory.low is supposed to express non-OOMing memory priorities between cgroups. The reason for this is proportional memory.low reclaim. When cgroups are below their memory.low threshold, reclaim passes them over in the first round, and then retries if it couldn't find pages anywhere else. But when cgroups are slightly above their memory.low setting, page scan force is scaled down and diminished in proportion to the overage, to the point where it can cause reclaim to fail as well - only in that case we currently don't retry, and instead trigger OOM. To fix this, hook proportional reclaim into the same retry logic we have in place for when cgroups are skipped entirely. This way if reclaim fails and some cgroups were scanned with diminished pressure, we'll try another full-force cycle before giving up and OOMing. [akpm@linux-foundation.org: coding-style fixes] Link: https://lkml.kernel.org/r/20210817180506.220056-1-hannes@cmpxchg.org Fixes: 9783aa9917f8 ("mm, memcg: proportional memory.{low,min} reclaim") Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Leon Yang <lnyng@fb.com> Reviewed-by: Rik van Riel <riel@surriel.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Chris Down <chris@chrisdown.name> Acked-by: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> [5.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/memcontrol.h29
1 files changed, 15 insertions, 14 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index bfe5c486f4ad..24797929d8a1 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -612,12 +612,15 @@ static inline bool mem_cgroup_disabled(void)
return !cgroup_subsys_enabled(memory_cgrp_subsys);
}
-static inline unsigned long mem_cgroup_protection(struct mem_cgroup *root,
- struct mem_cgroup *memcg,
- bool in_low_reclaim)
+static inline void mem_cgroup_protection(struct mem_cgroup *root,
+ struct mem_cgroup *memcg,
+ unsigned long *min,
+ unsigned long *low)
{
+ *min = *low = 0;
+
if (mem_cgroup_disabled())
- return 0;
+ return;
/*
* There is no reclaim protection applied to a targeted reclaim.
@@ -653,13 +656,10 @@ static inline unsigned long mem_cgroup_protection(struct mem_cgroup *root,
*
*/
if (root == memcg)
- return 0;
-
- if (in_low_reclaim)
- return READ_ONCE(memcg->memory.emin);
+ return;
- return max(READ_ONCE(memcg->memory.emin),
- READ_ONCE(memcg->memory.elow));
+ *min = READ_ONCE(memcg->memory.emin);
+ *low = READ_ONCE(memcg->memory.elow);
}
void mem_cgroup_calculate_protection(struct mem_cgroup *root,
@@ -1147,11 +1147,12 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm,
{
}
-static inline unsigned long mem_cgroup_protection(struct mem_cgroup *root,
- struct mem_cgroup *memcg,
- bool in_low_reclaim)
+static inline void mem_cgroup_protection(struct mem_cgroup *root,
+ struct mem_cgroup *memcg,
+ unsigned long *min,
+ unsigned long *low)
{
- return 0;
+ *min = *low = 0;
}
static inline void mem_cgroup_calculate_protection(struct mem_cgroup *root,