From 03960e33187ae969187281c3aa6c308d7282c468 Mon Sep 17 00:00:00 2001
From: Chris Down <chris@chrisdown.name>
Date: Thu, 25 Jun 2020 20:30:22 -0700
Subject: [PATCH] mm/memcontrol.c: prevent missed memory.low load tears
Looks like one of these got missed when massaging in f86b810c2610 ("mm,
memcg: prevent memory.low load/store tearing") with other linux-mm
changes.
Link: http://lkml.kernel.org/r/20200612174437.GA391453@chrisdown.name
Signed-off-by: Chris Down <chris@chrisdown.name>
Reported-by: Michal Koutny <mkoutny@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/memcontrol.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index da15b686caa86..19622328e4b5a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6423,7 +6423,7 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
if (parent == root) {
memcg->memory.emin = READ_ONCE(memcg->memory.min);
- memcg->memory.elow = memcg->memory.low;
+ memcg->memory.elow = READ_ONCE(memcg->memory.low);
goto out;
}
@@ -6435,7 +6435,8 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
atomic_long_read(&parent->memory.children_min_usage)));
WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage,
- memcg->memory.low, READ_ONCE(parent->memory.elow),
+ READ_ONCE(memcg->memory.low),
+ READ_ONCE(parent->memory.elow),
atomic_long_read(&parent->memory.children_low_usage)));
out:
--
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