The patch titled
Subject: mm, memcg: prevent mem_cgroup_protected store tearing
has been added to the -mm tree. Its filename is
mm-memcg-prevent-mem_cgroup_protected-store-tearing.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-prevent-mem_cgroup_protected-store-tearing.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-prevent-mem_cgroup_protected-store-tearing.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Chris Down <chris@xxxxxxxxxxxxxx>
Subject: mm, memcg: prevent mem_cgroup_protected store tearing
The read side of this is all protected, but we can still tear if multiple
iterations of mem_cgroup_protected are going at the same time.
There's some intentional racing in mem_cgroup_protected which is ok, but
load/store tearing should be avoided.
Link: http://lkml.kernel.org/r/d1e9fbc0379fe8db475d82c8b6fbe048876e12ae.1584034301.git.chris@xxxxxxxxxxxxxx
Signed-off-by: Chris Down <chris@xxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/mm/memcontrol.c~mm-memcg-prevent-mem_cgroup_protected-store-tearing
+++ a/mm/memcontrol.c
@@ -6397,14 +6397,14 @@ enum mem_cgroup_protection mem_cgroup_pr
parent_usage = page_counter_read(&parent->memory);
- memcg->memory.emin = effective_protection(usage, parent_usage,
+ WRITE_ONCE(memcg->memory.emin, effective_protection(usage, parent_usage,
READ_ONCE(memcg->memory.min),
READ_ONCE(parent->memory.emin),
- atomic_long_read(&parent->memory.children_min_usage));
+ atomic_long_read(&parent->memory.children_min_usage)));
- memcg->memory.elow = effective_protection(usage, parent_usage,
+ WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage,
memcg->memory.low, READ_ONCE(parent->memory.elow),
- atomic_long_read(&parent->memory.children_low_usage));
+ atomic_long_read(&parent->memory.children_low_usage)));
out:
if (usage <= memcg->memory.emin)
_
Patches currently in -mm which might be from chris@xxxxxxxxxxxxxx are
mm-memcg-fix-corruption-on-64-bit-divisor-in-memoryhigh-throttling.patch
mm-memcg-throttle-allocators-based-on-ancestral-memoryhigh.patch
mm-memcg-prevent-memoryhigh-load-store-tearing.patch
mm-memcg-prevent-memorymax-load-tearing.patch
mm-memcg-prevent-memorylow-load-store-tearing.patch
mm-memcg-prevent-memorymin-load-store-tearing.patch
mm-memcg-prevent-memoryswapmax-load-tearing.patch
mm-memcg-prevent-mem_cgroup_protected-store-tearing.patch
