Re: [PATCH] mm: memcontrol: flush percpu vmevents before releasing memcg

[Andrew Morton]

On Mon, 12 Aug 2019 16:37:54 -0700 Roman Gushchin <guro@xxxxxx> wrote:

> Similar to vmstats, percpu caching of local vmevents leads to an
> accumulation of errors on non-leaf levels. This happens because
> some leftovers may remain in percpu caches, so that they are
> never propagated up by the cgroup tree and just disappear into
> nonexistence with on releasing of the memory cgroup.
> 
> To fix this issue let's accumulate and propagate percpu vmevents
> values before releasing the memory cgroup similar to what we're
> doing with vmstats.
> 
> Since on cpu hotplug we do flush percpu vmstats anyway, we can
> iterate only over online cpus.
> 
> Fixes: 42a300353577 ("mm: memcontrol: fix recursive statistics correctness & scalabilty")

No cc:stable?