memcg: cleanup racy sum avoidance code
authorShakeel Butt <shakeelb@google.com>
Thu, 2 Sep 2021 21:55:46 +0000 (14:55 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 3 Sep 2021 16:58:13 +0000 (09:58 -0700)
commit96e51ccf1af33e82f429a0d6baebba29c6448d0f
treeb6e92e3a402685373678b78ca0480d5b2a4eedd4
parentec403e2ae0dfc85996aad6e944a98a16e6dfcc6d
memcg: cleanup racy sum avoidance code

We used to have per-cpu memcg and lruvec stats and the readers have to
traverse and sum the stats from each cpu.  This summing was racy and may
expose transient negative values.  So, an explicit check was added to
avoid such scenarios.  Now these stats are moved to rstat infrastructure
and are no more per-cpu, so we can remove the fixup for transient negative
values.

Link: https://lkml.kernel.org/r/20210728012243.3369123-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/memcontrol.h