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authorShakeel Butt <shakeelb@google.com>2021-09-02 14:55:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-03 09:58:13 -0700
commit96e51ccf1af33e82f429a0d6baebba29c6448d0f (patch)
treeb6e92e3a402685373678b78ca0480d5b2a4eedd4 /include
parentec403e2ae0dfc85996aad6e944a98a16e6dfcc6d (diff)
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>
Diffstat (limited to 'include')
-rw-r--r--include/linux/memcontrol.h15
1 files changed, 2 insertions, 13 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index c4c5b652d3af..2ee20509ac71 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -977,30 +977,19 @@ static inline void mod_memcg_state(struct mem_cgroup *memcg,
static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
{
- long x = READ_ONCE(memcg->vmstats.state[idx]);
-#ifdef CONFIG_SMP
- if (x < 0)
- x = 0;
-#endif
- return x;
+ return READ_ONCE(memcg->vmstats.state[idx]);
}
static inline unsigned long lruvec_page_state(struct lruvec *lruvec,
enum node_stat_item idx)
{
struct mem_cgroup_per_node *pn;
- long x;
if (mem_cgroup_disabled())
return node_page_state(lruvec_pgdat(lruvec), idx);
pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
- x = READ_ONCE(pn->lruvec_stats.state[idx]);
-#ifdef CONFIG_SMP
- if (x < 0)
- x = 0;
-#endif
- return x;
+ return READ_ONCE(pn->lruvec_stats.state[idx]);
}
static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,