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| author | Yosry Ahmed <yosryahmed@google.com> | 2023-03-30 21:17:59 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-19 01:29:50 +0200 |
| commit | 4009b2f1887036d30637bc06dd0ade7e18408bb3 (patch) | |
| tree | c1d37c77b18d1669e0e279ef08abb0ae9a23b255 /mm/workingset.c | |
| parent | memcg: sleep during flushing stats in safe contexts (diff) | |
| download | linux-4009b2f1887036d30637bc06dd0ade7e18408bb3.tar.xz linux-4009b2f1887036d30637bc06dd0ade7e18408bb3.zip | |
workingset: memcg: sleep when flushing stats in workingset_refault()
In workingset_refault(), we call
mem_cgroup_flush_stats_atomic_ratelimited() to read accurate stats within
an RCU read section and with sleeping disallowed. Move the call above the
RCU read section to make it non-atomic.
Flushing is an expensive operation that scales with the number of cpus and
the number of cgroups in the system, so avoid doing it atomically where
possible.
Since workingset_refault() is the only caller of
mem_cgroup_flush_stats_atomic_ratelimited(), just make it non-atomic, and
rename it to mem_cgroup_flush_stats_ratelimited().
Link: https://lkml.kernel.org/r/20230330191801.1967435-7-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vasily Averin <vasily.averin@linux.dev>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/workingset.c')
| -rw-r--r-- | mm/workingset.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/workingset.c b/mm/workingset.c index dab0c362b9e3..3025beee9b34 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -406,6 +406,9 @@ void workingset_refault(struct folio *folio, void *shadow) unpack_shadow(shadow, &memcgid, &pgdat, &eviction, &workingset); eviction <<= bucket_order; + /* Flush stats (and potentially sleep) before holding RCU read lock */ + mem_cgroup_flush_stats_ratelimited(); + rcu_read_lock(); /* * Look up the memcg associated with the stored ID. It might @@ -461,8 +464,6 @@ void workingset_refault(struct folio *folio, void *shadow) lruvec = mem_cgroup_lruvec(memcg, pgdat); mod_lruvec_state(lruvec, WORKINGSET_REFAULT_BASE + file, nr); - - mem_cgroup_flush_stats_atomic_ratelimited(); /* * Compare the distance to the existing workingset size. We * don't activate pages that couldn't stay resident even if |