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| author | Michal Hocko <mhocko@suse.com> | 2016-03-15 14:57:01 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-15 16:55:16 -0700 |
| commit | 0db2cb8da89d991762ec2aece45e55ceaee34664 (patch) | |
| tree | b8821119e212ee45266cc73ba36a04a84247b6f6 /mm/vmscan.c | |
| parent | d7206a70af5c094446927b5dea8704f0f96303e3 (diff) | |
| download | lwn-0db2cb8da89d991762ec2aece45e55ceaee34664.tar.gz lwn-0db2cb8da89d991762ec2aece45e55ceaee34664.zip | |
mm, vmscan: make zone_reclaimable_pages more precise
zone_reclaimable_pages() is used in should_reclaim_retry() which uses it
to calculate the target for the watermark check. This means that
precise numbers are important for the correct decision.
zone_reclaimable_pages uses zone_page_state which can contain stale data
with per-cpu diffs not synced yet (the last vmstat_update might have run
1s in the past).
Use zone_page_state_snapshot() in zone_reclaimable_pages() instead.
None of the current callers is in a hot path where getting the precise
value (which involves per-cpu iteration) would cause an unreasonable
overhead.
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Suggested-by: David Rientjes <rientjes@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index db5722a07d4f..039f08d369a5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -195,21 +195,21 @@ static unsigned long zone_reclaimable_pages(struct zone *zone) { unsigned long nr; - nr = zone_page_state(zone, NR_ACTIVE_FILE) + - zone_page_state(zone, NR_INACTIVE_FILE) + - zone_page_state(zone, NR_ISOLATED_FILE); + nr = zone_page_state_snapshot(zone, NR_ACTIVE_FILE) + + zone_page_state_snapshot(zone, NR_INACTIVE_FILE) + + zone_page_state_snapshot(zone, NR_ISOLATED_FILE); if (get_nr_swap_pages() > 0) - nr += zone_page_state(zone, NR_ACTIVE_ANON) + - zone_page_state(zone, NR_INACTIVE_ANON) + - zone_page_state(zone, NR_ISOLATED_ANON); + nr += zone_page_state_snapshot(zone, NR_ACTIVE_ANON) + + zone_page_state_snapshot(zone, NR_INACTIVE_ANON) + + zone_page_state_snapshot(zone, NR_ISOLATED_ANON); return nr; } bool zone_reclaimable(struct zone *zone) { - return zone_page_state(zone, NR_PAGES_SCANNED) < + return zone_page_state_snapshot(zone, NR_PAGES_SCANNED) < zone_reclaimable_pages(zone) * 6; } |