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| From | Michal Hocko <mhocko@kernel.org> |
| Newsgroups | linux.kernel |
| Subject | [PATCH 5/3] mm, vmscan: make zone_reclaimable_pages more precise |
| Date | Thu, 28 Jan 2016 22:20:02 +0100 |
| Message-ID | <qW28W-R2-3@gated-at.bofh.it> (permalink) |
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| X-Original-Cc | Linus Torvalds <torvalds@linux-foundation.org>, Johannes Weiner <hannes@cmpxchg.org>, Mel Gorman <mgorman@suse.de>, David Rientjes <rientjes@google.com>, Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>, Hillf Danton <hillf.zj@alibaba-inc.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Michal Hocko <mhocko@suse.com> |
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From: Michal Hocko <mhocko@suse.com>
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.
Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
---
mm/vmscan.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 489212252cd6..9145e3f89eab 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -196,21 +196,21 @@ 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;
}
--
2.7.0.rc3
Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread
[PATCH 5/3] mm, vmscan: make zone_reclaimable_pages more precise Michal Hocko <mhocko@kernel.org> - 2016-01-28 22:20 +0100
Re: [PATCH 5/3] mm, vmscan: make zone_reclaimable_pages more precise David Rientjes <rientjes@google.com> - 2016-01-29 00:30 +0100
Re: [PATCH 5/3] mm, vmscan: make zone_reclaimable_pages more precise "Hillf Danton" <hillf.zj@alibaba-inc.com> - 2016-01-29 04:50 +0100
Re: [PATCH 5/3] mm, vmscan: make zone_reclaimable_pages more precise Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-01-29 11:40 +0100
Re: [PATCH 5/3] mm, vmscan: make zone_reclaimable_pages more precise Michal Hocko <mhocko@kernel.org> - 2016-01-29 16:20 +0100
Re: [PATCH 5/3] mm, vmscan: make zone_reclaimable_pages more precise Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-01-29 22:40 +0100
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