From: Tao Ma <tm@tao.ma>
To: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org,
David Rientjes <rientjes@google.com>,
Minchan Kim <minchan.kim@gmail.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Mel Gorman <mel@csn.ul.ie>, Johannes Weiner <jweiner@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH] mm: do not drain pagevecs for mlock
Date: Fri, 30 Dec 2011 14:36:01 +0800 [thread overview]
Message-ID: <1325226961-4271-1-git-send-email-tm@tao.ma> (raw)
In our test of mlock, we have found some severe performance regression
in it. Some more investigations show that mlocked is blocked heavily
by lur_add_drain_all which calls schedule_on_each_cpu and flush the work
queue which is very slower if we have several cpus.
So we have tried 2 ways to solve it:
1. Add a per cpu counter for all the pagevecs so that we don't schedule
and flush the lru_drain work if the cpu doesn't have any pagevecs(I
have finished the codes already).
2. Remove the lru_add_drain_all.
The first one has some problems since in our product system, all the cpus
are busy, so I guess there is very little chance for a cpu to have 0 pagevecs
except that you run several consecutive mlocks.
>From the commit log which added this function(8891d6da), it seems that we
don't have to call it. So the 2nd one seems to be both easy and workable and
comes this patch.
Thanks
Tao
next reply other threads:[~2011-12-30 6:36 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-30 6:36 Tao Ma [this message]
2011-12-30 8:11 ` KOSAKI Motohiro
2011-12-30 8:48 ` Tao Ma
2011-12-30 9:31 ` KOSAKI Motohiro
2011-12-30 9:45 ` Tao Ma
2011-12-30 10:07 ` KOSAKI Motohiro
2012-01-01 7:30 ` [PATCH 1/2] mm,mlock: drain pagevecs asynchronously kosaki.motohiro
2012-01-04 1:17 ` Minchan Kim
2012-01-04 2:38 ` KOSAKI Motohiro
2012-01-10 8:53 ` Tao Ma
2012-01-04 2:56 ` Hugh Dickins
2012-01-04 22:05 ` Andrew Morton
2012-01-04 23:33 ` KOSAKI Motohiro
2012-01-05 0:19 ` Hugh Dickins
2012-01-01 7:30 ` [PATCH 2/2] sysvshm: SHM_LOCK use lru_add_drain_all_async() kosaki.motohiro
2012-01-04 1:51 ` Hugh Dickins
2012-01-04 2:19 ` KOSAKI Motohiro
2012-01-04 5:17 ` Hugh Dickins
2012-01-04 8:34 ` KOSAKI Motohiro
2012-01-06 6:13 ` [PATCH] mm: do not drain pagevecs for mlock Tao Ma
2012-01-06 6:18 ` KOSAKI Motohiro
2012-01-06 6:30 ` Tao Ma
2012-01-06 6:33 ` KOSAKI Motohiro
2012-01-06 6:46 ` Tao Ma
2012-01-09 23:58 ` KOSAKI Motohiro
2012-01-10 2:08 ` Tao Ma
2012-01-09 7:25 ` Tao Ma
2011-12-30 10:14 ` KOSAKI Motohiro
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