From: Rik van Riel <riel@redhat.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, kamezawa.hiroyu@jp.fujitsu.com,
minchan.kim@gmail.com
Subject: Re: [PATCH 3/3] vmscan: implement swap token priority decay
Date: Sun, 15 May 2011 18:34:23 -0400 [thread overview]
Message-ID: <4DD054EF.4020300@redhat.com> (raw)
In-Reply-To: <4DCD1913.2090200@jp.fujitsu.com>
On 05/13/2011 07:42 AM, KOSAKI Motohiro wrote:
> While testing for memcg aware swap token, I observed a swap token
> was often grabbed an intermittent running process (eg init, auditd)
> and they never release a token.
>
> Why? Currently, swap toke priority is only decreased at page fault
> path. Then, if the process sleep immediately after to grab swap
> token, their swap token priority never be decreased. That makes
> obviously undesired result.
>
> This patch implement very poor (and lightweight) priority decay
> mechanism. It only be affect to the above corner case and doesn't
> change swap tendency workload performance (eg multi process qsbench
> load)
Ohhh, good catch. The original swap token algorithm did
not have this problem, and I never caught the fact that
the replacement (which is better in many ways) does...
> Signed-off-by: KOSAKI Motohiro<kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Rik van Riel<riel@redhat.com>
--
All rights reversed
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, kamezawa.hiroyu@jp.fujitsu.com,
minchan.kim@gmail.com
Subject: Re: [PATCH 3/3] vmscan: implement swap token priority decay
Date: Sun, 15 May 2011 18:34:23 -0400 [thread overview]
Message-ID: <4DD054EF.4020300@redhat.com> (raw)
In-Reply-To: <4DCD1913.2090200@jp.fujitsu.com>
On 05/13/2011 07:42 AM, KOSAKI Motohiro wrote:
> While testing for memcg aware swap token, I observed a swap token
> was often grabbed an intermittent running process (eg init, auditd)
> and they never release a token.
>
> Why? Currently, swap toke priority is only decreased at page fault
> path. Then, if the process sleep immediately after to grab swap
> token, their swap token priority never be decreased. That makes
> obviously undesired result.
>
> This patch implement very poor (and lightweight) priority decay
> mechanism. It only be affect to the above corner case and doesn't
> change swap tendency workload performance (eg multi process qsbench
> load)
Ohhh, good catch. The original swap token algorithm did
not have this problem, and I never caught the fact that
the replacement (which is better in many ways) does...
> Signed-off-by: KOSAKI Motohiro<kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Rik van Riel<riel@redhat.com>
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next prev parent reply other threads:[~2011-05-15 22:34 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-13 11:38 [PATCH 0/3] swap token revisit KOSAKI Motohiro
2011-05-13 11:38 ` KOSAKI Motohiro
2011-05-13 11:40 ` [PATCH 1/3] vmscan,memcg: memcg aware swap token KOSAKI Motohiro
2011-05-13 11:40 ` KOSAKI Motohiro
2011-05-15 17:56 ` Rik van Riel
2011-05-15 17:56 ` Rik van Riel
2011-05-16 8:01 ` KAMEZAWA Hiroyuki
2011-05-16 8:01 ` KAMEZAWA Hiroyuki
2011-05-13 11:40 ` [PATCH 2/3] vmscan: implement swap token trace KOSAKI Motohiro
2011-05-13 11:40 ` KOSAKI Motohiro
2011-05-15 22:26 ` Rik van Riel
2011-05-15 22:26 ` Rik van Riel
2011-05-16 8:02 ` KAMEZAWA Hiroyuki
2011-05-16 8:02 ` KAMEZAWA Hiroyuki
2011-05-13 11:42 ` [PATCH 3/3] vmscan: implement swap token priority decay KOSAKI Motohiro
2011-05-13 11:42 ` KOSAKI Motohiro
2011-05-15 22:34 ` Rik van Riel [this message]
2011-05-15 22:34 ` Rik van Riel
2011-05-16 8:22 ` KAMEZAWA Hiroyuki
2011-05-16 8:22 ` KAMEZAWA Hiroyuki
2011-05-18 1:08 ` KOSAKI Motohiro
2011-05-18 1:08 ` KOSAKI Motohiro
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