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From: Andrew Morton <akpm@linux-foundation.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Minchan Kim <minchan@kernel.org>,
	Dave Chinner <david@fromorbit.com>,
	nowhere <nowhere@hakkenden.ath.cx>, Michal Hocko <mhocko@suse.cz>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: Kswapd in 3.2.0-rc5 is a CPU hog
Date: Tue, 10 Jan 2012 14:33:30 -0800	[thread overview]
Message-ID: <20120110143330.44cf1ccf.akpm@linux-foundation.org> (raw)
In-Reply-To: <20111227135658.08c8016a.kamezawa.hiroyu@jp.fujitsu.com>

On Tue, 27 Dec 2011 13:56:58 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> Hmm, if I understand correctly,
> 
>  - dd's speed down is caused by kswapd's cpu consumption.
>  - kswapd's cpu consumption is enlarged by shrink_slab() (by perf)
>  - kswapd can't stop because NORMAL zone is small.
>  - memory reclaim speed is enough because dd can't get enough cpu.
> 
> I wonder reducing to call shrink_slab() may be a help but I'm not sure
> where lock conention comes from...

Nikolay, it sounds as if this problem has only recently started
happening?  Was 3.1 OK?

If so, we should work out what we did post-3.1 to cause this.

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  reply	other threads:[~2012-01-10 22:33 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1324437036.4677.5.camel@hakkenden.homenet>
2011-12-21  9:52 ` Kswapd in 3.2.0-rc5 is a CPU hog Michal Hocko
2011-12-21 10:15   ` nowhere
2011-12-21 10:24     ` Michal Hocko
2011-12-21 10:52       ` nowhere
2011-12-21 14:06       ` Alex Elder
2011-12-21 14:19         ` nowhere
2011-12-21 22:55   ` Dave Chinner
2011-12-23  9:01     ` nowhere
2011-12-23 10:20       ` Dave Chinner
2011-12-23 11:04         ` nowhere
2011-12-23 20:45           ` Dave Chinner
2011-12-25  9:09             ` Hillf Danton
2011-12-25 10:21               ` Nikolay S.
2011-12-26 12:35                 ` Hillf Danton
2011-12-27  0:20                   ` KAMEZAWA Hiroyuki
2011-12-27 13:33                     ` Hillf Danton
2011-12-28  0:06                       ` KAMEZAWA Hiroyuki
2011-12-27  2:15             ` KAMEZAWA Hiroyuki
2011-12-27  2:50               ` Nikolay S.
2011-12-27  4:44                 ` KAMEZAWA Hiroyuki
2011-12-27  6:06                   ` nowhere
2011-12-28 21:33                   ` Dave Chinner
2011-12-28 22:57                     ` KOSAKI Motohiro
2012-01-02  7:00                       ` Dave Chinner
2011-12-27  3:57               ` Minchan Kim
2011-12-27  4:56                 ` KAMEZAWA Hiroyuki
2012-01-10 22:33                   ` Andrew Morton [this message]
2012-01-11  3:25                     ` Nikolay S.
2012-01-11  4:42                       ` Andrew Morton
2012-01-11  0:33                   ` Dave Chinner
2012-01-11  1:17                 ` Rik van Riel

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