From: Jens Axboe <jens.axboe@oracle.com>
To: Jan Engelhardt <jengelh@medozas.de>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: kswapd continuously active
Date: Fri, 5 Feb 2010 14:00:02 +0100 [thread overview]
Message-ID: <20100205130002.GI1025@kernel.dk> (raw)
In-Reply-To: <alpine.LSU.2.01.1002051329090.7843@obet.zrqbmnf.qr>
On Fri, Feb 05 2010, Jan Engelhardt wrote:
>
> On Monday 2010-01-25 14:22, Jan Engelhardt wrote:
> >On Monday 2010-01-25 14:06, Jens Axboe wrote:
> >>>
> >>> with 2.6.32.2 on sparc64 I am seeing that there is a sync(1) process
> >>> busy in D state, with the following trace:
> >>>
> >>> sync D 000000000079299c 7552 4851 1 0x208061101000004
> >>> Call Trace:
> >>> [000000000053ca58] bdi_sched_wait+0xc/0x1c[...]
> >>> [000000000053ca78] sync_inodes_sb+0x10/0xfc
> >>>
> >>> kswapd is also active all the time, writing something to disk[...]
> >>
> >>That doesn't sound good. What does /proc/meminfo say? What file systems
> >>are you using?
>
> >January 25 Feb-05
> >MemTotal: 8166752 kB 8166752
> >MemFree: 3243552 kB 3781776
> >Buffers: 207968 kB 4912
> >Cached: 2728216 kB 2684400
> >SwapCached: 0 kB 0
> >Active: 2203136 kB 495624
> >Inactive: 2152544 kB 3263136
> >Active(anon): 1167256 kB 488168
> >Inactive(anon): 252952 kB 583912
> >Active(file): 1035880 kB 7456
> >Inactive(file): 1899592 kB 2679224
> >Unevictable: 0 kB 0
> >Mlocked: 0 kB 0
> >SwapTotal: 0 kB 0
> >SwapFree: 0 kB 0
> >Dirty: 141624 kB 2662184
> >Writeback: 0 kB ..
>
> Today this happened again. So I looked at /proc/meminfo to paste today's
> values next to those from January. That is when I noticed the "Dirty"
> value - and thus I ran
>
> watch -d -n 1 'grep Dirty /proc/meminfo'
>
> What I see is that the dirty amount - a sync is currently running -
> only decreases with at most 400 KB/sec, often less than that.
I'm guessing the barriers and commits are what is killing your
performance. What happens with barrier=0?
--
Jens Axboe
next prev parent reply other threads:[~2010-02-05 13:00 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-22 23:52 kswapd continuously active Jan Engelhardt
2010-01-25 13:06 ` Jens Axboe
2010-01-25 13:22 ` Jan Engelhardt
2010-02-05 12:35 ` Jan Engelhardt
2010-02-05 13:00 ` Jens Axboe [this message]
2010-02-05 13:09 ` Jan Engelhardt
2010-02-05 13:12 ` Jens Axboe
2010-02-05 13:24 ` Jan Engelhardt
2010-02-07 10:50 ` Jan Engelhardt
2010-02-08 0:07 ` Jan Engelhardt
2010-02-08 14:08 ` Jens Axboe
2010-02-10 15:18 ` Jan Engelhardt
2010-02-10 15:23 ` Jan Engelhardt
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