From: Dave Chinner <david@fromorbit.com>
To: Keith Keller <kkeller@wombat.san-francisco.ca.us>
Cc: linux-xfs@oss.sgi.com
Subject: Re: high load and xfsaild in d
Date: Fri, 23 Nov 2012 13:56:24 +1100 [thread overview]
Message-ID: <20121123025624.GC32450@dastard> (raw)
In-Reply-To: <sn23o9xkh3.ln2@goaway.wombat.san-francisco.ca.us>
On Thu, Nov 22, 2012 at 06:13:48PM -0800, Keith Keller wrote:
> Hello all,
>
> I recently deployed a new CentOS 6.3 file server, and soon after I
> noticed that the load was consistenly at around 4, even with no obvious
> activity. After checking around a bit, the only unusual thing I could
> find is that the xfsaild threads are all consistently in D state:
>
> root 1744 0.0 0.0 0 0 ? D Nov16 7:46 [xfsaild/dm-2]
> root 1756 0.0 0.0 0 0 ? D Nov16 7:44 [xfsaild/dm-1]
> root 1759 0.0 0.0 0 0 ? D Nov16 7:57 [xfsaild/dm-3]
> root 1762 0.0 0.0 0 0 ? D Nov16 5:59 [xfsaild/dm-0]
That's a side effect of a minimal set of bug fixes that were needed
to avoid a load related log space hang. Those fixes disabled the
aild idling logic so the aild acts as a watchdog, so they wake up
every 50ms to check if there's anything to do. You'll find that
3.0.x stable kernels have the same behaviour.
The aild idling logic was re-enabled in mainstream kernels after the
root cause of the log space hangs was diagnosed and fixed, but I
can't see it ever being re-enabled in a CentOS 6.3 kernel....
Cheers,
Dave
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2012-11-23 2:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-23 2:13 high load and xfsaild in d Keith Keller
2012-11-23 2:56 ` Dave Chinner [this message]
2012-11-23 4:34 ` Keith Keller
2012-11-23 5:39 ` Dave Chinner
2012-11-23 20:19 ` Keith Keller
2012-11-23 21:33 ` Dave Chinner
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