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Date: Wed, 18 Sep 2002 17:35:29 -0700
From: Andrew Morton <akpm@digeo.com>
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To: Duncan Sands <duncan.sands@math.u-psud.fr>
CC: linux-kernel@vger.kernel.org
Subject: Re: fsync 50 times slower after 2.5.27
References: <200209190222.33276.duncan.sands@math.u-psud.fr>
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Duncan Sands wrote:
> 
> I noticed a performance degradation in recent kernels:
> fsync takes around 50 times longer in kernels 2.5.28 to
> 2.5.34 when the system is under heavy load, as compared
> to kernels <= 2.5.27.  I noticed this because it makes kmail
> unusable.  2.5.34 is the most recent kernel I tested.
> 

Please try replacing the yield() in fs/jbd/transaction.c
with

	set_current_state(TASK_RUNNING);
	schedule();