Date: Fri, 19 Mar 2004 21:46:32 +0100
Message-ID: <s5h3c8436qf.wl@alsa2.suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: Andrew Morton <akpm@osdl.org>
Cc: Chris Mason <mason@suse.com>, andrea@suse.de, linux-kernel@vger.kernel.org
Subject: Re: CONFIG_PREEMPT and server workloads
In-Reply-To: <20040318155745.36d4785d.akpm@osdl.org>
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At Thu, 18 Mar 2004 15:57:45 -0800,
Andrew Morton wrote:
> 
> Chris Mason <mason@suse.com> wrote:
> >
> > > What we're doing here is walking (under spinlock) a ring of buffers
> > > searching for unlocked dirty ones to write out.
> > > 
> > > Suppose the ring has thousands of locked buffers and there is a RT task
> > > scheduling at 1kHz.  Each time need_resched() comes true we break out of
> > > the search, schedule away and then restart the search from the beginning.
> > > 
> > Why not just put all the locked buffers onto a different list as you
> > find them or lock them.  That way you can always make progress...
> 
> Coz that made me look at the code and hence rewrite the whole thing, damn
> you.  It's definitely better, but is of scary scope.

wow, interesting, i'll give a shot with your patch.
thanks!


Takashi
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