Date: Mon, 2 Nov 2009 17:38:38 +0000
From: Mel Gorman <mel@csn.ul.ie>
To: Frans Pop <elendil@planet.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>, stable@kernel.org,
       linux-kernel@vger.kernel.org, "linux-mm@kvack.org" <linux-mm@kvack.org>,
       Jiri Kosina <jkosina@suse.cz>,
       Sven Geggus <lists@fuchsschwanzdomain.de>,
       Karol Lewandowski <karol.k.lewandowski@gmail.com>,
       Tobias Oetiker <tobi@oetiker.ch>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Pekka Enberg <penberg@cs.helsinki.fi>, Rik van Riel <riel@redhat.com>,
       Christoph Lameter <cl@linux-foundation.org>,
       Stephan von Krawczynski <skraw@ithnet.com>,
       Kernel Testers List <kernel-testers@vger.kernel.org>
Subject: Re: [PATCH 3/3] vmscan: Force kswapd to take notice faster when
	high-order watermarks are being hit
Message-ID: <20091102173837.GB22046@csn.ul.ie>
References: <1256650833-15516-1-git-send-email-mel@csn.ul.ie> <20091028124756.7af44b6b.akpm@linux-foundation.org> <20091102160534.GA22046@csn.ul.ie> <200911021832.59035.elendil@planet.nl>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-15
Content-Disposition: inline
In-Reply-To: <200911021832.59035.elendil@planet.nl>
User-Agent: Mutt/1.5.17+20080114 (2008-01-14)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1589
Lines: 35

On Mon, Nov 02, 2009 at 06:32:54PM +0100, Frans Pop wrote:
> On Monday 02 November 2009, Mel Gorman wrote:
> > vmscan: Help debug kswapd issues by counting number of rewakeups and
> > premature sleeps
> >
> > There is a growing amount of anedotal evidence that high-order atomic
> > allocation failures have been increasing since 2.6.31-rc1. The two
> > strongest possibilities are a marked increase in the number of
> > GFP_ATOMIC allocations and alterations in timing. Debugging printk
> > patches have shown for example that kswapd is sleeping for shorter
> > intervals and going to sleep when watermarks are still not being met.
> >
> > This patch adds two kswapd counters to help identify if timing is an
> > issue. The first counter kswapd_highorder_rewakeup counts the number of
> > times that kswapd stops reclaiming at one order and restarts at a higher
> > order. The second counter kswapd_slept_prematurely counts the number of
> > times kswapd went to sleep when the high watermark was not met.
> 
> What testing would you like done with this patch?
> 

Same reproduction as before except post what the contents of
/proc/vmstat were after the problem was triggered.

Thanks

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/