From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 6F8A26B006A for ; Mon, 2 Nov 2009 12:38:47 -0500 (EST) Date: Mon, 2 Nov 2009 17:38:38 +0000 From: Mel Gorman 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> Sender: owner-linux-mm@kvack.org To: Frans Pop Cc: Andrew Morton , stable@kernel.org, linux-kernel@vger.kernel.org, "linux-mm@kvack.org" , Jiri Kosina , Sven Geggus , Karol Lewandowski , Tobias Oetiker , KOSAKI Motohiro , Pekka Enberg , Rik van Riel , Christoph Lameter , Stephan von Krawczynski , Kernel Testers List List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org