From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 163036B0169 for ; Fri, 29 Jul 2011 14:21:51 -0400 (EDT) Message-ID: <4E32FA3D.5060100@draigBrady.com> Date: Fri, 29 Jul 2011 19:21:49 +0100 From: =?ISO-8859-1?Q?P=E1draig_Brady?= MIME-Version: 1.0 Subject: Re: [PATCH] kswapd: avoid unnecessary rebalance after an unsuccessful balancing References: <1311952990-3844-1-git-send-email-alex.shi@intel.com> In-Reply-To: <1311952990-3844-1-git-send-email-alex.shi@intel.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Alex Shi Cc: linux-mm@kvack.org, mgorman@suse.de, linux-kernel@vger.kernel.org, andrea@cpushare.com, tim.c.chen@intel.com, shaohua.li@intel.com, akpm@linux-foundation.org, riel@redhat.com, luto@mit.edu On 07/29/2011 04:23 PM, Alex Shi wrote: > In commit 215ddd66, Mel Gorman said kswapd is better to sleep after a > unsuccessful balancing if there is tighter reclaim request pending in > the balancing. In this scenario, the 'order' and 'classzone_idx' > that are checked for tighter request judgment is incorrect, since they > aren't the one kswapd should read from new pgdat, but the last time pgdat > value for just now balancing. Then kswapd will skip try_to_sleep func > and rebalance the last pgdat request. It's not our expected behavior. > > So, I added new variables to distinguish the returned order/classzone_idx > from last balancing, that can resolved above issue in that scenario. > > I tested the patch on our LKP system with swap-cp/fio mmap randrw > benchmarks. The performance has no change. > > Padraig Brady, would you like to test this patch for your scenario. This + your previous 2 line patch + Mel's 3 patches + 2.6.38.4 still works fine for me. cheers, Padraig. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org