From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id DFAE36B005A for ; Wed, 29 Jul 2009 12:19:41 -0400 (EDT) Message-ID: <4A707696.6080301@redhat.com> Date: Wed, 29 Jul 2009 12:19:34 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH -mm] throttle direct reclaim when too many pages are isolated already (v3) References: <20090715223854.7548740a@bree.surriel.com> <20090715194820.237a4d77.akpm@linux-foundation.org> <4A5E9A33.3030704@redhat.com> <20090715202114.789d36f7.akpm@linux-foundation.org> <4A5E9E4E.5000308@redhat.com> <20090715203854.336de2d5.akpm@linux-foundation.org> <20090715235318.6d2f5247@bree.surriel.com> <20090729150443.GB1534@ucw.cz> In-Reply-To: <20090729150443.GB1534@ucw.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Pavel Machek Cc: Andrew Morton , KOSAKI Motohiro , LKML , linux-mm , Wu Fengguang List-ID: Pavel Machek wrote: > On Wed 2009-07-15 23:53:18, Rik van Riel wrote: >> When way too many processes go into direct reclaim, it is possible >> for all of the pages to be taken off the LRU. One result of this >> is that the next process in the page reclaim code thinks there are >> no reclaimable pages left and triggers an out of memory kill. >> >> One solution to this problem is to never let so many processes into >> the page reclaim path that the entire LRU is emptied. Limiting the >> system to only having half of each inactive list isolated for >> reclaim should be safe. > > Is this still racy? Like on 100cpu machine, with LRU size of 50...? If a 100 CPU system gets down to just 100 reclaimable pages, getting the OOM killer to trigger sounds desirable. The goal of this patch is to avoid _false_ OOM kills, when the system still has enough reclaimable memory available. -- All rights reversed. -- 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