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 827996B03BC for ; Mon, 23 Aug 2010 09:38:34 -0400 (EDT) Date: Mon, 23 Aug 2010 08:38:25 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator V2 In-Reply-To: <20100823130127.GP19797@csn.ul.ie> Message-ID: References: <1282550442-15193-1-git-send-email-mel@csn.ul.ie> <20100823130127.GP19797@csn.ul.ie> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: Andrew Morton , Linux Kernel List , linux-mm@kvack.org, Rik van Riel , Johannes Weiner , Minchan Kim , KAMEZAWA Hiroyuki , KOSAKI Motohiro List-ID: On Mon, 23 Aug 2010, Mel Gorman wrote: > > The maximum time for which the livelock can exists is the vm stat > > interval. By default the counters are brought up to date at least once per > > second or if a certain delta was violated. Drifts are controlled by the > > delta configuration. > > > > While there is a maximum time (2 seconds I think) the drift can exist > in, a machine under enough pressure can make a mess of the watermarks > during that time. If it wasn't the case, these livelocks with 0 pages > free wouldn't be happening. So because we go way beyond the watermarks we reach a state in which a livelock exists that does not go away when the counters are finally updated? -- 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