From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx198.postini.com [74.125.245.198]) by kanga.kvack.org (Postfix) with SMTP id 158BC6B0002 for ; Sun, 24 Mar 2013 15:00:13 -0400 (EDT) Received: by mail-ee0-f43.google.com with SMTP id c50so2978388eek.2 for ; Sun, 24 Mar 2013 12:00:11 -0700 (PDT) Message-ID: <514F4D37.5030304@suse.cz> Date: Sun, 24 Mar 2013 20:00:07 +0100 From: Jiri Slaby MIME-Version: 1.0 Subject: Re: [RFC PATCH 0/8] Reduce system disruption due to kswapd References: <1363525456-10448-1-git-send-email-mgorman@suse.de> In-Reply-To: <1363525456-10448-1-git-send-email-mgorman@suse.de> Content-Type: text/plain; charset=ISO-8859-2 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman , Linux-MM Cc: Jiri Slaby , Valdis Kletnieks , Rik van Riel , Zlatko Calusic , Johannes Weiner , dormando , Satoru Moriya , Michal Hocko , LKML On 03/17/2013 02:04 PM, Mel Gorman wrote: > Kswapd and page reclaim behaviour has been screwy in one way or the other > for a long time. Very broadly speaking it worked in the far past because > machines were limited in memory so it did not have that many pages to scan > and it stalled congestion_wait() frequently to prevent it going completely > nuts. In recent times it has behaved very unsatisfactorily with some of > the problems compounded by the removal of stall logic and the introduction > of transparent hugepage support with high-order reclaims. > > There are many variations of bugs that are rooted in this area. One example > is reports of a large copy operations or backup causing the machine to > grind to a halt or applications pushed to swap. Sometimes in low memory > situations a large percentage of memory suddenly gets reclaimed. In other > cases an application starts and kswapd hits 100% CPU usage for prolonged > periods of time and so on. There is now talk of introducing features like > an extra free kbytes tunable to work around aspects of the problem instead > of trying to deal with it. It's compounded by the problem that it can be > very workload and machine specific. > > This RFC is aimed at investigating if kswapd can be address these various > problems in a relatively straight-forward fashion without a fundamental > rewrite. > > Patches 1-2 limits the number of pages kswapd reclaims while still obeying > the anon/file proportion of the LRUs it should be scanning. Hi, patch 1 does not apply (on the top of -next), so I can't test this :(. thanks, -- js suse labs -- 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