From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx206.postini.com [74.125.245.206]) by kanga.kvack.org (Postfix) with SMTP id 6C42B6B0005 for ; Tue, 19 Mar 2013 04:23:35 -0400 (EDT) Date: Tue, 19 Mar 2013 09:23:30 +0100 From: Michal Hocko Subject: Re: [PATCH 03/10] mm: vmscan: Flatten kswapd priority loop Message-ID: <20130319082330.GA7869@dhcp22.suse.cz> References: <1363525456-10448-1-git-send-email-mgorman@suse.de> <1363525456-10448-4-git-send-email-mgorman@suse.de> <5147D6A7.5060008@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5147D6A7.5060008@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Simon Jeons Cc: Mel Gorman , Linux-MM , Jiri Slaby , Valdis Kletnieks , Rik van Riel , Zlatko Calusic , Johannes Weiner , dormando , Satoru Moriya , LKML On Tue 19-03-13 11:08:23, Simon Jeons wrote: > Hi Mel, > On 03/17/2013 09:04 PM, Mel Gorman wrote: > >kswapd stops raising the scanning priority when at least SWAP_CLUSTER_MAX > >pages have been reclaimed or the pgdat is considered balanced. It then > >rechecks if it needs to restart at DEF_PRIORITY and whether high-order > >reclaim needs to be reset. This is not wrong per-se but it is confusing > > per-se is short for what? > > >to follow and forcing kswapd to stay at DEF_PRIORITY may require several > >restarts before it has scanned enough pages to meet the high watermark even > >at 100% efficiency. This patch irons out the logic a bit by controlling > >when priority is raised and removing the "goto loop_again". > > > >This patch has kswapd raise the scanning priority until it is scanningmm: vmscan: Flatten kswapd priority loop > >enough pages that it could meet the high watermark in one shrink of the > >LRU lists if it is able to reclaim at 100% efficiency. It will not raise > > Which kind of reclaim can be treated as 100% efficiency? nr_scanned == nr_reclaimed > >the scanning prioirty higher unless it is failing to reclaim any pages. > > > >To avoid infinite looping for high-order allocation requests kswapd will > >not reclaim for high-order allocations when it has reclaimed at least > >twice the number of pages as the allocation request. > > > >Signed-off-by: Mel Gorman [...] -- Michal Hocko 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