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 65D8F6B002D for ; Thu, 10 Nov 2011 11:07:53 -0500 (EST) Date: Thu, 10 Nov 2011 17:06:28 +0100 From: Johannes Weiner Subject: Re: [rfc 2/3] mm: vmscan: treat inactive cycling as neutral Message-ID: <20111110160628.GM3153@redhat.com> References: <20110808110658.31053.55013.stgit@localhost6> <4E3FD403.6000400@parallels.com> <20111102163056.GG19965@redhat.com> <20111102163213.GI19965@redhat.com> <20111107113417.1b7581a5.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111107113417.1b7581a5.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: Konstantin Khlebnikov , Pekka Enberg , "linux-mm@kvack.org" , Andrew Morton , "linux-kernel@vger.kernel.org" , Wu Fengguang , Johannes Weiner , Rik van Riel , Mel Gorman , Minchan Kim , Gene Heskett On Mon, Nov 07, 2011 at 11:34:17AM +0900, KAMEZAWA Hiroyuki wrote: > On Wed, 2 Nov 2011 17:32:13 +0100 > Johannes Weiner wrote: > > > Each page that is scanned but put back to the inactive list is counted > > as a successful reclaim, which tips the balance between file and anon > > lists more towards the cycling list. > > > > This does - in my opinion - not make too much sense, but at the same > > time it was not much of a problem, as the conditions that lead to an > > inactive list cycle were mostly temporary - locked page, concurrent > > page table changes, backing device congested - or at least limited to > > a single reclaimer that was not allowed to unmap or meddle with IO. > > More important than being moderately rare, those conditions should > > apply to both anon and mapped file pages equally and balance out in > > the end. > > > > Recently, we started cycling file pages in particular on the inactive > > list much more aggressively, for used-once detection of mapped pages, > > and when avoiding writeback from direct reclaim. > > > > Those rotated pages do not exactly speak for the reclaimability of the > > list they sit on and we risk putting immense pressure on file list for > > no good reason. > > > > Instead, count each page not reclaimed and put back to any list, > > active or inactive, as rotated, so they are neutral with respect to > > the scan/rotate ratio of the list class, as they should be. > > > > Signed-off-by: Johannes Weiner > > I think this makes sense. > > Acked-by: KAMEZAWA Hiroyuki > > I wonder it may be better to have victim list for written-backed pages.. Do you mean an extra LRU list that holds dirty pages? -- 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