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 9211C6B0087 for ; Tue, 7 Dec 2010 01:30:13 -0500 (EST) Received: from m1.gw.fujitsu.co.jp ([10.0.50.71]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id oB76UAdJ018283 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Tue, 7 Dec 2010 15:30:10 +0900 Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id BE13545DE76 for ; Tue, 7 Dec 2010 15:30:10 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 97E5645DE80 for ; Tue, 7 Dec 2010 15:30:10 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 83D90E38002 for ; Tue, 7 Dec 2010 15:30:10 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.249.87.107]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 3988BE38007 for ; Tue, 7 Dec 2010 15:30:10 +0900 (JST) Date: Tue, 7 Dec 2010 15:24:23 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 1/4] Add kswapd descriptor. Message-Id: <20101207152423.1ba94270.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20101207061503.GH3158@balbir.in.ibm.com> References: <1291099785-5433-1-git-send-email-yinghan@google.com> <1291099785-5433-2-git-send-email-yinghan@google.com> <20101130160838.4c66febf.kamezawa.hiroyu@jp.fujitsu.com> <20101130172710.38de418b.kamezawa.hiroyu@jp.fujitsu.com> <20101130175443.f01f4d09.kamezawa.hiroyu@jp.fujitsu.com> <20101207061503.GH3158@balbir.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: balbir@linux.vnet.ibm.com Cc: Minchan Kim , Ying Han , Daisuke Nishimura , Andrew Morton , Mel Gorman , Johannes Weiner , Christoph Lameter , Wu Fengguang , Andi Kleen , Hugh Dickins , Rik van Riel , KOSAKI Motohiro , Tejun Heo , linux-mm@kvack.org List-ID: On Tue, 7 Dec 2010 11:45:03 +0530 Balbir Singh wrote: > * KAMEZAWA Hiroyuki [2010-11-30 17:54:43]: > > > On Tue, 30 Nov 2010 17:27:10 +0900 > > KAMEZAWA Hiroyuki wrote: > > > > > On Tue, 30 Nov 2010 17:15:37 +0900 > > > Minchan Kim wrote: > > > > > > > Ideally, I hope we unify global and memcg of kswapd for easy > > > > maintainance if it's not a big problem. > > > > When we make patches about lru pages, we always have to consider what > > > > I should do for memcg. > > > > And when we review patches, we also should consider what the patch is > > > > missing for memcg. > > > > It makes maintainance cost big. Of course, if memcg maintainers is > > > > involved with all patches, it's no problem as it is. > > > > > > > I know it's not. But thread control of kswapd will not have much merging point. > > > And balance_pgdat() is fully replaced in patch/3. The effort for merging seems > > > not big. > > > > > > > kswapd's balance_pgdat() is for following > > - reclaim pages within a node. > > - balancing zones in a pgdat. > > > > memcg's background reclaim needs followings. > > - reclaim pages within a memcg > > - reclaim pages from arbitrary zones, if it's fair, it's good. > > But it's not important from which zone the pages are reclaimed from. > > (I'm not sure we can select "the oldest" pages from divided LRU.) > > > > Yes, if it is fair, then we don't break what kswapd tries to do, so > fairness is quite important, in that we don't leaves zones unbalanced > (at least by very much) as we try to do background reclaim. But > sometimes it cannot be helped, specially if there are policies that > bias the allocation. > > > Then, merging will put 2 _very_ different functionalities into 1 function. > > > > So, I thought it's simpler to implement > > > > 1. a victim node selector (This algorithm will never be in kswapd.) > > A victim node selector per memcg? Could you clarify the context of > node here? > An argument to balance_pgdat_for_memcg() or a start point of zonelist[]. i.e. zone_list = NODE_DATA(victim)->zonelist[0 or 1] for_each_zone_zonelist(z, zone_list).... But, this is just an example, we just need to determine where we reclaim page from before start walking. Thanks, -Kame -- 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org