Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751331Ab1BJFlr (ORCPT ); Thu, 10 Feb 2011 00:41:47 -0500 Received: from mail-iw0-f174.google.com ([209.85.214.174]:51809 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750924Ab1BJFlp convert rfc822-to-8bit (ORCPT ); Thu, 10 Feb 2011 00:41:45 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=xcts2ihYWrl8xi/NPpeuDpMX0GBvf5CUtTe2algxcAMdAUrsrd+ubDfqcccX3kQnzv u5yWPZ7+kqF3HHlMa/RLvFiYQFcA8xKNqLI3LK9puYkpls2x84t9BlQnG4HWJGWwIZdq /P+QKv/Q2EqU1JROktf6tHD7pt0ysSleqxs8c= MIME-Version: 1.0 In-Reply-To: References: <20110125051003.13762.35120.stgit@localhost6.localdomain6> <20110125051015.13762.13429.stgit@localhost6.localdomain6> <20110128064851.GB5054@balbir.in.ibm.com> <20110128111833.GD5054@balbir.in.ibm.com> Date: Thu, 10 Feb 2011 14:41:44 +0900 Message-ID: Subject: Re: [PATCH 3/3] Provide control over unmapped pages (v4) From: Minchan Kim To: balbir@linux.vnet.ibm.com Cc: linux-mm@kvack.org, akpm@linux-foundation.org, npiggin@kernel.dk, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, kosaki.motohiro@jp.fujitsu.com, cl@linux.com, kamezawa.hiroyu@jp.fujitsu.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2536 Lines: 85 I don't know why the part of message is deleted only when I send you. Maybe it's gmail bug. I hope mail sending is successful in this turn. :) On Thu, Feb 10, 2011 at 2:33 PM, Minchan Kim wrote: > Sorry for late response. > > On Fri, Jan 28, 2011 at 8:18 PM, Balbir Singh wrote: >> * MinChan Kim [2011-01-28 16:24:19]: >> >>> > >>> > But the assumption for LRU order to change happens only if the page >>> > cannot be successfully freed, which means it is in some way active.. >>> > and needs to be moved no? >>> >>> 1. holded page by someone >>> 2. mapped pages >>> 3. active pages >>> >>> 1 is rare so it isn't the problem. >>> Of course, in case of 3, we have to activate it so no problem. >>> The problem is 2. >>> >> >> 2 is a problem, but due to the size aspects not a big one. Like you >> said even lumpy reclaim affects it. May be the reclaim code could >> honour may_unmap much earlier. > > Even if it is, it's a trade-off to get a big contiguous memory. I > don't want to add new mess. (In addition, lumpy is weak by compaction > as time goes by) > What I have in mind for preventing LRU ignore is that put the page > into original position instead of head of lru. Maybe it can help the > situation both lumpy and your case. But it's another story. > > How about the idea? > > I borrow the idea from CFLRU[1] > - PCFLRU(Page-Cache First LRU) > > When we allocates new page for page cache, we adds the page into LRU's tail. > When we map the page cache into page table, we rotate the page into LRU's head. > > So, inactive list's result is following as. > > M.P : mapped page > N.P : none-mapped page > > HEAD-M.P-M.P-M.P-M.P-N.P-N.P-N.P-N.P-N.P-TAIL > > Admin can set threshold window size which determines stop reclaiming > none-mapped page contiguously. > > I think it needs some tweak of page cache/page mapping functions but > we can use kswapd/direct reclaim without change. > > Also, it can change page reclaim policy totally but it's just what you > want, I think. > > [1] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.100.6188&rep=rep1&type=pdf > >> >> -- >>        Three Cheers, >>        Balbir >> > > > > -- > Kind regards, > Minchan Kim > -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/