From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id DDAF78D0039 for ; Thu, 10 Feb 2011 00:41:46 -0500 (EST) Received: by iyi20 with SMTP id 20so977317iyi.14 for ; Wed, 09 Feb 2011 21:41:45 -0800 (PST) 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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: 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 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 ta= il. > 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=3D10.1.1.100.6188&r= ep=3Drep1&type=3Dpdf > >> >> -- >> =C2=A0 =C2=A0 =C2=A0 =C2=A0Three Cheers, >> =C2=A0 =C2=A0 =C2=A0 =C2=A0Balbir >> > > > > -- > Kind regards, > Minchan Kim > --=20 Kind regards, Minchan Kim -- 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