Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755191Ab0LIATs (ORCPT ); Wed, 8 Dec 2010 19:19:48 -0500 Received: from mail-iw0-f172.google.com ([209.85.214.172]:55215 "EHLO mail-iw0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751872Ab0LIATr convert rfc822-to-8bit (ORCPT ); Wed, 8 Dec 2010 19:19:47 -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=xp6EJuCGPjuxMenm3qa+GgQ4itr5AUVpx37/HrOccAHk8+cf4Conot2zrIWw0Kk5tC teoxoPpNRJZ9bx/n4APKHYZHflJTMpsnIA8QrSmFj0Amw90Hc+6LKGDgfgbImN6OwDRk Di6IQrLJHyGhfr4J2BbWPR1nU8AG4cyMTJbPc= MIME-Version: 1.0 In-Reply-To: <20101208065650.GP3158@balbir.in.ibm.com> References: <20101207144923.GB2356@cmpxchg.org> <20101207150710.GA26613@barrios-desktop> <20101207151939.GF2356@cmpxchg.org> <20101207152625.GB608@barrios-desktop> <20101207155645.GG2356@cmpxchg.org> <20101208095642.8128ab33.kamezawa.hiroyu@jp.fujitsu.com> <20101208105637.5103de75.kamezawa.hiroyu@jp.fujitsu.com> <20101208065650.GP3158@balbir.in.ibm.com> Date: Thu, 9 Dec 2010 09:19:46 +0900 Message-ID: Subject: Re: [PATCH v4 2/7] deactivate invalidated pages From: Minchan Kim To: balbir@linux.vnet.ibm.com Cc: KAMEZAWA Hiroyuki , Johannes Weiner , Andrew Morton , Rik van Riel , KOSAKI Motohiro , linux-mm , LKML , Peter Zijlstra , Wu Fengguang , Nick Piggin , Mel Gorman Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3719 Lines: 112 On Wed, Dec 8, 2010 at 3:56 PM, Balbir Singh wrote: > * MinChan Kim [2010-12-08 11:15:19]: > >> On Wed, Dec 8, 2010 at 10:56 AM, KAMEZAWA Hiroyuki >> wrote: >> > On Wed, 8 Dec 2010 10:43:08 +0900 >> > Minchan Kim wrote: >> > >> >> Hi Kame, >> >> >> > Hi, >> > >> >> > I wonder ...how about adding "victim" list for "Reclaim" pages ? Then, we don't need >> >> > extra LRU rotation. >> >> >> >> It can make the code clean. >> >> As far as I think, victim list does following as. >> >> >> >> 1. select victim pages by strong hint >> >> 2. move the page from LRU to victim >> >> 3. reclaimer always peeks victim list before diving into LRU list. >> >> 4-1. If the victim pages is used by others or dirty, it can be moved >> >> into LRU, again or remain the page in victim list. >> >> If the page is remained victim, when do we move it into LRU again if >> >> the reclaimer continues to fail the page? >> > When sometone touches it. >> > >> >> We have to put the new rule. >> >> 4-2. If the victim pages isn't used by others and clean, we can >> >> reclaim the page asap. >> >> >> >> AFAIK, strong hints are just two(invalidation, readahead max window heuristic). >> >> I am not sure it's valuable to add new hierarchy(ie, LRU, victim, >> >> unevictable) for cleaning the minor codes. >> >> In addition, we have to put the new rule so it would make the LRU code >> >> complicated. >> >> I remember how unevictable feature merge is hard. >> >> >> > yes, it was hard. >> > >> >> But I am not against if we have more usecases. In this case, it's >> >> valuable to implement it although it's not easy. >> >> >> > >> > I wonder "victim list" can be used for something like Cleancache, when >> > we have very-low-latency backend devices. >> > And we may able to have page-cache-limit, which Balbir proposed as. >> >> Yes, I thought that, too. I think it would be a good feature in embedded system. >> >> > >> > ?- kvictimed? will move unmappedd page caches to victim list >> > This may work like a InactiveClean list which we had before and make >> > sizing easy. >> > >> >> Before further discuss, we need customer's confirm. >> We know very well it is very hard to merge if anyone doesn't use. >> >> Balbir, What do think about it? >> > > The idea seems interesting, I am in the process of refreshing my > patches for unmapped page cache control. I presume the process of > filling the victim list will be similar to what I have or unmapped > page cache isolation. I saw your previous implementation. It doesn't have any benefit from victim list. It needs scanning pfns, select unmapped page and move it into victim list. I think we might need kvictimd as Kame said but I am not convinced. If I have a trouble with implementing my series, I might think it. But until now, I think it's not bad and rough test result isn't bad. To be honest, I think victim list(or cleanlist) is to be another project. If it is completed, maybe we can make my patches simple. I approve page cache limit control POV but it should be another project. So I want to merge this series then if we need really victim list, let's consider at that time. Anyway, I will see your next version to find needs of victim list. > >> >> > Thanks, >> > -Kame >> > >> > >> > >> > >> >> >> >> -- >> Kind regards, >> Minchan Kim > > -- > ? ? ? ?Three Cheers, > ? ? ? ?Balbir > -- 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/