From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751479AbZHSMZ5 (ORCPT ); Wed, 19 Aug 2009 08:25:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751161AbZHSMZ4 (ORCPT ); Wed, 19 Aug 2009 08:25:56 -0400 Received: from mail-yw0-f173.google.com ([209.85.211.173]:42877 "EHLO mail-yw0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751132AbZHSMZ4 convert rfc822-to-8bit (ORCPT ); Wed, 19 Aug 2009 08:25:56 -0400 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=UkoOu5mgfyzunGCFxSY87L7xW4dQb9iPkH+zmz8ogDM85nhBYeEir1AYuKvN1n9dCB ABLzN+jHzEtSs7so0SoZJbwHGJS7rKTsmTXfoQ+jGHdFdaq9ov9JShIStXdDOgl1X0Ax IPo25syeUITGQdOfFkKwqBlWFOSO806qm2k+A= MIME-Version: 1.0 In-Reply-To: <20090819121017.GA8226@localhost> References: <20090816051502.GB13740@localhost> <20090816112910.GA3208@localhost> <20090818234310.A64B.A69D9226@jp.fujitsu.com> <20090819120117.GB7306@localhost> <2f11576a0908190505h6da96280xf67c962aa3f5ba07@mail.gmail.com> <20090819121017.GA8226@localhost> Date: Wed, 19 Aug 2009 21:25:56 +0900 Message-ID: <28c262360908190525i6e56ead0mb8dcb01c3d1a69f1@mail.gmail.com> Subject: Re: [RFC] respect the referenced bit of KVM guest pages? From: Minchan Kim To: Wu Fengguang Cc: KOSAKI Motohiro , Rik van Riel , Jeff Dike , Avi Kivity , Andrea Arcangeli , "Yu, Wilfred" , "Kleen, Andi" , Hugh Dickins , Andrew Morton , Christoph Lameter , Mel Gorman , LKML , linux-mm 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 On Wed, Aug 19, 2009 at 9:10 PM, Wu Fengguang wrote: > On Wed, Aug 19, 2009 at 08:05:19PM +0800, KOSAKI Motohiro wrote: >> >> page_referenced_file? >> >> I think we should change page_referenced(). >> > >> > Yeah, good catch. >> > >> >> >> >> Instead, How about this? >> >> ============================================== >> >> >> >> Subject: [PATCH] mm: stop circulating of referenced mlocked pages >> >> >> >> Currently, mlock() systemcall doesn't gurantee to mark the page PG_Mlocked >> > >> >                                                    mark PG_mlocked >> > >> >> because some race prevent page grabbing. >> >> In that case, instead vmscan move the page to unevictable lru. >> >> >> >> However, Recently Wu Fengguang pointed out current vmscan logic isn't so >> >> efficient. >> >> mlocked page can move circulatly active and inactive list because >> >> vmscan check the page is referenced _before_ cull mlocked page. >> >> >> >> Plus, vmscan should mark PG_Mlocked when cull mlocked page. >> > >> >                           PG_mlocked >> > >> >> Otherwise vm stastics show strange number. >> >> >> >> This patch does that. >> > >> > Reviewed-by: Wu Fengguang >> >> Thanks. >> >> >> >> >> Index: b/mm/rmap.c >> >> =================================================================== >> >> --- a/mm/rmap.c       2009-08-18 19:48:14.000000000 +0900 >> >> +++ b/mm/rmap.c       2009-08-18 23:47:34.000000000 +0900 >> >> @@ -362,7 +362,9 @@ static int page_referenced_one(struct pa >> >>        * unevictable list. >> >>        */ >> >>       if (vma->vm_flags & VM_LOCKED) { >> >> -             *mapcount = 1;  /* break early from loop */ >> >> +             *mapcount = 1;          /* break early from loop */ >> >> +             *vm_flags |= VM_LOCKED; /* for prevent to move active list */ >> > >> >> +             try_set_page_mlocked(vma, page); >> > >> > That call is not absolutely necessary? >> >> Why? I haven't catch your point. > > Because we'll eventually hit another try_set_page_mlocked() when > trying to unmap the page. Ie. duplicated with another call you added > in this patch. Yes. we don't have to call it and we can make patch simple. I already sent patch on yesterday. http://marc.info/?l=linux-mm&m=125059325722370&w=2 I think It's more simple than KOSAKI's idea. Is any problem in my patch ? > > Thanks, > Fengguang > > -- > 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/ . > Don't email: email@kvack.org > -- Kind regards, Minchan Kim