From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756564AbZEJJgk (ORCPT ); Sun, 10 May 2009 05:36:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756356AbZEJJgW (ORCPT ); Sun, 10 May 2009 05:36:22 -0400 Received: from mail-gx0-f166.google.com ([209.85.217.166]:56440 "EHLO mail-gx0-f166.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756084AbZEJJgV convert rfc822-to-8bit (ORCPT ); Sun, 10 May 2009 05:36:21 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=Mn5kNvj8Bo1k+P4xxxHacdzQmGdhQAu00I6DphAzPtNJawNiDTQdSiUin7b9sDeLmJ yBVzJrvxP3pLgk8tvMVKblW44s91P+PhZSVu80glAQPhRqdBoB6lZxdPreGds4QVT+nW x0elR4PxGpz2h9nLXiEQpRuRMQ36BlzScEXrA= MIME-Version: 1.0 In-Reply-To: <1241946446.6317.42.camel@laptop> References: <20090430181340.6f07421d.akpm@linux-foundation.org> <1241432635.7620.4732.camel@twins> <20090507121101.GB20934@localhost> <20090507151039.GA2413@cmpxchg.org> <20090507134410.0618b308.akpm@linux-foundation.org> <20090508081608.GA25117@localhost> <20090508125859.210a2a25.akpm@linux-foundation.org> <20090508230045.5346bd32@lxorguk.ukuu.org.uk> <2f11576a0905100159m32c36a9ep9fb7cc5604c60b2@mail.gmail.com> <1241946446.6317.42.camel@laptop> Date: Sun, 10 May 2009 18:36:19 +0900 X-Google-Sender-Auth: a78d85e703672d0b Message-ID: <2f11576a0905100236u15d45f7fm32d470776659cfec@mail.gmail.com> Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen From: KOSAKI Motohiro To: Peter Zijlstra Cc: Alan Cox , Andrew Morton , Wu Fengguang , hannes@cmpxchg.org, riel@redhat.com, linux-kernel@vger.kernel.org, tytso@mit.edu, linux-mm@kvack.org, elladan@eskimo.com, npiggin@suse.de, cl@linux-foundation.org, minchan.kim@gmail.com 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 >> How about this? >> if priority < DEF_PRIORITY-2, aggressive lumpy reclaim in >> shrink_inactive_list() already >> reclaim the active page forcely. >> then, this patch don't change kernel reclaim policy. >> >> anyway, user process non-changable preventing "nice my process up >> hack" seems makes sense to me. >> >> test result: >> >> echo 100 > /proc/sys/vm/dirty_ratio >> echo 100 > /proc/sys/vm/dirty_background_ratio >> run modified qsbench (use mmap(PROT_EXEC) instead malloc) >> >>            active2active vs active2inactive ratio >> before    5:5 >> after       1:9 >> >> please don't ask performance number. I haven't reproduce Wu's patch >> improvemnt ;) >> >> Wu, What do you think? > > I don't think this is desirable, like Andrew already said, there's tons > of ways to defeat any of this and we've so far always priorized mappings > over !mappings. Limiting this to only PROT_EXEC mappings is already less > than it used to be. I don't oppose this policy. PROT_EXEC seems good viewpoint. The problem is PROT_EXEC'ed page isn't gurantee rarely. if all pages claim "Hey, I'm higher priority page, please don't reclaim me", end-user get suck result easily. before 2.6.27 kernel have similar problems. many mapped page cause bad latency easily. I don't want reproduce this. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id 156866B0083 for ; Sun, 10 May 2009 05:35:47 -0400 (EDT) Received: by gxk20 with SMTP id 20so4968764gxk.14 for ; Sun, 10 May 2009 02:36:19 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1241946446.6317.42.camel@laptop> References: <20090430181340.6f07421d.akpm@linux-foundation.org> <1241432635.7620.4732.camel@twins> <20090507121101.GB20934@localhost> <20090507151039.GA2413@cmpxchg.org> <20090507134410.0618b308.akpm@linux-foundation.org> <20090508081608.GA25117@localhost> <20090508125859.210a2a25.akpm@linux-foundation.org> <20090508230045.5346bd32@lxorguk.ukuu.org.uk> <2f11576a0905100159m32c36a9ep9fb7cc5604c60b2@mail.gmail.com> <1241946446.6317.42.camel@laptop> Date: Sun, 10 May 2009 18:36:19 +0900 Message-ID: <2f11576a0905100236u15d45f7fm32d470776659cfec@mail.gmail.com> Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen From: KOSAKI Motohiro Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: Alan Cox , Andrew Morton , Wu Fengguang , hannes@cmpxchg.org, riel@redhat.com, linux-kernel@vger.kernel.org, tytso@mit.edu, linux-mm@kvack.org, elladan@eskimo.com, npiggin@suse.de, cl@linux-foundation.org, minchan.kim@gmail.com List-ID: >> How about this? >> if priority < DEF_PRIORITY-2, aggressive lumpy reclaim in >> shrink_inactive_list() already >> reclaim the active page forcely. >> then, this patch don't change kernel reclaim policy. >> >> anyway, user process non-changable preventing "nice my process up >> hack" seems makes sense to me. >> >> test result: >> >> echo 100 > /proc/sys/vm/dirty_ratio >> echo 100 > /proc/sys/vm/dirty_background_ratio >> run modified qsbench (use mmap(PROT_EXEC) instead malloc) >> >> =A0 =A0 =A0 =A0 =A0 =A0active2active vs active2inactive ratio >> before =A0 =A05:5 >> after =A0 =A0 =A0 1:9 >> >> please don't ask performance number. I haven't reproduce Wu's patch >> improvemnt ;) >> >> Wu, What do you think? > > I don't think this is desirable, like Andrew already said, there's tons > of ways to defeat any of this and we've so far always priorized mappings > over !mappings. Limiting this to only PROT_EXEC mappings is already less > than it used to be. I don't oppose this policy. PROT_EXEC seems good viewpoint. The problem is PROT_EXEC'ed page isn't gurantee rarely. if all pages claim "Hey, I'm higher priority page, please don't reclaim me", end-user get suck result easily. before 2.6.27 kernel have similar problems. many mapped page cause bad late= ncy easily. I don't want reproduce this. -- 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