From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422663AbXCGJd4 (ORCPT ); Wed, 7 Mar 2007 04:33:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422668AbXCGJd4 (ORCPT ); Wed, 7 Mar 2007 04:33:56 -0500 Received: from amsfep17-int.chello.nl ([213.46.243.15]:26734 "EHLO amsfep13-int.chello.nl" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1422663AbXCGJdz (ORCPT ); Wed, 7 Mar 2007 04:33:55 -0500 Subject: Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear) From: Peter Zijlstra To: Andrew Morton Cc: Miklos Szeredi , mingo@elte.hu, npiggin@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, benh@kernel.crashing.org In-Reply-To: <20070307010756.b31c8190.akpm@linux-foundation.org> References: <20070221023656.6306.246.sendpatchset@linux.site> <20070221023735.6306.83373.sendpatchset@linux.site> <20070306225101.f393632c.akpm@linux-foundation.org> <20070307070853.GB15877@wotan.suse.de> <20070307081948.GA9563@wotan.suse.de> <20070307082755.GA25733@elte.hu> <20070307004709.432ddf97.akpm@linux-foundation.org> <20070307010756.b31c8190.akpm@linux-foundation.org> Content-Type: text/plain Date: Wed, 07 Mar 2007 10:32:22 +0100 Message-Id: <1173259942.6374.125.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-03-07 at 01:07 -0800, Andrew Morton wrote: > On Wed, 07 Mar 2007 09:51:57 +0100 Miklos Szeredi wrote: > > > > > Dirty page accounting doesn't work either on > > > > non-linear mappings > > > > > > It doesn't? Confused - these things don't have anything to do with each > > > other do they? > > > > Look in page_mkclean(). Where does it handle non-linear mappings? > > > > OK, I'd forgotten about that. It won't break dirty memory accounting, > but it'll potentially break dirty memory balancing. > > If we have the wrong page (due to nonlinear), page_check_address() will > fail and we'll leave the pte dirty. That puts us back to the pre-2.6.17 > algorithms and I guess it'll break the msync guarantees. > > Peter, I thought we went through the nonlinear problem ages ago and decided > it was OK? Can recollect as much, I modelled it after page_referenced() and can't find any VM_NONLINEAR specific code in there either. Will have a hard look, but if its broken, then page_referenced if equally broken it seems, which would make page reclaim funny in the light of nonlinear mappings. From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear) From: Peter Zijlstra In-Reply-To: <20070307010756.b31c8190.akpm@linux-foundation.org> References: <20070221023656.6306.246.sendpatchset@linux.site> <20070221023735.6306.83373.sendpatchset@linux.site> <20070306225101.f393632c.akpm@linux-foundation.org> <20070307070853.GB15877@wotan.suse.de> <20070307081948.GA9563@wotan.suse.de> <20070307082755.GA25733@elte.hu> <20070307004709.432ddf97.akpm@linux-foundation.org> <20070307010756.b31c8190.akpm@linux-foundation.org> Content-Type: text/plain Date: Wed, 07 Mar 2007 10:32:22 +0100 Message-Id: <1173259942.6374.125.camel@twins> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Miklos Szeredi , mingo@elte.hu, npiggin@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, benh@kernel.crashing.org List-ID: On Wed, 2007-03-07 at 01:07 -0800, Andrew Morton wrote: > On Wed, 07 Mar 2007 09:51:57 +0100 Miklos Szeredi wrote: > > > > > Dirty page accounting doesn't work either on > > > > non-linear mappings > > > > > > It doesn't? Confused - these things don't have anything to do with each > > > other do they? > > > > Look in page_mkclean(). Where does it handle non-linear mappings? > > > > OK, I'd forgotten about that. It won't break dirty memory accounting, > but it'll potentially break dirty memory balancing. > > If we have the wrong page (due to nonlinear), page_check_address() will > fail and we'll leave the pte dirty. That puts us back to the pre-2.6.17 > algorithms and I guess it'll break the msync guarantees. > > Peter, I thought we went through the nonlinear problem ages ago and decided > it was OK? Can recollect as much, I modelled it after page_referenced() and can't find any VM_NONLINEAR specific code in there either. Will have a hard look, but if its broken, then page_referenced if equally broken it seems, which would make page reclaim funny in the light of nonlinear mappings. -- 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