From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 42A6460023A for ; Wed, 17 Mar 2010 07:59:05 -0400 (EDT) Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [202.81.31.247]) by e23smtp06.au.ibm.com (8.14.3/8.13.1) with ESMTP id o2HBwn3O017856 for ; Wed, 17 Mar 2010 22:58:49 +1100 Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o2HBr1sM1507328 for ; Wed, 17 Mar 2010 22:53:01 +1100 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o2HBwtgS008917 for ; Wed, 17 Mar 2010 22:58:56 +1100 Date: Wed, 17 Mar 2010 17:28:55 +0530 From: Balbir Singh Subject: Re: [PATCH -mmotm 1/5] memcg: disable irq at page cgroup lock Message-ID: <20100317115855.GS18054@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <1268609202-15581-1-git-send-email-arighi@develer.com> <1268609202-15581-2-git-send-email-arighi@develer.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1268609202-15581-2-git-send-email-arighi@develer.com> Sender: owner-linux-mm@kvack.org To: Andrea Righi Cc: KAMEZAWA Hiroyuki , Daisuke Nishimura , Vivek Goyal , Peter Zijlstra , Trond Myklebust , Suleiman Souhlal , Greg Thelen , "Kirill A. Shutemov" , Andrew Morton , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: * Andrea Righi [2010-03-15 00:26:38]: > From: KAMEZAWA Hiroyuki > > Now, file-mapped is maintaiend. But more generic update function > will be needed for dirty page accounting. > > For accountig page status, we have to guarantee lock_page_cgroup() > will be never called under tree_lock held. > To guarantee that, we use trylock at updating status. > By this, we do fuzzy accounting, but in almost all case, it's correct. > I don't like this at all, but in almost all cases is not acceptable for statistics, since decisions will be made on them and having them incorrect is really bad. Could we do a form of deferred statistics and fix this. -- Three Cheers, Balbir -- 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