From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 1A9B26B013E for ; Thu, 18 Mar 2010 00:20:02 -0400 (EDT) Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.31.245]) by e23smtp07.au.ibm.com (8.14.3/8.13.1) with ESMTP id o2I4JrS0031003 for ; Thu, 18 Mar 2010 15:19:53 +1100 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o2I4Jrnd1585276 for ; Thu, 18 Mar 2010 15:19:53 +1100 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o2I4JqZg022825 for ; Thu, 18 Mar 2010 15:19:53 +1100 Date: Thu, 18 Mar 2010 09:49:44 +0530 From: Balbir Singh Subject: Re: [PATCH -mmotm 1/5] memcg: disable irq at page cgroup lock Message-ID: <20100318041944.GA18054@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> <20100317115855.GS18054@balbir.in.ibm.com> <20100318085411.834e1e46.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20100318085411.834e1e46.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Andrea Righi , 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: * KAMEZAWA Hiroyuki [2010-03-18 08:54:11]: > On Wed, 17 Mar 2010 17:28:55 +0530 > Balbir Singh wrote: > > > * 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. > > > > plz show your implementation which has no performance regresssion. > For me, I don't neee file_mapped accounting, at all. If we can remove that, > we can add simple migration lock. That doesn't matter, if you need it, I think the larger user base matters. Unmapped and mapped page cache is critical and I use it almost daily. > file_mapped is a feattue you added. please improve it. > I will, but please don't break it silently -- 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