From mboxrd@z Thu Jan 1 00:00:00 1970 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH -mmotm 1/5] memcg: disable irq at page cgroup lock Date: Thu, 18 Mar 2010 08:54:11 +0900 Message-ID: <20100318085411.834e1e46.kamezawa.hiroyu__46243.6295151294$1268870393$gmane$org@jp.fujitsu.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> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100317115855.GS18054-SINUvgVNF2CyUtPGxGje5AC/G2K4zDHf@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: balbir-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Andrea Righi , Daisuke Nishimura , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Trond Myklebust , Greg-FOgKQjlUJ6BQetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Suleiman Souhlal , Andrew Morton , Peter-FOgKQjlUJ6BQetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Vivek Goyal List-Id: containers.vger.kernel.org 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. file_mapped is a feattue you added. please improve it. Thanks, -Kame