From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 58CC38D0069 for ; Thu, 20 Jan 2011 18:45:34 -0500 (EST) Received: from m3.gw.fujitsu.co.jp (unknown [10.0.50.73]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 40DA33EE0B3 for ; Fri, 21 Jan 2011 08:45:31 +0900 (JST) Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 2523245DE4D for ; Fri, 21 Jan 2011 08:45:31 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 05E2445DE57 for ; Fri, 21 Jan 2011 08:45:31 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id E5B5BE18004 for ; Fri, 21 Jan 2011 08:45:30 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.249.87.105]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id A9FD4E08002 for ; Fri, 21 Jan 2011 08:45:30 +0900 (JST) Date: Fri, 21 Jan 2011 08:39:30 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 4/4] memcg: fix rmdir, force_empty with THP Message-Id: <20110121083930.d803126f.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110120134108.GO2232@cmpxchg.org> References: <20110118113528.fd24928f.kamezawa.hiroyu@jp.fujitsu.com> <20110118114348.9e1dba9b.kamezawa.hiroyu@jp.fujitsu.com> <20110120134108.GO2232@cmpxchg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" List-ID: On Thu, 20 Jan 2011 14:41:08 +0100 Johannes Weiner wrote: > On Tue, Jan 18, 2011 at 11:43:48AM +0900, KAMEZAWA Hiroyuki wrote: > > > > Now, when THP is enabled, memcg's rmdir() function is broken > > because move_account() for THP page is not supported. > > > > This will cause account leak or -EBUSY issue at rmdir(). > > This patch fixes the issue by supporting move_account() THP pages. > > > > Changelog: > > - style fix. > > - add compound_lock for avoiding races. > > > > Signed-off-by: KAMEZAWA Hiroyuki > > --- > > mm/memcontrol.c | 37 ++++++++++++++++++++++++++----------- > > 1 file changed, 26 insertions(+), 11 deletions(-) > > > > Index: mmotm-0107/mm/memcontrol.c > > =================================================================== > > --- mmotm-0107.orig/mm/memcontrol.c > > +++ mmotm-0107/mm/memcontrol.c > > > @@ -2267,6 +2274,8 @@ static int mem_cgroup_move_parent(struct > > struct cgroup *cg = child->css.cgroup; > > struct cgroup *pcg = cg->parent; > > struct mem_cgroup *parent; > > + int charge = PAGE_SIZE; > > No need to initialize, you assign it unconditionally below. > > It's also a bit unfortunate that the parameter/variable with this > meaning appears under a whole bunch of different names. page_size, > charge_size, and now charge. Could you stick with page_size? > charge_size != page_size. Clean up as you like, later. I'll Ack. > > @@ -2278,17 +2287,23 @@ static int mem_cgroup_move_parent(struct > > goto out; > > if (isolate_lru_page(page)) > > goto put; > > + /* The page is isolated from LRU and we have no race with splitting */ > > + charge = PAGE_SIZE << compound_order(page); > > Why is LRU isolation preventing the splitting? > That's my mistake of comment, which was in the older patch. I use compound_lock now. I'll post clean up. > I think we need the compound lock to get a stable read, like > compound_trans_order() does. > Thanks, -Kame > Hannes > > > parent = mem_cgroup_from_cont(pcg); > > - ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, > > - PAGE_SIZE); > > + ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, charge); > > if (ret || !parent) > > goto put_back; > > > > - ret = mem_cgroup_move_account(pc, child, parent, true); > > + if (charge > PAGE_SIZE) > > + flags = compound_lock_irqsave(page); > > + > > + ret = mem_cgroup_move_account(pc, child, parent, true, charge); > > if (ret) > > - mem_cgroup_cancel_charge(parent, PAGE_SIZE); > > + mem_cgroup_cancel_charge(parent, charge); > > put_back: > > + if (charge > PAGE_SIZE) > > + compound_unlock_irqrestore(page, flags); > > putback_lru_page(page); > > put: > > put_page(page); -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org