From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 7C7FD6B0092 for ; Tue, 25 Jan 2011 02:07:49 -0500 (EST) Date: Tue, 25 Jan 2011 08:07:44 +0100 From: Johannes Weiner Subject: Re: [PATCH 3/3] memcg: fix race at move_parent around compound_order() Message-ID: <20110125070744.GB2217@cmpxchg.org> References: <20110125145720.cd0cbe16.kamezawa.hiroyu@jp.fujitsu.com> <20110125150516.fb2f5e06.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110125150516.fb2f5e06.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" , "akpm@linux-foundation.org" List-ID: On Tue, Jan 25, 2011 at 03:05:16PM +0900, KAMEZAWA Hiroyuki wrote: > Based on > 2.6.38-rc2 + > mm-memcontrolc-fix-uninitialized-variable-use-in-mem_cgroup_move_parent.patch > == > From: KAMEZAWA Hiroyuki > > A fix up mem_cgroup_move_parent() which use compound_order() in > asynchrnous manner. This compound_order() may return unknown value > because we don't take lock. Use PageTransHuge() and HPAGE_SIZE instead of > it. > > Also clean up for mem_cgroup_move_parent(). > - remove unnecessary initialization of local variable. > - rename charge_size -> page_size > - remove unnecessary (wrong) comment. > - added a comment about THP. > > Changelog: > - fixed page size calculation for avoiding race. > > Note: > Current design take compound_page_lock() in caller of move_account(). > This should be revisited when we implement direct move_task of hugepage > without splitting. > > Signed-off-by: KAMEZAWA Hiroyuki Reviewed-by: Johannes Weiner -- 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