From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx113.postini.com [74.125.245.113]) by kanga.kvack.org (Postfix) with SMTP id DC1C76B007E for ; Thu, 8 Mar 2012 04:43:11 -0500 (EST) Date: Thu, 8 Mar 2012 12:35:10 +0200 From: "Kirill A. Shutemov" Subject: Re: [PATCH] memcg: Free spare array to avoid memory leak Message-ID: <20120308103510.GA12897@shutemov.name> References: <1331036004-7550-1-git-send-email-handai.szj@taobao.com> <20120307230819.GA10238@shutemov.name> <4F581554.6020801@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F581554.6020801@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Sha Zhengju Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, Sha Zhengju On Thu, Mar 08, 2012 at 10:11:32AM +0800, Sha Zhengju wrote: > On 03/08/2012 07:08 AM, Kirill A. Shutemov wrote: > >On Tue, Mar 06, 2012 at 08:13:24PM +0800, Sha Zhengju wrote: > >>From: Sha Zhengju > >> > >>When the last event is unregistered, there is no need to keep the spare > >>array anymore. So free it to avoid memory leak. > >It's not a leak. It will be freed on next event register. > > > Yeah, I noticed that. But what if it is just the last one and no more > event registering ? See my question below. ;) > >Yeah, we don't have to keep spare if primary is empty. But is it worth to > >make code more complicated to save few bytes of memory? > > > >>Signed-off-by: Sha Zhengju > >> > >>--- > >> mm/memcontrol.c | 6 ++++++ > >> 1 files changed, 6 insertions(+), 0 deletions(-) > >> > >>diff --git a/mm/memcontrol.c b/mm/memcontrol.c > >>index 22d94f5..3c09a84 100644 > >>--- a/mm/memcontrol.c > >>+++ b/mm/memcontrol.c > >>@@ -4412,6 +4412,12 @@ static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp, > >> swap_buffers: > >> /* Swap primary and spare array */ > >> thresholds->spare = thresholds->primary; > >>+ /* If all events are unregistered, free the spare array */ > >>+ if (!new) { > >>+ kfree(thresholds->spare); > >>+ thresholds->spare = NULL; > >>+ } > >>+ > >> rcu_assign_pointer(thresholds->primary, new); > >> > >> /* To be sure that nobody uses thresholds */ > >>-- > >>1.7.4.1 > >> > -- Kirill A. Shutemov -- 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 internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org