From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx137.postini.com [74.125.245.137]) by kanga.kvack.org (Postfix) with SMTP id 051326B002C for ; Wed, 7 Mar 2012 21:11:35 -0500 (EST) Received: by pbcup15 with SMTP id up15so1270686pbc.14 for ; Wed, 07 Mar 2012 18:11:35 -0800 (PST) Message-ID: <4F581554.6020801@gmail.com> Date: Thu, 08 Mar 2012 10:11:32 +0800 From: Sha Zhengju MIME-Version: 1.0 Subject: Re: [PATCH] memcg: Free spare array to avoid memory leak References: <1331036004-7550-1-git-send-email-handai.szj@taobao.com> <20120307230819.GA10238@shutemov.name> In-Reply-To: <20120307230819.GA10238@shutemov.name> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, Sha Zhengju 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 ? Thanks, Sha > 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 >> -- 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