From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx152.postini.com [74.125.245.152]) by kanga.kvack.org (Postfix) with SMTP id DC0516B00EC for ; Wed, 16 May 2012 02:21:26 -0400 (EDT) Message-ID: <4FB346E3.5060507@parallels.com> Date: Wed, 16 May 2012 10:19:15 +0400 From: Glauber Costa MIME-Version: 1.0 Subject: Re: [PATCH v2 19/29] skip memcg kmem allocations in specified code regions References: <1336758272-24284-1-git-send-email-glommer@parallels.com> <1336758272-24284-20-git-send-email-glommer@parallels.com> <4FB1C398.1010000@jp.fujitsu.com> In-Reply-To: <4FB1C398.1010000@jp.fujitsu.com> Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Tejun Heo , Li Zefan , Greg Thelen , Suleiman Souhlal , Michal Hocko , Johannes Weiner , devel@openvz.org, Christoph Lameter , Pekka Enberg On 05/15/2012 06:46 AM, KAMEZAWA Hiroyuki wrote: > (2012/05/12 2:44), Glauber Costa wrote: > >> This patch creates a mechanism that skip memcg allocations during >> certain pieces of our core code. It basically works in the same way >> as preempt_disable()/preempt_enable(): By marking a region under >> which all allocations will be accounted to the root memcg. >> >> We need this to prevent races in early cache creation, when we >> allocate data using caches that are not necessarily created already. >> >> Signed-off-by: Glauber Costa >> CC: Christoph Lameter >> CC: Pekka Enberg >> CC: Michal Hocko >> CC: Kamezawa Hiroyuki >> CC: Johannes Weiner >> CC: Suleiman Souhlal > > > The concept seems okay to me but... > >> --- >> include/linux/sched.h | 1 + >> mm/memcontrol.c | 25 +++++++++++++++++++++++++ >> 2 files changed, 26 insertions(+), 0 deletions(-) >> >> diff --git a/include/linux/sched.h b/include/linux/sched.h >> index 81a173c..0501114 100644 >> --- a/include/linux/sched.h >> +++ b/include/linux/sched.h >> @@ -1613,6 +1613,7 @@ struct task_struct { >> unsigned long nr_pages; /* uncharged usage */ >> unsigned long memsw_nr_pages; /* uncharged mem+swap usage */ >> } memcg_batch; >> + atomic_t memcg_kmem_skip_account; > > > If only 'current' thread touch this, you don't need to make this atomic counter. > you can use 'long'. > You're absolutely right, Kame, thanks. I first used atomic_t because I had it tested against current->mm->owner. Do you, btw, agree to use current instead of owner here? You can find the rationale in earlier mails between me and Suleiman. -- 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