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 B8A048D0039 for ; Fri, 18 Mar 2011 00:43:38 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp (unknown [10.0.50.73]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id CB1E83EE0C0 for ; Fri, 18 Mar 2011 13:43:32 +0900 (JST) Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id B260745DF47 for ; Fri, 18 Mar 2011 13:43:32 +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 91DF945DED9 for ; Fri, 18 Mar 2011 13:43:32 +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 806B4E08003 for ; Fri, 18 Mar 2011 13:43:32 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 3A143E08001 for ; Fri, 18 Mar 2011 13:43:32 +0900 (JST) Date: Fri, 18 Mar 2011 13:35:34 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [patch] memcg: give current access to memory reserves if it's trying to die Message-Id: <20110318133534.818707d2.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110317165319.07be118e.akpm@linux-foundation.org> References: <20110308115108.36b184c5.kamezawa.hiroyu@jp.fujitsu.com> <20110308121332.de003f81.kamezawa.hiroyu@jp.fujitsu.com> <20110308131723.e434cb89.kamezawa.hiroyu@jp.fujitsu.com> <20110308144901.fe34abd0.kamezawa.hiroyu@jp.fujitsu.com> <20110309150452.29883939.kamezawa.hiroyu@jp.fujitsu.com> <20110309161621.f890c148.kamezawa.hiroyu@jp.fujitsu.com> <20110317165319.07be118e.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: David Rientjes , Balbir Singh , Daisuke Nishimura , linux-mm@kvack.org On Thu, 17 Mar 2011 16:53:19 -0700 Andrew Morton wrote: > On Wed, 9 Mar 2011 13:27:50 -0800 (PST) > David Rientjes wrote: > > > When a memcg is oom and current has already received a SIGKILL, then give > > it access to memory reserves with a higher scheduling priority so that it > > may quickly exit and free its memory. > > > > This is identical to the global oom killer and is done even before > > checking for panic_on_oom: a pending SIGKILL here while panic_on_oom is > > selected is guaranteed to have come from userspace; the thread only needs > > access to memory reserves to exit and thus we don't unnecessarily panic > > the machine until the kernel has no last resort to free memory. > > > > Signed-off-by: David Rientjes > > --- > > mm/oom_kill.c | 11 +++++++++++ > > 1 files changed, 11 insertions(+), 0 deletions(-) > > > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > > --- a/mm/oom_kill.c > > +++ b/mm/oom_kill.c > > @@ -537,6 +537,17 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask) > > unsigned int points = 0; > > struct task_struct *p; > > > > + /* > > + * If current has a pending SIGKILL, then automatically select it. The > > + * goal is to allow it to allocate so that it may quickly exit and free > > + * its memory. > > + */ > > + if (fatal_signal_pending(current)) { > > + set_thread_flag(TIF_MEMDIE); > > + boost_dying_task_prio(current, NULL); > > + return; > > + } > > + > > check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL); > > limit = mem_cgroup_get_limit(mem) >> PAGE_SHIFT; > > read_lock(&tasklist_lock); > > The code duplication seems a bit gratuitous. > > > > Was it deliberate that mem_cgroup_out_of_memory() ignores the oom > notifier callbacks? > I'm not sure for what purpose notifier chain for oom exists. At a loock, it's for s390/powerpc Collaborative Memory Manager.. ? About memcg, notifier to userland already exists and I though I don't need to call CMM callbacks (for now, there is no user with memcg, I guess.) Thanks, -kame > (Why does that notifier list exist at all? Wouldn't it be better to do > this via a vmscan shrinker? Perhaps altered to be passed the scanning > priority?) > > -- > 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 > -- 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