From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id 18C616B003B for ; Wed, 13 Nov 2013 17:43:59 -0500 (EST) Received: by mail-pa0-f54.google.com with SMTP id lj1so1129244pab.13 for ; Wed, 13 Nov 2013 14:43:58 -0800 (PST) Received: from psmtp.com ([74.125.245.206]) by mx.google.com with SMTP id g10si272759pao.279.2013.11.13.14.19.06 for ; Wed, 13 Nov 2013 14:19:07 -0800 (PST) Received: by mail-pd0-f182.google.com with SMTP id y13so1037555pdi.41 for ; Wed, 13 Nov 2013 14:19:05 -0800 (PST) Date: Wed, 13 Nov 2013 14:19:00 -0800 (PST) From: David Rientjes Subject: Re: [patch] mm, memcg: add memory.oom_control notification for system oom In-Reply-To: <20131031054942.GA26301@cmpxchg.org> Message-ID: References: <20131031054942.GA26301@cmpxchg.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Michal Hocko , KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org On Thu, 31 Oct 2013, Johannes Weiner wrote: > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > > --- a/include/linux/memcontrol.h > > +++ b/include/linux/memcontrol.h > > @@ -155,6 +155,7 @@ static inline bool task_in_memcg_oom(struct task_struct *p) > > } > > > > bool mem_cgroup_oom_synchronize(bool wait); > > +void mem_cgroup_root_oom_notify(void); > > > > #ifdef CONFIG_MEMCG_SWAP > > extern int do_swap_account; > > @@ -397,6 +398,10 @@ static inline bool mem_cgroup_oom_synchronize(bool wait) > > return false; > > } > > > > +static inline void mem_cgroup_root_oom_notify(void) > > +{ > > +} > > + > > static inline void mem_cgroup_inc_page_stat(struct page *page, > > enum mem_cgroup_stat_index idx) > > { > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -5641,6 +5641,15 @@ static void mem_cgroup_oom_notify(struct mem_cgroup *memcg) > > mem_cgroup_oom_notify_cb(iter); > > } > > > > +/* > > + * Notify any process waiting on the root memcg's memory.oom_control, but do not > > + * notify any child memcgs to avoid triggering their per-memcg oom handlers. > > + */ > > +void mem_cgroup_root_oom_notify(void) > > +{ > > + mem_cgroup_oom_notify_cb(root_mem_cgroup); > > +} > > + > > static int mem_cgroup_usage_register_event(struct cgroup_subsys_state *css, > > struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) > > { > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > > --- a/mm/oom_kill.c > > +++ b/mm/oom_kill.c > > @@ -632,6 +632,10 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, > > return; > > } > > > > + /* Avoid waking up processes for oom kills triggered by sysrq */ > > + if (!force_kill) > > + mem_cgroup_root_oom_notify(); > > We have an API for global OOM notifications, please just use > register_oom_notifier() instead. > We can't use register_oom_notifier() because we don't want to notify the root memcg for a system oom handler if existing oom notifiers free memory (powerpc or s390). We also don't want to notify the root memcg when current is exiting or has a pending SIGKILL, we just want to silently give it access to memory reserves and exit. The mem_cgroup_root_oom_notify() here is placed correctly. -- 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/ . Don't email: email@kvack.org