From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f44.google.com (mail-wm0-f44.google.com [74.125.82.44]) by kanga.kvack.org (Postfix) with ESMTP id 3BD0E6B0005 for ; Wed, 16 Mar 2016 08:03:02 -0400 (EDT) Received: by mail-wm0-f44.google.com with SMTP id l68so69019357wml.1 for ; Wed, 16 Mar 2016 05:03:02 -0700 (PDT) Received: from mail-wm0-f46.google.com (mail-wm0-f46.google.com. [74.125.82.46]) by mx.google.com with ESMTPS id g139si4391209wmd.7.2016.03.16.05.03.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Mar 2016 05:03:00 -0700 (PDT) Received: by mail-wm0-f46.google.com with SMTP id p65so69028144wmp.0 for ; Wed, 16 Mar 2016 05:03:00 -0700 (PDT) Date: Wed, 16 Mar 2016 13:02:59 +0100 From: Michal Hocko Subject: Re: [PATCH] oom, oom_reaper: protect oom_reaper_list using simpler way Message-ID: <20160316120258.GB21228@dhcp22.suse.cz> References: <1458124527-5441-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1458124527-5441-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> Sender: owner-linux-mm@kvack.org List-ID: To: Tetsuo Handa Cc: akpm@linux-foundation.org, linux-mm@kvack.org, David Rientjes , Mel Gorman , Oleg Nesterov , Hugh Dickins , Rik van Riel On Wed 16-03-16 19:35:27, Tetsuo Handa wrote: > "oom, oom_reaper: disable oom_reaper for oom_kill_allocating_task" tried > to protect oom_reaper_list using MMF_OOM_KILLED flag. But we can do it > by simply checking tsk->oom_reaper_list != NULL. I thought you would go with a replacement of the original patch but an incremental one is also OK. Thanks this looks much more simpler One could wonder why we do not have to check for oom_reaper_list under the spinlock but this is not needed because the context calling wake_oom_reaper is already synchronized. > Signed-off-by: Tetsuo Handa > Cc: Michal Hocko > Cc: David Rientjes > Cc: Mel Gorman > Cc: Oleg Nesterov > Cc: Hugh Dickins > Cc: Rik van Riel Acked-by: Michal Hocko Thanks! > --- > include/linux/sched.h | 2 -- > mm/oom_kill.c | 8 ++------ > 2 files changed, 2 insertions(+), 8 deletions(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 888bc15..e4dc0c9 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -512,8 +512,6 @@ static inline int get_dumpable(struct mm_struct *mm) > #define MMF_HAS_UPROBES 19 /* has uprobes */ > #define MMF_RECALC_UPROBES 20 /* MMF_HAS_UPROBES can be wrong */ > > -#define MMF_OOM_KILLED 21 /* OOM killer has chosen this mm */ > - > #define MMF_INIT_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK) > > struct sighand_struct { > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 23b8b06..31bbdc6 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -543,7 +543,7 @@ static int oom_reaper(void *unused) > > static void wake_oom_reaper(struct task_struct *tsk) > { > - if (!oom_reaper_th) > + if (!oom_reaper_th || tsk->oom_reaper_list) > return; > > get_task_struct(tsk); > @@ -677,7 +677,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, > unsigned int victim_points = 0; > static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL, > DEFAULT_RATELIMIT_BURST); > - bool can_oom_reap; > + bool can_oom_reap = true; > > /* > * If the task is already exiting, don't alarm the sysadmin or kill > @@ -739,10 +739,6 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, > /* Get a reference to safely compare mm after task_unlock(victim) */ > mm = victim->mm; > atomic_inc(&mm->mm_count); > - > - /* Make sure we do not try to oom reap the mm multiple times */ > - can_oom_reap = !test_and_set_bit(MMF_OOM_KILLED, &mm->flags); > - > /* > * We should send SIGKILL before setting TIF_MEMDIE in order to prevent > * the OOM victim from depleting the memory reserves from the user > -- > 1.8.3.1 > -- Michal Hocko SUSE Labs -- 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