From: Michal Hocko <mhocko@kernel.org> To: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de>, Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>, David Rientjes <rientjes@google.com>, Linus Torvalds <torvalds@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>, Hugh Dickins <hughd@google.com>, Andrea Argangeli <andrea@kernel.org>, Rik van Riel <riel@redhat.com>, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 1/2] mm, oom: introduce oom reaper Date: Fri, 18 Dec 2015 12:48:33 +0100 [thread overview] Message-ID: <20151218114832.GD28443@dhcp22.suse.cz> (raw) In-Reply-To: <20151217161521.57fb536085aca377cb93fe1e@linux-foundation.org> On Thu 17-12-15 16:15:21, Andrew Morton wrote: > On Tue, 15 Dec 2015 19:36:15 +0100 Michal Hocko <mhocko@kernel.org> wrote: > > > This patch reduces the probability of such a lockup by introducing a > > specialized kernel thread (oom_reaper) > > CONFIG_MMU=n: > > slub.c:(.text+0x4184): undefined reference to `tlb_gather_mmu' > slub.c:(.text+0x41bc): undefined reference to `unmap_page_range' > slub.c:(.text+0x41d8): undefined reference to `tlb_finish_mmu' > > I did the below so I can get an mmotm out the door, but hopefully > there's a cleaner way. Sorry about that and thanks for your fixup! I am not very familiar with !MMU world and haven't heard about issues with the OOM deadlocks yet. So I guess making this MMU only makes some sense. I would just get rid of ifdefs in oom_kill_process and provide an empty wake_oom_reaper for !CONFIG_MMU. The following on top of yours: --- diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 4b0a5d8b92e1..56ff1ff18c0e 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -537,6 +537,10 @@ static int __init oom_init(void) return 0; } module_init(oom_init) +#else +static void wake_oom_reaper(struct mm_struct *mm) +{ +} #endif /** @@ -648,9 +652,7 @@ 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); -#ifdef CONFIG_MMU bool can_oom_reap = true; -#endif /* * If the task is already exiting, don't alarm the sysadmin or kill @@ -743,7 +745,6 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, continue; if (is_global_init(p)) continue; -#ifdef CONFIG_MMU if (unlikely(p->flags & PF_KTHREAD) || p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { /* @@ -754,15 +755,12 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, can_oom_reap = false; continue; } -#endif do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true); } rcu_read_unlock(); -#ifdef CONFIG_MMU if (can_oom_reap) wake_oom_reaper(mm); -#endif mmdrop(mm); put_task_struct(victim); -- Michal Hocko SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org> To: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de>, Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>, David Rientjes <rientjes@google.com>, Linus Torvalds <torvalds@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>, Hugh Dickins <hughd@google.com>, Andrea Argangeli <andrea@kernel.org>, Rik van Riel <riel@redhat.com>, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 1/2] mm, oom: introduce oom reaper Date: Fri, 18 Dec 2015 12:48:33 +0100 [thread overview] Message-ID: <20151218114832.GD28443@dhcp22.suse.cz> (raw) In-Reply-To: <20151217161521.57fb536085aca377cb93fe1e@linux-foundation.org> On Thu 17-12-15 16:15:21, Andrew Morton wrote: > On Tue, 15 Dec 2015 19:36:15 +0100 Michal Hocko <mhocko@kernel.org> wrote: > > > This patch reduces the probability of such a lockup by introducing a > > specialized kernel thread (oom_reaper) > > CONFIG_MMU=n: > > slub.c:(.text+0x4184): undefined reference to `tlb_gather_mmu' > slub.c:(.text+0x41bc): undefined reference to `unmap_page_range' > slub.c:(.text+0x41d8): undefined reference to `tlb_finish_mmu' > > I did the below so I can get an mmotm out the door, but hopefully > there's a cleaner way. Sorry about that and thanks for your fixup! I am not very familiar with !MMU world and haven't heard about issues with the OOM deadlocks yet. So I guess making this MMU only makes some sense. I would just get rid of ifdefs in oom_kill_process and provide an empty wake_oom_reaper for !CONFIG_MMU. The following on top of yours: --- diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 4b0a5d8b92e1..56ff1ff18c0e 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -537,6 +537,10 @@ static int __init oom_init(void) return 0; } module_init(oom_init) +#else +static void wake_oom_reaper(struct mm_struct *mm) +{ +} #endif /** @@ -648,9 +652,7 @@ 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); -#ifdef CONFIG_MMU bool can_oom_reap = true; -#endif /* * If the task is already exiting, don't alarm the sysadmin or kill @@ -743,7 +745,6 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, continue; if (is_global_init(p)) continue; -#ifdef CONFIG_MMU if (unlikely(p->flags & PF_KTHREAD) || p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { /* @@ -754,15 +755,12 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, can_oom_reap = false; continue; } -#endif do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true); } rcu_read_unlock(); -#ifdef CONFIG_MMU if (can_oom_reap) wake_oom_reaper(mm); -#endif mmdrop(mm); put_task_struct(victim); -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2015-12-18 11:48 UTC|newest] Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-12-15 18:36 [PATCH 1/2] mm, oom: introduce oom reaper Michal Hocko 2015-12-15 18:36 ` Michal Hocko 2015-12-17 0:50 ` Andrew Morton 2015-12-17 0:50 ` Andrew Morton 2015-12-17 13:02 ` Michal Hocko 2015-12-17 13:02 ` Michal Hocko 2015-12-17 19:55 ` Linus Torvalds 2015-12-17 19:55 ` Linus Torvalds 2015-12-17 20:00 ` Andrew Morton 2015-12-17 20:00 ` Andrew Morton 2015-12-18 11:54 ` Michal Hocko 2015-12-18 11:54 ` Michal Hocko 2015-12-18 21:14 ` Andrew Morton 2015-12-18 21:14 ` Andrew Morton 2015-12-21 8:38 ` Michal Hocko 2015-12-21 8:38 ` Michal Hocko 2015-12-17 21:13 ` Andrew Morton 2015-12-17 21:13 ` Andrew Morton 2015-12-18 12:11 ` Michal Hocko 2015-12-18 12:11 ` Michal Hocko 2015-12-18 12:10 ` Tetsuo Handa 2015-12-18 12:10 ` Tetsuo Handa 2015-12-20 7:14 ` Tetsuo Handa 2015-12-20 7:14 ` Tetsuo Handa 2015-12-18 0:15 ` Andrew Morton 2015-12-18 0:15 ` Andrew Morton 2015-12-18 11:48 ` Michal Hocko [this message] 2015-12-18 11:48 ` Michal Hocko 2015-12-21 20:38 ` Paul Gortmaker 2015-12-21 20:38 ` Paul Gortmaker 2016-01-06 9:10 ` Michal Hocko 2016-01-06 9:10 ` Michal Hocko 2016-01-06 14:26 ` Paul Gortmaker 2016-01-06 14:26 ` Paul Gortmaker 2016-01-06 15:00 ` Michal Hocko 2016-01-06 15:00 ` Michal Hocko 2015-12-23 23:00 ` Ross Zwisler 2015-12-23 23:00 ` Ross Zwisler 2015-12-24 9:47 ` Michal Hocko 2015-12-24 9:47 ` Michal Hocko 2015-12-24 11:06 ` Tetsuo Handa 2015-12-24 11:06 ` Tetsuo Handa 2015-12-24 20:39 ` Ross Zwisler 2015-12-24 20:39 ` Ross Zwisler 2015-12-25 11:41 ` Michal Hocko 2015-12-25 11:41 ` Michal Hocko 2015-12-24 20:44 ` Ross Zwisler 2015-12-24 20:44 ` Ross Zwisler 2015-12-25 11:35 ` Michal Hocko 2015-12-25 11:35 ` Michal Hocko 2015-12-25 11:44 ` Michal Hocko 2015-12-25 11:44 ` Michal Hocko 2016-01-06 15:42 [PATCH 0/2 -mm] oom reaper v4 Michal Hocko 2016-01-06 15:42 ` [PATCH 1/2] mm, oom: introduce oom reaper Michal Hocko 2016-01-06 15:42 ` Michal Hocko 2016-01-07 11:23 ` Tetsuo Handa 2016-01-07 11:23 ` Tetsuo Handa 2016-01-07 12:30 ` Michal Hocko 2016-01-07 12:30 ` Michal Hocko 2016-01-11 22:54 ` Andrew Morton 2016-01-11 22:54 ` Andrew Morton 2016-01-12 8:16 ` Michal Hocko 2016-01-12 8:16 ` Michal Hocko 2016-01-28 1:28 ` David Rientjes 2016-01-28 1:28 ` David Rientjes 2016-01-28 21:42 ` Michal Hocko 2016-01-28 21:42 ` Michal Hocko 2016-02-02 3:02 ` David Rientjes 2016-02-02 3:02 ` David Rientjes 2016-02-02 8:57 ` Michal Hocko 2016-02-02 8:57 ` Michal Hocko 2016-02-02 11:48 ` Tetsuo Handa 2016-02-02 11:48 ` Tetsuo Handa 2016-02-02 22:55 ` David Rientjes 2016-02-02 22:55 ` David Rientjes 2016-02-02 22:51 ` David Rientjes 2016-02-02 22:51 ` David Rientjes 2016-02-03 10:31 ` Tetsuo Handa 2016-02-03 10:31 ` Tetsuo Handa
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