Re: [PATCH 1/2] mm, oom: introduce oom reaper

[Michal Hocko <mhocko@kernel.org>]

On Fri 18-12-15 13:14:00, Andrew Morton wrote:
> On Fri, 18 Dec 2015 12:54:55 +0100 Michal Hocko <mhocko@kernel.org> wrote:
> 
> >  	/* Retry the down_read_trylock(mmap_sem) a few times */
> > -	while (attempts++ < 10 && !__oom_reap_vmas(mm))
> > -		msleep_interruptible(100);
> > +	while (attempts++ < 10 && !__oom_reap_vmas(mm)) {
> > +		__set_task_state(current, TASK_IDLE);
> > +		schedule_timeout(HZ/10);
> > +	}
> 
> If you won't, I shall ;)
> 
> 
> From: Andrew Morton <akpm@linux-foundation.org>
> Subject: sched: add schedule_timeout_idle()
> 
> This will be needed in the patch "mm, oom: introduce oom reaper".
> 
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Thanks! This makes more sense.

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
> 
>  include/linux/sched.h |    1 +
>  kernel/time/timer.c   |   11 +++++++++++
>  2 files changed, 12 insertions(+)
> 
> diff -puN kernel/time/timer.c~sched-add-schedule_timeout_idle kernel/time/timer.c
> --- a/kernel/time/timer.c~sched-add-schedule_timeout_idle
> +++ a/kernel/time/timer.c
> @@ -1566,6 +1566,17 @@ signed long __sched schedule_timeout_uni
>  }
>  EXPORT_SYMBOL(schedule_timeout_uninterruptible);
>  
> +/*
> + * Like schedule_timeout_uninterruptible(), except this task will not contribute
> + * to load average.
> + */
> +signed long __sched schedule_timeout_idle(signed long timeout)
> +{
> +	__set_current_state(TASK_IDLE);
> +	return schedule_timeout(timeout);
> +}
> +EXPORT_SYMBOL(schedule_timeout_idle);
> +
>  #ifdef CONFIG_HOTPLUG_CPU
>  static void migrate_timer_list(struct tvec_base *new_base, struct hlist_head *head)
>  {
> diff -puN include/linux/sched.h~sched-add-schedule_timeout_idle include/linux/sched.h
> --- a/include/linux/sched.h~sched-add-schedule_timeout_idle
> +++ a/include/linux/sched.h
> @@ -423,6 +423,7 @@ extern signed long schedule_timeout(sign
>  extern signed long schedule_timeout_interruptible(signed long timeout);
>  extern signed long schedule_timeout_killable(signed long timeout);
>  extern signed long schedule_timeout_uninterruptible(signed long timeout);
> +extern signed long schedule_timeout_idle(signed long timeout);
>  asmlinkage void schedule(void);
>  extern void schedule_preempt_disabled(void);
>  
> _

-- 
Michal Hocko
SUSE Labs