Re: [PATCH 7/6] mm, oom: task_will_free_mem should skip oom_reaped tasks

[Michal Hocko <mhocko@kernel.org>]

On Fri 03-06-16 00:24:31, Tetsuo Handa wrote:
> Michal Hocko wrote:
> > diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> > index dacfb6ab7b04..d6e121decb1a 100644
> > --- a/mm/oom_kill.c
> > +++ b/mm/oom_kill.c
> > @@ -766,6 +766,15 @@ bool task_will_free_mem(struct task_struct *task)
> >  		return true;
> >  	}
> >  
> > +	/*
> > +	 * This task has already been drained by the oom reaper so there are
> > +	 * only small chances it will free some more
> > +	 */
> > +	if (test_bit(MMF_OOM_REAPED, &mm->flags)) {
> > +		task_unlock(p);
> > +		return false;
> > +	}
> > +
> 
> I think this check should be done before
> 
> 	if (atomic_read(&mm->mm_users) <= 1) {
> 		task_unlock(p);
> 		return true;
> 	}
> 
> because it is possible that task_will_free_mem(task) is the only thread
> using task->mm (i.e. atomic_read(&mm->mm_users) == 1).

definitely true. I am growing blind for this code.

Thanks!

-- 
Michal Hocko
SUSE Labs

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