Re: [PATCH 6/6] mm, oom: fortify task_will_free_mem

[Michal Hocko]

On Thu 26-05-16 23:11:47, Tetsuo Handa wrote:
[...]
> > +	if (mm) {
> > +		rcu_read_lock();
> > +		for_each_process(p) {
> > +			bool vfork;
> > +
> > +			/*
> > +			 * skip over vforked tasks because they are mostly
> > +			 * independent and will drop the mm soon
> > +			 */
> > +			task_lock(p);
> > +			vfork = p->vfork_done;
> > +			task_unlock(p);
> > +			if (vfork)
> > +				continue;
> > +
> > +			if (!__task_will_free_mem(p))
> > +				break;
> > +		}
> > +		rcu_read_unlock();
> > +		mmdrop(mm);
> 
> Did you forget "if (something) return false;" here?

Dohh, I screwed when cleaning up the code before submission. Thanks for
catching that.

> 
> > +	}
> > +
> 
> If task_will_free_mem() == true is always followed by mark_oom_victim()
> and wake_oom_reaper(), can we call them from here?

I would rather keep the function doing only the check. We never know
when this could be reused somewhere else. All the callsites are quite
trivial so we do not duplicate a lot of code.
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