Re: [PATCH V3] mm: slub: fix flush_cpu_slab()/__free_slab() invocations in task context.

[Hyeonggon Yoo]

On Tue, Sep 20, 2022 at 09:56:59AM +0200, Sebastian Andrzej Siewior wrote:
> On 2022-09-20 16:46:41 [+0900], Hyeonggon Yoo wrote:
> > > @@ -2730,7 +2735,7 @@ static void flush_all_cpus_locked(struct kmem_cache *s)
> > >  		INIT_WORK(&sfw->work, flush_cpu_slab);
> > >  		sfw->skip = false;
> > >  		sfw->s = s;
> > > -		schedule_work_on(cpu, &sfw->work);
> > > +		queue_work_on(cpu, flushwq, &sfw->work);
> > 
> > Hi. what happens here if flushwq failed?
> > 
> > I think avoiding BUG_ON() makes sense,
> > but shouldn't we have fallback method?
> 
> You get an output to act on and fix. The point is that it shouldn't have
> happen in the first place. With the bug_on() that early, chances are
> that you never see anything but a blank screen. So with the warn_on you
> get probably to see the warn_on before you get here.
> 
> Sebastian

Thank you for kind explanation.
Makes sense!

-- 
Thanks,
Hyeonggon