Re: [PATCH] mm,page_alloc: PF_WQ_WORKER threads must sleep at should_reclaim_retry().

From: Michal Hocko
Date: Wed Sep 05 2018 - 10:04:57 EST


On Wed 05-09-18 22:53:33, Tetsuo Handa wrote:
> On 2018/09/05 22:40, Michal Hocko wrote:
> > Changelog said
> >
> > "Although this is possible in principle let's wait for it to actually
> > happen in real life before we make the locking more complex again."
> >
> > So what is the real life workload that hits it? The log you have pasted
> > below doesn't tell much.
>
> Nothing special. I just ran a multi-threaded memory eater on a CONFIG_PREEMPT=y kernel.

I strongly suspec that your test doesn't really represent or simulate
any real and useful workload. Sure it triggers a rare race and we kill
another oom victim. Does this warrant to make the code more complex?
Well, I am not convinced, as I've said countless times.
--
Michal Hocko
SUSE Labs