Re: [PATCH] mm/slab: fix kmemcg cache creation delayed issue

From: Michal Hocko
Date: Fri Oct 07 2016 - 04:21:10 EST

On Fri 07-10-16 14:14:01, Joonsoo Kim wrote:
> On Thu, Oct 06, 2016 at 09:02:00AM -0700, Doug Smythies wrote:
> > It was my (limited) understanding that the subsequent 2 patch set
> > superseded this patch. Indeed, the 2 patch set seems to solve
> > both the SLAB and SLUB bug reports.
> It would mean that patch 1 solves both the SLAB and SLUB bug reports
> since patch 2 is only effective for SLUB.
> Reason that I send this patch is that although patch 1 fixes the
> issue that too many kworkers are created, kmem_cache creation/destory
> is still slowed by synchronize_sched() and it would cause kmemcg
> usage counting delayed. I'm not sure how bad it is but it's generally
> better to start accounting as soon as possible. With patch 2 for SLUB
> and this patch for SLAB, performance of kmem_cache
> creation/destory would recover.

OK, so do we really want/need it for stable as well. I am not opposing
that but the effect doesn't seem to be a clear cut.
Michal Hocko