Re: [PATCH 3/9] slab: simplify shutdown_memcg_caches()

Tejun Heo
2017-01-14T15:38:01Z

On Sat, Jan 14, 2017 at 04:27:22PM +0300, Vladimir Davydov wrote:
> > - * Second, shutdown all caches left from memory cgroups that are now
> > - * offline.
> > + * Shutdown all caches.
> > */
> > list_for_each_entry_safe(c, c2, &s->memcg_params.list,
> > memcg_params.list)
> > shutdown_cache(c);
>
> The point of this complexity was to leave caches that happen to have
> objects when kmem_cache_destroy() is called on the list, so that they
> could be reused later. This behavior was inherited from the global

Ah, right, I misread the branch. I don't quite get how the cache can
be reused later tho? This is called when the memcg gets released and
a clear error condition - the caller, kmem_cache_destroy(), handles it
as an error condition too.

> caches - if kmem_cache_destroy() is called on a cache that still has
> object, we print a warning message and don't destroy the cache. This
> patch changes this behavior.

Hmm... yeah, we're missing the error return propagation. I think
that's the only meaningful difference tho, right? Will update the
patch.

Thanks!

--
tejun