From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: Re: [PATCH v4 24/25] memcg/slub: shrink dead caches Date: Fri, 20 Jul 2012 19:16:56 -0300 Message-ID: <5009D8D8.6040509@parallels.com> References: <1340015298-14133-1-git-send-email-glommer@parallels.com> <1340015298-14133-25-git-send-email-glommer@parallels.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Christoph Lameter Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Pekka Enberg , David Rientjes , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Frederic Weisbecker , Suleiman Souhlal , Pekka Enberg , Michal Hocko , Johannes Weiner On 07/06/2012 12:16 PM, Christoph Lameter wrote: > On Mon, 18 Jun 2012, Glauber Costa wrote: > >> In the slub allocator, when the last object of a page goes away, we >> don't necessarily free it - there is not necessarily a test for empty >> page in any slab_free path. > > This is the same btw in SLAB which keeps objects in per cpu caches and > keeps empty slab pages on special queues. > >> This patch marks all memcg caches as dead. kmem_cache_shrink is called >> for the ones who are not yet dead - this will force internal cache >> reorganization, and then all references to empty pages will be removed. > > You need to call this also for slab to drain the caches and free the pages > on the empty list. > Doesn't the SLAB have a time-based reaper for that? That's why I was less concerned with the SLAB, but I can certainly call it for both.