From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx109.postini.com [74.125.245.109]) by kanga.kvack.org (Postfix) with SMTP id 268496B0071 for ; Wed, 4 Jul 2012 09:05:11 -0400 (EDT) Received: by ghrr18 with SMTP id r18so7927248ghr.14 for ; Wed, 04 Jul 2012 06:05:10 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1340389359-2407-2-git-send-email-js1304@gmail.com> References: <1340389359-2407-1-git-send-email-js1304@gmail.com> <1340389359-2407-2-git-send-email-js1304@gmail.com> Date: Wed, 4 Jul 2012 16:05:09 +0300 Message-ID: Subject: Re: [PATCH 2/3] slub: reduce failure of this_cpu_cmpxchg in put_cpu_partial() after unfreezing From: Pekka Enberg Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Joonsoo Kim Cc: Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Rientjes On Fri, Jun 22, 2012 at 9:22 PM, Joonsoo Kim wrote: > In current implementation, after unfreezing, we doesn't touch oldpage, > so it remain 'NOT NULL'. When we call this_cpu_cmpxchg() > with this old oldpage, this_cpu_cmpxchg() is mostly be failed. > > We can change value of oldpage to NULL after unfreezing, > because unfreeze_partial() ensure that all the cpu partial slabs is removed > from cpu partial list. In this time, we could expect that > this_cpu_cmpxchg is mostly succeed. > > Signed-off-by: Joonsoo Kim > > diff --git a/mm/slub.c b/mm/slub.c > index 92f1c0e..531d8ed 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -1968,6 +1968,7 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) > local_irq_save(flags); > unfreeze_partials(s); > local_irq_restore(flags); > + oldpage = NULL; > pobjects = 0; > pages = 0; > stat(s, CPU_PARTIAL_DRAIN); Makes sense. Christoph, David? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org