From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx130.postini.com [74.125.245.130]) by kanga.kvack.org (Postfix) with SMTP id 17E186B0071 for ; Thu, 5 Jul 2012 10:20:07 -0400 (EDT) Date: Thu, 5 Jul 2012 09:20:04 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH 2/3] slub: reduce failure of this_cpu_cmpxchg in put_cpu_partial() after unfreezing In-Reply-To: Message-ID: References: <1340389359-2407-1-git-send-email-js1304@gmail.com> <1340389359-2407-2-git-send-email-js1304@gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Joonsoo Kim , linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Rientjes On Wed, 4 Jul 2012, Pekka Enberg wrote: > 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? Acked-by: Christoph Lameter -- 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