From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f174.google.com (mail-lb0-f174.google.com [209.85.217.174]) by kanga.kvack.org (Postfix) with ESMTP id 86CD56B0037 for ; Wed, 21 May 2014 11:14:35 -0400 (EDT) Received: by mail-lb0-f174.google.com with SMTP id n15so1686069lbi.19 for ; Wed, 21 May 2014 08:14:34 -0700 (PDT) Received: from mx2.parallels.com (mx2.parallels.com. [199.115.105.18]) by mx.google.com with ESMTPS id g5si13027130laa.34.2014.05.21.08.14.33 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 May 2014 08:14:33 -0700 (PDT) Date: Wed, 21 May 2014 19:14:24 +0400 From: Vladimir Davydov Subject: Re: [PATCH RFC 3/3] slub: reparent memcg caches' slabs on memcg offline Message-ID: <20140521151423.GC23193@esperanza> References: <20140515071650.GB32113@esperanza> <20140516132234.GF32113@esperanza> <20140519152437.GB25889@esperanza> <537A4D27.1050909@parallels.com> <20140521135826.GA23193@esperanza> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: hannes@cmpxchg.org, mhocko@suse.cz, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Wed, May 21, 2014 at 09:45:54AM -0500, Christoph Lameter wrote: > On Wed, 21 May 2014, Vladimir Davydov wrote: > > > Seems I've found a better way to avoid this race, which does not involve > > messing up free hot paths. The idea is to explicitly zap each per-cpu > > partial list by setting it pointing to an invalid ptr. Since > > put_cpu_partial(), which is called from __slab_free(), uses atomic > > cmpxchg for adding a new partial slab to a per cpu partial list, it is > > enough to add a check if partials are zapped there and bail out if so. > > > > The patch doing the trick is attached. Could you please take a look at > > it once time permit? > > Well if you set s->cpu_partial = 0 then the slab should not be added to > the partial lists. Ok its put on there temporarily but then immediately > moved to the node partial list in put_cpu_partial(). Don't think so. AFAIU put_cpu_partial() first checks if the per-cpu partial list has more than s->cpu_partial objects draining it if so, but then it adds the newly frozen slab there anyway. Thanks. -- 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