From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f43.google.com (mail-qg0-f43.google.com [209.85.192.43]) by kanga.kvack.org (Postfix) with ESMTP id 72CB26B0036 for ; Wed, 21 May 2014 10:41:07 -0400 (EDT) Received: by mail-qg0-f43.google.com with SMTP id 63so3400022qgz.30 for ; Wed, 21 May 2014 07:41:07 -0700 (PDT) Received: from qmta09.emeryville.ca.mail.comcast.net (qmta09.emeryville.ca.mail.comcast.net. [2001:558:fe2d:43:76:96:30:96]) by mx.google.com with ESMTP id q20si1630562qax.103.2014.05.21.07.41.06 for ; Wed, 21 May 2014 07:41:06 -0700 (PDT) Date: Wed, 21 May 2014 09:41:03 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH RFC 3/3] slub: reparent memcg caches' slabs on memcg offline In-Reply-To: <537A4D27.1050909@parallels.com> Message-ID: References: <6eafe1e95d9a934228e9af785f5b5de38955aa6a.1399982635.git.vdavydov@parallels.com> <20140515071650.GB32113@esperanza> <20140516132234.GF32113@esperanza> <20140519152437.GB25889@esperanza> <537A4D27.1050909@parallels.com> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Vladimir Davydov Cc: hannes@cmpxchg.org, mhocko@suse.cz, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, 19 May 2014, Vladimir Davydov wrote: > 3) Per cpu partial slabs. We can disable this feature for dead caches by > adding appropriate check to kmem_cache_has_cpu_partial. There is already a s->cpu_partial number in kmem_cache. If that is zero then no partial cpu slabs should be kept. > So far, everything looks very simple - it seems we don't have to modify > __slab_free at all if we follow the instruction above. > > However, there is one thing regarding preemptable kernels. The problem > is after forbidding the cache store free slabs in per-cpu/node partial > lists by setting min_partial=0 and kmem_cache_has_cpu_partial=false > (i.e. marking the cache as dead), we have to make sure that all frees > that saw the cache as alive are over, otherwise they can occasionally > add a free slab to a per-cpu/node partial list *after* the cache was > marked dead. For instance, Ok then lets switch off preeempt there? Preemption is not supported by most distribution and so will have the least impact. -- 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