Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752600Ab3FNQIG (ORCPT ); Fri, 14 Jun 2013 12:08:06 -0400 Received: from a9-50.smtp-out.amazonses.com ([54.240.9.50]:45346 "EHLO a9-50.smtp-out.amazonses.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751864Ab3FNQIF (ORCPT ); Fri, 14 Jun 2013 12:08:05 -0400 Date: Fri, 14 Jun 2013 16:08:02 +0000 From: Christoph Lameter To: Roman Gushchin cc: Pekka Enberg , mpm@selenic.com, akpm@linux-foundation.org, mgorman@suse.de, David Rientjes , glommer@gmail.com, hannes@cmpxchg.org, minchan@kernel.org, jiang.liu@huawei.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] slub: Avoid direct compaction if possible In-Reply-To: <51BB33FE.1020403@yandex-team.ru> Message-ID: <0000013f43718d4d-7bb260e7-8115-4891-bb26-6febacb7169d-000000@email.amazonses.com> References: <51BB1802.8050108@yandex-team.ru> <0000013f4319cb46-a5a3de58-1207-4037-ae39-574b58135ea2-000000@email.amazonses.com> <51BB33FE.1020403@yandex-team.ru> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SES-Outgoing: 2013.06.14-54.240.9.50 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1068 Lines: 22 On Fri, 14 Jun 2013, Roman Gushchin wrote: > But there is an actual problem, that this patch solves. > Sometimes I saw the following issue on some machines: > all CPUs are performing compaction, system time is about 80%, > system is completely unreliable. It occurs only on machines > with specific workload (distributed data storage system, so, > intensive disk i/o is performed). A system can fall into > this state fast and unexpectedly or by progressive degradation. Well that is not a slab allocator specific issue but related to compaction concurrency. Likely cache line contention is causing a severe slowday. But that issue could be triggered by any subsystem that does lots of memory allocations. I would suggest that we try to address the problem in the compaction logic rather than modifying allocators. Mel? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/