Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270817AbTHFRWK (ORCPT ); Wed, 6 Aug 2003 13:22:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270765AbTHFRWK (ORCPT ); Wed, 6 Aug 2003 13:22:10 -0400 Received: from dbl.q-ag.de ([80.146.160.66]:17067 "EHLO dbl.q-ag.de") by vger.kernel.org with ESMTP id S270817AbTHFRVX (ORCPT ); Wed, 6 Aug 2003 13:21:23 -0400 Message-ID: <3F31390B.2000605@colorfullife.com> Date: Wed, 06 Aug 2003 19:21:15 +0200 From: Manfred Spraul User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.3) Gecko/20030313 X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Scott L. Burson" CC: linux-kernel@vger.kernel.org Subject: Re: SMP performance problem in 2.4 (was: Athlon spinlock performance) Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1068 Lines: 28 Scott wrote: >The problem is in `try_to_free_pages' and its associated routines, >`shrink_caches' and `shrink_cache', in `mm/vmscan.c'. After I made some >changes to greatly reduce lock contention in the slab allocator and >`shrink_cache', > How did you change the slab locking? > and then instrumented `shrink_cache' to see what it was >doing, the problem showed up very clearly. > >In one approximately 60-second period with the problematic workload running, >`try_to_free_pages' was called 511 times. It made 2597 calls to >`shrink_caches', which made 2592 calls to `shrink_cache' (i.e. it was very >rare for `kmem_cache_reap' to release enough pages itself). > 2.6 contains a simple fix: I've removed kmem_cache_reap. Instead the code checks for empty pages in the slab caches every other second. -- Manfred - 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/