Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754286AbXEBRZu (ORCPT ); Wed, 2 May 2007 13:25:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754305AbXEBRZt (ORCPT ); Wed, 2 May 2007 13:25:49 -0400 Received: from netops-testserver-4-out.sgi.com ([192.48.171.29]:56978 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754253AbXEBRZs (ORCPT ); Wed, 2 May 2007 13:25:48 -0400 Date: Wed, 2 May 2007 10:25:47 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Hugh Dickins cc: Andrew Morton , haveblue@ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: 2.6.22 -mm merge plans: slub In-Reply-To: Message-ID: References: <20070430162007.ad46e153.akpm@linux-foundation.org> <20070501125559.9ab42896.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2062 Lines: 53 On Wed, 2 May 2007, Hugh Dickins wrote: > I presume the answer is just to extend your quicklist work to > powerpc's lowest level of pagetables. The only other architecture > which is using kmem_cache for them is arm26, which has > "#error SMP is not supported", so won't be giving this problem. In the meantime we would need something like this to disable SLUB in this particular configuration. Note that I have not tested this and the <= for the comparision with SPLIT_PTLOCK_CPUS may not work (Never seen such a construct in a Kconfig file but it is needed here). PowerPC: Disable SLUB for configurations in which slab page structs are modified PowerPC uses the slab allocator to manage the lowest level of the page table. In high cpu configurations we also use the page struct to split the page table lock. Disallow the selection of SLUB for that case. [Not tested: I am not familiar with powerpc build procedures etc] Signed-off-by: Christoph Lameter Index: linux-2.6.21-rc7-mm2/arch/powerpc/Kconfig =================================================================== --- linux-2.6.21-rc7-mm2.orig/arch/powerpc/Kconfig 2007-05-02 10:07:34.000000000 -0700 +++ linux-2.6.21-rc7-mm2/arch/powerpc/Kconfig 2007-05-02 10:13:37.000000000 -0700 @@ -117,6 +117,19 @@ config GENERIC_BUG default y depends on BUG +# +# Powerpc uses the slab allocator to manage its ptes and the +# page structs of ptes are used for splitting the page table +# lock for configurations supporting more than SPLIT_PTLOCK_CPUS. +# +# In that special configuration the page structs of slabs are modified. +# This setting disables the selection of SLUB as a slab allocator. +# +config ARCH_USES_SLAB_PAGE_STRUCT + bool + default y + depends on SPLIT_PTLOCK_CPUS <= NR_CPUS + config DEFAULT_UIMAGE bool help - 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/