Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030230AbWAZXYf (ORCPT ); Thu, 26 Jan 2006 18:24:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030232AbWAZXYf (ORCPT ); Thu, 26 Jan 2006 18:24:35 -0500 Received: from e32.co.us.ibm.com ([32.97.110.150]:47237 "EHLO e32.co.us.ibm.com") by vger.kernel.org with ESMTP id S1030230AbWAZXYf (ORCPT ); Thu, 26 Jan 2006 18:24:35 -0500 Message-ID: <43D95A2E.4020002@us.ibm.com> Date: Thu, 26 Jan 2006 15:24:30 -0800 From: Matthew Dobson User-Agent: Mozilla Thunderbird 1.0.7 (X11/20051011) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Christoph Lameter CC: linux-kernel@vger.kernel.org, sri@us.ibm.com, andrea@suse.de, pavel@suse.cz, linux-mm@kvack.org Subject: Re: [patch 3/9] mempool - Make mempools NUMA aware References: <20060125161321.647368000@localhost.localdomain> <1138233093.27293.1.camel@localhost.localdomain> <43D953C4.5020205@us.ibm.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1569 Lines: 40 Christoph Lameter wrote: > On Thu, 26 Jan 2006, Matthew Dobson wrote: > > >>Not all requests for memory from a specific node are performance >>enhancements, some are for correctness. With large machines, especially as > > > alloc_pages_node and friends do not guarantee allocation on that specific > node. That argument for "correctness" is bogus. alloc_pages_node() does not guarantee allocation on a specific node, but calling __alloc_pages() with a specific nodelist would. >>>You do not need this.... >> >>I do not agree... > > > There is no way that you would need this patch. My goal was to not change the behavior of the slab allocator when inserting a mempool-backed allocator "under" it. Without support for at least *requesting* allocations from a specific node when allocating from a mempool, this would change how the slab allocator works. That would be bad. The slab allocator now does not guarantee that, for example, a kmalloc_node() request is satisfied by memory from the requested node, but it does at least TRY. Without adding mempool_alloc_node() then I would never be able to even TRY to satisfy a mempool-backed kmalloc_node() request from the correct node. I believe that would constitute an unacceptable breakage from normal, documented behavior. So, I *do* need this patch. -Matt - 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/