From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755046Ab0HQIAE (ORCPT ); Tue, 17 Aug 2010 04:00:04 -0400 Received: from hera.kernel.org ([140.211.167.34]:33632 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751955Ab0HQIAD (ORCPT ); Tue, 17 Aug 2010 04:00:03 -0400 Message-ID: <4C6A408C.6040203@kernel.org> Date: Tue, 17 Aug 2010 09:55:56 +0200 From: Tejun Heo User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.2.8) Gecko/20100802 Thunderbird/3.1.2 MIME-Version: 1.0 To: David Rientjes CC: Christoph Lameter , Pekka Enberg , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Nick Piggin Subject: Re: [S+Q3 00/23] SLUB: The Unified slab allocator (V3) References: <20100804024514.139976032@linux.com> In-Reply-To: X-Enigmail-Version: 1.1.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Tue, 17 Aug 2010 07:59:02 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On 08/17/2010 06:56 AM, David Rientjes wrote: > I'm adding Tejun Heo to the cc because of another thing that may be > problematic: alloc_percpu() allocates GFP_KERNEL memory, so when we try to > allocate kmem_cache_cpu for a DMA cache we may be returning memory from a > node that doesn't include lowmem so there will be no affinity between the > struct and the slab. I'm wondering if it would be better for the percpu > allocator to be extended for kzalloc_node(), or vmalloc_node(), when > allocating memory after the slab layer is up. Hmmm... do you mean adding @gfp_mask to percpu allocation function? I've been thinking about adding it for atomic allocations (Christoph, do you still want it?). I've been sort of against it because I primarily don't really like atomic allocations (it often just pushes error handling complexities elsewhere where it becomes more complex) and it would also require making vmalloc code do atomic allocations. Most of percpu use cases seem pretty happy with GFP_KERNEL allocation, so I'm still quite reluctant to change that. We can add a semi internal interface w/ @gfp_mask but w/o GFP_ATOMIC support, which is a bit ugly. How important would this be? Thanks. -- tejun From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 44C486B01F0 for ; Tue, 17 Aug 2010 03:59:29 -0400 (EDT) Message-ID: <4C6A408C.6040203@kernel.org> Date: Tue, 17 Aug 2010 09:55:56 +0200 From: Tejun Heo MIME-Version: 1.0 Subject: Re: [S+Q3 00/23] SLUB: The Unified slab allocator (V3) References: <20100804024514.139976032@linux.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: David Rientjes Cc: Christoph Lameter , Pekka Enberg , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Nick Piggin List-ID: Hello, On 08/17/2010 06:56 AM, David Rientjes wrote: > I'm adding Tejun Heo to the cc because of another thing that may be > problematic: alloc_percpu() allocates GFP_KERNEL memory, so when we try to > allocate kmem_cache_cpu for a DMA cache we may be returning memory from a > node that doesn't include lowmem so there will be no affinity between the > struct and the slab. I'm wondering if it would be better for the percpu > allocator to be extended for kzalloc_node(), or vmalloc_node(), when > allocating memory after the slab layer is up. Hmmm... do you mean adding @gfp_mask to percpu allocation function? I've been thinking about adding it for atomic allocations (Christoph, do you still want it?). I've been sort of against it because I primarily don't really like atomic allocations (it often just pushes error handling complexities elsewhere where it becomes more complex) and it would also require making vmalloc code do atomic allocations. Most of percpu use cases seem pretty happy with GFP_KERNEL allocation, so I'm still quite reluctant to change that. We can add a semi internal interface w/ @gfp_mask but w/o GFP_ATOMIC support, which is a bit ugly. How important would this be? Thanks. -- tejun -- 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