Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262174AbTIMUGi (ORCPT ); Sat, 13 Sep 2003 16:06:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262177AbTIMUGi (ORCPT ); Sat, 13 Sep 2003 16:06:38 -0400 Received: from dbl.q-ag.de ([80.146.160.66]:13469 "EHLO dbl.q-ag.de") by vger.kernel.org with ESMTP id S262174AbTIMUGh (ORCPT ); Sat, 13 Sep 2003 16:06:37 -0400 Message-ID: <3F6378B0.8040606@colorfullife.com> Date: Sat, 13 Sep 2003 22:06:08 +0200 From: Manfred Spraul User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030701 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ravikiran G Thirumalai CC: akpm@osdl.org, linux-kernel@vger.kernel.org, Robert Love , dipankar@in.ibm.com Subject: Re: [patch] Make slab allocator work with SLAB_MUST_HWCACHE_ALIGN References: <20030910081654.GA1129@llm08.in.ibm.com> <1063208464.700.35.camel@localhost> <20030911055428.GA1140@llm08.in.ibm.com> <20030911110853.GB3700@llm08.in.ibm.com> <3F60A08A.7040504@colorfullife.com> <20030912085921.GB1128@llm08.in.ibm.com> In-Reply-To: <20030912085921.GB1128@llm08.in.ibm.com> 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: 1325 Lines: 32 Ravikiran G Thirumalai wrote: >I am working on a simplistic allocator for alloc_percpu which >1. Minimises cache footprint (simple pointer arithmetic to get to each cpus > version >2. Does numa aware allocation >3. Does not fragment >4. Is simple and extends simple pointer arithmetic to get to cpus offsets > >I wouldn't be using the slab at all because using slabs would mean using >NR_CPUs pointers and one extra dereference which is bad as we had found out >earlier. But I guess slab will have to do node local allocations for >other applications. > > Interesting. Slab internally uses lots of large per-cpu arrays. Alltogether something like around 40 kB/cpu. Right now implemented with NR_CPUs pointers. In the long run I'll try to switch to your allocator. But back to the patch that started this thread: Do you still need the ability to set an explicit alignment for slab allocations? If yes, then I'd polish my patch, double check all kmem_cache_create callers and then send the patch to akpm. Otherwise I'd wait - the patch is not a bugfix. -- 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/