From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261270AbVFCN5n (ORCPT ); Fri, 3 Jun 2005 09:57:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261274AbVFCN5n (ORCPT ); Fri, 3 Jun 2005 09:57:43 -0400 Received: from dvhart.com ([64.146.134.43]:23207 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S261270AbVFCN5l (ORCPT ); Fri, 3 Jun 2005 09:57:41 -0400 Date: Fri, 03 Jun 2005 06:57:42 -0700 From: "Martin J. Bligh" Reply-To: "Martin J. Bligh" To: Nick Piggin Cc: "David S. Miller" , jschopp@austin.ibm.com, mel@csn.ul.ie, linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@osdl.org Subject: Re: Avoiding external fragmentation with a placement policy Version 12 Message-ID: <369850000.1117807062@[10.10.2.4]> In-Reply-To: <429FFC21.1020108@yahoo.com.au> References: <429E50B8.1060405@yahoo.com.au><429F2B26.9070509@austin.ibm.com><1117770488.5084.25.camel@npiggin-nld.site> <20050602.214927.59657656.davem@davemloft.net> <357240000.1117776882@[10.10.2.4]> <429FFC21.1020108@yahoo.com.au> X-Mailer: Mulberry/2.2.1 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >>> Actually, even with TSO enabled, you'll get large order >>> allocations, but for receive packets, and these allocations >>> happen in software interrupt context. >> >> Sounds like we still need to cope then ... ? > > Sure. Although we should try to not use higher order allocs if > possible of course. Even with a fallback mode, you will still be > putting more pressure on higher order areas and thus degrading > the service for *other* allocators, so such schemes should > obviously be justified by performance improvements. My point is that outside of a benchmark situation (where we just rebooted the machine to run a test) you will NEVER get an order 4 block free anyway, so it's pointless. Moreover, if we use non-contig order 0 blocks, we can use cache hot pages ;-) M.