From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261203AbVFCEtv (ORCPT ); Fri, 3 Jun 2005 00:49:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261190AbVFCEtv (ORCPT ); Fri, 3 Jun 2005 00:49:51 -0400 Received: from dsl027-180-168.sfo1.dsl.speakeasy.net ([216.27.180.168]:745 "EHLO sunset.davemloft.net") by vger.kernel.org with ESMTP id S261248AbVFCEtp (ORCPT ); Fri, 3 Jun 2005 00:49:45 -0400 Date: Thu, 02 Jun 2005 21:49:27 -0700 (PDT) Message-Id: <20050602.214927.59657656.davem@davemloft.net> To: nickpiggin@yahoo.com.au Cc: jschopp@austin.ibm.com, mbligh@mbligh.org, 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 From: "David S. Miller" In-Reply-To: <1117770488.5084.25.camel@npiggin-nld.site> References: <429E50B8.1060405@yahoo.com.au> <429F2B26.9070509@austin.ibm.com> <1117770488.5084.25.camel@npiggin-nld.site> X-Mailer: Mew version 3.3 on Emacs 21.4 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Nick Piggin Date: Fri, 03 Jun 2005 13:48:08 +1000 > It would really help your cause in the short term if you can > demonstrate improvements for say order-3 allocations (eg. use > gige networking, TSO, jumbo frames, etc). TSO chops up the user data into PAGE_SIZE chunks, it doesn't make use of non-zero page orders. AF_UNIX sockets, however, will happily use higher order pages. But even this is limited to SKB_MAX_ORDER which is currently defined to 2. So the only way to get order 3 or larger allocations with the networking is to use jumbo frames but without TSO enabled. Actually, even with TSO enabled, you'll get large order allocations, but for receive packets, and these allocations happen in software interrupt context.