Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758628AbXH3I15 (ORCPT ); Thu, 30 Aug 2007 04:27:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756034AbXH3I1u (ORCPT ); Thu, 30 Aug 2007 04:27:50 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:41026 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755906AbXH3I1u (ORCPT ); Thu, 30 Aug 2007 04:27:50 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Hugh Dickins Cc: Daniel Drake , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: speeding up swapoff References: <1188394172.22156.67.camel@localhost> Date: Thu, 30 Aug 2007 02:27:29 -0600 In-Reply-To: (Hugh Dickins's message of "Wed, 29 Aug 2007 16:36:37 +0100 (BST)") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1015 Lines: 23 Hugh Dickins writes: > The speedups I've imagined making, were a need demonstrated, have > been more on the lines of batching (dealing with a range of pages > in one go) and hashing (using the swapmap's ushort, so often 1 or > 2 or 3, to hold an indicator of where to look for its references). There is one other possibility. Typically the swap code is using compatibility disk I/O functions instead of the best the kernel can offer. I haven't looked recently but it might be worth just making certain that there isn't some low-level optimization or cleanup possible on that path. Although I may just be thinking of swapfiles. I know there were tremendous gains ago when I removed the functions that wrote pages synchronously to swapfiles. Eric - 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/