From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) 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: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org Return-Path: To: Hugh Dickins Cc: Daniel Drake , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: 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, 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