Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261496AbVBNRmD (ORCPT ); Mon, 14 Feb 2005 12:42:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261500AbVBNRmC (ORCPT ); Mon, 14 Feb 2005 12:42:02 -0500 Received: from ppp-217-133-42-200.cust-adsl.tiscali.it ([217.133.42.200]:34566 "EHLO opteron.random") by vger.kernel.org with ESMTP id S261496AbVBNRmA (ORCPT ); Mon, 14 Feb 2005 12:42:00 -0500 Date: Mon, 14 Feb 2005 18:41:58 +0100 From: Andrea Arcangeli To: Hugh Dickins Cc: IWAMOTO Toshihiro , linux-kernel@vger.kernel.org, lhms-devel@lists.sourceforge.net Subject: Re: [RFC] Changing COW detection to be memory hotplug friendly Message-ID: <20050214174158.GE13712@opteron.random> References: <20050203035605.C981A7046E@sv1.valinux.co.jp> <20050210190521.GN18573@opteron.random> <20050210204025.GS18573@opteron.random> <20050211085239.GD18573@opteron.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-AA-GPG-Key: 1024D/68B9CB43 13D9 8355 295F 4823 7C49 C012 DFA1 686E 68B9 CB43 X-Cpushare-GPG-Key: 1024D/4D11C21C 5F99 3C8B 5142 EB62 26C3 2325 8989 B72A 4D11 C21C X-Cpushare-SSL-SHA1-Cert: 3812 CD76 E482 94AF 020C 0FFA E1FF 559D 9B4F A59B X-Cpushare-SSL-MD5-Cert: EDA5 F2DA 1D32 7560 5E07 6C91 BFFC B885 User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 845 Lines: 15 > By the way, while we're talking of remove_exclusive_swap_page: > a more functional issue I sometimes wonder about, why don't we > remove_exclusive_swap_page on write fault? Keeping the swap slot > is valuable if read fault, but once the page is dirtied, wouldn't > it usually be better to free that slot and allocate another later? Avoiding swap fragmentation is one reason to leave it allocated. So you can swapin/swapout/swapin/swapout always in the same place on disk as long as there's plenty of swap still available. I'm not sure how much speedup this provides, but certainly it makes sense. - 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/