From owner-cvs-src@FreeBSD.ORG Sun Feb 29 08:48:51 2004 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5969E16A4D0 for ; Sun, 29 Feb 2004 08:48:51 -0800 (PST) Received: from tx0.oucs.ox.ac.uk (tx0.oucs.ox.ac.uk [129.67.1.163]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9A76743D31 for ; Sun, 29 Feb 2004 08:48:50 -0800 (PST) (envelope-from colin.percival@wadham.ox.ac.uk) Received: from scan0.oucs.ox.ac.uk ([129.67.1.162] helo=localhost) by tx0.oucs.ox.ac.uk with esmtp (Exim 4.24) id 1AxU7V-00050b-FW for cvs-src@FreeBSD.org; Sun, 29 Feb 2004 16:48:49 +0000 Received: from rx0.oucs.ox.ac.uk ([129.67.1.161]) by localhost (scan0.oucs.ox.ac.uk [129.67.1.162]) (amavisd-new, port 25) with ESMTP id 19214-01 for ; Sun, 29 Feb 2004 16:48:49 +0000 (GMT) Received: from gateway.wadham.ox.ac.uk ([163.1.161.253]) by rx0.oucs.ox.ac.uk with smtp (Exim 4.24) id 1AxU7V-00050R-1u for cvs-src@FreeBSD.org; Sun, 29 Feb 2004 16:48:49 +0000 Received: (qmail 955 invoked by uid 0); 29 Feb 2004 16:48:49 -0000 Received: from colin.percival@wadham.ox.ac.uk by gateway by uid 71 with qmail-scanner-1.16 (sweep: 2.14/3.71. spamassassin: 2.53. Clear:. Processed in 1.291463 secs); 29 Feb 2004 16:48:49 -0000 X-Qmail-Scanner-Mail-From: colin.percival@wadham.ox.ac.uk via gateway X-Qmail-Scanner: 1.16 (Clear:. Processed in 1.291463 secs) Received: from dhcp1131.wadham.ox.ac.uk (HELO piii600.wadham.ox.ac.uk) (163.1.161.131) by gateway.wadham.ox.ac.uk with SMTP; 29 Feb 2004 16:48:48 -0000 Message-Id: <6.0.1.1.1.20040229164027.040109e8@imap.sfu.ca> X-Sender: cperciva@imap.sfu.ca (Unverified) X-Mailer: QUALCOMM Windows Eudora Version 6.0.1.1 Date: Sun, 29 Feb 2004 16:48:40 +0000 To: Colin Percival From: Colin Percival In-Reply-To: <200402291558.i1TFwsGw035149@repoman.freebsd.org> References: <200402291558.i1TFwsGw035149@repoman.freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed cc: cvs-src@FreeBSD.org cc: src-committers@FreeBSD.org cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/dev/md md.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 29 Feb 2004 16:48:51 -0000 At 15:58 29/02/2004, Colin Percival wrote: > Modified files: > sys/dev/md md.c > Log: > Use DEV_BSIZE byte sectors instead of PAGE_SIZE byte sectors for > swap-backed memory disks. This reduces filesystem allocation overhead > and makes swap-backed memory disks compatible with broken code (dd, > for example) which expects to see 512 byte sectors. The size of a > swap-backed memory disk must still be a multiple of the page size. I should probably add here that anyone who regularly uses filesystems on swap-backed memory disks might like to revisit them and examine the sizes and inode densities they're using. Existing filesystem images will work fine, since ufs keeps track of the sector size it is using, but creating a new filesystem and dumping everything across will save space (and thus memory and time). Colin Percival