From owner-cvs-all Sun Apr 2 9: 8:44 2000 Delivered-To: cvs-all@freebsd.org Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.40.131]) by hub.freebsd.org (Postfix) with ESMTP id 47F8037BB3A; Sun, 2 Apr 2000 09:08:33 -0700 (PDT) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (localhost.freebsd.dk [127.0.0.1]) by critter.freebsd.dk (8.9.3/8.9.3) with ESMTP id SAA14636; Sun, 2 Apr 2000 18:08:20 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Bruce Evans Cc: "Justin T. Gibbs" , cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern kern_mib.c vfs_bio.c src/sys/sys buf.h In-reply-to: Your message of "Mon, 03 Apr 2000 01:54:07 +1000." Date: Sun, 02 Apr 2000 18:08:20 +0200 Message-ID: <14634.954691700@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message , Bruce Ev ans writes: >"struct bio" is unfortunately even more block-specific than "struct buf", >since it doesn't have anything like "off_t b_offset". b_offset is >currently used mainly in the acd driver to handle weird block sizes. Well, I have b_offset in my cross-hair, because I know sos will roast me if I don't handle that case also :-) As far as I know, b_offset is only really used for physio and the only two drivers who understand non DEV_BSIZE multiple requests are the scsi-tape and atapi-cd drivers. This ties in somewhat with Justins email where he restates the idea Bruce half-jokingly proposed about a year ago: use struct uio for io carrier. The question at the heart of this is really: do we want to suffer the overhead of converting from byte offsets to sector number all the time or do we want to optimize for the predominantly used concept of sectors ? -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." FreeBSD -- It will take a long time before progress goes too far! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message