From owner-freebsd-current Fri Aug 27 0:24:10 1999 Delivered-To: freebsd-current@freebsd.org Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (Postfix) with ESMTP id 48C4215167 for ; Fri, 27 Aug 1999 00:22:52 -0700 (PDT) (envelope-from grog@freebie.lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.9.1/8.9.0) with ESMTP id QAA11622; Fri, 27 Aug 1999 16:51:21 +0930 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id QAA05866; Fri, 27 Aug 1999 16:51:20 +0930 (CST) Date: Fri, 27 Aug 1999 16:51:20 +0930 From: Greg Lehey To: Poul-Henning Kamp Cc: Matthew Dillon , Christopher Masto , "John W. DeBoskey" , julian@whistle.com, freebsd-current@FreeBSD.ORG Subject: Re: -current kernel problems (spec_getpages & vm_fault) Message-ID: <19990827165120.Y483@freebie.lemis.com> References: <19990827160950.X483@freebie.lemis.com> <3839.935736904@critter.freebsd.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.4i In-Reply-To: <3839.935736904@critter.freebsd.dk>; from Poul-Henning Kamp on Fri, Aug 27, 1999 at 08:55:04AM +0200 WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Friday, 27 August 1999 at 8:55:04 +0200, Poul-Henning Kamp wrote: > In message <19990827160950.X483@freebie.lemis.com>, Greg Lehey writes: >> On Thursday, 26 August 1999 at 16:25:14 -0700, Matthew Dillon wrote: >>>>>> int devminor; /* minor number */ >>>>>> >>>>>> devminor = minor(dev); >>>>>> + dev->si_bsize_phys = DEV_BSIZE; >>>>>> + dev->si_bsize_best = BLKDEV_IOSIZE; >>>>>> + dev->si_bsize_max = MAXBSIZE; >>>>> >>>>> Bingo! Thank you. >>>> >>>> Cool, I expect grog will commit it soon. >> >> So did I until I read this message. >> >>> The patch for ccd is not quite right. Here is the patch from my >>> big fat patch at http://www.backplane.com/FreeBSD4/ >>> >>> The problem is that you cannot simply set the physical sector >>> size to DEV_BSIZE if the underlying device has a larger sector >>> size. If you do, specfs's blocksize alignment (another fix in >>> my big fat patch) will be incorrect and result in an I/O error >>> on the physical media. >>> >>> For example, swap-backed VN devices have a sector size of one page, >>> i.e. 4K. >> >> Vinum currently doesn't track the sector size of the drives. I'll >> have to put some code in there to DTRT. In the meantime, I'll set >> si_bsize_best to 4K in the hope that this will be OK. Are there any >> larger block sizes in current use? > > 4K is probably too conservative, it only applies if you have a > swap-backed vn device at the bottom, which would be a truly > weird thing to do with vinum. I think I've heard of people doing things like this. Cybernet were thinking of it a long time ago, but I think I've talked them out of it. > Don't spend too much time on tracking the sector size yet. I think > the si_bsize stuff needs some thinking before we do more with it. OK, I'll set it to 4 kB at the moment and make a note to myself to fix it when dev_t stops changing. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message