From owner-freebsd-current Thu Mar 23 15:13:15 2000 Delivered-To: freebsd-current@freebsd.org Received: from yana.lemis.com (yana.lemis.com [192.109.197.140]) by hub.freebsd.org (Postfix) with ESMTP id BF3D437B523 for ; Thu, 23 Mar 2000 15:13:04 -0800 (PST) (envelope-from grog@mojave.worldwide.lemis.com) Received: from mojave.worldwide.lemis.com ([216.88.157.130]) by yana.lemis.com (8.8.8/8.8.8) with ESMTP id JAA02312; Fri, 24 Mar 2000 09:42:40 +1030 (CST) (envelope-from grog@mojave.worldwide.lemis.com) Received: (from grog@localhost) by mojave.worldwide.lemis.com (8.9.3/8.9.3) id PAA09453; Thu, 23 Mar 2000 15:12:20 -0800 (PST) (envelope-from grog) Date: Thu, 23 Mar 2000 15:12:20 -0800 From: Greg Lehey To: Poul-Henning Kamp Cc: Matthew Dillon , current@FreeBSD.ORG Subject: Re: patches for test / review Message-ID: <20000323151220.A9318@mojave.worldwide.lemis.com> Reply-To: Greg Lehey References: <200003201846.KAA70820@apollo.backplane.com> <20074.953579833@critter.freebsd.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <20074.953579833@critter.freebsd.dk>; from phk@critter.freebsd.dk on Mon, Mar 20, 2000 at 08:17:13PM +0100 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 Monday, 20 March 2000 at 20:17:13 +0100, Poul-Henning Kamp wrote: > In message <200003201846.KAA70820@apollo.backplane.com>, Matthew Dillon writes: > >> Well, let me tell you what the fuzzy goal is first and then maybe we >> can work backwards. >> >> Eventually all physical I/O needs a physical address. The quickest >> way to get to a physical address is to be given an array of vm_page_t's >> (which can be trivially translated to physical addresses). > > Not all: PIO access to ATA needs virtual access. RAID5 needs > virtual access to calculate parity. I'm not sure what you mean by "virtual access". If you mean file-related rather than partition-related, no: like the rest of Vinum, RAID-5 uses only partition-related offsets. >> What we want to do is to try to extend VMIO (aka the vm_page_t) all >> the way through the I/O system - both VFS and DEV I/O, in order to >> remove all the nasty back and forth translations. > > I agree, but some drivers need mapping we need to cater for those. > They could simply call a vm_something(struct buf *) call which would > map the pages and things would "just work". > > For RAID5 we have the opposite problem also: data is created which > has only a mapped existance and the b_pages[] array is not > populated. Hmm. I really need to check that I'm not missing something here. Greg -- Finger grog@lemis.com for PGP public key See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message