From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [DO NOT APPLY] sd take advantage of rotation speed Date: Wed, 25 Jun 2008 13:06:55 -0500 Message-ID: <1214417215.5674.36.camel@localhost.localdomain> References: <20080619160342.GJ4392@parisc-linux.org> <20080625134705.GZ20851@kernel.dk> <4862552A.5010900@gmail.com> <48627184.9010609@panasas.com> <20080625165759.GC20851@kernel.dk> <20080625172015.GR4392@parisc-linux.org> <20080625172638.GE20851@kernel.dk> <20080625173444.GS4392@parisc-linux.org> <1214415830.5674.30.camel@localhost.localdomain> <20080625175303.GT4392@parisc-linux.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from accolon.hansenpartnership.com ([76.243.235.52]:53206 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752477AbYFYSG7 (ORCPT ); Wed, 25 Jun 2008 14:06:59 -0400 In-Reply-To: <20080625175303.GT4392@parisc-linux.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Matthew Wilcox Cc: Jens Axboe , Boaz Harrosh , Ric Wheeler , linux-scsi@vger.kernel.org On Wed, 2008-06-25 at 11:53 -0600, Matthew Wilcox wrote: > On Wed, Jun 25, 2008 at 12:43:50PM -0500, James Bottomley wrote: > > On Wed, 2008-06-25 at 11:34 -0600, Matthew Wilcox wrote: > > > On Wed, Jun 25, 2008 at 07:26:39PM +0200, Jens Axboe wrote: > > > > Uhm, but it IS "a blatant layering violation", it's doing things from > > > > the wrong side up :-) > > > > > > That's just "doing things from a spot Jens doesn't approve of". A > > > layering violation would be SCSI knowing how elevators work. > > > > When it was setting particular elevators, it was a layering violation > > (as I said at the time). If it's just setting a seek cost hint, that's > > acceptable. > > You're both being silly. Interacting with a subsystem via its exposed > interfaces is not a layering violation. It depends on the interface: sys_open is an exposed interface, but any SCSI driver trying to use it will be caught and shot for egregious layering violations. The elevator setting interface is a policy interface designed for users, not for lower layers of the I/O stack. > > I don't think there is any IDE work to do ... the last I heard from the > > manufacturers, they were all not going to bother with PATA interfaces to > > SSDs ... unless this has changed? > > There are people with PATA->SATA adapters. I think there's one in your > P7120 (or is that one a PATA->SATA adapter?) No ... it's using an IHC6 with two interfaces, one SATA and one PATA. > In any case, I don't think > we need to do anything until someone complains. Agreed. James