From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pete Zaitcev Subject: Re: Patch for 256 disks in 2.4 Date: Mon, 22 Jul 2002 16:48:56 -0400 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20020722164856.D19904@devserv.devel.redhat.com> References: <20020720195729.C20953@devserv.devel.redhat.com> <20020722170840.GB19587@nbkurt.etpnet.phys.tue.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20020722170840.GB19587@nbkurt.etpnet.phys.tue.nl>; from garloff@suse.de on Mon, Jul 22, 2002 at 07:08:40PM +0200 List-Id: linux-scsi@vger.kernel.org To: Kurt Garloff , Pete Zaitcev , Linux SCSI list , Linux kernel list > Date: Mon, 22 Jul 2002 19:08:40 +0200 > From: Kurt Garloff > > For those who do not follow, John Cagle allocated 8 more SCSI > > disk majors. > > Have those officially been assigned to SCSI disks? > So disks 128 -- 255 have majors 128 thr. 135? I do not understand what your problem is. Do you refuse to recognise John as the LANANA chair or something? My patch is done in accordance with this: http://www.lanana.org/docs/device-list/devices.txt > > Here's a patch to make use of them. I am not sure > > if we want a 2.5 version; it's going to be all devicefs anyhow... > > I've written a patch for sd that makes the allocation of majors > dynamic. The driver just takes 8 at sd_init and further majors are > allocated when disks are attached. Which saves a lot of memory for > all the gendisk and hd_struct stuff in case you do not have a lot of > SCSI disks connected. The patch does support up to 160 SD majors, > though currently, it won't succeed getting more than 132 majors. That's wonderful, but we cannot ship that. There is no userland support to create device nodes in dynamic fashion and to ensure that they do not conflict. This is why Arjan filed for and received additional majors. Dynamic solutions need some time to float about the community, I think. BTW, DASD does the same thing already. I never saw any memo or document explaining how to use this capability properly. Perhaps SuSE people support it. Kurt, can you tell anything about it? > Do you have any idea why we can't just sync all mounted filesystems > in do_emergency_sync()? > DASD? LVM? EVMS? MD? Loop? NBD? DRBD? What's the rationale > of restricting the sync to only IDE and SCSI? Deadlock avoidance? I suspect it is a deadlock prevention thing, too. I cannot say if it ever worked satisfactory... :) > I'm gonna post my patches tomorrow ... Thanks, that's interesting. Like I said, they are not likely to get to the distro soon, but I'd love to look at them. -- Pete