From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Higdon Subject: Re: mpt sets 64bit consistent mask yet requires mapping in same 4 GB chunk?!? Date: Fri, 13 Feb 2004 15:39:00 -0800 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20040213233900.GE504054@sgi.com> References: <0E3FA95632D6D047BA649F95DAB60E5703EF915E@exa-atlanta.se.lsil.com> <20040213213043.GB20323@sgi.com> <200402131552.43935.bjorn.helgaas@hp.com> <20040213231308.GT31168@parcelfarce.linux.theplanet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mtvcafw.sgi.com ([192.48.171.6]:56634 "EHLO zok.sgi.com") by vger.kernel.org with ESMTP id S267192AbUBMXjS (ORCPT ); Fri, 13 Feb 2004 18:39:18 -0500 Content-Disposition: inline In-Reply-To: <20040213231308.GT31168@parcelfarce.linux.theplanet.co.uk> List-Id: linux-scsi@vger.kernel.org To: Matthew Wilcox Cc: Bjorn Helgaas , Jesse Barnes , "Moore, Eric Dean" , Alex Williamson , linux-scsi@vger.kernel.org, linux-ia64@vger.kernel.org On Fri, Feb 13, 2004 at 11:13:08PM +0000, Matthew Wilcox wrote: > On Fri, Feb 13, 2004 at 03:52:43PM -0700, Bjorn Helgaas wrote: > > > I think Alex's second suggestion would be the best--do a single > > > allocation rather than falling back to a 32 bit consistent mask. > > > > But even with a single allocation, there's nothing to prevent it > > from crossing a 4GB boundary, is there? > > Since we use buddy allocators everywhere, we'd need to be doing 8GB > allocations to cross a 4GB barrier. Of course if we change allocators ... ... and this particular behavior, then I think lots of hardware will stop working, because LSI is not the only vendor with this sort of limitation :-) jeremy