From mboxrd@z Thu Jan 1 00:00:00 1970 From: "'David Gibson'" Date: Fri, 24 Feb 2006 02:46:44 +0000 Subject: Re: IA64 non-contiguous memory space bugs Message-Id: <20060224024644.GD28368@localhost.localdomain> List-Id: References: <20060224001146.GC25101@localhost.localdomain> <200602240114.k1O1E4g05231@unix-os.sc.intel.com> In-Reply-To: <200602240114.k1O1E4g05231@unix-os.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Chen, Kenneth W" Cc: Hugh Dickins , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org On Thu, Feb 23, 2006 at 05:14:03PM -0800, Chen, Kenneth W wrote: > David Gibson wrote on Thursday, February 23, 2006 4:12 PM > > It doesn't really mean different things - "touches a hugepage > > exclusive area" is the correct semantic, the ia64 implementation > > doesn't quite encode that, but is equivalent for valid address > > ranges. (though I wonder if that's another bug associated with by > > task-region-max patch, without that patch invalid address ranges can > > slip through, so maybe it's possible on ia64 to create a normalpage VM > > with its start in the address space gap and its end in the hugepage > > region, ouch). > > This is getting complicated that my little brain hurts. There has been > so many iterations that the semantic is ambiguous. If the semantic is > decided to be "overlap", then The semantic is "! is this range ok for a normalpage VMA", so that we can do that check on the MAP_FIXED path. That implies "overlap" - except that if you assume it's passed a valid user address range in the first place, then just checking the region is sufficient on ia64. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson