From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: Xen-unstable panic: FATAL PAGE FAULT Date: Tue, 31 Aug 2010 16:07:23 +0100 Message-ID: <4C7D36CB0200007800013394@vpn.id2.novell.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: MaoXiaoyun , xen devel List-Id: xen-devel@lists.xenproject.org >>> On 31.08.10 at 16:49, Keir Fraser wrote: > I'm cc'ing Jan to see what we can get away with in doing arithmetic on > page_info pointers. What's the guaranteed smallest aligned contiguous = ranges > of mfn in the frame_table now, Jan? (i.e., ranges in which adjacent > page_info structs relate to adjacent MFNs) Any range of struct page_info-s that crosses a 2Mb boundary is unsafe to make assumptions upon (with 32-byte struct page_info that means 256Mb of memory, but if struct page_info grows that range might shrink). If that limit is too low, we might need to enforce a lower limit on the bit positions on which compression may be done (possibly at the price of doing less compression). Jan