From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH 1/2] Revert "xen: properly account for _PAGE_NUMA during xen pte translations" Date: Tue, 25 Mar 2014 17:13:51 +0000 Message-ID: <5331B94F.9020601@citrix.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: David Sutton Cc: "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On 25/03/14 15:28, David Sutton wrote: > David, > >> This reverts commit a9c8e4beeeb64c22b84c803747487857fe424b68. >> > Please note: this particular patch also helped to resolve an issue > reported by some of the people using the xen package under Arch Linux, > where they would see stability issues running certain software > (particularly firefox) under dom0 - the software would start crashing > under relatively light usage, with a kernel BUG message. We are aware that Xen PV guests will not work if CONFIG_NUMA_BALANCING is enabled with this revert. But that patch introduced fundamental breakage to how a guest must read/write non-present page tables entries which caused even worse breakage. I suspect that the problematic patch 1667918b6483 ("mm: numa: clear numa hinting information on mprotect") is not needed on x86 and could be safely reverted as a temporarily fix. David