From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Dunlap Subject: Re: [PATCH] xen: postpone updating domains' node affinity when removing a CPU from a cpupool Date: Wed, 11 Mar 2015 15:01:15 +0000 Message-ID: <550058BB.7000102@eu.citrix.com> References: <20150309164901.11859.95044.stgit@Solace.station> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150309164901.11859.95044.stgit@Solace.station> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Dario Faggioli , Xen-devel Cc: Juergen Gross , Keir Fraser , Justin Weaver , Jan Beulich List-Id: xen-devel@lists.xenproject.org On 03/09/2015 04:49 PM, Dario Faggioli wrote: > 93be8285 ("update domU's node-affinity on the cpupool_unassign_cpu() > path") does the right thing, but does it too early. In fact, it > is necessary to call domain_update_node_affinity() when a pCPU is > removed from a cpupool, but that must happen after the pCPU is > really gone from there. > > More specifically, it is important that the update happens not > before cpu_disable_scheduler() is called on that pCPU, to give > that function the chance to fixup the vCPU affinity of the > domains residing in the cpupool, if that is necessary. It looks like domain_update_node_affinity() is already called for each domain in the cpupool in cpu_disable_scheduler(). It doesn't look like there should be a need to call it twice. Can we just remove the call to domain_update_node_affinity() in cpupool_unassign_cpu() and not add it back? -George