Reviewed: https://review.openstack.org/391416 Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=9f12b592d1d26a985699fefde2a7ce0164d0b5d3 Submitter: Jenkins Branch: master
commit 9f12b592d1d26a985699fefde2a7ce0164d0b5d3 Author: Sergey Nikitin <[email protected]> Date: Fri Dec 9 17:42:14 2016 +0400 Mark sibling CPUs as 'used' for cpu_thread_policy = 'isolated' 'isolated' CPU allocation thread policy is guarantee that no vCPUs from other guests wouldn't be able to be placed on the cores of booted VM (In this case core is a set of sibling vCPUs). But we still able to boot VMs with 'dedicated' CPU allocation policy on these cores. This problem is actual for hosts without HyperThreading. In this case sets of siblings vCPUs are empty for each core but we are still trying to work with them as with HyperThreading cores. This causes the problem when one "isolated" core is used by several VMs. To fix it we must use method unpin_cpus_with_siblings() only if NUMA cell has siblings (i.e. has HyperThreading). For cells without HyperThreading CPU isolation is guaranteed by 'dedicated' CPU allocation policy. Closes-Bug: #1635674 Change-Id: I8f72187153c930cd941b7ee7e835a20ed0c0de03 ** Changed in: nova Status: In Progress => Fix Released -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1635674 Title: 'hw:cpu_thread_policy=isolate' is not accounted properly on non-HT hosts Status in OpenStack Compute (nova): Fix Released Bug description: If an instance with 'hw:cpu_thread_policy=isolate' is scheduled on a non-HT host, the pinned pCPUs are not properly accounted for. This can lead to multiple instances running on the same pCPUs The problem is that in LibvirtDriver._get_host_numa_topology() when calculating the NUMACell.siblings field we filter out single cpus. On a non-HT host this means that NUMACell.siblings is an empty list. Later when _update_usage() runs it ends up eventually running NUMACell.pin_cpus_with_siblings(). This contains the following code: def pin_cpus_with_siblings(self, cpus): pin_siblings = set() for sib in self.siblings: if cpus & sib: pin_siblings.update(sib) self.pin_cpus(pin_siblings) Since "self.siblings" is empty, we end up calling self.pin_cpus() with an empty list, which means that we don't update self.pinned_cpus. Stephen Finucane has suggested the correct fix might be to leave single pCPUs in the NUMACell.siblings field. This needs to be verified to make sure that it doesn't cause other problems. To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1635674/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : [email protected] Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
