Hi, The actual BP that links to the approved spec is here: [1] and 2 outstanding patches are [2][3]. Apart from the usual empathy-inspired reasons to allow this (code's been up for a while, yet only had real review on the last day etc.) which are not related to the technical merit of the work, there is also the fact that two initial patches that add locking around updates of the in-memory host map ([4] and [5]) have already been merged. They add the overhead of locking to the scheduler, but without the final work they don't provide any benefits (races will not be detected, without [2]). I don't have any numbers on this but the result is likely that we made things worse, for the sake of adhering to random and made-up dates. With this in mind I think it only makes sense to do our best to merge the 2 outstanding patches. Cheers, N. [1] https://blueprints.launchpad.net/openstack/?searchtext=host-state-level-locking [2] https://review.openstack.org/#/c/262938/ [3] https://review.openstack.org/#/c/262939/ [4] https://review.openstack.org/#/c/259891/ [5] https://review.openstack.org/#/c/259892/