Some IRC discussion here (~1731 - 1744): http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23openstack-nova.2016-10-21.log.html
I think there's some consensus that we can solve both cases without using negative values by leveraging used instead of free and making the appropriate checks in the filters.
Some IRC discussion here (~1731 - 1744): http:// eavesdrop. openstack. org/irclogs/ %23openstack- nova/%23opensta ck-nova. 2016-10- 21.log. html
I think there's some consensus that we can solve both cases without using negative values by leveraging used instead of free and making the appropriate checks in the filters.