So, Wily can be "more safe" with both: 874bbfe & 22b886d, since the upstream decision described in:
"The local CPU guarantee was accidental more than anything else and we
want to get rid of it anyway. As, with the vmstat case fixed,
874bbfe600a6 is causing more problems than it's fixing, it has been
decided to take the chance and officially break the guarantee by
reverting the commit. A debug feature will be added to force foreign
CPU assignment to expose cases relying on the guarantee and fixes for
the individual cases will be backported to stable as necessary.
"
Assures that removing patch 874bbfe will indeed break the "guarantee".
So, Wily can be "more safe" with both: 874bbfe & 22b886d, since the upstream decision described in:
"The local CPU guarantee was accidental more than anything else and we
want to get rid of it anyway. As, with the vmstat case fixed,
874bbfe600a6 is causing more problems than it's fixing, it has been
decided to take the chance and officially break the guarantee by
reverting the commit. A debug feature will be added to force foreign
CPU assignment to expose cases relying on the guarantee and fixes for
the individual cases will be backported to stable as necessary.
"
Assures that removing patch 874bbfe will indeed break the "guarantee".
So, IMO, this is a (using upstream tags):
Trusty: Remove 874bbfe
Wily: Keep 874bbfe & 22b886d
Xenial: Follow upstream