On Fri, Dec 07, 2018 at 02:14:03AM +0000, Huang, Kai wrote:

Alternatively, we can choose to use per-socket keyID, but not to program
keyID globally across all sockets, so you don't have to save key while
still supporting CPU hotplug.

Per-socket KeyID approach would make things more complex. For instance
KeyID on its own will not be enough to refer a key. You will need a node
too. It will also require a way to track whether theirs an KeyID on other
node for the key.

It also makes memory management less flexible: runtime migration of the
memory between nodes will be limited and it can hurt memory availablity
for non-encrypted tasks too.

In general, I don't see per-socket KeyID handling very attractive. It
creates more problems than solves.

-- 
 Kirill A. Shutemov