On Sat, May 09, 2020 at 12:05:29PM -0700, Andy Lutomirski wrote:

On x86_64, the only real advantage is that the handful of corner cases
that make vmalloc faults unpleasant (mostly relating to vmap stacks)
go away.  On x86_32, a bunch of mind-bending stuff (everything your
series deletes but also almost everything your series *adds*) goes
away.  There may be a genuine tiny performance hit on 2-level systems
due to the loss of huge pages in vmalloc space, but I'm not sure I
care or that we use them anyway on these systems.  And PeterZ can stop
even thinking about RCU.

Am I making sense?

I think it'll work for x86_64 and that is really all I care about :-)