K 10
svn:author
V 3
mjg
K 8
svn:date
V 27
2019-10-06T22:13:35.131869Z
K 7
svn:log
V 527
amd64 pmap: implement per-superpage locks

The current 256-lock sized array is a problem in the following ways:
- it's way too small
- there are 2 locks per cacheline
- it is not NUMA-aware

Solve these issues by introducing per-superpage locks backed by pages
allocated from respective domains.

This significantly reduces contention e.g. during poudriere -j 104.
See the review for results.

Reviewed by:	kib
Discussed with:	jeff
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D21833

END