Make it possible to reclaim items from a specific NUMA domain.
- Add uma_zone_reclaim_domain() and uma_reclaim_domain().
- Permit parallel reclamations. Use a counter instead of a flag to
synchronize with zone_dtor().
- Use the zone lock to protect cache_shrink() now that parallel reclaims
can happen.
- Add a sysctl that can be used to trigger reclamation from a specific
domain.
Currently the new KPIs are unused, so there should be no functional
change.
Reviewed by: mav
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29685
aabe13f145