|author||Mark Johnston <markj@FreeBSD.org>||2020-02-28 16:05:18 +0000|
|committer||Mark Johnston <markj@FreeBSD.org>||2020-02-28 16:05:18 +0000|
Add a blocking counter KPI.
refcount(9) was recently extended to support waiting on a refcount to drop to zero, as this was needed for a lockless VM object paging-in-progress counter. However, this adds overhead to all uses of refcount(9) and doesn't really match traditional refcounting semantics: once a counter has dropped to zero, the protected object may be freed at any point and it is not safe to dereference the counter. This change removes that extension and instead adds a new set of KPIs, blockcount_*, for use by VM object PIP and busy. Reviewed by: jeff, kib, mjg Tested by: pho Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D23723
Notes: svn path=/head/; revision=358432
Diffstat (limited to 'cddl/contrib')
0 files changed, 0 insertions, 0 deletions