This enables locking consumers to pass their own structures around as const and
be able to assert locks embedded into those structures.
Reviewed by: ed, kib, jhb
- add rm_try_rlock().
- add RM_SLEEPABLE to use sx(9) as the back-end lock in order to sleep while
holding the write lock.
- change rm_noreadtoken to a cpu bitmask to indicate which CPUs need to go
through the lock/unlock in order to synchronize. As a side effect, this
also avoids IPI to CPUs without any readers during rm_wlock.
Discussed with: ups@, rwatson@ on arch@
Sponsored by: Isilon Systems, Inc.
- Add rm_init_flags() and accept extended options only for that variation.
- Add a flags space specifically for rm_init_flags(), rather than borrowing
the lock_init() flag space.
- Define flag RM_RECURSE to use instead of LO_RECURSABLE.
- Define flag RM_NOWITNESS to allow an rmlock to be exempt from WITNESS
checking; this wasn't possible previously as rm_init() always passed
LO_WITNESS when initializing an rmlock's struct lock.
- Add RM_SYSINIT_FLAGS().
- Rename embedded mutex in rmlocks to make it more obvious what it is.
- Update consumers.
- Update man page.
* Correct spelling and grammar
* Re-structure sentences in BUGS section for legibility
* Break long lines appropriately
* Break lines at full stops
* Add mdoc(9) commands where applicable
* Remove superfluous .Ft in the SYNOPSIS section
* Various other mdoc(9) fixes
lock optimized for almost exclusive reader access. (see also rmlock.9)
TODO:
Convert to per cpu variables linkerset as soon as it is available.
Optimize UP (single processor) case.
