Usable lock implementation with SX-semantics

MaxLaier

DmitriyMarchenko AttilioRao

The current sx(9) implementation has several problems that make it unusable in many areas:

• Might sleep (cv_wait) on the shared lock acquisition
• implicit, hardcoded priority order without starvation protection
• …

Things to look at:

• Solaris' rwlock
• Use turnstiles instead of conditional variables
  • Priority propagation
  • No longer just one owner
  • shared/read locks might be acquired recursively

TBD