diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-03-11 18:33:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-03-11 18:33:03 -0700 |
| commit | a5b1a017cb76e4898dd62fcb97e8aee6a63b33b5 (patch) | |
| tree | af38e275caeceed23ec5dea73cf71aa7818da75b /kernel/locking/rtmutex.c | |
| parent | b0402403e54ae9eb94ce1cbb53c7def776e97426 (diff) | |
| parent | ce3576ebd62d99f79c1dc98824e2ef6d6ab68434 (diff) | |
Merge tag 'locking-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
- Micro-optimize local_xchg() and the rtmutex code on x86
- Fix percpu-rwsem contention tracepoints
- Simplify debugging Kconfig dependencies
- Update/clarify the documentation of atomic primitives
- Misc cleanups
* tag 'locking-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Use try_cmpxchg_relaxed() in mark_rt_mutex_waiters()
locking/x86: Implement local_xchg() using CMPXCHG without the LOCK prefix
locking/percpu-rwsem: Trigger contention tracepoints only if contended
locking/rwsem: Make DEBUG_RWSEMS and PREEMPT_RT mutually exclusive
locking/rwsem: Clarify that RWSEM_READER_OWNED is just a hint
locking/mutex: Simplify <linux/mutex.h>
locking/qspinlock: Fix 'wait_early' set but not used warning
locking/atomic: scripts: Clarify ordering of conditional atomics
Diffstat (limited to 'kernel/locking/rtmutex.c')
| -rw-r--r-- | kernel/locking/rtmutex.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 4a10e8c16fd2..88d08eeb8bc0 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -237,12 +237,13 @@ static __always_inline bool rt_mutex_cmpxchg_release(struct rt_mutex_base *lock, */ static __always_inline void mark_rt_mutex_waiters(struct rt_mutex_base *lock) { - unsigned long owner, *p = (unsigned long *) &lock->owner; + unsigned long *p = (unsigned long *) &lock->owner; + unsigned long owner, new; + owner = READ_ONCE(*p); do { - owner = *p; - } while (cmpxchg_relaxed(p, owner, - owner | RT_MUTEX_HAS_WAITERS) != owner); + new = owner | RT_MUTEX_HAS_WAITERS; + } while (!try_cmpxchg_relaxed(p, &owner, new)); /* * The cmpxchg loop above is relaxed to avoid back-to-back ACQUIRE |