iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
7d8296b250
linux/kernel/locking
History
Uros Bizjak ce3576ebd6 locking/rtmutex: Use try_cmpxchg_relaxed() in mark_rt_mutex_waiters() 
Use try_cmpxchg() instead of cmpxchg(*ptr, old, new) == old.

The x86 CMPXCHG instruction returns success in the ZF flag, so this change
saves a compare after CMPXCHG (and related move instruction in front of CMPXCHG).

Also, try_cmpxchg() implicitly assigns old *ptr value to "old" when CMPXCHG
fails. There is no need to re-read the value in the loop.

Note that the value from *ptr should be read using READ_ONCE() to prevent
the compiler from merging, refetching or reordering the read.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20240124104953.612063-1-ubizjak@gmail.com
2024-03-01 13:02:05 +01:00
..
irqflag-debug.c
lock_events_list.h
lock_events.c locking/debug: Fix debugfs API return value checks to use IS_ERR() 2023-10-03 10:11:25 +02:00
lock_events.h locking: add lockevent_read() prototype 2023-06-09 17:44:15 -07:00
lockdep_internals.h locking/lockdep: Iterate lock_classes directly when reading lockdep files 2022-02-16 15:57:58 +01:00
lockdep_proc.c locking/lockdep: Fix string sizing bug that triggers a format-truncation compiler-warning 2023-10-12 20:37:59 +02:00
lockdep_states.h
lockdep.c lockdep: Fix block chain corruption 2023-11-24 11:04:54 +01:00
locktorture.c locktorture: Increase Hamming distance between call_rcu_chain and rcu_call_chains 2023-11-23 11:58:18 +05:30
Makefile lockdep: allow instrumenting lockdep.c with KMSAN 2022-12-11 18:12:11 -08:00
mcs_spinlock.h locking: Fix typos in comments 2021-03-22 02:45:52 +01:00
mutex-debug.c locking/ww_mutex: Gather mutex_waiter initialization 2021-08-17 19:04:41 +02:00
mutex.c locking/mutex: Document that mutex_unlock() is non-atomic 2023-12-01 11:27:43 +01:00
mutex.h locking/mutex: Move the 'struct mutex_waiter' definition from <linux/mutex.h> to the internal header 2021-08-17 18:24:31 +02:00
osq_lock.c locking/osq_lock: Clarify osq_wait_next() 2023-12-30 10:25:51 -08:00
percpu-rwsem.c locking/percpu-rwsem: Trigger contention tracepoints only if contended 2024-02-28 13:10:29 +01:00
qrwlock.c locking: Add __lockfunc to slow path functions 2022-08-19 19:47:51 +02:00
qspinlock_paravirt.h locking/qspinlock: Fix 'wait_early' set but not used warning 2024-02-28 13:08:37 +01:00
qspinlock_stat.h
qspinlock.c locking/qspinlock: Micro-optimize pending state waiting for unlock 2023-01-05 11:01:50 +01:00
rtmutex_api.c locking/rtmutex: Fix task->pi_waiters integrity 2023-07-17 13:59:10 +02:00
rtmutex_common.h locking/rtmutex: Fix task->pi_waiters integrity 2023-07-17 13:59:10 +02:00
rtmutex.c locking/rtmutex: Use try_cmpxchg_relaxed() in mark_rt_mutex_waiters() 2024-03-01 13:02:05 +01:00
rwbase_rt.c locking/rtmutex: Add a lockdep assert to catch potential nested blocking 2023-09-20 09:31:14 +02:00
rwsem.c locking/rwsem: Clarify that RWSEM_READER_OWNED is just a hint 2024-02-28 13:08:38 +01:00
semaphore.c locking: Add __sched to semaphore functions 2022-09-15 16:14:03 +02:00
spinlock_debug.c sched.h: move pid helpers to pid.h 2023-12-20 19:26:31 -05:00
spinlock_rt.c locking/rtmutex: Add a lockdep assert to catch potential nested blocking 2023-09-20 09:31:14 +02:00
spinlock.c locking/spinlocks: Mark spinlocks noinline when inline spinlocks are disabled 2022-08-04 11:05:43 +02:00
test-ww_mutex.c locking/ww_mutex/test: Make sure we bail out instead of livelock 2023-09-22 09:43:41 +02:00
ww_mutex.h locking/rtmutex: Fix task->pi_waiters integrity 2023-07-17 13:59:10 +02:00
ww_rt_mutex.c locking/rtmutex: Avoid unconditional slowpath for DEBUG_RT_MUTEXES 2023-09-20 09:31:11 +02:00