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authorLinus Torvalds <torvalds@linux-foundation.org>2022-05-24 10:18:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-05-24 10:18:23 -0700
commit2319be135672f6e45aa937bceaae6c2668c7867c (patch)
tree5d2210243fac4345bbb204064f9602fe9477b785 /kernel/locking/mutex.c
parent143a6252e1b8ab424b4b293512a97cca7295c182 (diff)
parent8491d1bdf5de152f27fc941e2dcdc4e66c950542 (diff)
Merge tag 'locking-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar: - rwsem cleanups & optimizations/fixes: - Conditionally wake waiters in reader/writer slowpaths - Always try to wake waiters in out_nolock path - Add try_cmpxchg64() implementation, with arch optimizations - and use it to micro-optimize sched_clock_{local,remote}() - Various force-inlining fixes to address objdump instrumentation-check warnings - Add lock contention tracepoints: lock:contention_begin lock:contention_end - Misc smaller fixes & cleanups * tag 'locking-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/clock: Use try_cmpxchg64 in sched_clock_{local,remote} locking/atomic/x86: Introduce arch_try_cmpxchg64 locking/atomic: Add generic try_cmpxchg64 support futex: Remove a PREEMPT_RT_FULL reference. locking/qrwlock: Change "queue rwlock" to "queued rwlock" lockdep: Delete local_irq_enable_in_hardirq() locking/mutex: Make contention tracepoints more consistent wrt adaptive spinning locking: Apply contention tracepoints in the slow path locking: Add lock contention tracepoints locking/rwsem: Always try to wake waiters in out_nolock path locking/rwsem: Conditionally wake waiters in reader/writer slowpaths locking/rwsem: No need to check for handoff bit if wait queue empty lockdep: Fix -Wunused-parameter for _THIS_IP_ x86/mm: Force-inline __phys_addr_nodebug() x86/kvm/svm: Force-inline GHCB accessors task_stack, x86/cea: Force-inline stack helpers
Diffstat (limited to 'kernel/locking/mutex.c')
-rw-r--r--kernel/locking/mutex.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 5e3585950ec8..d973fe6041bf 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -30,6 +30,9 @@
#include <linux/debug_locks.h>
#include <linux/osq_lock.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/lock.h>
+
#ifndef CONFIG_PREEMPT_RT
#include "mutex.h"
@@ -599,12 +602,14 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
preempt_disable();
mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
+ trace_contention_begin(lock, LCB_F_MUTEX | LCB_F_SPIN);
if (__mutex_trylock(lock) ||
mutex_optimistic_spin(lock, ww_ctx, NULL)) {
/* got the lock, yay! */
lock_acquired(&lock->dep_map, ip);
if (ww_ctx)
ww_mutex_set_context_fastpath(ww, ww_ctx);
+ trace_contention_end(lock, 0);
preempt_enable();
return 0;
}
@@ -641,6 +646,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
}
set_current_state(state);
+ trace_contention_begin(lock, LCB_F_MUTEX);
for (;;) {
bool first;
@@ -680,10 +686,16 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
* state back to RUNNING and fall through the next schedule(),
* or we must see its unlock and acquire.
*/
- if (__mutex_trylock_or_handoff(lock, first) ||
- (first && mutex_optimistic_spin(lock, ww_ctx, &waiter)))
+ if (__mutex_trylock_or_handoff(lock, first))
break;
+ if (first) {
+ trace_contention_begin(lock, LCB_F_MUTEX | LCB_F_SPIN);
+ if (mutex_optimistic_spin(lock, ww_ctx, &waiter))
+ break;
+ trace_contention_begin(lock, LCB_F_MUTEX);
+ }
+
raw_spin_lock(&lock->wait_lock);
}
raw_spin_lock(&lock->wait_lock);
@@ -707,6 +719,7 @@ acquired:
skip_wait:
/* got the lock - cleanup and rejoice! */
lock_acquired(&lock->dep_map, ip);
+ trace_contention_end(lock, 0);
if (ww_ctx)
ww_mutex_lock_acquired(ww, ww_ctx);
@@ -719,6 +732,7 @@ err:
__set_current_state(TASK_RUNNING);
__mutex_remove_waiter(lock, &waiter);
err_early_kill:
+ trace_contention_end(lock, ret);
raw_spin_unlock(&lock->wait_lock);
debug_mutex_free_waiter(&waiter);
mutex_release(&lock->dep_map, ip);