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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-24 10:18:23 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-24 10:18:23 -0700 |
commit | 2319be135672f6e45aa937bceaae6c2668c7867c (patch) | |
tree | 5d2210243fac4345bbb204064f9602fe9477b785 /kernel/locking/mutex.c | |
parent | 143a6252e1b8ab424b4b293512a97cca7295c182 (diff) | |
parent | 8491d1bdf5de152f27fc941e2dcdc4e66c950542 (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.c | 18 |
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); |