diff options
author | Peter Zijlstra <peterz@infradead.org> | 2022-03-30 14:06:54 +0300 |
---|---|---|
committer | Peter Zijlstra <peterz@infradead.org> | 2022-04-05 11:24:36 +0300 |
commit | dc1f7893a70fe403983bd8492f177bf993940e2c (patch) | |
tree | 0601a9c8f14c338fbae6755284036b50e98501d1 /kernel/locking/mutex.c | |
parent | ee042be16cb455116d0fe99b77c6bc8baf87c8c6 (diff) | |
download | linux-dc1f7893a70fe403983bd8492f177bf993940e2c.tar.xz |
locking/mutex: Make contention tracepoints more consistent wrt adaptive spinning
Have the trace_contention_*() tracepoints consistently include
adaptive spinning. In order to differentiate between the spinning and
non-spinning states add LCB_F_MUTEX and combine with LCB_F_SPIN.
The consequence is that a mutex contention can now triggler multiple
_begin() tracepoints before triggering an _end().
Additionally, this fixes one path where mutex would trigger _end()
without ever seeing a _begin().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Diffstat (limited to 'kernel/locking/mutex.c')
-rw-r--r-- | kernel/locking/mutex.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index c88deda77cf2..d973fe6041bf 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -602,12 +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; } @@ -644,7 +646,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas } set_current_state(state); - trace_contention_begin(lock, 0); + trace_contention_begin(lock, LCB_F_MUTEX); for (;;) { bool first; @@ -684,10 +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); @@ -723,8 +731,8 @@ skip_wait: err: __set_current_state(TASK_RUNNING); __mutex_remove_waiter(lock, &waiter); - trace_contention_end(lock, ret); 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); |