On Wed, Mar 16, 2022 at 03:45:48PM -0700, Namhyung Kim wrote: [...] > @@ -209,6 +210,7 @@ static inline int __sched __down_common(struct semaphore *sem, long state, > long timeout) > { > struct semaphore_waiter waiter; > + bool tracing = false; > > list_add_tail(&waiter.list, &sem->wait_list); > waiter.task = current; > @@ -220,18 +222,28 @@ static inline int __sched __down_common(struct semaphore *sem, long state, > if (unlikely(timeout <= 0)) > goto timed_out; > __set_current_state(state); > + if (!tracing) { > + trace_contention_begin(sem, 0); This looks a littl ugly ;-/ Maybe we can rename __down_common() to ___down_common() and implement __down_common() as: static inline int __sched __down_common(...) { int ret; trace_contention_begin(sem, 0); ret = ___down_common(...); trace_contention_end(sem, ret); return ret; } Thoughts? Regards, Boqun > + tracing = true; > + } > raw_spin_unlock_irq(&sem->lock); > timeout = schedule_timeout(timeout); > raw_spin_lock_irq(&sem->lock); > - if (waiter.up) > + if (waiter.up) { > + trace_contention_end(sem, 0); > return 0; > + } > } > > timed_out: > + if (tracing) > + trace_contention_end(sem, -ETIME); > list_del(&waiter.list); > return -ETIME; > > interrupted: > + if (tracing) > + trace_contention_end(sem, -EINTR); > list_del(&waiter.list); > return -EINTR; > } > -- > 2.35.1.894.gb6a874cedc-goog >