On Fri, Mar 18, 2022 at 08:55:32PM +0800, Boqun Feng wrote:
> 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 ;-/
I agree this can be simplified a bit.
> 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?
>
But IMO inlining tracepoints is generally not a good idea.
Will increase kernel size a lot.
> 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
> >
