From 4d5550070fe5e80ff2296a71239c568c774b9ceb Mon Sep 17 00:00:00 2001 From: ivmarkov Date: Mon, 24 Oct 2022 09:17:43 +0300 Subject: Change time Driver contract to never fire the alarm synchronously --- embassy-executor/src/raw/mod.rs | 72 +++++++++++++++++++++++------------------ 1 file changed, 40 insertions(+), 32 deletions(-) (limited to 'embassy-executor/src') diff --git a/embassy-executor/src/raw/mod.rs b/embassy-executor/src/raw/mod.rs index e1258ebb5..5bcb1e6e7 100644 --- a/embassy-executor/src/raw/mod.rs +++ b/embassy-executor/src/raw/mod.rs @@ -354,46 +354,54 @@ impl Executor { /// somehow schedule for `poll()` to be called later, at a time you know for sure there's /// no `poll()` already running. pub unsafe fn poll(&'static self) { - #[cfg(feature = "integrated-timers")] - self.timer_queue.dequeue_expired(Instant::now(), |task| wake_task(task)); + loop { + #[cfg(feature = "integrated-timers")] + self.timer_queue.dequeue_expired(Instant::now(), |task| wake_task(task)); - self.run_queue.dequeue_all(|p| { - let task = p.as_ref(); + self.run_queue.dequeue_all(|p| { + let task = p.as_ref(); - #[cfg(feature = "integrated-timers")] - task.expires_at.set(Instant::MAX); - - let state = task.state.fetch_and(!STATE_RUN_QUEUED, Ordering::AcqRel); - if state & STATE_SPAWNED == 0 { - // If task is not running, ignore it. This can happen in the following scenario: - // - Task gets dequeued, poll starts - // - While task is being polled, it gets woken. It gets placed in the queue. - // - Task poll finishes, returning done=true - // - RUNNING bit is cleared, but the task is already in the queue. - return; - } + #[cfg(feature = "integrated-timers")] + task.expires_at.set(Instant::MAX); + + let state = task.state.fetch_and(!STATE_RUN_QUEUED, Ordering::AcqRel); + if state & STATE_SPAWNED == 0 { + // If task is not running, ignore it. This can happen in the following scenario: + // - Task gets dequeued, poll starts + // - While task is being polled, it gets woken. It gets placed in the queue. + // - Task poll finishes, returning done=true + // - RUNNING bit is cleared, but the task is already in the queue. + return; + } - #[cfg(feature = "rtos-trace")] - trace::task_exec_begin(p.as_ptr() as u32); + #[cfg(feature = "rtos-trace")] + trace::task_exec_begin(p.as_ptr() as u32); - // Run the task - task.poll_fn.read()(p as _); + // Run the task + task.poll_fn.read()(p as _); - #[cfg(feature = "rtos-trace")] - trace::task_exec_end(); + #[cfg(feature = "rtos-trace")] + trace::task_exec_end(); + + // Enqueue or update into timer_queue + #[cfg(feature = "integrated-timers")] + self.timer_queue.update(p); + }); - // Enqueue or update into timer_queue #[cfg(feature = "integrated-timers")] - self.timer_queue.update(p); - }); + { + // If this is already in the past, set_alarm might return false + // In that case do another poll loop iteration. + let next_expiration = self.timer_queue.next_expiration(); + if driver::set_alarm(self.alarm, next_expiration.as_ticks()) { + break; + } + } - #[cfg(feature = "integrated-timers")] - { - // If this is already in the past, set_alarm will immediately trigger the alarm. - // This will cause `signal_fn` to be called, which will cause `poll()` to be called again, - // so we immediately do another poll loop iteration. - let next_expiration = self.timer_queue.next_expiration(); - driver::set_alarm(self.alarm, next_expiration.as_ticks()); + #[cfg(not(feature = "integrated-timers"))] + { + break; + } } #[cfg(feature = "rtos-trace")] -- cgit