Fixed a bug in the timer queue

When a waker was dequeued, and it had already exipired, the dequeue
was not re-run to set a proper new compare match for the monotonic.
This is now fixed.
This commit is contained in:
Emil Fresk 2022-10-08 20:40:45 +02:00
parent 4ccc7d3dcb
commit 613b3c59fc

View file

@ -136,8 +136,7 @@ where
instant: Mono::Instant, instant: Mono::Instant,
mono: &mut Mono, mono: &mut Mono,
) -> Option<(Task, u8)> { ) -> Option<(Task, u8)> {
let now = mono.now(); if instant <= mono.now() {
if instant <= now {
// task became ready // task became ready
let nr = unsafe { self.task_queue.pop_unchecked() }; let nr = unsafe { self.task_queue.pop_unchecked() };
Some((nr.task, nr.index)) Some((nr.task, nr.index))
@ -149,7 +148,7 @@ where
// dequeue. If the monotonic is fast enough it can happen that from the // dequeue. If the monotonic is fast enough it can happen that from the
// read of now to the set of the compare, the time can overflow. This is to // read of now to the set of the compare, the time can overflow. This is to
// guard against this. // guard against this.
if instant <= now { if instant <= mono.now() {
let nr = unsafe { self.task_queue.pop_unchecked() }; let nr = unsafe { self.task_queue.pop_unchecked() };
Some((nr.task, nr.index)) Some((nr.task, nr.index))
} else { } else {
@ -158,12 +157,15 @@ where
} }
} }
fn dequeue_waker_queue(&mut self, instant: Mono::Instant, mono: &mut Mono) { fn dequeue_waker_queue(&mut self, instant: Mono::Instant, mono: &mut Mono) -> bool {
let now = mono.now(); let mut did_wake = false;
if instant <= now {
if instant <= mono.now() {
// Task became ready, wake the waker // Task became ready, wake the waker
if let Some(v) = self.waker_queue.pop() { if let Some(v) = self.waker_queue.pop() {
v.val.waker.wake_by_ref() v.val.waker.wake_by_ref();
did_wake = true;
} }
} else { } else {
// Set compare // Set compare
@ -173,12 +175,16 @@ where
// dequeue. If the monotonic is fast enough it can happen that from the // dequeue. If the monotonic is fast enough it can happen that from the
// read of now to the set of the compare, the time can overflow. This is to // read of now to the set of the compare, the time can overflow. This is to
// guard against this. // guard against this.
if instant <= now { if instant <= mono.now() {
if let Some(v) = self.waker_queue.pop() { if let Some(v) = self.waker_queue.pop() {
v.val.waker.wake_by_ref() v.val.waker.wake_by_ref();
did_wake = true;
} }
} }
} }
did_wake
} }
/// Dequeue a task from the ``TimerQueue`` /// Dequeue a task from the ``TimerQueue``
@ -188,6 +194,7 @@ where
{ {
mono.clear_compare_flag(); mono.clear_compare_flag();
loop {
let tq = self.task_queue.peek().map(|p| p.instant); let tq = self.task_queue.peek().map(|p| p.instant);
let wq = self.waker_queue.peek().map(|p| p.instant); let wq = self.waker_queue.peek().map(|p| p.instant);
@ -224,10 +231,12 @@ where
} }
if dequeue_task { if dequeue_task {
self.dequeue_task_queue(instant, mono) return self.dequeue_task_queue(instant, mono);
} else if !self.dequeue_waker_queue(instant, mono) {
return None;
} else { } else {
self.dequeue_waker_queue(instant, mono); // Run the dequeue again
None }
} }
} }
} }