Make ntasks an atomic counter.
Fixes
@@ -44,7 +44,12 @@ pub struct Isolate {
ptr: *const libdeno::isolate,
dispatch: Dispatch,
rx: mpsc::Receiver<(i32, Buf)>,
- ntasks: i32,
+ // Although Isolate is only accessed on the main thread, we use an atomic
+ // variable here to workaround an issue probably caused by our poor usage
+ // of Box::leak in Isolate::from_c()
+ // https://github.com/denoland/deno/issues/919
+ // ntasks ought to be i32.
+ ntasks: atomic::AtomicIsize,
pub timeout_due: Option<Instant>,
pub state: Arc<IsolateState>,
}
@@ -86,7 +91,7 @@ impl Isolate {
ptr: 0 as *const libdeno::isolate,
dispatch,
rx,
- ntasks: 0,
+ ntasks: atomic::AtomicIsize::new(0),
timeout_due: None,
state: Arc::new(IsolateState {
dir: deno_dir::DenoDir::new(flags.reload, None).unwrap(),
@@ -189,25 +194,18 @@ impl Isolate {
}
fn ntasks_increment(&mut self) {
- assert!(self.ntasks >= 0);
- self.ntasks = self.ntasks + 1;
+ let previous_ntasks = self.ntasks.fetch_add(1, atomic::Ordering::SeqCst);
+ assert!(previous_ntasks >= 0);
}
fn ntasks_decrement(&mut self) {
- // Do something that has no effect. This is done to work around a spooky
- // bug that happens in release mode only (presumably a compiler bug), that
- // causes nsize to unexpectedly contain zero.
- // TODO: remove this workaround when no longer necessary.
- #[allow(unused)]
- static UNUSED: atomic::AtomicIsize = atomic::AtomicIsize::new(0);
- UNUSED.fetch_add(self.ntasks as isize, atomic::Ordering::AcqRel);
- // Actually decrement the tasks counter here.
- self.ntasks = self.ntasks - 1;
- assert!(self.ntasks >= 0);
+ let previous_ntasks = self.ntasks.fetch_sub(1, atomic::Ordering::SeqCst);
+ assert!(previous_ntasks >= 1);
}
fn is_idle(&self) -> bool {
- self.ntasks == 0 && self.timeout_due.is_none()
+ let n = self.ntasks.load(atomic::Ordering::SeqCst);
+ n == 0 && self.timeout_due.is_none()
}
}
