diff options
Diffstat (limited to 'components/servo_arc')
| -rw-r--r-- | components/servo_arc/lib.rs | 11 |
1 files changed, 3 insertions, 8 deletions
diff --git a/components/servo_arc/lib.rs b/components/servo_arc/lib.rs index e2063c79a9c..3e6cd65e85d 100644 --- a/components/servo_arc/lib.rs +++ b/components/servo_arc/lib.rs @@ -349,15 +349,10 @@ impl<T: ?Sized> Arc<T> { #[inline] pub fn is_unique(&self) -> bool { - // We can use Relaxed here, but the justification is a bit subtle. + // See the extensive discussion in [1] for why this needs to be Acquire. // - // The reason to use Acquire would be to synchronize with other threads - // that are modifying the refcount with Release, i.e. to ensure that - // their writes to memory guarded by this refcount are flushed. However, - // we know that threads only modify the contents of the Arc when they - // observe the refcount to be 1, and no other thread could observe that - // because we're holding one strong reference here. - self.inner().count.load(Relaxed) == 1 + // [1] https://github.com/servo/servo/issues/21186 + self.inner().count.load(Acquire) == 1 } } |