Merge pull request #1420 from spacejam/tyler_fix_arm_cas

Fix arm compare_exchange_weak behavior

Author: spacejam

src/fastlock.rs

@@ -3,7 +3,7 @@ use std::{
     ops::{Deref, DerefMut},
     sync::atomic::{
         AtomicBool,
-        Ordering::{Acquire, Release},
+        Ordering::{AcqRel, Acquire, Release},
     },
 };
 
@@ -56,7 +56,7 @@ impl<T> FastLock<T> {
 
     pub fn try_lock(&self) -> Option<FastLockGuard<'_, T>> {
         let lock_result =
-            self.lock.compare_exchange_weak(false, true, Acquire, Acquire);
+            self.lock.compare_exchange_weak(false, true, AcqRel, Acquire);
 
         let success = lock_result.is_ok();
 

src/lru.rs

@@ -97,11 +97,11 @@ impl AccessQueue {
                 // install new writer
                 let new = Box::into_raw(Box::new(AccessBlock::new(item)));
                 debug_delay();
-                let res = self.writing.compare_exchange_weak(
+                let res = self.writing.compare_exchange(
                     head,
                     new,
-                    Ordering::Release,
-                    Ordering::Relaxed,
+                    Ordering::AcqRel,
+                    Ordering::Acquire,
                 );
                 if res.is_err() {
                     // we lost the CAS, free the new item that was
@@ -120,11 +120,11 @@ impl AccessQueue {
                     // we loop because maybe other threads are pushing stuff too
                     block.next.store(full_list_ptr, Ordering::Release);
                     debug_delay();
-                    ret = self.full_list.compare_exchange_weak(
+                    ret = self.full_list.compare_exchange(
                         full_list_ptr,
                         head,
-                        Ordering::Release,
-                        Ordering::Relaxed,
+                        Ordering::AcqRel,
+                        Ordering::Acquire,
                     );
                     ret.is_err()
                 } {