mutex: Revert spin flag load op

It made locking much slower on ARM64. This reverts commit 77c9ce0.
lhmouse · Nov 7, 2024 · c4b87c5 · c4b87c5
1 parent 32ffbaa
commit c4b87c5
Showing 1 changed file with 2 additions and 4 deletions.
diff --git a/mcfgthread/mutex.c b/mcfgthread/mutex.c
@@ -94,10 +94,8 @@ _MCF_mutex_lock_slow(_MCF_mutex* mutex, const int64_t* timeout_opt)
         spin_count --;
         YieldProcessor();
 
-        /* Wait for my turn.  */
-        if(_MCF_atomic_load_b_rlx(do_spin_byte_ptr(mutex, my_mask)) == false)
-          continue;
-
+        /* Wait for my turn. It's the simplest and fastest way to perform
+         * just an atomic exchange, on both x86 and ARM.  */
         if(_MCF_atomic_xchg_b_rlx(do_spin_byte_ptr(mutex, my_mask), false) == false)
           continue;