changes

[model-checker-benchmarks.git] / seqlock / seqlock.h

diff --git a/seqlock/seqlock.h b/seqlock/seqlock.h
index c5a965cb8243bbb191ebe0620a72bdc50c0e4105..73e471f350618e6310e9eb8cea8e942a0802c0ea 100644 (file)
--- a/seqlock/seqlock.h
+++ b/seqlock/seqlock.h
@@ -1,5 +1,6 @@
 #include <stdatomic.h>
 #include <threads.h>
+#include "common.h"
 
 typedef struct seqlock {
        // Sequence for reader consistency check
@@ -25,14 +26,16 @@ typedef struct seqlock {
        }
        
        void write(int new_data) {
-               int old_seq = _seq.load(memory_order_acquire); // acquire
                while (true) {
+                       // #1: either here or #2 must be acquire
+                       int old_seq = _seq.load(memory_order_acquire); // acquire
                        // This might be a relaxed too
                        if (old_seq % 2 == 1)
                                continue; // Retry
 
+                       // #2
                        if (_seq.compare_exchange_strong(old_seq, old_seq + 1,
-                               memory_order_acq_rel, memory_order_acquire)) 
+                               memory_order_relaxed, memory_order_relaxed)) 
                                break;
                }