sync_core to smp_mb transition

[urcu.git] / urcu.c

diff --git a/urcu.c b/urcu.c
index 2a225c4ed19d4c626b8f7fb9af5efa702bf3f371..b71e162b3fca1e29f83e02b6cd405e68b154147e 100644 (file)
--- a/urcu.c
+++ b/urcu.c
@@ -254,12 +254,11 @@ void synchronize_rcu(void)
         */
 
        /*
-        * Current RCU formal verification model assumes sequential execution of
-        * the write-side. Add core synchronization instructions. Can be removed
-        * if the formal model is extended to prove that reordering is still
-        * correct.
+        * Adding a smp_mb() which is _not_ formally required, but makes the
+        * model easier to understand. It does not have a big performance impact
+        * anyway, given this is the write-side.
         */
-       sync_core();    /* Formal model assumes serialized execution */
+       smp_mb();
 
        /*
         * Wait for previous parity to be empty of readers.
@@ -274,7 +273,12 @@ void synchronize_rcu(void)
         * Ensured by STORE_SHARED and LOAD_SHARED.
         */
 
-       sync_core();    /* Formal model assumes serialized execution */
+       /*
+        * Adding a smp_mb() which is _not_ formally required, but makes the
+        * model easier to understand. It does not have a big performance impact
+        * anyway, given this is the write-side.
+        */
+       smp_mb();
 
        switch_next_urcu_qparity();     /* 1 -> 0 */
 
@@ -286,7 +290,12 @@ void synchronize_rcu(void)
         * Ensured by STORE_SHARED and LOAD_SHARED.
         */
 
-       sync_core();    /* Formal model assumes serialized execution */
+       /*
+        * Adding a smp_mb() which is _not_ formally required, but makes the
+        * model easier to understand. It does not have a big performance impact
+        * anyway, given this is the write-side.
+        */
+       smp_mb();
 
        /*
         * Wait for previous parity to be empty of readers.