qsbr: micro optimization of the gp use.

[urcu.git] / urcu-qsbr-static.h

diff --git a/urcu-qsbr-static.h b/urcu-qsbr-static.h
index 752d4b9aced8630a94fca3bcf1e6338b012d0e36..8d8aa3f8f60519620dbcfb78aef1b007c6183e5c 100644 (file)
--- a/urcu-qsbr-static.h
+++ b/urcu-qsbr-static.h
@@ -171,10 +171,12 @@ extern long __thread rcu_reader_qs_gp;
 
 static inline int rcu_gp_ongoing(long *value)
 {
+       long reader_gp;
+
        if (value == NULL)
                return 0;
-
-       return LOAD_SHARED(*value) & 1;
+       reader_gp = LOAD_SHARED(*value);
+       return reader_gp && (reader_gp - urcu_gp_ctr < 0);
 }
 
 static inline void _rcu_read_lock(void)
@@ -189,19 +191,19 @@ static inline void _rcu_read_unlock(void)
 static inline void _rcu_quiescent_state(void)
 {
        smp_mb();       
-       rcu_reader_qs_gp = ACCESS_ONCE(urcu_gp_ctr) + 1;
+       _STORE_SHARED(rcu_reader_qs_gp, _LOAD_SHARED(urcu_gp_ctr));
        smp_mb();
 }
 
 static inline void _rcu_thread_offline(void)
 {
        smp_mb();
-       rcu_reader_qs_gp = ACCESS_ONCE(urcu_gp_ctr);
+       STORE_SHARED(rcu_reader_qs_gp, 0);
 }
 
 static inline void _rcu_thread_online(void)
 {
-       rcu_reader_qs_gp = ACCESS_ONCE(urcu_gp_ctr) + 1;
+       _STORE_SHARED(rcu_reader_qs_gp, LOAD_SHARED(urcu_gp_ctr));
        smp_mb();
 }