urcu-bp: move quiescent threads to separate list

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

diff --git a/urcu/static/urcu-bp.h b/urcu/static/urcu-bp.h
index c52a68870dbadfb9c45ca2e688a5e45d39d25f3c..c7f532640e3c0feab165cb5a699c4c3760df011d 100644 (file)
--- a/urcu/static/urcu-bp.h
+++ b/urcu/static/urcu-bp.h
@@ -58,6 +58,12 @@ extern "C" {
 #define rcu_assert(args...)
 #endif
 
+enum rcu_state {
+       RCU_READER_ACTIVE_CURRENT,
+       RCU_READER_ACTIVE_OLD,
+       RCU_READER_INACTIVE,
+};
+
 #ifdef DEBUG_YIELD
 #include <sched.h>
 #include <time.h>
@@ -129,11 +135,11 @@ extern void rcu_bp_register(void);
  * Using a int rather than a char to eliminate false register dependencies
  * causing stalls on some architectures.
  */
-extern long rcu_gp_ctr;
+extern unsigned long rcu_gp_ctr;
 
 struct rcu_reader {
        /* Data used by both reader and synchronize_rcu() */
-       long ctr;
+       unsigned long ctr;
        /* Data used for registry */
        struct cds_list_head node __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
        pthread_t tid;
@@ -147,19 +153,22 @@ struct rcu_reader {
  */
 extern DECLARE_URCU_TLS(struct rcu_reader *, rcu_reader);
 
-static inline int rcu_old_gp_ongoing(long *value)
+static inline enum rcu_state rcu_reader_state(unsigned long *ctr)
 {
-       long v;
+       unsigned long v;
 
-       if (value == NULL)
-               return 0;
+       if (ctr == NULL)
+               return RCU_READER_INACTIVE;
        /*
         * Make sure both tests below are done on the same version of *value
         * to insure consistency.
         */
-       v = CMM_LOAD_SHARED(*value);
-       return (v & RCU_GP_CTR_NEST_MASK) &&
-                ((v ^ rcu_gp_ctr) & RCU_GP_CTR_PHASE);
+       v = CMM_LOAD_SHARED(*ctr);
+       if (!(v & RCU_GP_CTR_NEST_MASK))
+               return RCU_READER_INACTIVE;
+       if (!((v ^ rcu_gp_ctr) & RCU_GP_CTR_PHASE))
+               return RCU_READER_ACTIVE_CURRENT;
+       return RCU_READER_ACTIVE_OLD;
 }
 
 /*
@@ -190,7 +199,7 @@ static inline void _rcu_read_lock_update(unsigned long tmp)
  */
 static inline void _rcu_read_lock(void)
 {
-       long tmp;
+       unsigned long tmp;
 
        if (caa_unlikely(!URCU_TLS(rcu_reader)))
                rcu_bp_register(); /* If not yet registered. */