Cleanup: remove trailing whitespaces at EOL

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

diff --git a/urcu/static/urcu-bp.h b/urcu/static/urcu-bp.h
index 2f365206afad6db4c561654109def617ef559ce5..6e52d84bafe84f75dfd45593a2b58cad6431bcd0 100644 (file)
--- a/urcu/static/urcu-bp.h
+++ b/urcu/static/urcu-bp.h
@@ -39,6 +39,7 @@
 #include <urcu/uatomic.h>
 #include <urcu/list.h>
 #include <urcu/tls-compat.h>
+#include <urcu/debug.h>
 
 /*
  * This code section can only be included in LGPL 2.1 compatible source code.
@@ -52,70 +53,12 @@
 extern "C" {
 #endif
 
-#ifdef DEBUG_RCU
-#define rcu_assert(args...)    assert(args)
-#else
-#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>
-#include <pthread.h>
-#include <unistd.h>
-
-#define RCU_YIELD_READ         (1 << 0)
-#define RCU_YIELD_WRITE        (1 << 1)
-
-/*
- * Updates without RCU_MB are much slower. Account this in
- * the delay.
- */
-/* maximum sleep delay, in us */
-#define MAX_SLEEP 50
-
-extern unsigned int rcu_yield_active;
-extern DECLARE_URCU_TLS(unsigned int, rcu_rand_yield);
-
-static inline void rcu_debug_yield_read(void)
-{
-       if (rcu_yield_active & RCU_YIELD_READ)
-               if (rand_r(&URCU_TLS(rcu_rand_yield)) & 0x1)
-                       usleep(rand_r(&URCU_TLS(rcu_rand_yield)) % MAX_SLEEP);
-}
-
-static inline void rcu_debug_yield_write(void)
-{
-       if (rcu_yield_active & RCU_YIELD_WRITE)
-               if (rand_r(&URCU_TLS(rcu_rand_yield)) & 0x1)
-                       usleep(rand_r(&URCU_TLS(rcu_rand_yield)) % MAX_SLEEP);
-}
-
-static inline void rcu_debug_yield_init(void)
-{
-       URCU_TLS(rcu_rand_yield) = time(NULL) ^ (unsigned long) pthread_self();
-}
-#else
-static inline void rcu_debug_yield_read(void)
-{
-}
-
-static inline void rcu_debug_yield_write(void)
-{
-}
-
-static inline void rcu_debug_yield_init(void)
-{
-
-}
-#endif
-
 /*
  * The trick here is that RCU_GP_CTR_PHASE must be a multiple of 8 so we can use a
  * full 8-bits, 16-bits or 32-bits bitmask for the lower order bits.
@@ -130,12 +73,18 @@ static inline void rcu_debug_yield_init(void)
  */
 extern void rcu_bp_register(void);
 
-/*
- * Global quiescent period counter with low-order bits unused.
- * Using a int rather than a char to eliminate false register dependencies
- * causing stalls on some architectures.
- */
-extern unsigned long rcu_gp_ctr;
+struct rcu_gp {
+       /*
+        * Global grace period counter.
+        * Contains the current RCU_GP_CTR_PHASE.
+        * Also has a RCU_GP_COUNT of 1, to accelerate the reader fast path.
+        * Written to only by writer with mutex taken.
+        * Read by both writer and readers.
+        */
+       unsigned long ctr;
+} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
+
+extern struct rcu_gp rcu_gp;
 
 struct rcu_reader {
        /* Data used by both reader and synchronize_rcu() */
@@ -153,6 +102,16 @@ struct rcu_reader {
  */
 extern DECLARE_URCU_TLS(struct rcu_reader *, rcu_reader);
 
+extern int urcu_bp_has_sys_membarrier;
+
+static inline void urcu_bp_smp_mb_slave(void)
+{
+       if (caa_likely(urcu_bp_has_sys_membarrier))
+               cmm_barrier();
+       else
+               cmm_smp_mb();
+}
+
 static inline enum rcu_state rcu_reader_state(unsigned long *ctr)
 {
        unsigned long v;
@@ -166,13 +125,13 @@ static inline enum rcu_state rcu_reader_state(unsigned long *ctr)
        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))
+       if (!((v ^ rcu_gp.ctr) & RCU_GP_CTR_PHASE))
                return RCU_READER_ACTIVE_CURRENT;
        return RCU_READER_ACTIVE_OLD;
 }
 
 /*
- * Helper for _rcu_read_lock().  The format of rcu_gp_ctr (as well as
+ * Helper for _rcu_read_lock().  The format of rcu_gp.ctr (as well as
  * the per-thread rcu_reader.ctr) has the upper bits containing a count of
  * _rcu_read_lock() nesting, and a lower-order bit that contains either zero
  * or RCU_GP_CTR_PHASE.  The smp_mb_slave() ensures that the accesses in
@@ -181,8 +140,8 @@ static inline enum rcu_state rcu_reader_state(unsigned long *ctr)
 static inline void _rcu_read_lock_update(unsigned long tmp)
 {
        if (caa_likely(!(tmp & RCU_GP_CTR_NEST_MASK))) {
-               _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, _CMM_LOAD_SHARED(rcu_gp_ctr));
-               cmm_smp_mb();
+               _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, _CMM_LOAD_SHARED(rcu_gp.ctr));
+               urcu_bp_smp_mb_slave();
        } else
                _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, tmp + RCU_GP_COUNT);
 }
@@ -205,6 +164,7 @@ static inline void _rcu_read_lock(void)
                rcu_bp_register(); /* If not yet registered. */
        cmm_barrier();  /* Ensure the compiler does not reorder us with mutex */
        tmp = URCU_TLS(rcu_reader)->ctr;
+       urcu_assert((tmp & RCU_GP_CTR_NEST_MASK) != RCU_GP_CTR_NEST_MASK);
        _rcu_read_lock_update(tmp);
 }
 
@@ -215,11 +175,13 @@ static inline void _rcu_read_lock(void)
  */
 static inline void _rcu_read_unlock(void)
 {
-       /*
-        * Finish using rcu before decrementing the pointer.
-        */
-       cmm_smp_mb();
-       _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, URCU_TLS(rcu_reader)->ctr - RCU_GP_COUNT);
+       unsigned long tmp;
+
+       tmp = URCU_TLS(rcu_reader)->ctr;
+       urcu_assert(tmp & RCU_GP_CTR_NEST_MASK);
+       /* Finish using rcu before decrementing the pointer. */
+       urcu_bp_smp_mb_slave();
+       _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, tmp - RCU_GP_COUNT);
        cmm_barrier();  /* Ensure the compiler does not reorder us with mutex */
 }
 
@@ -237,7 +199,7 @@ static inline int _rcu_read_ongoing(void)
        return URCU_TLS(rcu_reader)->ctr & RCU_GP_CTR_NEST_MASK;
 }
 
-#ifdef __cplusplus 
+#ifdef __cplusplus
 }
 #endif