X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu.h;h=03764ab33dbe241b643b72ef9cbfd6757662fa3b;hp=2e8c0424abb0d413b6a64035ba05acced231d253;hb=bb48818526ec4317f9e6daeb0aa1cd64d528f754;hpb=581a270d427d9598c06a4da9ae7f9a9fc5354ec0

diff --git a/urcu.h b/urcu.h
index 2e8c042..03764ab 100644
--- a/urcu.h
+++ b/urcu.h
@@ -121,10 +121,19 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
 #include <sched.h>
 #include <time.h>
 #include <pthread.h>
+#include <unistd.h>
 
 #define YIELD_READ 	(1 << 0)
 #define YIELD_WRITE	(1 << 1)
 
+/* Updates without DEBUG_FULL_MB are much slower. Account this in the delay */
+#ifdef DEBUG_FULL_MB
+/* maximum sleep delay, in us */
+#define MAX_SLEEP 50
+#else
+#define MAX_SLEEP 30000
+#endif
+
 extern unsigned int yield_active;
 extern unsigned int __thread rand_yield;
 
@@ -132,14 +141,14 @@ static inline void debug_yield_read(void)
 {
 	if (yield_active & YIELD_READ)
 		if (rand_r(&rand_yield) & 0x1)
-			sched_yield();
+			usleep(rand_r(&rand_yield) % MAX_SLEEP);
 }
 
 static inline void debug_yield_write(void)
 {
 	if (yield_active & YIELD_WRITE)
 		if (rand_r(&rand_yield) & 0x1)
-			sched_yield();
+			usleep(rand_r(&rand_yield) % MAX_SLEEP);
 }
 
 static inline void debug_yield_init(void)
@@ -161,12 +170,25 @@ static inline void debug_yield_init(void)
 }
 #endif
 
+#ifdef DEBUG_FULL_MB
+static inline void read_barrier()
+{
+	mb();
+}
+#else
+static inline void read_barrier()
+{
+	barrier();
+}
+#endif
+
 /*
- * Limiting the nesting level to 256 to keep instructions small in the read
- * fast-path.
+ * The trick here is that RCU_GP_CTR_BIT 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.
  */
-#define RCU_GP_COUNT		(1U << 0)
-#define RCU_GP_CTR_BIT		(1U << 8)
+#define RCU_GP_COUNT		(1UL << 0)
+/* Use the amount of bits equal to half of the architecture long size */
+#define RCU_GP_CTR_BIT		(1UL << (sizeof(long) << 2))
 #define RCU_GP_CTR_NEST_MASK	(RCU_GP_CTR_BIT - 1)
 
 /*
@@ -174,13 +196,13 @@ static inline void debug_yield_init(void)
  * Using a int rather than a char to eliminate false register dependencies
  * causing stalls on some architectures.
  */
-extern int urcu_gp_ctr;
+extern long urcu_gp_ctr;
 
-extern int __thread urcu_active_readers;
+extern long __thread urcu_active_readers;
 
-static inline int rcu_old_gp_ongoing(int *value)
+static inline int rcu_old_gp_ongoing(long *value)
 {
-	int v;
+	long v;
 
 	if (value == NULL)
 		return 0;
@@ -193,13 +215,14 @@ static inline int rcu_old_gp_ongoing(int *value)
 
 static inline void rcu_read_lock(void)
 {
-	int tmp;
+	long tmp;
 
 	debug_yield_read();
 	tmp = urcu_active_readers;
 	debug_yield_read();
+	/* urcu_gp_ctr = RCU_GP_COUNT | (~RCU_GP_CTR_BIT or RCU_GP_CTR_BIT) */
 	if (likely(!(tmp & RCU_GP_CTR_NEST_MASK)))
-		urcu_active_readers = urcu_gp_ctr + RCU_GP_COUNT;
+		urcu_active_readers = urcu_gp_ctr;
 	else
 		urcu_active_readers = tmp + RCU_GP_COUNT;
 	debug_yield_read();
@@ -207,14 +230,14 @@ static inline void rcu_read_lock(void)
 	 * Increment active readers count before accessing the pointer.
 	 * See force_mb_all_threads().
 	 */
-	barrier();
+	read_barrier();
 	debug_yield_read();
 }
 
 static inline void rcu_read_unlock(void)
 {
 	debug_yield_read();
-	barrier();
+	read_barrier();
 	debug_yield_read();
 	/*
 	 * Finish using rcu before decrementing the pointer.