X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu-static.h;h=dce15b7122cad8c3c44c3d7881cf97b81c92fb3e;hp=d46613196f5d471b21e584a85c0eaa7f60154e18;hb=eaf2c3f4b9041d2a6a85d7f9e56f6014603367d4;hpb=9d7e3f89772f08cca26d727f47d44ecd47c94401

diff --git a/urcu-static.h b/urcu-static.h
index d466131..dce15b7 100644
--- a/urcu-static.h
+++ b/urcu-static.h
@@ -9,7 +9,7 @@
  * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See urcu.h for linking
  * dynamically with the userspace rcu library.
  *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
  *
  * This library is free software; you can redistribute it and/or
@@ -45,6 +45,27 @@
 extern "C" {
 #endif 
 
+/* Default is RCU_MEMBARRIER */
+#if !defined(RCU_MEMBARRIER) && !defined(RCU_MB) && !defined(RCU_SIGNAL)
+#define RCU_MEMBARRIER
+#endif
+
+#ifdef RCU_MEMBARRIER
+#include <unistd.h>
+#include <sys/syscall.h>
+
+/* If the headers do not support SYS_membarrier, statically use RCU_MB */
+#ifdef SYS_membarrier
+# define MEMBARRIER_EXPEDITED		(1 << 0)
+# define MEMBARRIER_DELAYED		(1 << 1)
+# define MEMBARRIER_QUERY		(1 << 16)
+# define membarrier(...)		syscall(SYS_membarrier, __VA_ARGS__)
+#else
+# undef RCU_MEMBARRIER
+# define RCU_MB
+#endif
+#endif
+
 /*
  * This code section can only be included in LGPL 2.1 compatible source code.
  * See below for the function call wrappers which can be used in code meant to
@@ -56,7 +77,12 @@ extern "C" {
 /*
  * The signal number used by the RCU library can be overridden with
  * -DSIGRCU= when compiling the library.
+ * Provide backward compatibility for liburcu 0.3.x SIGURCU.
  */
+#ifdef SIGURCU
+#define SIGRCU SIGURCU
+#endif
+
 #ifndef SIGRCU
 #define SIGRCU SIGUSR1
 #endif
@@ -89,14 +115,13 @@ extern "C" {
 #define YIELD_WRITE	(1 << 1)
 
 /*
- * Updates without RCU_MB are much slower. Account this in
- * the delay.
+ * Updates with RCU_SIGNAL are much slower. Account this in the delay.
  */
-#ifdef RCU_MB
+#ifdef RCU_SIGNAL
 /* maximum sleep delay, in us */
-#define MAX_SLEEP 50
-#else
 #define MAX_SLEEP 30000
+#else
+#define MAX_SLEEP 50
 #endif
 
 extern unsigned int yield_active;
@@ -135,13 +160,42 @@ static inline void debug_yield_init(void)
 }
 #endif
 
+/*
+ * RCU memory barrier broadcast group. Currently, only broadcast to all process
+ * threads is supported (group 0).
+ *
+ * Slave barriers are only guaranteed to be ordered wrt master barriers.
+ *
+ * The pair ordering is detailed as (O: ordered, X: not ordered) :
+ *               slave  master
+ *        slave    X      O
+ *        master   O      O
+ */
+
+#define MB_GROUP_ALL		0
+#define RCU_MB_GROUP		MB_GROUP_ALL
+
+#ifdef RCU_MEMBARRIER
+extern int has_sys_membarrier;
+
+static inline void smp_mb_slave(int group)
+{
+	if (likely(has_sys_membarrier))
+		barrier();
+	else
+		smp_mb();
+}
+#endif
+
 #ifdef RCU_MB
-static inline void smp_mb_light()
+static inline void smp_mb_slave(int group)
 {
 	smp_mb();
 }
-#else
-static inline void smp_mb_light()
+#endif
+
+#ifdef RCU_SIGNAL
+static inline void smp_mb_slave(int group)
 {
 	barrier();
 }
@@ -153,7 +207,7 @@ static inline void smp_mb_light()
  */
 #define RCU_GP_COUNT		(1UL << 0)
 /* Use the amount of bits equal to half of the architecture long size */
-#define RCU_GP_CTR_PHASE	(1UL << (sizeof(long) << 2))
+#define RCU_GP_CTR_PHASE	(1UL << (sizeof(unsigned long) << 2))
 #define RCU_GP_CTR_NEST_MASK	(RCU_GP_CTR_PHASE - 1)
 
 /*
@@ -161,14 +215,14 @@ static inline void smp_mb_light()
  * 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;
 	char need_mb;
 	/* Data used for registry */
-	struct list_head head __attribute__((aligned(CACHE_LINE_SIZE)));
+	struct list_head node __attribute__((aligned(CACHE_LINE_SIZE)));
 	pthread_t tid;
 };
 
@@ -188,24 +242,22 @@ static inline void wake_up_gp(void)
 	}
 }
 
-static inline int rcu_old_gp_ongoing(long *value)
+static inline int rcu_gp_ongoing(unsigned long *ctr)
 {
-	long v;
+	unsigned long v;
 
-	if (value == NULL)
-		return 0;
 	/*
 	 * Make sure both tests below are done on the same version of *value
 	 * to insure consistency.
 	 */
-	v = LOAD_SHARED(*value);
+	v = LOAD_SHARED(*ctr);
 	return (v & RCU_GP_CTR_NEST_MASK) &&
 		 ((v ^ rcu_gp_ctr) & RCU_GP_CTR_PHASE);
 }
 
 static inline void _rcu_read_lock(void)
 {
-	long tmp;
+	unsigned long tmp;
 
 	tmp = rcu_reader.ctr;
 	/*
@@ -216,9 +268,9 @@ static inline void _rcu_read_lock(void)
 		_STORE_SHARED(rcu_reader.ctr, _LOAD_SHARED(rcu_gp_ctr));
 		/*
 		 * Set active readers count for outermost nesting level before
-		 * accessing the pointer. See smp_mb_heavy().
+		 * accessing the pointer. See smp_mb_master().
 		 */
-		smp_mb_light();
+		smp_mb_slave(RCU_MB_GROUP);
 	} else {
 		_STORE_SHARED(rcu_reader.ctr, tmp + RCU_GP_COUNT);
 	}
@@ -226,25 +278,25 @@ static inline void _rcu_read_lock(void)
 
 static inline void _rcu_read_unlock(void)
 {
-	long tmp;
+	unsigned long tmp;
 
 	tmp = rcu_reader.ctr;
 	/*
 	 * Finish using rcu before decrementing the pointer.
-	 * See smp_mb_heavy().
+	 * See smp_mb_master().
 	 */
 	if (likely((tmp & RCU_GP_CTR_NEST_MASK) == RCU_GP_COUNT)) {
-		smp_mb_light();
+		smp_mb_slave(RCU_MB_GROUP);
 		_STORE_SHARED(rcu_reader.ctr, rcu_reader.ctr - RCU_GP_COUNT);
 		/* write rcu_reader.ctr before read futex */
-		smp_mb_light();
+		smp_mb_slave(RCU_MB_GROUP);
 		wake_up_gp();
 	} else {
 		_STORE_SHARED(rcu_reader.ctr, rcu_reader.ctr - RCU_GP_COUNT);
 	}
 }
 
-#ifdef __cplusplus 
+#ifdef __cplusplus
 }
 #endif