X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu.c;h=83d2fe4d6d9c367796d123fb05286f8305dfc332;hp=c55a5a2be9395ad691876e8e1b58d787729207d4;hb=9d335088c7c7eb6219e32ec9426d336f3a211a77;hpb=f69f195a06af55b7501ed2f59ed719970727ce5b

diff --git a/urcu.c b/urcu.c
index c55a5a2..83d2fe4 100644
--- a/urcu.c
+++ b/urcu.c
@@ -1,3 +1,13 @@
+/*
+ * urcu.c
+ *
+ * Userspace RCU library
+ *
+ * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * Distributed under GPLv2
+ */
+
 #include <stdio.h>
 #include <pthread.h>
 #include <signal.h>
@@ -22,10 +32,36 @@ struct reader_data {
 	int *urcu_active_readers;
 };
 
+#ifdef DEBUG_YIELD
+unsigned int yield_active;
+unsigned int __thread rand_yield;
+#endif
+
 static struct reader_data *reader_data;
 static int num_readers, alloc_readers;
 static int sig_done;
 
+void internal_urcu_lock(void)
+{
+	int ret;
+	ret = pthread_mutex_lock(&urcu_mutex);
+	if (ret) {
+		perror("Error in pthread mutex lock");
+		exit(-1);
+	}
+}
+
+void internal_urcu_unlock(void)
+{
+	int ret;
+
+	ret = pthread_mutex_unlock(&urcu_mutex);
+	if (ret) {
+		perror("Error in pthread mutex unlock");
+		exit(-1);
+	}
+}
+
 /*
  * called with urcu_mutex held.
  */
@@ -45,17 +81,24 @@ static void force_mb_all_threads(void)
 	 */
 	if (!reader_data)
 		return;
+	debug_yield_write();
 	sig_done = 0;
+	debug_yield_write();
 	mb();	/* write sig_done before sending the signals */
-	for (index = reader_data; index < reader_data + num_readers; index++)
+	debug_yield_write();
+	for (index = reader_data; index < reader_data + num_readers; index++) {
 		pthread_kill(index->tid, SIGURCU);
+		debug_yield_write();
+	}
 	/*
 	 * Wait for sighandler (and thus mb()) to execute on every thread.
 	 * BUSY-LOOP.
 	 */
 	while (sig_done < num_readers)
 		barrier();
+	debug_yield_write();
 	mb();	/* read sig_done before ending the barrier */
+	debug_yield_write();
 }
 
 void wait_for_quiescent_state(int parity)
@@ -70,7 +113,7 @@ void wait_for_quiescent_state(int parity)
 		/*
 		 * BUSY-LOOP.
 		 */
-		while (*index->urcu_active_readers != 0)
+		while (index->urcu_active_readers[parity] != 0)
 			barrier();
 	}
 	/*
@@ -82,20 +125,47 @@ void wait_for_quiescent_state(int parity)
 	force_mb_all_threads();
 }
 
+static void switch_qparity(void)
+{
+	int prev_parity;
+
+	/* All threads should read qparity before accessing data structure. */
+	/* Write ptr before changing the qparity */
+	force_mb_all_threads();
+	debug_yield_write();
+	prev_parity = switch_next_urcu_qparity();
+	debug_yield_write();
+
+	/*
+	 * Wait for previous parity to be empty of readers.
+	 */
+	wait_for_quiescent_state(prev_parity);
+}
+
+void synchronize_rcu(void)
+{
+	debug_yield_write();
+	internal_urcu_lock();
+	debug_yield_write();
+	switch_qparity();
+	debug_yield_write();
+	switch_qparity();
+	debug_yield_write();
+	internal_urcu_lock();
+	debug_yield_write();
+}
+
 /*
  * Return old pointer, OK to free, no more reference exist.
+ * Called under rcu_write_lock.
  */
 void *urcu_publish_content(void **ptr, void *new)
 {
-	int ret, prev_parity;
 	void *oldptr;
 
-	ret = pthread_mutex_lock(&urcu_mutex);
-	if (ret) {
-		perror("Error in pthread mutex lock");
-		exit(-1);
-	}
-
+	debug_yield_write();
+	internal_urcu_lock();
+	debug_yield_write();
 	/*
 	 * We can publish the new pointer before we change the current qparity.
 	 * Readers seeing the new pointer while being in the previous qparity
@@ -107,25 +177,17 @@ void *urcu_publish_content(void **ptr, void *new)
 	 * when the next quiescent state window will be over.
 	 */
 	oldptr = *ptr;
+	debug_yield_write();
 	*ptr = new;
-	wmb();		/* Write ptr before changing the qparity */
-	/* All threads should read qparity before ptr */
-	force_mb_all_threads();
-	prev_parity = switch_next_urcu_qparity();
 
-	/*
-	 * Wait for previous parity to be empty of readers.
-	 */
-	wait_for_quiescent_state(prev_parity);
-	/*
-	 * Deleting old data is ok !
-	 */
-	
-	ret = pthread_mutex_unlock(&urcu_mutex);
-	if (ret) {
-		perror("Error in pthread mutex lock");
-		exit(-1);
-	}
+	debug_yield_write();
+	switch_qparity();
+	debug_yield_write();
+	switch_qparity();
+	debug_yield_write();
+	internal_urcu_unlock();
+	debug_yield_write();
+
 	return oldptr;
 }
 
@@ -164,7 +226,7 @@ void urcu_remove_reader(pthread_t id)
 
 	assert(reader_data != NULL);
 	for (index = reader_data; index < reader_data + num_readers; index++) {
-		if (index->tid == id) {
+		if (pthread_equal(index->tid, id)) {
 			memcpy(index, &reader_data[num_readers - 1],
 				sizeof(struct reader_data));
 			reader_data[num_readers - 1].tid = 0;
@@ -179,44 +241,16 @@ void urcu_remove_reader(pthread_t id)
 
 void urcu_register_thread(void)
 {
-	pthread_t self = pthread_self();
-	int ret;
-
-	ret = pthread_mutex_lock(&urcu_mutex);
-	if (ret) {
-		perror("Error in pthread mutex lock");
-		exit(-1);
-	}
-
-	urcu_add_reader(self);
-
-
-	ret = pthread_mutex_unlock(&urcu_mutex);
-	if (ret) {
-		perror("Error in pthread mutex unlock");
-		exit(-1);
-	}
+	internal_urcu_lock();
+	urcu_add_reader(pthread_self());
+	internal_urcu_unlock();
 }
 
 void urcu_unregister_thread(void)
 {
-	pthread_t self = pthread_self();
-	int ret;
-
-	ret = pthread_mutex_lock(&urcu_mutex);
-	if (ret) {
-		perror("Error in pthread mutex lock");
-		exit(-1);
-	}
-
-	urcu_remove_reader(self);
-
-	ret = pthread_mutex_unlock(&urcu_mutex);
-	if (ret) {
-		perror("Error in pthread mutex unlock");
-		exit(-1);
-	}
-
+	internal_urcu_lock();
+	urcu_remove_reader(pthread_self());
+	internal_urcu_unlock();
 }
 
 void sigurcu_handler(int signo, siginfo_t *siginfo, void *context)