X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=urcu.c;h=23a985b9f9f4cdaf992c227322720e38bc139d85;hb=e462817ecdce42b00f0cb0825e2425b08943105b;hp=232a57bb718fbf12be651cebd6a808b01976c924;hpb=f858d07ab45c9a50e458cdcc9d5b26cbaa765de3;p=urcu.git

diff --git a/urcu.c b/urcu.c
index 232a57b..23a985b 100644
--- a/urcu.c
+++ b/urcu.c
@@ -19,10 +19,10 @@
 
 pthread_mutex_t urcu_mutex = PTHREAD_MUTEX_INITIALIZER;
 
-/* Global quiescent period parity */
-int urcu_qparity;
+/* Global grace period counter */
+int urcu_gp_ctr;
 
-int __thread urcu_active_readers[2];
+int __thread urcu_active_readers;
 
 /* Thread IDs of registered readers */
 #define INIT_NUM_THREADS 4
@@ -32,11 +32,16 @@ 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 rcu_write_lock(void)
+void internal_urcu_lock(void)
 {
 	int ret;
 	ret = pthread_mutex_lock(&urcu_mutex);
@@ -46,7 +51,7 @@ void rcu_write_lock(void)
 	}
 }
 
-void rcu_write_unlock(void)
+void internal_urcu_unlock(void)
 {
 	int ret;
 
@@ -60,11 +65,9 @@ void rcu_write_unlock(void)
 /*
  * called with urcu_mutex held.
  */
-static int switch_next_urcu_qparity(void)
+static void switch_next_urcu_qparity(void)
 {
-	int old_parity = urcu_qparity;
-	urcu_qparity = 1 - old_parity;
-	return old_parity;
+	urcu_gp_ctr ^= RCU_GP_CTR_BIT;
 }
 
 static void force_mb_all_threads(void)
@@ -76,20 +79,27 @@ 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)
+void wait_for_quiescent_state(void)
 {
 	struct reader_data *index;
 
@@ -101,7 +111,7 @@ void wait_for_quiescent_state(int parity)
 		/*
 		 * BUSY-LOOP.
 		 */
-		while (index->urcu_active_readers[parity] != 0)
+		while (rcu_old_gp_ongoing(index->urcu_active_readers))
 			barrier();
 	}
 	/*
@@ -113,15 +123,45 @@ void wait_for_quiescent_state(int parity)
 	force_mb_all_threads();
 }
 
+static void switch_qparity(void)
+{
+	/* All threads should read qparity before accessing data structure. */
+	/* Write ptr before changing the qparity */
+	force_mb_all_threads();
+	debug_yield_write();
+	switch_next_urcu_qparity();
+	debug_yield_write();
+
+	/*
+	 * Wait for previous parity to be empty of readers.
+	 */
+	wait_for_quiescent_state();
+}
+
+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;
 
+	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
@@ -133,20 +173,17 @@ void *urcu_publish_content(void **ptr, void *new)
 	 * when the next quiescent state window will be over.
 	 */
 	oldptr = *ptr;
-	*ptr = new;
-	/* All threads should read qparity before ptr */
-	/* Write ptr before changing the qparity */
-	force_mb_all_threads();
-	prev_parity = switch_next_urcu_qparity();
+	debug_yield_write();
+	rcu_assign_pointer(*ptr, new);
+
+	debug_yield_write();
+	switch_qparity();
+	debug_yield_write();
+	switch_qparity();
+	debug_yield_write();
+	internal_urcu_unlock();
+	debug_yield_write();
 
-	/*
-	 * Wait for previous parity to be empty of readers.
-	 */
-	wait_for_quiescent_state(prev_parity);
-	/*
-	 * Deleting old data is ok !
-	 */
-	
 	return oldptr;
 }
 
@@ -171,7 +208,7 @@ void urcu_add_reader(pthread_t id)
 	}
 	reader_data[num_readers].tid = id;
 	/* reference to the TLS of _this_ reader thread. */
-	reader_data[num_readers].urcu_active_readers = urcu_active_readers;
+	reader_data[num_readers].urcu_active_readers = &urcu_active_readers;
 	num_readers++;
 }
 
@@ -185,7 +222,7 @@ 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;
@@ -200,17 +237,16 @@ void urcu_remove_reader(pthread_t id)
 
 void urcu_register_thread(void)
 {
-	rcu_write_lock();
+	internal_urcu_lock();
 	urcu_add_reader(pthread_self());
-	rcu_write_unlock();
+	internal_urcu_unlock();
 }
 
 void urcu_unregister_thread(void)
 {
-	pthread_t self = pthread_self();
-	rcu_write_lock();
+	internal_urcu_lock();
 	urcu_remove_reader(pthread_self());
-	rcu_write_unlock();
+	internal_urcu_unlock();
 }
 
 void sigurcu_handler(int signo, siginfo_t *siginfo, void *context)