X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=lib%2Feal%2Ffreebsd%2Feal_thread.c;h=3b18030d735bf5df340d6ddc01494b3ffd01a8be;hb=4042dc2037a1509596f7eb48370185434bad39cc;hp=bbc3a8e985730846b5bdd77044f08365e2621ad2;hpb=33969e9c61385fc397f1934324e231ece9750404;p=dpdk.git

diff --git a/lib/eal/freebsd/eal_thread.c b/lib/eal/freebsd/eal_thread.c
index bbc3a8e985..3b18030d73 100644
--- a/lib/eal/freebsd/eal_thread.c
+++ b/lib/eal/freebsd/eal_thread.c
@@ -28,7 +28,7 @@
 /*
  * Send a message to a worker lcore identified by worker_id to call a
  * function f with argument arg. Once the execution is done, the
- * remote lcore switch in FINISHED state.
+ * remote lcore switches to WAIT state.
  */
 int
 rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned worker_id)
@@ -39,11 +39,19 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned worker_id)
 	int w2m = lcore_config[worker_id].pipe_worker2main[0];
 	int rc = -EBUSY;
 
-	if (lcore_config[worker_id].state != WAIT)
+	/* Check if the worker is in 'WAIT' state. Use acquire order
+	 * since 'state' variable is used as the guard variable.
+	 */
+	if (__atomic_load_n(&lcore_config[worker_id].state,
+					__ATOMIC_ACQUIRE) != WAIT)
 		goto finish;
 
-	lcore_config[worker_id].f = f;
 	lcore_config[worker_id].arg = arg;
+	/* Ensure that all the memory operations are completed
+	 * before the worker thread starts running the function.
+	 * Use worker thread function as the guard variable.
+	 */
+	__atomic_store_n(&lcore_config[worker_id].f, f, __ATOMIC_RELEASE);
 
 	/* send message */
 	n = 0;
@@ -100,6 +108,7 @@ eal_thread_loop(__rte_unused void *arg)
 
 	/* read on our pipe to get commands */
 	while (1) {
+		lcore_function_t *f;
 		void *fct_arg;
 
 		/* wait command */
@@ -110,7 +119,11 @@ eal_thread_loop(__rte_unused void *arg)
 		if (n <= 0)
 			rte_panic("cannot read on configuration pipe\n");
 
-		lcore_config[lcore_id].state = RUNNING;
+		/* Set the state to 'RUNNING'. Use release order
+		 * since 'state' variable is used as the guard variable.
+		 */
+		__atomic_store_n(&lcore_config[lcore_id].state, RUNNING,
+					__ATOMIC_RELEASE);
 
 		/* send ack */
 		n = 0;
@@ -119,17 +132,29 @@ eal_thread_loop(__rte_unused void *arg)
 		if (n < 0)
 			rte_panic("cannot write on configuration pipe\n");
 
-		if (lcore_config[lcore_id].f == NULL)
-			rte_panic("NULL function pointer\n");
+		/* Load 'f' with acquire order to ensure that
+		 * the memory operations from the main thread
+		 * are accessed only after update to 'f' is visible.
+		 * Wait till the update to 'f' is visible to the worker.
+		 */
+		while ((f = __atomic_load_n(&lcore_config[lcore_id].f,
+			__ATOMIC_ACQUIRE)) == NULL)
+			rte_pause();
 
 		/* call the function and store the return value */
 		fct_arg = lcore_config[lcore_id].arg;
-		ret = lcore_config[lcore_id].f(fct_arg);
+		ret = f(fct_arg);
 		lcore_config[lcore_id].ret = ret;
 		lcore_config[lcore_id].f = NULL;
 		lcore_config[lcore_id].arg = NULL;
-		rte_wmb();
-		lcore_config[lcore_id].state = FINISHED;
+
+		/* Store the state with release order to ensure that
+		 * the memory operations from the worker thread
+		 * are completed before the state is updated.
+		 * Use 'state' as the guard variable.
+		 */
+		__atomic_store_n(&lcore_config[lcore_id].state, WAIT,
+					__ATOMIC_RELEASE);
 	}
 
 	/* never reached */