Ensure that the memory operations in worker thread, that happen
before it returns the status of the assigned function, are
visible to the main thread.
Signed-off-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
---
lib/librte_eal/common/eal_common_launch.c | 8 ++++----
lib/librte_eal/freebsd/eal_thread.c | 10 ++++++++--
lib/librte_eal/linux/eal_thread.c | 17 ++++++++++++-----
lib/librte_eal/windows/eal_thread.c | 9 +++++++--
4 files changed, 31 insertions(+), 13 deletions(-)
diff --git a/lib/librte_eal/common/eal_common_launch.c
b/lib/librte_eal/common/eal_common_launch.c
index 78fd94026..9cc71801a 100644
--- a/lib/librte_eal/common/eal_common_launch.c
+++ b/lib/librte_eal/common/eal_common_launch.c
@@ -23,14 +23,14 @@
int
rte_eal_wait_lcore(unsigned worker_id)
{
- if (lcore_config[worker_id].state == WAIT)
+ if (__atomic_load_n(&lcore_config[worker_id].state,
+ __ATOMIC_ACQUIRE) == WAIT)
return 0;
- while (lcore_config[worker_id].state != WAIT)
+ while (__atomic_load_n(&lcore_config[worker_id].state,
+ __ATOMIC_ACQUIRE) != WAIT)
rte_pause();
- rte_rmb();
-
return lcore_config[worker_id].ret;
}
diff --git a/lib/librte_eal/freebsd/eal_thread.c
b/lib/librte_eal/freebsd/eal_thread.c
index 6d6f1e2fd..58c8502de 100644
--- a/lib/librte_eal/freebsd/eal_thread.c
+++ b/lib/librte_eal/freebsd/eal_thread.c
@@ -139,8 +139,14 @@ eal_thread_loop(__rte_unused void *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 = WAIT;
+
+ /* 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 */
diff --git a/lib/librte_eal/linux/eal_thread.c
b/lib/librte_eal/linux/eal_thread.c
index 7b9463df3..eab6fa652 100644
--- a/lib/librte_eal/linux/eal_thread.c
+++ b/lib/librte_eal/linux/eal_thread.c
@@ -39,13 +39,14 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned
int worker_id)
int w2m = lcore_config[worker_id].pipe_worker2main[0];
int rc = -EBUSY;
- if (lcore_config[worker_id].state != WAIT)
+ if (__atomic_load_n(&lcore_config[worker_id].state,
+ __ATOMIC_ACQUIRE) != WAIT)
goto finish;
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.
+ * Use worker thread function pointer as the guard variable.
*/
__atomic_store_n(&lcore_config[worker_id].f, f, __ATOMIC_RELEASE);
@@ -115,7 +116,8 @@ eal_thread_loop(__rte_unused void *arg)
if (n <= 0)
rte_panic("cannot read on configuration pipe\n");
- lcore_config[lcore_id].state = RUNNING;
+ __atomic_store_n(&lcore_config[lcore_id].state, RUNNING,
+ __ATOMIC_RELEASE);
/* send ack */
n = 0;
@@ -139,9 +141,14 @@ eal_thread_loop(__rte_unused void *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 = WAIT;
+ /* 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 */
diff --git a/lib/librte_eal/windows/eal_thread.c
b/lib/librte_eal/windows/eal_thread.c
index 35d059a30..fb1ec4b4f 100644
--- a/lib/librte_eal/windows/eal_thread.c
+++ b/lib/librte_eal/windows/eal_thread.c
@@ -123,9 +123,14 @@ eal_thread_loop(void *arg __rte_unused)
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 = WAIT;
+ /* 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);
}
}
--
2.17.1
