Ensure that the memory operations before the call to
rte_eal_remote_launch are visible to the worker thread.
Use the function pointer to execute in worker thread
as the guard variable.
Signed-off-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
Reviewed-by: Ola Liljedahl <ola.liljed...@arm.com>
Reviewed-by: Feifei Wang <feifei.w...@arm.com>
---
lib/eal/freebsd/eal_thread.c | 19 +++++++++++++++----
lib/eal/linux/eal_thread.c | 19 +++++++++++++++----
lib/eal/windows/eal_thread.c | 19 +++++++++++++++----
3 files changed, 45 insertions(+), 12 deletions(-)
diff --git a/lib/eal/freebsd/eal_thread.c b/lib/eal/freebsd/eal_thread.c
index bbc3a8e985..17b8f39966 100644
--- a/lib/eal/freebsd/eal_thread.c
+++ b/lib/eal/freebsd/eal_thread.c
@@ -42,8 +42,12 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned
worker_id)
if (lcore_config[worker_id].state != 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 +104,7 @@ 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 */
@@ -119,12 +124,18 @@ 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;
diff --git a/lib/eal/linux/eal_thread.c b/lib/eal/linux/eal_thread.c
index 8f3c0dafd6..a0a0091040 100644
--- a/lib/eal/linux/eal_thread.c
+++ b/lib/eal/linux/eal_thread.c
@@ -42,8 +42,12 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned
int worker_id)
if (lcore_config[worker_id].state != 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 +104,7 @@ 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 */
@@ -119,12 +124,18 @@ 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;
diff --git a/lib/eal/windows/eal_thread.c b/lib/eal/windows/eal_thread.c
index df1df5d02c..e08abcf21f 100644
--- a/lib/eal/windows/eal_thread.c
+++ b/lib/eal/windows/eal_thread.c
@@ -32,8 +32,12 @@ rte_eal_remote_launch(lcore_function_t *f, void *arg,
unsigned int worker_id)
if (lcore_config[worker_id].state != WAIT)
return -EBUSY;
- 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;
@@ -84,6 +88,7 @@ eal_thread_loop(void *arg __rte_unused)
/* read on our pipe to get commands */
while (1) {
+ lcore_function_t *f;
void *fct_arg;
/* wait command */
@@ -103,12 +108,18 @@ eal_thread_loop(void *arg __rte_unused)
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;
--
2.25.1
