eal: simplify control thread creation

[dpdk.git] / lib / eal / common / eal_common_thread.c

diff --git a/lib/eal/common/eal_common_thread.c b/lib/eal/common/eal_common_thread.c
index 1a52f42..bb6fc80 100644 (file)
--- a/lib/eal/common/eal_common_thread.c
+++ b/lib/eal/common/eal_common_thread.c
@@ -166,38 +166,42 @@ __rte_thread_uninit(void)
        RTE_PER_LCORE(_lcore_id) = LCORE_ID_ANY;
 }
 
+enum __rte_ctrl_thread_status {
+       CTRL_THREAD_LAUNCHING, /* Yet to call pthread_create function */
+       CTRL_THREAD_RUNNING, /* Control thread is running successfully */
+       CTRL_THREAD_ERROR /* Control thread encountered an error */
+};
+
 struct rte_thread_ctrl_params {
        void *(*start_routine)(void *);
        void *arg;
-       pthread_barrier_t configured;
-       unsigned int refcnt;
+       int ret;
+       /* Control thread status.
+        * If the status is CTRL_THREAD_ERROR, 'ret' has the error code.
+        */
+       enum __rte_ctrl_thread_status ctrl_thread_status;
 };
 
-static void ctrl_params_free(struct rte_thread_ctrl_params *params)
-{
-       if (__atomic_sub_fetch(&params->refcnt, 1, __ATOMIC_ACQ_REL) == 0) {
-               (void)pthread_barrier_destroy(&params->configured);
-               free(params);
-       }
-}
-
 static void *ctrl_thread_init(void *arg)
 {
        struct internal_config *internal_conf =
                eal_get_internal_configuration();
        rte_cpuset_t *cpuset = &internal_conf->ctrl_cpuset;
        struct rte_thread_ctrl_params *params = arg;
-       void *(*start_routine)(void *);
+       void *(*start_routine)(void *) = params->start_routine;
        void *routine_arg = params->arg;
 
        __rte_thread_init(rte_lcore_id(), cpuset);
-
-       pthread_barrier_wait(&params->configured);
-       start_routine = params->start_routine;
-       ctrl_params_free(params);
-
-       if (start_routine == NULL)
+       params->ret = pthread_setaffinity_np(pthread_self(), sizeof(*cpuset),
+               cpuset);
+       if (params->ret != 0) {
+               __atomic_store_n(&params->ctrl_thread_status,
+                       CTRL_THREAD_ERROR, __ATOMIC_RELEASE);
                return NULL;
+       }
+
+       __atomic_store_n(&params->ctrl_thread_status,
+               CTRL_THREAD_RUNNING, __ATOMIC_RELEASE);
 
        return start_routine(routine_arg);
 }
@@ -207,10 +211,8 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
                const pthread_attr_t *attr,
                void *(*start_routine)(void *), void *arg)
 {
-       struct internal_config *internal_conf =
-               eal_get_internal_configuration();
-       rte_cpuset_t *cpuset = &internal_conf->ctrl_cpuset;
        struct rte_thread_ctrl_params *params;
+       enum __rte_ctrl_thread_status ctrl_thread_status;
        int ret;
 
        params = malloc(sizeof(*params));
@@ -219,15 +221,14 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
 
        params->start_routine = start_routine;
        params->arg = arg;
-       params->refcnt = 2;
-
-       ret = pthread_barrier_init(&params->configured, NULL, 2);
-       if (ret != 0)
-               goto fail_no_barrier;
+       params->ret = 0;
+       params->ctrl_thread_status = CTRL_THREAD_LAUNCHING;
 
        ret = pthread_create(thread, attr, ctrl_thread_init, (void *)params);
-       if (ret != 0)
-               goto fail_with_barrier;
+       if (ret != 0) {
+               free(params);
+               return -ret;
+       }
 
        if (name != NULL) {
                ret = rte_thread_setname(*thread, name);
@@ -236,24 +237,24 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
                                "Cannot set name for ctrl thread\n");
        }
 
-       ret = pthread_setaffinity_np(*thread, sizeof(*cpuset), cpuset);
-       if (ret != 0)
-               params->start_routine = NULL;
-
-       pthread_barrier_wait(&params->configured);
-       ctrl_params_free(params);
+       /* Wait for the control thread to initialize successfully */
+       while ((ctrl_thread_status =
+                       __atomic_load_n(&params->ctrl_thread_status,
+                       __ATOMIC_ACQUIRE)) == CTRL_THREAD_LAUNCHING) {
+               /* Yield the CPU. Using sched_yield call requires maintaining
+                * another implementation for Windows as sched_yield is not
+                * supported on Windows.
+                */
+               rte_delay_us_sleep(1);
+       }
 
-       if (ret != 0)
-               /* start_routine has been set to NULL above; */
-               /* ctrl thread will exit immediately */
+       /* Check if the control thread encountered an error */
+       if (ctrl_thread_status == CTRL_THREAD_ERROR) {
+               /* ctrl thread is exiting */
                pthread_join(*thread, NULL);
+       }
 
-       return -ret;
-
-fail_with_barrier:
-       (void)pthread_barrier_destroy(&params->configured);
-
-fail_no_barrier:
+       ret = params->ret;
        free(params);
 
        return -ret;