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eal: simplify control thread creation

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Remove the usage of pthread barrier and replace it with
synchronization using atomic variable.
This also removes the use of reference count required to synchronize
freeing the memory.

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Olivier Matz <olivier.matz@6wind.com>
This commit is contained in:
Honnappa Nagarahalli 2021-10-21 16:32:20 -05:00 committed by David Marchand
parent 8cb5d08db9
commit 705356f081
2 changed files with 48 additions and 46 deletions
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85
lib/eal/common/eal_common_thread.c
View File

@ -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;
/* 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);
}
pthread_barrier_wait(&params->configured);
ctrl_params_free(params);
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;

9
lib/eal/include/rte_lcore.h
View File

@ -405,10 +405,11 @@ rte_thread_unregister(void);
/**
* Create a control thread.
*
* Wrapper to pthread_create(), pthread_setname_np() and
* pthread_setaffinity_np(). The affinity of the new thread is based
* on the CPU affinity retrieved at the time rte_eal_init() was called,
* the dataplane and service lcores are then excluded.
* Creates a control thread with the given name and attributes. The
* affinity of the new thread is based on the CPU affinity retrieved
* at the time rte_eal_init() was called, the dataplane and service
* lcores are then excluded. If setting the name of the thread fails,
* the error is ignored and a debug message is logged.
*
* @param thread
* Filled with the thread id of the new created thread.