/*
* Broadcast a condition variable
*/
int lthread_cond_broadcast(struct lthread_cond *c)
{
struct lthread *lt;
if (c == NULL) {
DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, 0);
do {
/* drain the queue waking everybody */
lt = _lthread_queue_remove(c->blocked);
if (lt != NULL) {
DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, lt);
/* wake up */
_ready_queue_insert((struct lthread_sched *)lt->sched,
lt);
}
} while (!_lthread_queue_empty(c->blocked));
_reschedule();
DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, 0);
return 0;
}
/*
* Unlock a mutex
*/
int lthread_mutex_unlock(struct lthread_mutex *m)
{
struct lthread *lt = THIS_LTHREAD;
struct lthread *unblocked;
if ((m == NULL) || (m->blocked == NULL)) {
DIAG_EVENT(m, LT_DIAG_MUTEX_UNLOCKED, m, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
/* fail if its owned */
if (m->owner != lt || m->owner == NULL) {
DIAG_EVENT(m, LT_DIAG_MUTEX_UNLOCKED, m, POSIX_ERRNO(EPERM));
return POSIX_ERRNO(EPERM);
}
rte_atomic64_dec(&m->count);
/* if there are blocked threads then make one ready */
while (rte_atomic64_read(&m->count) > 0) {
unblocked = _lthread_queue_remove(m->blocked);
if (unblocked != NULL) {
rte_atomic64_dec(&m->count);
DIAG_EVENT(m, LT_DIAG_MUTEX_UNLOCKED, m, unblocked);
RTE_ASSERT(unblocked->sched != NULL);
_ready_queue_insert((struct lthread_sched *)
unblocked->sched, unblocked);
break;
}
}
/* release the lock */
m->owner = NULL;
return 0;
}
/* try to lock a mutex but don't block */
int lthread_mutex_trylock(struct lthread_mutex *m)
{
struct lthread *lt = THIS_LTHREAD;
if ((m == NULL) || (m->blocked == NULL)) {
DIAG_EVENT(m, LT_DIAG_MUTEX_TRYLOCK, m, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
if (m->owner == lt) {
/* no recursion */
DIAG_EVENT(m, LT_DIAG_MUTEX_TRYLOCK, m, POSIX_ERRNO(EDEADLK));
return POSIX_ERRNO(EDEADLK);
}
rte_atomic64_inc(&m->count);
if (rte_atomic64_cmpset
((uint64_t *) &m->owner, (uint64_t) NULL, (uint64_t) lt)) {
/* got the lock */
DIAG_EVENT(m, LT_DIAG_MUTEX_TRYLOCK, m, 0);
return 0;
}
/* failed so return busy */
rte_atomic64_dec(&m->count);
DIAG_EVENT(m, LT_DIAG_MUTEX_TRYLOCK, m, POSIX_ERRNO(EBUSY));
return POSIX_ERRNO(EBUSY);
}
/*
* Signal a condition variable
* attempt to resume any blocked thread
*/
int lthread_cond_signal(struct lthread_cond *c)
{
struct lthread *lt;
if (c == NULL) {
DIAG_EVENT(c, LT_DIAG_COND_SIGNAL, c, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
lt = _lthread_queue_remove(c->blocked);
if (lt != NULL) {
/* okay wake up this thread */
DIAG_EVENT(c, LT_DIAG_COND_SIGNAL, c, lt);
_ready_queue_insert((struct lthread_sched *)lt->sched, lt);
}
return 0;
}
/*
* Try to obtain a mutex
*/
int lthread_mutex_lock(struct lthread_mutex *m)
{
struct lthread *lt = THIS_LTHREAD;
if ((m == NULL) || (m->blocked == NULL)) {
DIAG_EVENT(m, LT_DIAG_MUTEX_LOCK, m, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
/* allow no recursion */
if (m->owner == lt) {
DIAG_EVENT(m, LT_DIAG_MUTEX_LOCK, m, POSIX_ERRNO(EDEADLK));
return POSIX_ERRNO(EDEADLK);
}
for (;;) {
rte_atomic64_inc(&m->count);
do {
if (rte_atomic64_cmpset
((uint64_t *) &m->owner, 0, (uint64_t) lt)) {
/* happy days, we got the lock */
DIAG_EVENT(m, LT_DIAG_MUTEX_LOCK, m, 0);
return 0;
}
/* spin due to race with unlock when
* nothing was blocked
*/
} while ((rte_atomic64_read(&m->count) == 1) &&
(m->owner == NULL));
/* queue the current thread in the blocked queue
* we defer this to after we return to the scheduler
* to ensure that the current thread context is saved
* before unlock could result in it being dequeued and
* resumed
*/
DIAG_EVENT(m, LT_DIAG_MUTEX_BLOCKED, m, lt);
lt->pending_wr_queue = m->blocked;
/* now relinquish cpu */
_suspend();
/* resumed, must loop and compete for the lock again */
}
return 0;
}
/*
* Destroy a condition variable
*/
int lthread_cond_destroy(struct lthread_cond *c)
{
if (c == NULL) {
DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
/* try to free it */
if (_lthread_queue_destroy(c->blocked) < 0) {
/* queue in use */
DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, POSIX_ERRNO(EBUSY));
return POSIX_ERRNO(EBUSY);
}
/* okay free it */
_lthread_objcache_free(c->root_sched->cond_cache, c);
DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, 0);
return 0;
}
/*
* Create a scheduler on the current lcore
*/
struct lthread_sched *_lthread_sched_create(size_t stack_size)
{
int status;
struct lthread_sched *new_sched;
unsigned lcoreid = rte_lcore_id();
RTE_ASSERT(stack_size <= LTHREAD_MAX_STACK_SIZE);
if (stack_size == 0)
stack_size = LTHREAD_MAX_STACK_SIZE;
new_sched =
rte_calloc_socket(NULL, 1, sizeof(struct lthread_sched),
RTE_CACHE_LINE_SIZE,
rte_socket_id());
if (new_sched == NULL) {
RTE_LOG(CRIT, LTHREAD,
"Failed to allocate memory for scheduler\n");
return NULL;
}
_lthread_key_pool_init();
new_sched->stack_size = stack_size;
new_sched->birth = rte_rdtsc();
THIS_SCHED = new_sched;
status = _lthread_sched_alloc_resources(new_sched);
if (status != SCHED_ALLOC_OK) {
RTE_LOG(CRIT, LTHREAD,
"Failed to allocate resources for scheduler code = %d\n",
status);
rte_free(new_sched);
return NULL;
}
bzero(&new_sched->ctx, sizeof(struct ctx));
new_sched->lcore_id = lcoreid;
schedcore[lcoreid] = new_sched;
new_sched->run_flag = 1;
DIAG_EVENT(new_sched, LT_DIAG_SCHED_CREATE, rte_lcore_id(), 0);
rte_wmb();
return new_sched;
}
/*
* Wait on a condition variable
*/
int lthread_cond_wait(struct lthread_cond *c, __rte_unused uint64_t reserved)
{
struct lthread *lt = THIS_LTHREAD;
if (c == NULL) {
DIAG_EVENT(c, LT_DIAG_COND_WAIT, c, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
DIAG_EVENT(c, LT_DIAG_COND_WAIT, c, 0);
/* queue the current thread in the blocked queue
* this will be written when we return to the scheduler
* to ensure that the current thread context is saved
* before any signal could result in it being dequeued and
* resumed
*/
lt->pending_wr_queue = c->blocked;
_suspend();
/* the condition happened */
return 0;
}
/*
* Destroy a mutex
*/
int lthread_mutex_destroy(struct lthread_mutex *m)
{
if ((m == NULL) || (m->blocked == NULL)) {
DIAG_EVENT(m, LT_DIAG_MUTEX_DESTROY, m, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
if (m->owner == NULL) {
/* try to delete the blocked queue */
if (_lthread_queue_destroy(m->blocked) < 0) {
DIAG_EVENT(m, LT_DIAG_MUTEX_DESTROY,
m, POSIX_ERRNO(EBUSY));
return POSIX_ERRNO(EBUSY);
}
/* free the mutex to cache */
_lthread_objcache_free(m->root_sched->mutex_cache, m);
DIAG_EVENT(m, LT_DIAG_MUTEX_DESTROY, m, 0);
return 0;
}
/* can't do its still in use */
DIAG_EVENT(m, LT_DIAG_MUTEX_DESTROY, m, POSIX_ERRNO(EBUSY));
return POSIX_ERRNO(EBUSY);
}
/*
* Handle sleep timer expiry
*/
void
_sched_timer_cb(struct rte_timer *tim, void *arg)
{
struct lthread *lt = (struct lthread *) arg;
uint64_t state = lt->state;
DIAG_EVENT(lt, LT_DIAG_LTHREAD_TMR_EXPIRED, <->tim, 0);
rte_timer_stop(tim);
if (lt->state & BIT(ST_LT_CANCELLED))
(THIS_SCHED)->nb_blocked_threads--;
lt->state = state | BIT(ST_LT_EXPIRED);
_lthread_resume(lt);
lt->state = state & CLEARBIT(ST_LT_EXPIRED);
}
/*
* migrate the current thread to another scheduler running
* on the specified lcore.
*/
int lthread_set_affinity(unsigned lcoreid)
{
struct lthread *lt = THIS_LTHREAD;
struct lthread_sched *dest_sched;
if (unlikely(lcoreid >= LTHREAD_MAX_LCORES))
return POSIX_ERRNO(EINVAL);
DIAG_EVENT(lt, LT_DIAG_LTHREAD_AFFINITY, lcoreid, 0);
dest_sched = schedcore[lcoreid];
if (unlikely(dest_sched == NULL))
return POSIX_ERRNO(EINVAL);
if (likely(dest_sched != THIS_SCHED)) {
lt->sched = dest_sched;
lt->pending_wr_queue = dest_sched->pready;
_affinitize();
return 0;
}
return 0;
}
static inline void _lthread_resume(struct lthread *lt)
{
struct lthread_sched *sched = THIS_SCHED;
struct lthread_stack *s;
uint64_t state = lt->state;
#if LTHREAD_DIAG
int init = 0;
#endif
sched->current_lthread = lt;
if (state & (BIT(ST_LT_CANCELLED) | BIT(ST_LT_EXITED))) {
/* if detached we can free the thread now */
if (state & BIT(ST_LT_DETACH)) {
_lthread_free(lt);
sched->current_lthread = NULL;
return;
}
}
if (state & BIT(ST_LT_INIT)) {
/* first time this thread has been run */
/* assign thread to this scheduler */
lt->sched = THIS_SCHED;
/* allocate stack */
s = _stack_alloc();
lt->stack_container = s;
_lthread_set_stack(lt, s->stack, s->stack_size);
/* allocate memory for TLS used by this thread */
_lthread_tls_alloc(lt);
lt->state = BIT(ST_LT_READY);
#if LTHREAD_DIAG
init = 1;
#endif
}
DIAG_EVENT(lt, LT_DIAG_LTHREAD_RESUMED, init, lt);
/* switch to the new thread */
ctx_switch(<->ctx, &sched->ctx);
/* If posting to a queue that could be read by another lcore
* we defer the queue write till now to ensure the context has been
* saved before the other core tries to resume it
* This applies to blocking on mutex, cond, and to set_affinity
*/
if (lt->pending_wr_queue != NULL) {
struct lthread_queue *dest = lt->pending_wr_queue;
lt->pending_wr_queue = NULL;
/* queue the current thread to the specified queue */
_lthread_queue_insert_mp(dest, lt);
}
sched->current_lthread = NULL;
}
