};
static struct urcu_workqueue *cds_lfht_workqueue;
-static unsigned long cds_lfht_workqueue_user_count;
/*
* Mutex ensuring mutual exclusion between workqueue initialization and
*/
static int cds_lfht_workqueue_atfork_nesting;
+static void __attribute__((destructor)) cds_lfht_exit(void);
static void cds_lfht_init_worker(const struct rcu_flavor_struct *flavor);
-static void cds_lfht_fini_worker(const struct rcu_flavor_struct *flavor);
#ifdef CONFIG_CDS_LFHT_ITER_DEBUG
work[thread].len = partition_len;
work[thread].start = thread * partition_len;
work[thread].fct = fct;
- ret = pthread_create(&(work[thread].thread_id), ht->resize_attr,
+ ret = pthread_create(&(work[thread].thread_id),
+ ht->caller_resize_attr ? &ht->resize_attr : NULL,
partition_resize_thread, &work[thread]);
if (ret == EAGAIN) {
/*
ht->flags = flags;
ht->flavor = flavor;
- ht->resize_attr = attr;
+ ht->caller_resize_attr = attr;
+ if (attr)
+ ht->resize_attr = *attr;
alloc_split_items_count(ht);
/* this mutex should not nest in read-side C.S. */
pthread_mutex_init(&ht->resize_mutex, NULL);
return is_removed(CMM_LOAD_SHARED(node->next));
}
+static
+bool cds_lfht_is_empty(struct cds_lfht *ht)
+{
+ struct cds_lfht_node *node, *next;
+ bool empty = true;
+ bool was_online;
+
+ was_online = ht->flavor->read_ongoing();
+ if (!was_online) {
+ ht->flavor->thread_online();
+ ht->flavor->read_lock();
+ }
+ /* Check that the table is empty */
+ node = bucket_at(ht, 0);
+ do {
+ next = rcu_dereference(node->next);
+ if (!is_bucket(next)) {
+ empty = false;
+ break;
+ }
+ node = clear_flag(next);
+ } while (!is_end(node));
+ if (!was_online) {
+ ht->flavor->read_unlock();
+ ht->flavor->thread_offline();
+ }
+ return empty;
+}
+
static
int cds_lfht_delete_bucket(struct cds_lfht *ht)
{
return 0;
}
+static
+void do_auto_resize_destroy_cb(struct urcu_work *work)
+{
+ struct cds_lfht *ht = caa_container_of(work, struct cds_lfht, destroy_work);
+ int ret;
+
+ ht->flavor->register_thread();
+ ret = cds_lfht_delete_bucket(ht);
+ if (ret)
+ urcu_die(ret);
+ free_split_items_count(ht);
+ ret = pthread_mutex_destroy(&ht->resize_mutex);
+ if (ret)
+ urcu_die(ret);
+ ht->flavor->unregister_thread();
+ poison_free(ht);
+}
+
/*
* Should only be called when no more concurrent readers nor writers can
* possibly access the table.
int ret;
if (ht->flags & CDS_LFHT_AUTO_RESIZE) {
+ /*
+ * Perform error-checking for emptiness before queuing
+ * work, so we can return error to the caller. This runs
+ * concurrently with ongoing resize.
+ */
+ if (!cds_lfht_is_empty(ht))
+ return -EPERM;
/* Cancel ongoing resize operations. */
_CMM_STORE_SHARED(ht->in_progress_destroy, 1);
- /* Wait for in-flight resize operations to complete */
- urcu_workqueue_flush_queued_work(cds_lfht_workqueue);
+ if (attr) {
+ *attr = ht->caller_resize_attr;
+ ht->caller_resize_attr = NULL;
+ }
+ /*
+ * Queue destroy work after prior queued resize
+ * operations. Given there are no concurrent writers
+ * accessing the hash table at this point, no resize
+ * operations can be queued after this destroy work.
+ */
+ urcu_workqueue_queue_work(cds_lfht_workqueue,
+ &ht->destroy_work, do_auto_resize_destroy_cb);
+ return 0;
}
ret = cds_lfht_delete_bucket(ht);
if (ret)
return ret;
free_split_items_count(ht);
if (attr)
- *attr = ht->resize_attr;
+ *attr = ht->caller_resize_attr;
ret = pthread_mutex_destroy(&ht->resize_mutex);
if (ret)
ret = -EBUSY;
- if (ht->flags & CDS_LFHT_AUTO_RESIZE)
- cds_lfht_fini_worker(ht->flavor);
poison_free(ht);
return ret;
}
flavor->register_rculfhash_atfork(&cds_lfht_atfork);
mutex_lock(&cds_lfht_fork_mutex);
- if (cds_lfht_workqueue_user_count++)
- goto end;
- cds_lfht_workqueue = urcu_workqueue_create(0, -1, NULL,
- NULL, cds_lfht_worker_init, NULL, NULL, NULL, NULL, NULL);
-end:
+ if (!cds_lfht_workqueue)
+ cds_lfht_workqueue = urcu_workqueue_create(0, -1, NULL,
+ NULL, cds_lfht_worker_init, NULL, NULL, NULL, NULL, NULL);
mutex_unlock(&cds_lfht_fork_mutex);
}
-static void cds_lfht_fini_worker(const struct rcu_flavor_struct *flavor)
+static void cds_lfht_exit(void)
{
mutex_lock(&cds_lfht_fork_mutex);
- if (--cds_lfht_workqueue_user_count)
- goto end;
- urcu_workqueue_destroy(cds_lfht_workqueue);
- cds_lfht_workqueue = NULL;
-end:
+ if (cds_lfht_workqueue) {
+ urcu_workqueue_flush_queued_work(cds_lfht_workqueue);
+ urcu_workqueue_destroy(cds_lfht_workqueue);
+ cds_lfht_workqueue = NULL;
+ }
mutex_unlock(&cds_lfht_fork_mutex);
-
- flavor->unregister_rculfhash_atfork(&cds_lfht_atfork);
}
static struct call_rcu_data *default_call_rcu_data;
static struct urcu_atfork *registered_rculfhash_atfork;
-static unsigned long registered_rculfhash_atfork_refcount;
/*
* If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are
void urcu_register_rculfhash_atfork(struct urcu_atfork *atfork)
{
+ if (CMM_LOAD_SHARED(registered_rculfhash_atfork))
+ return;
call_rcu_lock(&call_rcu_mutex);
- if (registered_rculfhash_atfork_refcount++)
- goto end;
- registered_rculfhash_atfork = atfork;
-end:
+ if (!registered_rculfhash_atfork)
+ registered_rculfhash_atfork = atfork;
call_rcu_unlock(&call_rcu_mutex);
}
+/*
+ * This unregistration function is deprecated, meant only for internal
+ * use by rculfhash.
+ */
+__attribute__((noreturn))
void urcu_unregister_rculfhash_atfork(struct urcu_atfork *atfork __attribute__((unused)))
{
- call_rcu_lock(&call_rcu_mutex);
- if (--registered_rculfhash_atfork_refcount)
- goto end;
- registered_rculfhash_atfork = NULL;
-end:
- call_rcu_unlock(&call_rcu_mutex);
+ urcu_die(EPERM);
}
projects / urcu.git / commitdiff
