#define _URCU_WFCQUEUE_STATIC_H
/*
- * wfcqueue-static.h
+ * urcu/static/wfcqueue.h
*
* Userspace RCU library - Concurrent Queue with Wait-Free Enqueue/Blocking Dequeue
*
* Waiting for enqueuer to complete enqueue and return the next node.
*/
static inline struct cds_wfcq_node *
-___cds_wfcq_node_sync_next(struct cds_wfcq_node *node)
+___cds_wfcq_node_sync_next(struct cds_wfcq_node *node, int blocking)
{
struct cds_wfcq_node *next;
int attempt = 0;
* Adaptative busy-looping waiting for enqueuer to complete enqueue.
*/
while ((next = CMM_LOAD_SHARED(node->next)) == NULL) {
+ if (!blocking)
+ return CDS_WFCQ_WOULDBLOCK;
if (++attempt >= WFCQ_ADAPT_ATTEMPTS) {
poll(NULL, 0, WFCQ_WAIT); /* Wait for 10ms */
attempt = 0;
return next;
}
-/*
- * __cds_wfcq_first_blocking: get first node of a queue, without dequeuing.
- *
- * Content written into the node before enqueue is guaranteed to be
- * consistent, but no other memory ordering is ensured.
- * Dequeue/splice/iteration mutual exclusion should be ensured by the
- * caller.
- *
- * Used by for-like iteration macros in urcu/wfqueue.h:
- * __cds_wfcq_for_each_blocking()
- * __cds_wfcq_for_each_blocking_safe()
- */
static inline struct cds_wfcq_node *
-___cds_wfcq_first_blocking(struct cds_wfcq_head *head,
- struct cds_wfcq_tail *tail)
+___cds_wfcq_first(struct cds_wfcq_head *head,
+ struct cds_wfcq_tail *tail,
+ int blocking)
{
struct cds_wfcq_node *node;
if (_cds_wfcq_empty(head, tail))
return NULL;
- node = ___cds_wfcq_node_sync_next(&head->node);
+ node = ___cds_wfcq_node_sync_next(&head->node, blocking);
/* Load head->node.next before loading node's content */
cmm_smp_read_barrier_depends();
return node;
}
/*
- * __cds_wfcq_next_blocking: get next node of a queue, without dequeuing.
+ * __cds_wfcq_first_blocking: get first node of a queue, without dequeuing.
*
* Content written into the node before enqueue is guaranteed to be
* consistent, but no other memory ordering is ensured.
* __cds_wfcq_for_each_blocking_safe()
*/
static inline struct cds_wfcq_node *
-___cds_wfcq_next_blocking(struct cds_wfcq_head *head,
+___cds_wfcq_first_blocking(struct cds_wfcq_head *head,
+ struct cds_wfcq_tail *tail)
+{
+ return ___cds_wfcq_first(head, tail, 1);
+}
+
+
+/*
+ * __cds_wfcq_first_nonblocking: get first node of a queue, without dequeuing.
+ *
+ * Same as __cds_wfcq_first_blocking, but returns CDS_WFCQ_WOULDBLOCK if
+ * it needs to block.
+ */
+static inline struct cds_wfcq_node *
+___cds_wfcq_first_nonblocking(struct cds_wfcq_head *head,
+ struct cds_wfcq_tail *tail)
+{
+ return ___cds_wfcq_first(head, tail, 0);
+}
+
+static inline struct cds_wfcq_node *
+___cds_wfcq_next(struct cds_wfcq_head *head,
struct cds_wfcq_tail *tail,
- struct cds_wfcq_node *node)
+ struct cds_wfcq_node *node,
+ int blocking)
{
struct cds_wfcq_node *next;
cmm_smp_rmb();
if (CMM_LOAD_SHARED(tail->p) == node)
return NULL;
- next = ___cds_wfcq_node_sync_next(node);
+ next = ___cds_wfcq_node_sync_next(node, blocking);
}
/* Load node->next before loading next's content */
cmm_smp_read_barrier_depends();
}
/*
- * __cds_wfcq_dequeue_blocking: dequeue a node from the queue.
+ * __cds_wfcq_next_blocking: get next node of a queue, without dequeuing.
*
* Content written into the node before enqueue is guaranteed to be
* consistent, but no other memory ordering is ensured.
- * It is valid to reuse and free a dequeued node immediately.
* Dequeue/splice/iteration mutual exclusion should be ensured by the
* caller.
+ *
+ * Used by for-like iteration macros in urcu/wfqueue.h:
+ * __cds_wfcq_for_each_blocking()
+ * __cds_wfcq_for_each_blocking_safe()
*/
static inline struct cds_wfcq_node *
-___cds_wfcq_dequeue_blocking(struct cds_wfcq_head *head,
- struct cds_wfcq_tail *tail)
+___cds_wfcq_next_blocking(struct cds_wfcq_head *head,
+ struct cds_wfcq_tail *tail,
+ struct cds_wfcq_node *node)
+{
+ return ___cds_wfcq_next(head, tail, node, 1);
+}
+
+/*
+ * __cds_wfcq_next_blocking: get next node of a queue, without dequeuing.
+ *
+ * Same as __cds_wfcq_next_blocking, but returns CDS_WFCQ_WOULDBLOCK if
+ * it needs to block.
+ */
+static inline struct cds_wfcq_node *
+___cds_wfcq_next_nonblocking(struct cds_wfcq_head *head,
+ struct cds_wfcq_tail *tail,
+ struct cds_wfcq_node *node)
+{
+ return ___cds_wfcq_next(head, tail, node, 0);
+}
+
+static inline struct cds_wfcq_node *
+___cds_wfcq_dequeue(struct cds_wfcq_head *head,
+ struct cds_wfcq_tail *tail,
+ int blocking)
{
struct cds_wfcq_node *node, *next;
if (_cds_wfcq_empty(head, tail))
return NULL;
- node = ___cds_wfcq_node_sync_next(&head->node);
+ node = ___cds_wfcq_node_sync_next(&head->node, blocking);
if ((next = CMM_LOAD_SHARED(node->next)) == NULL) {
/*
_cds_wfcq_node_init(&head->node);
if (uatomic_cmpxchg(&tail->p, node, &head->node) == node)
return node;
- next = ___cds_wfcq_node_sync_next(node);
+ next = ___cds_wfcq_node_sync_next(node, blocking);
}
/*
}
/*
- * __cds_wfcq_splice_blocking: enqueue all src_q nodes at the end of dest_q.
+ * __cds_wfcq_dequeue_blocking: dequeue a node from the queue.
*
- * Dequeue all nodes from src_q.
- * dest_q must be already initialized.
- * Dequeue/splice/iteration mutual exclusion for src_q should be ensured
- * by the caller.
+ * Content written into the node before enqueue is guaranteed to be
+ * consistent, but no other memory ordering is ensured.
+ * It is valid to reuse and free a dequeued node immediately.
+ * Dequeue/splice/iteration mutual exclusion should be ensured by the
+ * caller.
*/
-static inline void
-___cds_wfcq_splice_blocking(
+static inline struct cds_wfcq_node *
+___cds_wfcq_dequeue_blocking(struct cds_wfcq_head *head,
+ struct cds_wfcq_tail *tail)
+{
+ return ___cds_wfcq_dequeue(head, tail, 1);
+}
+
+/*
+ * __cds_wfcq_dequeue_nonblocking: dequeue a node from a wait-free queue.
+ *
+ * Same as __cds_wfcq_dequeue_blocking, but returns CDS_WFCQ_WOULDBLOCK
+ * if it needs to block.
+ */
+static inline struct cds_wfcq_node *
+___cds_wfcq_dequeue_nonblocking(struct cds_wfcq_head *head,
+ struct cds_wfcq_tail *tail)
+{
+ return ___cds_wfcq_dequeue(head, tail, 0);
+}
+
+static inline int
+___cds_wfcq_splice(
struct cds_wfcq_head *dest_q_head,
struct cds_wfcq_tail *dest_q_tail,
struct cds_wfcq_head *src_q_head,
- struct cds_wfcq_tail *src_q_tail)
+ struct cds_wfcq_tail *src_q_tail,
+ int blocking)
{
struct cds_wfcq_node *head, *tail;
if (_cds_wfcq_empty(src_q_head, src_q_tail))
- return;
+ return 0;
- head = ___cds_wfcq_node_sync_next(&src_q_head->node);
+ head = ___cds_wfcq_node_sync_next(&src_q_head->node, blocking);
+ if (head == CDS_WFCQ_WOULDBLOCK)
+ return -1;
_cds_wfcq_node_init(&src_q_head->node);
/*
* require mutual exclusion on dest_q (wait-free).
*/
___cds_wfcq_append(dest_q_head, dest_q_tail, head, tail);
+ return 0;
+}
+
+
+/*
+ * __cds_wfcq_splice_blocking: enqueue all src_q nodes at the end of dest_q.
+ *
+ * Dequeue all nodes from src_q.
+ * dest_q must be already initialized.
+ * Dequeue/splice/iteration mutual exclusion for src_q should be ensured
+ * by the caller.
+ */
+static inline void
+___cds_wfcq_splice_blocking(
+ struct cds_wfcq_head *dest_q_head,
+ struct cds_wfcq_tail *dest_q_tail,
+ struct cds_wfcq_head *src_q_head,
+ struct cds_wfcq_tail *src_q_tail)
+{
+ (void) ___cds_wfcq_splice(dest_q_head, dest_q_tail,
+ src_q_head, src_q_tail, 1);
+}
+
+/*
+ * __cds_wfcq_splice_nonblocking: enqueue all src_q nodes at the end of dest_q.
+ *
+ * Same as __cds_wfcq_splice_blocking, but returns nonzero if it needs to
+ * block.
+ */
+static inline int
+___cds_wfcq_splice_nonblocking(
+ struct cds_wfcq_head *dest_q_head,
+ struct cds_wfcq_tail *dest_q_tail,
+ struct cds_wfcq_head *src_q_head,
+ struct cds_wfcq_tail *src_q_tail)
+{
+ return ___cds_wfcq_splice(dest_q_head, dest_q_tail,
+ src_q_head, src_q_tail, 0);
}
/*
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