workqueue: only awaken a single sibling

[userspace-rcu.git] / urcu / workqueue-fifo.h

diff --git a/urcu/workqueue-fifo.h b/urcu/workqueue-fifo.h
index ffdb974bb5a720f317ff9e539e15fcfd31eef468..1d7528db7e1327b6507141f8f6fbfd992fca7571 100644 (file)
--- a/urcu/workqueue-fifo.h
+++ b/urcu/workqueue-fifo.h
@@ -220,17 +220,18 @@ int __urcu_steal_work(struct urcu_workqueue *queue,
 }
 
 static inline
-void ___urcu_wakeup_sibling(struct urcu_worker *sibling)
+bool ___urcu_wakeup_sibling(struct urcu_worker *sibling)
 {
-       urcu_adaptative_wake_up(&sibling->wait_node);
+       return urcu_adaptative_wake_up(&sibling->wait_node);
 }
 
 static inline
-void __urcu_wakeup_siblings(struct urcu_workqueue *queue,
+bool __urcu_wakeup_siblings(struct urcu_workqueue *queue,
                struct urcu_worker *worker)
 {
        struct urcu_worker *sibling_prev, *sibling_next;
        struct cds_list_head *sibling_node;
+       bool wakeup_performed = 0;
 
        if (!(worker->flags & URCU_WORKER_STEAL))
                return;
@@ -247,7 +248,9 @@ void __urcu_wakeup_siblings(struct urcu_workqueue *queue,
        sibling_next = caa_container_of(sibling_node, struct urcu_worker,
                        sibling_node);
        if (sibling_next != worker)
-               ___urcu_wakeup_sibling(sibling_next);
+               wakeup_performed = ___urcu_wakeup_sibling(sibling_next);
+       if (wakeup_performed)
+               goto end;
 
        sibling_node = rcu_dereference(worker->sibling_node.prev);
        if (sibling_node == &queue->sibling_head)
@@ -255,9 +258,11 @@ void __urcu_wakeup_siblings(struct urcu_workqueue *queue,
        sibling_prev = caa_container_of(sibling_node, struct urcu_worker,
                        sibling_node);
        if (sibling_prev != worker && sibling_prev != sibling_next)
-               ___urcu_wakeup_sibling(sibling_prev);
-
+               wakeup_performed = ___urcu_wakeup_sibling(sibling_prev);
+end:
        rcu_read_unlock();
+
+       return wakeup_performed;
 }
 
 static inline
@@ -324,7 +329,7 @@ do_work:
         * We will be busy handling the work batch, awaken siblings so
         * they can steal from us.
         */
-       __urcu_wakeup_siblings(queue, worker);
+       (void) __urcu_wakeup_siblings(queue, worker);
 }
 
 static inline