workqueue: handle congestion by clearing queue

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

diff --git a/urcu/workqueue-fifo.h b/urcu/workqueue-fifo.h
index 458d97663ff599b3163c797c7b239cfc79dcdf07..ff0c650571a175ae6c809eee41d9f3135131ce36 100644 (file)
--- a/urcu/workqueue-fifo.h
+++ b/urcu/workqueue-fifo.h
@@ -502,4 +502,29 @@ void urcu_workqueue_shutdown(struct urcu_workqueue *queue)
        __urcu_workqueue_wakeup_all(queue);
 }
 
+/*
+ * Use to let dispatcher steal work from the entire queue in case of
+ * stall. The "worker" parameter need to be intialized, but is usually
+ * not registered.
+ */
+static inline
+bool urcu_workqueue_steal_all(struct urcu_workqueue *queue,
+               struct urcu_worker *worker)
+{
+       struct urcu_worker *sibling;
+       bool has_work = false;
+
+       rcu_read_lock();
+       /* Steal from each worker */
+       cds_list_for_each_entry_rcu(sibling, &queue->sibling_head,
+                       sibling_node)
+               has_work |= ___urcu_grab_work(worker, &sibling->head,
+                                       &sibling->tail, 1);
+       rcu_read_unlock();
+
+       /* Steal from global workqueue */
+       has_work |= ___urcu_grab_work(worker, &queue->head, &queue->tail, 0);
+       return has_work;
+}
+
 #endif /* _URCU_WORKQUEUE_FIFO_H */