WF queue cleanup

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/urcu/wfqueue.h b/urcu/wfqueue.h
index b4208dae65f28e0f0564c07dd77f338f72b4862b..2eaace1c260f99e7562a36649fc5129fdb03cce0 100644 (file)
--- a/urcu/wfqueue.h
+++ b/urcu/wfqueue.h
@@ -35,6 +35,9 @@ extern "C" {
 #error "Dynamic loader LGPL wrappers not implemented yet"
 #endif
 
+#define WFQ_ADAPT_ATTEMPTS             10      /* Retry if being set */
+#define WFQ_WAIT                       10      /* Wait 10 ms if being set */
+
 /*
  * Queue with wait-free enqueue/blocking dequeue.
  * This implementation adds a dummy head node when the queue is empty to ensure
@@ -101,7 +104,7 @@ struct wfq_node *
 __wfq_dequeue_blocking(struct wfq_queue *q)
 {
        struct wfq_node *node, *next;
-       int busy_wait = 16;
+       int attempt = 0;
 
        /*
         * Queue is empty if it only contains the dummy node.
@@ -114,11 +117,11 @@ __wfq_dequeue_blocking(struct wfq_queue *q)
         * Adaptative busy-looping waiting for enqueuer to complete enqueue.
         */
        while ((next = LOAD_SHARED(node->next)) == NULL) {
-               if (busy_wait > 0) {
-                       cpu_relax();
-                       busy_wait--;
+               if (++attempt >= WFQ_ADAPT_ATTEMPTS) {
+                       poll(NULL, 0, WFQ_WAIT);        /* Wait for 10ms */
+                       attempt = 0;
                } else
-                       poll(NULL, 0, 1);       /* Wait for 1ms */
+                       cpu_relax();
        }
        /*
         * Move queue head forward.