rbd: fixed busy-loop when using eventfd polling

[fio.git] / engines / rbd.c

diff --git a/engines/rbd.c b/engines/rbd.c
index 39501eb00551a1b1572c7a5bdc7921a5684e602c..8e7bd87c64d6bc251856ef9ec162f3c1097dbb73 100644 (file)
--- a/engines/rbd.c
+++ b/engines/rbd.c
@@ -146,7 +146,7 @@ static bool _fio_rbd_setup_poll(struct rbd_data *rbd)
        int r;
 
        /* add for rbd poll */
-       rbd->fd = eventfd(0, EFD_NONBLOCK);
+       rbd->fd = eventfd(0, EFD_SEMAPHORE);
        if (rbd->fd < 0) {
                log_err("eventfd failed.\n");
                return false;
@@ -366,25 +366,37 @@ static int rbd_iter_events(struct thread_data *td, unsigned int *events,
        int event_num = 0;
        struct fio_rbd_iou *fri = NULL;
        rbd_completion_t comps[min_evts];
+       uint64_t counter;
+       bool completed;
 
        struct pollfd pfd;
        pfd.fd = rbd->fd;
        pfd.events = POLLIN;
 
-       ret = poll(&pfd, 1, -1);
+       ret = poll(&pfd, 1, wait ? -1 : 0);
        if (ret <= 0)
                return 0;
-
-       assert(pfd.revents & POLLIN);
+       if (!(pfd.revents & POLLIN))
+               return 0;
 
        event_num = rbd_poll_io_events(rbd->image, comps, min_evts);
 
        for (i = 0; i < event_num; i++) {
                fri = rbd_aio_get_arg(comps[i]);
                io_u = fri->io_u;
+
+               /* best effort to decrement the semaphore */
+               ret = read(rbd->fd, &counter, sizeof(counter));
+               if (ret <= 0)
+                       log_err("rbd_iter_events failed to decrement semaphore.\n");
+
+               completed = fri_check_complete(rbd, io_u, events);
+               assert(completed);
+
+               this_events++;
+       }
 #else
        io_u_qiter(&td->io_u_all, io_u, i) {
-#endif
                if (!(io_u->flags & IO_U_F_FLIGHT))
                        continue;
                if (rbd_io_u_seen(io_u))
@@ -395,6 +407,7 @@ static int rbd_iter_events(struct thread_data *td, unsigned int *events,
                else if (wait)
                        rbd->sort_events[sidx++] = io_u;
        }
+#endif
 
        if (!wait || !sidx)
                return this_events;