raid10: improve random reads performance

[cascardo/linux.git] / drivers / md / raid10.c

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index f7f3c8a..cb1d887 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -905,7 +905,7 @@ static void raise_barrier(struct r10conf *conf, int force)
 
        /* Now wait for all pending IO to complete */
        wait_event_lock_irq(conf->wait_barrier,
-                           !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
+                           !atomic_read(&conf->nr_pending) && conf->barrier < RESYNC_DEPTH,
                            conf->resync_lock);
 
        spin_unlock_irq(&conf->resync_lock);
@@ -936,23 +936,23 @@ static void wait_barrier(struct r10conf *conf)
                 */
                wait_event_lock_irq(conf->wait_barrier,
                                    !conf->barrier ||
-                                   (conf->nr_pending &&
+                                   (atomic_read(&conf->nr_pending) &&
                                     current->bio_list &&
                                     !bio_list_empty(current->bio_list)),
                                    conf->resync_lock);
                conf->nr_waiting--;
+               if (!conf->nr_waiting)
+                       wake_up(&conf->wait_barrier);
        }
-       conf->nr_pending++;
+       atomic_inc(&conf->nr_pending);
        spin_unlock_irq(&conf->resync_lock);
 }
 
 static void allow_barrier(struct r10conf *conf)
 {
-       unsigned long flags;
-       spin_lock_irqsave(&conf->resync_lock, flags);
-       conf->nr_pending--;
-       spin_unlock_irqrestore(&conf->resync_lock, flags);
-       wake_up(&conf->wait_barrier);
+       if ((atomic_dec_and_test(&conf->nr_pending)) ||
+                       (conf->array_freeze_pending))
+               wake_up(&conf->wait_barrier);
 }
 
 static void freeze_array(struct r10conf *conf, int extra)
@@ -970,13 +970,15 @@ static void freeze_array(struct r10conf *conf, int extra)
         * we continue.
         */
        spin_lock_irq(&conf->resync_lock);
+       conf->array_freeze_pending++;
        conf->barrier++;
        conf->nr_waiting++;
        wait_event_lock_irq_cmd(conf->wait_barrier,
-                               conf->nr_pending == conf->nr_queued+extra,
+                               atomic_read(&conf->nr_pending) == conf->nr_queued+extra,
                                conf->resync_lock,
                                flush_pending_writes(conf));
 
+       conf->array_freeze_pending--;
        spin_unlock_irq(&conf->resync_lock);
 }
 
@@ -3542,6 +3544,7 @@ static struct r10conf *setup_conf(struct mddev *mddev)
 
        spin_lock_init(&conf->resync_lock);
        init_waitqueue_head(&conf->wait_barrier);
+       atomic_set(&conf->nr_pending, 0);
 
        conf->thread = md_register_thread(raid10d, mddev, "raid10");
        if (!conf->thread)