MFC r256956:

Improve ZFS N-way mirror read performance by using load and locality
information.

MFC r260713:
Fix ZFS mirror code for handling multiple DVA's

Also make the addition of the d_rotation_rate binary compatible. This allows
storage drivers compiled for 10.0 to work by preserving the ABI for disks.

Approved by:	re (gjb)
Sponsored by:	Multiplay

1 files changed, 25 insertions, 0 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c
index 733a108..de436f3 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c
@@ -289,6 +289,8 @@ vdev_queue_init(vdev_t *vd)
 		    vdev_queue_offset_compare,
 		    sizeof (zio_t), offsetof(struct zio, io_queue_node));
 	}
+
+	vq->vq_lastoffset = 0;
 }
 
 void
@@ -815,3 +817,26 @@ vdev_queue_io_done(zio_t *zio)
 
 	mutex_exit(&vq->vq_lock);
 }
+
+/*
+ * As these three methods are only used for load calculations we're not concerned
+ * if we get an incorrect value on 32bit platforms due to lack of vq_lock mutex
+ * use here, instead we prefer to keep it lock free for performance.
+ */ 
+int
+vdev_queue_length(vdev_t *vd)
+{
+	return (avl_numnodes(&vd->vdev_queue.vq_active_tree));
+}
+
+uint64_t
+vdev_queue_lastoffset(vdev_t *vd)
+{
+	return (vd->vdev_queue.vq_lastoffset);
+}
+
+void
+vdev_queue_register_lastoffset(vdev_t *vd, zio_t *zio)
+{
+	vd->vdev_queue.vq_lastoffset = zio->io_offset + zio->io_size;
+}