diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
index 335316e..e191fa3 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
@@ -135,6 +135,7 @@ typedef enum zio_priority {
 	ZIO_PRIORITY_ASYNC_READ,	/* prefetch */
 	ZIO_PRIORITY_ASYNC_WRITE,	/* spa_sync() */
 	ZIO_PRIORITY_SCRUB,		/* asynchronous scrub/resilver reads */
+	ZIO_PRIORITY_TRIM,		/* slow auxiliary commands like TRIM */
 	ZIO_PRIORITY_NUM_QUEUEABLE,
 
 	ZIO_PRIORITY_NOW		/* non-queued i/os (e.g. free) */
@@ -512,7 +513,7 @@ extern zio_t *zio_claim(zio_t *pio, spa_t *spa, uint64_t txg,
 
 extern zio_t *zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
     uint64_t offset, uint64_t size, zio_done_func_t *done, void *priv,
-    enum zio_flag flags);
+    zio_priority_t priority, enum zio_flag flags);
 
 extern zio_t *zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset,
     uint64_t size, void *data, int checksum,
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 d7d0dee..df86a03 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
@@ -145,6 +145,9 @@ uint32_t zfs_vdev_async_write_min_active = 1;
 uint32_t zfs_vdev_async_write_max_active = 10;
 uint32_t zfs_vdev_scrub_min_active = 1;
 uint32_t zfs_vdev_scrub_max_active = 2;
+uint32_t zfs_vdev_trim_min_active = 1;
+uint32_t zfs_vdev_trim_max_active = 1; /* XXX */
+
 
 /*
  * When the pool has less than zfs_vdev_async_write_active_min_dirty_percent
@@ -199,6 +202,8 @@ ZFS_VDEV_QUEUE_KNOB_MIN(async_write);
 ZFS_VDEV_QUEUE_KNOB_MAX(async_write);
 ZFS_VDEV_QUEUE_KNOB_MIN(scrub);
 ZFS_VDEV_QUEUE_KNOB_MAX(scrub);
+ZFS_VDEV_QUEUE_KNOB_MIN(trim);
+ZFS_VDEV_QUEUE_KNOB_MAX(trim);
 
 #undef ZFS_VDEV_QUEUE_KNOB
 
@@ -403,6 +408,8 @@ vdev_queue_class_min_active(zio_priority_t p)
 		return (zfs_vdev_async_write_min_active);
 	case ZIO_PRIORITY_SCRUB:
 		return (zfs_vdev_scrub_min_active);
+	case ZIO_PRIORITY_TRIM:
+		return (zfs_vdev_trim_min_active);
 	default:
 		panic("invalid priority %u", p);
 		return (0);
@@ -454,6 +461,8 @@ vdev_queue_class_max_active(spa_t *spa, zio_priority_t p)
 		    spa->spa_dsl_pool->dp_dirty_total));
 	case ZIO_PRIORITY_SCRUB:
 		return (zfs_vdev_scrub_max_active);
+	case ZIO_PRIORITY_TRIM:
+		return (zfs_vdev_trim_max_active);
 	default:
 		panic("invalid priority %u", p);
 		return (0);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
index 5546d6a..132dc69 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
@@ -839,14 +839,14 @@ zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
 zio_t *
 zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd, uint64_t offset,
     uint64_t size, zio_done_func_t *done, void *private,
-    enum zio_flag flags)
+    zio_priority_t priority, enum zio_flag flags)
 {
 	zio_t *zio;
 	int c;
 
 	if (vd->vdev_children == 0) {
 		zio = zio_create(pio, spa, 0, NULL, NULL, size, done, private,
-		    ZIO_TYPE_IOCTL, ZIO_PRIORITY_NOW, flags, vd, offset, NULL,
+		    ZIO_TYPE_IOCTL, priority, flags, vd, offset, NULL,
 		    ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE);
 
 		zio->io_cmd = cmd;
@@ -855,7 +855,7 @@ zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd, uint64_t offset,
 
 		for (c = 0; c < vd->vdev_children; c++)
 			zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd,
-			    offset, size, done, private, flags));
+			    offset, size, done, private, priority, flags));
 	}
 
 	return (zio);
@@ -985,7 +985,7 @@ void
 zio_flush(zio_t *zio, vdev_t *vd)
 {
 	zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE, 0, 0,
-	    NULL, NULL,
+	    NULL, NULL, ZIO_PRIORITY_NOW,
 	    ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY));
 }
 
@@ -996,7 +996,7 @@ zio_trim(zio_t *zio, spa_t *spa, vdev_t *vd, uint64_t offset, uint64_t size)
 	ASSERT(vd->vdev_ops->vdev_op_leaf);
 
 	return zio_ioctl(zio, spa, vd, DKIOCTRIM, offset, size,
-	    NULL, NULL,
+	    NULL, NULL, ZIO_PRIORITY_TRIM,
 	    ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY);
 }