commit 029bcbd8b076fd19787b8c73e58dd0a6f2c0caf1
author Josh Durgin <josh.durgin@dreamhost.com> Fri Jul 22 11:35:23 2011 -0700
committer Sage Weil <sage@newdream.net> Tue Jul 26 11:29:35 2011 -0700
tree 305128db78ecfb09e6a236caeeac1fbb9ece1175
parent e9852227431a0ed6ceda064f33e4218757acab6c

rbd: set blk_queue request sizes to object size

This improves performance since more requests can be merged.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>

drivers/block/rbd.c

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 7392d7a..15f65b5 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -630,6 +630,14 @@
 }
 
 /*
+ * returns the size of an object in the image
+ */
+static u64 rbd_obj_bytes(struct rbd_image_header *header)
+{
+	return 1 << header->obj_order;
+}
+
+/*
  * bio helpers
  */
 
@@ -1765,6 +1773,13 @@
 	q = blk_init_queue(rbd_rq_fn, &rbd_dev->lock);
 	if (!q)
 		goto out_disk;
+
+	/* set io sizes to object size */
+	blk_queue_max_hw_sectors(q, rbd_obj_bytes(&rbd_dev->header) / 512ULL);
+	blk_queue_max_segment_size(q, rbd_obj_bytes(&rbd_dev->header));
+	blk_queue_io_min(q, rbd_obj_bytes(&rbd_dev->header));
+	blk_queue_io_opt(q, rbd_obj_bytes(&rbd_dev->header));
+
 	blk_queue_merge_bvec(q, rbd_merge_bvec);
 	disk->queue = q;