[PATCH 11/21] nbd: limit blk_queue

Peter Zijlstra
2006-09-06T13:16:41Z

[-- Attachment #1: nbd_queue.patch --]
[-- Type: text/plain, Size: 1573 bytes --]

Limit each request to 1 page, so that the request throttling also limits the
number of in-flight pages and force the IO scheduler to NOOP as anything else
doesn't make sense anyway.

(Pavel, I will analyse those !NOOP deadlocks I got, I'm just re-posting so
people can comment on the rest)

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Daniel Phillips <phillips@google.com>
CC: Pavel Machek <pavel@ucw.cz>
---
drivers/block/nbd.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

Index: linux-2.6/drivers/block/nbd.c
===================================================================
--- linux-2.6.orig/drivers/block/nbd.c
+++ linux-2.6/drivers/block/nbd.c
@@ -628,11 +636,16 @@ static int __init nbd_init(void)
* every gendisk to have its very own request_queue struct.
* These structs are big so we dynamically allocate them.
*/
- disk->queue = blk_init_queue(do_nbd_request, &nbd_lock);
+ disk->queue = blk_init_queue_node_elv(do_nbd_request,
+ &nbd_lock, -1, "noop");
if (!disk->queue) {
put_disk(disk);
goto out;
}
+ blk_queue_pin_elevator(disk->queue);
+ blk_queue_max_segment_size(disk->queue, PAGE_SIZE);
+ blk_queue_max_hw_segments(disk->queue, 1);
+ blk_queue_max_phys_segments(disk->queue, 1);
}

if (register_blkdev(NBD_MAJOR, "nbd")) {