2005-10-24 03:27:41

by Tejun Heo

Subject: [PATCH linux-block-2.6:generic-dispatch] kill max_back_kb handling

Hello, Jens.

This patch kills max_back_kb handling from elv_dispatch_sort() and
kills max_back_kb field from struct request_queue. The implementation
was broken (subtracted bytes from blocks) and the usefulness of the
feature is doubtful.

Signed-off-by: Tejun Heo <[email protected]>

diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c
--- a/drivers/block/elevator.c
+++ b/drivers/block/elevator.c
@@ -136,7 +136,6 @@ static int elevator_attach(request_queue
q->elevator = eq;
q->end_sector = 0;
q->boundary_rq = NULL;
- q->max_back_kb = 0;

if (eq->ops->elevator_init_fn)
ret = eq->ops->elevator_init_fn(q, eq);
@@ -227,16 +226,13 @@ void elevator_exit(elevator_t *e)
void elv_dispatch_sort(request_queue_t *q, struct request *rq)
{
sector_t boundary;
- unsigned max_back;
struct list_head *entry;

if (q->last_merge == rq)
q->last_merge = NULL;

boundary = q->end_sector;
- max_back = q->max_back_kb * 2;
- boundary = boundary > max_back ? boundary - max_back : 0;
-
+
list_for_each_prev(entry, &q->queue_head) {
struct request *pos = list_entry_rq(entry);

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -339,7 +339,6 @@ struct request_queue
*/
sector_t end_sector;
struct request *boundary_rq;
- unsigned int max_back_kb;

/*
* Auto-unplugging state

2005-10-24 03:30:15

by Tejun Heo

Subject: Re: [PATCH linux-block-2.6:generic-dispatch] kill max_back_kb handling

On Mon, Oct 24, 2005 at 12:27:31PM +0900, Tejun Heo wrote:
> Hello, Jens.
>
> This patch kills max_back_kb handling from elv_dispatch_sort() and
> kills max_back_kb field from struct request_queue. The implementation
> was broken (subtracted bytes from blocks) and the usefulness of the

Oops, above line is wrong. Can you please kill the sentence about
breakage when committing? Thanks.

> feature is doubtful.

--
tejun

2005-10-24 06:29:06

by Jens Axboe

Subject: Re: [PATCH linux-block-2.6:generic-dispatch] kill max_back_kb handling

On Mon, Oct 24 2005, Tejun Heo wrote:
> On Mon, Oct 24, 2005 at 12:27:31PM +0900, Tejun Heo wrote:
> > Hello, Jens.
> >
> > This patch kills max_back_kb handling from elv_dispatch_sort() and
> > kills max_back_kb field from struct request_queue. The implementation
> > was broken (subtracted bytes from blocks) and the usefulness of the
>
> Oops, above line is wrong. Can you please kill the sentence about
> breakage when committing? Thanks.

Sure, committed.

--
Jens Axboe