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Commit 402a26f0 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block 

* 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block:
  [PATCH] block/elevator.c: remove unused exports
  [PATCH] splice: fix smaller sized splice reads
  [PATCH] Don't inherit ->splice_pipe across forks
  [patch] cleanup: use blk_queue_stopped
  [PATCH] Document online io scheduler switching
parents bf7cf6ee 4f73247f

Documentation/block/switching-sched.txt

0 → 100644
+22 −0
Original line number Diff line number Diff line 
As of the Linux 2.6.10 kernel, it is now possible to change the

IO scheduler for a given block device on the fly (thus making it possible,

for instance, to set the CFQ scheduler for the system default, but

set a specific device to use the anticipatory or noop schedulers - which

can improve that device's throughput).



To set a specific scheduler, simply do this:



echo SCHEDNAME > /sys/block/DEV/queue/scheduler



where SCHEDNAME is the name of a defined IO scheduler, and DEV is the

device name (hda, hdb, sga, or whatever you happen to have).



The list of defined schedulers can be found by simply doing

a "cat /sys/block/DEV/queue/scheduler" - the list of valid names

will be displayed, with the currently selected scheduler in brackets:



# cat /sys/block/hda/queue/scheduler

noop anticipatory deadline [cfq]

# echo anticipatory > /sys/block/hda/queue/scheduler

# cat /sys/block/hda/queue/scheduler

noop [anticipatory] deadline cfq

block/elevator.c

+0 −2
Original line number Diff line number Diff line
@@ -895,10 +895,8 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name) 
EXPORT_SYMBOL(elv_dispatch_sort);

EXPORT_SYMBOL(elv_add_request);

EXPORT_SYMBOL(__elv_add_request);

EXPORT_SYMBOL(elv_requeue_request);

EXPORT_SYMBOL(elv_next_request);

EXPORT_SYMBOL(elv_dequeue_request);

EXPORT_SYMBOL(elv_queue_empty);

EXPORT_SYMBOL(elv_completed_request);

EXPORT_SYMBOL(elevator_exit);

EXPORT_SYMBOL(elevator_init);

block/ll_rw_blk.c

+2 −2
Original line number Diff line number Diff line
@@ -1554,7 +1554,7 @@ void blk_plug_device(request_queue_t *q) 
	 * don't plug a stopped queue, it must be paired with blk_start_queue()

	 * which will restart the queueing

	 */

	if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))

	if (blk_queue_stopped(q))

		return;



	if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) {
@@ -1587,7 +1587,7 @@ EXPORT_SYMBOL(blk_remove_plug); 
 */

void __generic_unplug_device(request_queue_t *q)

{

	if (unlikely(test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)))

	if (unlikely(blk_queue_stopped(q)))

		return;



	if (!blk_remove_plug(q))

fs/splice.c

+12 −1
Original line number Diff line number Diff line
@@ -275,6 +275,15 @@ __generic_file_splice_read(struct file *in, loff_t *ppos, 
	error = 0;

	bytes = 0;

	for (i = 0; i < nr_pages; i++, index++) {

		unsigned int this_len;



		if (!len)

			break;



		/*

		 * this_len is the max we'll use from this page

		 */

		this_len = min(len, PAGE_CACHE_SIZE - loff);

find_page:

		/*

		 * lookup the page for this index
@@ -366,11 +375,13 @@ __generic_file_splice_read(struct file *in, loff_t *ppos, 
				 * force quit after adding this page

				 */

				nr_pages = i;

				this_len = min(this_len, loff);

			}

		}

fill_it:

		pages[i] = page;

		bytes += PAGE_CACHE_SIZE - loff;

		bytes += this_len;

		len -= this_len;

		loff = 0;

	}

kernel/fork.c

+1 −0
Original line number Diff line number Diff line
@@ -180,6 +180,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig) 
	atomic_set(&tsk->usage,2);

	atomic_set(&tsk->fs_excl, 0);

	tsk->btrace_seq = 0;

	tsk->splice_pipe = NULL;

	return tsk;

}