linux.git/block/blk-sysfs.c, branch v2.6.29

block: add sysfs file for controlling io stats accounting

2009-01-30T11:34:38+00:00

This allows us to turn off disk stat accounting completely, for the cases
where the 0.5-1% reduction in system time is important.

Signed-off-by: Jens Axboe

block: export SSD/non-rotational queue flag through sysfs

2009-01-30T11:34:37+00:00

For some devices (i.e. CFA ATA) we can't reliably detect whether
the device is of rotational or non-rotational type so we need to
leave the final decision about this setting to the user-space.

As a bonus do a minor CodingStyle fixup in queue_nomerges_store().

Suggested-by: Alan Cox 
Signed-off-by: Bartlomiej Zolnierkiewicz 
Signed-off-by: Jens Axboe

block: don't take lock on changing ra_pages

2008-12-29T07:28:43+00:00

There's no need to take queue_lock or kernel_lock when modifying
bdi->ra_pages. So remove them. Also remove out of date comment for
queue_max_sectors_store().

Signed-off-by: Wu Fengguang 
Signed-off-by: Jens Axboe

block: add support for IO CPU affinity

2008-10-09T06:56:09+00:00

This patch adds support for controlling the IO completion CPU of
either all requests on a queue, or on a per-request basis. We export
a sysfs variable (rq_affinity) which, if set, migrates completions
of requests to the CPU that originally submitted it. A bio helper
(bio_set_completion_cpu()) is also added, so that queuers can ask
for completion on that specific CPU.

In testing, this has been show to cut the system time by as much
as 20-40% on synthetic workloads where CPU affinity is desired.

This requires a little help from the architecture, so it'll only
work as designed for archs that are using the new generic smp
helper infrastructure.

Signed-off-by: Jens Axboe

block: implement and use {disk|part}_to_dev()

2008-10-09T06:56:07+00:00

Implement {disk|part}_to_dev() and use them to access generic device
instead of directly dereferencing {disk|part}->dev.  To make sure no
user is left behind, rename generic devices fields to __dev.

This is in preparation of unifying partition 0 handling with other
partitions.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: sysfs store function needs to grab queue_lock and use queue_flag_*()

2008-05-07T07:09:39+00:00

Concurrency isn't a big deal here since we have requests in flight
at this point, but do the locked variant to set a better example.

Signed-off-by: Jens Axboe

block: Skip I/O merges when disabled

2008-04-29T12:48:55+00:00

The block I/O + elevator + I/O scheduler code spend a lot of time trying
to merge I/Os -- rightfully so under "normal" circumstances. However,
if one were to know that the incoming I/O stream was /very/ random in
nature, the cycles are wasted.

This patch adds a per-request_queue tunable that (when set) disables
merge attempts (beyond the simple one-hit cache check), thus freeing up
a non-trivial amount of CPU cycles.

Signed-off-by: Alan D. Brunelle 
Signed-off-by: Jens Axboe

block: fix blk_register_queue() return value

2008-04-21T07:51:06+00:00

blk_register_queue() returns -ENXIO when queue->request_fn is NULL.  But there
are some block drivers that call blk_register_queue() via add_disk() with
queue->request_fn == NULL.  (For example, brd, loop)

Although no one checks return value of blk_register_queue(), this patch makes
it return 0 instead of -ENXIO when queue->request_fn is NULL,

Also this patch adds warning when blk_register_queue() and
blk_unregister_queue() are called with queue == NULL rather than ignore
invalid usage silently.

Signed-off-by: Akinobu Mita 
Cc: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

block: make core bits checkpatch compliant

2008-02-01T08:26:33+00:00

Signed-off-by: Jens Axboe

Expose hardware sector size

2008-01-29T20:55:17+00:00

Expose hardware sector size in sysfs queue directory.

Signed-off-by: Martin K. Petersen 
Signed-off-by: Jens Axboe