kernel/linux.git/block/blk-sysfs.c, branch linux-2.6.28.y

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

block: split tag and sysfs handling from blk-core.c

2008-01-29T20:55:07+00:00

Seperates the tag and sysfs handling from ll_rw_blk. Signed-off-by: Jens Axboe