kernel/linux.git/block/blk-core.c, branch linux-2.6.26.y

block: Move the second call to get_request to the end of the loop

2008-05-28T12:49:27+00:00

In function get_request_wait, the second call to get_request could be moved to the end of the while loop, because if the first call to get_request fails, the second call will fail without sleep. Signed-off-by: Zhang Yanmin Signed-off-by: Jens Axboe

Remove blkdev warning triggered by using md

2008-05-15T02:11:15+00:00

As setting and clearing queue flags now requires that we hold a spinlock on the queue, and as blk_queue_stack_limits is called without that lock, get the lock inside blk_queue_stack_limits. For blk_queue_stack_limits to be able to find the right lock, each md personality needs to set q->queue_lock to point to the appropriate lock. Those personalities which didn't previously use a spin_lock, us q->__queue_lock. So always initialise that lock when allocated. With this in place, setting/clearing of the QUEUE_FLAG_PLUGGED bit will no longer cause warnings as it will be clear that the proper lock is held. Thanks to Dan Williams for review and fixing the silly bugs. Signed-off-by: NeilBrown Cc: Dan Williams Cc: Jens Axboe Cc: Alistair John Strachan Cc: Nick Piggin Cc: "Rafael J. Wysocki" Cc: Jacek Luczak Cc: Prakash Punnoor Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

block: avoid duplicate calls to get_part() in disk stat code

2008-05-07T08:15:46+00:00

get_part() is fairly expensive, as it O(N) loops over partitions to find the right one. In lots of normal IO paths we end up looking up the partition twice, to make matters even worse. Change the stat add code to accept a passed in partition instead. Signed-off-by: Jens Axboe

block: optimize generic_unplug_device()

2008-05-07T07:48:17+00:00

Original patch from Mikulas Patocka Mike Anderson was doing an OLTP benchmark on a computer with 48 physical disks mapped to one logical device via device mapper. He found that there was a slowdown on request_queue->lock in function generic_unplug_device. The slowdown is caused by the fact that when some code calls unplug on the device mapper, device mapper calls unplug on all physical disks. These unplug calls take the lock, find that the queue is already unplugged, release the lock and exit. With the below patch, performance of the benchmark was increased by 18% (the whole OLTP application, not just block layer microbenchmarks). So I'm submitting this patch for upstream. I think the patch is correct, because when more threads call simultaneously plug and unplug, it is unspecified, if the queue is or isn't plugged (so the patch can't make this worse). And the caller that plugged the queue should unplug it anyway. (if it doesn't, there's 3ms timeout). Signed-off-by: Mikulas Patocka Signed-off-by: Jens Axboe

block: remove remaining FUNCTION occurrences

2008-05-01T15:04:02+00:00

__FUNCTION__ is gcc specific, use __func__ Signed-off-by: Harvey Harrison Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

block: add large command support

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

This patch changes rq->cmd from the static array to a pointer to support large commands. We rarely handle large commands. So for optimization, a struct request still has a static array for a command. rq_init sets rq->cmd pointer to the static array. Signed-off-by: FUJITA Tomonori Cc: Jens Axboe Signed-off-by: Jens Axboe

block: replace sizeof(rq->cmd) with BLK_MAX_CDB

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

This is a preparation for changing rq->cmd from the static array to a pointer. Signed-off-by: FUJITA Tomonori Cc: Boaz Harrosh Cc: Bartlomiej Zolnierkiewicz Cc: Jens Axboe Signed-off-by: Jens Axboe

block: rename and export rq_init()

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

This rename rq_init() blk_rq_init() and export it. Any path that hands the request to the block layer needs to call it to initialize the request. This is a preparation for large command support, which needs to initialize the request in a proper way (that is, just doing a memset() will not work). Signed-off-by: FUJITA Tomonori Cc: Jens Axboe Signed-off-by: Jens Axboe

block: make queue flags non-atomic

2008-04-29T12:48:33+00:00

We can save some atomic ops in the IO path, if we clearly define the rules of how to modify the queue flags. Signed-off-by: Jens Axboe

block: make rq_init() do a full memset()

2008-04-29T07:50:34+00:00

This requires moving rq_init() from get_request() to blk_alloc_request(). The upside is that we can now require an rq_init() from any path that wishes to hand the request to the block layer. rq_init() will be exported for the code that uses struct request without blk_get_request. This is a preparation for large command support, which needs to initialize struct request in a proper way (that is, just doing a memset() will not work). Signed-off-by: FUJITA Tomonori Signed-off-by: Jens Axboe

kernel/linux.git/block/blk-core.c, branch linux-2.6.26.y

block: Move the second call to get_request to the end of the loop

Remove blkdev warning triggered by using md

block: avoid duplicate calls to get_part() in disk stat code

block: optimize generic_unplug_device()

block: remove remaining __FUNCTION__ occurrences

block: add large command support

block: replace sizeof(rq->cmd) with BLK_MAX_CDB

block: rename and export rq_init()

block: make queue flags non-atomic

block: make rq_init() do a full memset()

block: remove remaining FUNCTION occurrences