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authorMartin K. Petersen <martin.petersen@oracle.com>2009-09-11 15:54:52 -0400
committerJens Axboe <jens.axboe@oracle.com>2009-09-14 02:24:52 -0400
commit3c5820c743479285ce2678fd3c12b1fd39fe998f (patch)
tree8f6b3980f5e8da4912b44eee4688d51ce12c97a3 /block/blk-settings.c
parent06d2188644c85c56d243efab914f368d1d23c4a3 (diff)
block: Optimal I/O limit wrapper
Implement blk_limits_io_opt() and make blk_queue_io_opt() a wrapper around it. DM needs this to avoid poking at the queue_limits directly. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-settings.c')
-rw-r--r--block/blk-settings.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 476d87065073..83413ff83739 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -428,6 +428,25 @@ void blk_queue_io_min(struct request_queue *q, unsigned int min)
428EXPORT_SYMBOL(blk_queue_io_min); 428EXPORT_SYMBOL(blk_queue_io_min);
429 429
430/** 430/**
431 * blk_limits_io_opt - set optimal request size for a device
432 * @limits: the queue limits
433 * @opt: smallest I/O size in bytes
434 *
435 * Description:
436 * Storage devices may report an optimal I/O size, which is the
437 * device's preferred unit for sustained I/O. This is rarely reported
438 * for disk drives. For RAID arrays it is usually the stripe width or
439 * the internal track size. A properly aligned multiple of
440 * optimal_io_size is the preferred request size for workloads where
441 * sustained throughput is desired.
442 */
443void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
444{
445 limits->io_opt = opt;
446}
447EXPORT_SYMBOL(blk_limits_io_opt);
448
449/**
431 * blk_queue_io_opt - set optimal request size for the queue 450 * blk_queue_io_opt - set optimal request size for the queue
432 * @q: the request queue for the device 451 * @q: the request queue for the device
433 * @opt: optimal request size in bytes 452 * @opt: optimal request size in bytes
@@ -442,7 +461,7 @@ EXPORT_SYMBOL(blk_queue_io_min);
442 */ 461 */
443void blk_queue_io_opt(struct request_queue *q, unsigned int opt) 462void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
444{ 463{
445 q->limits.io_opt = opt; 464 blk_limits_io_opt(&q->limits, opt);
446} 465}
447EXPORT_SYMBOL(blk_queue_io_opt); 466EXPORT_SYMBOL(blk_queue_io_opt);
448 467