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-rw-r--r--block/blk-settings.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index e1327ddfc13b..476d87065073 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -413,10 +413,13 @@ EXPORT_SYMBOL(blk_limits_io_min);
413 * @min: smallest I/O size in bytes 413 * @min: smallest I/O size in bytes
414 * 414 *
415 * Description: 415 * Description:
416 * Some devices have an internal block size bigger than the reported 416 * Storage devices may report a granularity or preferred minimum I/O
417 * hardware sector size. This function can be used to signal the 417 * size which is the smallest request the device can perform without
418 * smallest I/O the device can perform without incurring a performance 418 * incurring a performance penalty. For disk drives this is often the
419 * penalty. 419 * physical block size. For RAID arrays it is often the stripe chunk
420 * size. A properly aligned multiple of minimum_io_size is the
421 * preferred request size for workloads where a high number of I/O
422 * operations is desired.
420 */ 423 */
421void blk_queue_io_min(struct request_queue *q, unsigned int min) 424void blk_queue_io_min(struct request_queue *q, unsigned int min)
422{ 425{
@@ -430,8 +433,12 @@ EXPORT_SYMBOL(blk_queue_io_min);
430 * @opt: optimal request size in bytes 433 * @opt: optimal request size in bytes
431 * 434 *
432 * Description: 435 * Description:
433 * Drivers can call this function to set the preferred I/O request 436 * Storage devices may report an optimal I/O size, which is the
434 * size for devices that report such a value. 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.
435 */ 442 */
436void blk_queue_io_opt(struct request_queue *q, unsigned int opt) 443void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
437{ 444{