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author | Martin K. Petersen <martin.petersen@oracle.com> | 2009-09-11 21:54:52 +0200 |
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committer | Jens Axboe <jens.axboe@oracle.com> | 2009-09-14 08:24:52 +0200 |
commit | 3c5820c743479285ce2678fd3c12b1fd39fe998f (patch) | |
tree | 8f6b3980f5e8da4912b44eee4688d51ce12c97a3 /block/blk-settings.c | |
parent | cfq: choose a new next_req when a request is dispatched (diff) | |
download | linux-3c5820c743479285ce2678fd3c12b1fd39fe998f.tar.xz linux-3c5820c743479285ce2678fd3c12b1fd39fe998f.zip |
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.c | 21 |
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) EXPORT_SYMBOL(blk_queue_io_min); /** + * blk_limits_io_opt - set optimal request size for a device + * @limits: the queue limits + * @opt: smallest I/O size in bytes + * + * Description: + * Storage devices may report an optimal I/O size, which is the + * device's preferred unit for sustained I/O. This is rarely reported + * for disk drives. For RAID arrays it is usually the stripe width or + * the internal track size. A properly aligned multiple of + * optimal_io_size is the preferred request size for workloads where + * sustained throughput is desired. + */ +void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt) +{ + limits->io_opt = opt; +} +EXPORT_SYMBOL(blk_limits_io_opt); + +/** * blk_queue_io_opt - set optimal request size for the queue * @q: the request queue for the device * @opt: optimal request size in bytes @@ -442,7 +461,7 @@ EXPORT_SYMBOL(blk_queue_io_min); */ void blk_queue_io_opt(struct request_queue *q, unsigned int opt) { - q->limits.io_opt = opt; + blk_limits_io_opt(&q->limits, opt); } EXPORT_SYMBOL(blk_queue_io_opt); |