block: add queue flag for SSD/non-rotational devices

We don't want to idle in AS/CFQ if the device doesn't have a seek
penalty. So add a QUEUE_FLAG_NONROT to indicate a non-rotational
device, low level drivers should set this flag upon discovery of
an SSD or similar device type.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2008-09-24 13:03:33 +02:00
parent 9e49184c82
commit a68bbddba4
3 changed files with 14 additions and 0 deletions

View file

@ -442,6 +442,7 @@ struct request_queue
#define QUEUE_FLAG_SAME_COMP 11 /* force complete on same CPU */
#define QUEUE_FLAG_FAIL_IO 12 /* fake timeout */
#define QUEUE_FLAG_STACKABLE 13 /* supports request stacking */
#define QUEUE_FLAG_NONROT 14 /* non-rotational device (SSD) */
static inline int queue_is_locked(struct request_queue *q)
{
@ -547,6 +548,7 @@ enum {
#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
#define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
#define blk_queue_nonrot(q) test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
#define blk_queue_flushing(q) ((q)->ordseq)
#define blk_queue_stackable(q) \
test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)