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authorJens Axboe <jens.axboe@oracle.com>2008-09-24 13:03:33 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-10-09 08:56:19 +0200
commita68bbddba486020c9c74825ce90c4c1ec463e0e8 (patch)
treece0acea1e609185968310316d3d1ac6f730db983
parent9e49184c82e9ec3ab4d45f9ea5a17ccaf43869f0 (diff)
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>
-rw-r--r--block/as-iosched.c6
-rw-r--r--block/cfq-iosched.c6
-rw-r--r--include/linux/blkdev.h2
3 files changed, 14 insertions, 0 deletions
diff --git a/block/as-iosched.c b/block/as-iosched.c
index 80af9257e64..4c6fafbba93 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -745,6 +745,12 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
*/
static int as_can_anticipate(struct as_data *ad, struct request *rq)
{
+ /*
+ * SSD device without seek penalty, disable idling
+ */
+ if (blk_queue_nonrot(ad->q))
+ return 0;
+
if (!ad->io_context)
/*
* Last request submitted was a write
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 494b6fdcb18..03a5953bb5d 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -878,6 +878,12 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
struct cfq_io_context *cic;
unsigned long sl;
+ /*
+ * SSD device without seek penalty, disable idling
+ */
+ if (blk_queue_nonrot(cfqd->queue))
+ return;
+
WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
WARN_ON(cfq_cfqq_slice_new(cfqq));
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 86f77ef127f..0cf3e619fb2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -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)