From: Yu Kuai <yukuai3@xxxxxxxxxx>
bio->issue_time_ns is initialized for every bio, however, it's only used
by blk-iolatency. Add a new queue_flag and only set this flag when
blk-iolatency is enabled, so that extra blk_time_get_ns() can be saved
for disks that blk-iolatency is not enabled.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
block/blk-iolatency.c | 5 +++++
block/blk-mq-debugfs.c | 1 +
block/blk-mq.c | 8 +++++---
include/linux/blkdev.h | 1 +
4 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 554b191a6892..45bd18f68541 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -742,10 +742,15 @@ static void blkiolatency_enable_work_fn(struct work_struct *work)
*/
enabled = atomic_read(&blkiolat->enable_cnt);
if (enabled != blkiolat->enabled) {
+ struct request_queue *q = blkiolat->rqos.disk->queue;
unsigned int memflags;
memflags = blk_mq_freeze_queue(blkiolat->rqos.disk->queue);
blkiolat->enabled = enabled;
+ if (enabled)
+ blk_queue_flag_set(QUEUE_FLAG_BIO_ISSUE_TIME, q);
+ else
+ blk_queue_flag_clear(QUEUE_FLAG_BIO_ISSUE_TIME, q);
blk_mq_unfreeze_queue(blkiolat->rqos.disk->queue, memflags);
}
}
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 32c65efdda46..4896525b1c05 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -96,6 +96,7 @@ static const char *const blk_queue_flag_name[] = {
QUEUE_FLAG_NAME(DISABLE_WBT_DEF),
QUEUE_FLAG_NAME(NO_ELV_SWITCH),
QUEUE_FLAG_NAME(QOS_ENABLED),
+ QUEUE_FLAG_NAME(BIO_ISSUE_TIME),
};
#undef QUEUE_FLAG_NAME
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 2c0c8ead7080..31cc743ffad7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -396,10 +396,12 @@ static inline void blk_mq_rq_time_init(struct request *rq, u64 alloc_time_ns)
#endif
}
-static inline void blk_mq_bio_issue_init(struct bio *bio)
+static inline void blk_mq_bio_issue_init(struct request_queue *q,
+ struct bio *bio)
{
#ifdef CONFIG_BLK_CGROUP
- bio->issue_time_ns = blk_time_get_ns();
+ if (test_bit(QUEUE_FLAG_BIO_ISSUE_TIME, &q->queue_flags))
+ bio->issue_time_ns = blk_time_get_ns();
#endif
}
@@ -3175,7 +3177,7 @@ void blk_mq_submit_bio(struct bio *bio)
if (!bio_integrity_prep(bio))
goto queue_exit;
- blk_mq_bio_issue_init(bio);
+ blk_mq_bio_issue_init(q, bio);
if (blk_mq_attempt_bio_merge(q, bio, nr_segs))
goto queue_exit;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c8cb08b2ed29..7c542b1851fa 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -657,6 +657,7 @@ enum {
QUEUE_FLAG_DISABLE_WBT_DEF, /* for sched to disable/enable wbt */
QUEUE_FLAG_NO_ELV_SWITCH, /* can't switch elevator any more */
QUEUE_FLAG_QOS_ENABLED, /* qos is enabled */
+ QUEUE_FLAG_BIO_ISSUE_TIME, /* record bio->issue_time_ns */
QUEUE_FLAG_MAX
};
--
2.39.2
