Hi,
在 2025/09/04 0:54, Yu Kuai 写道:
Hi,
在 2025/9/3 21:24, Christoph Hellwig 写道:
On Mon, Sep 01, 2025 at 11:32:07AM +0800, Yu Kuai wrote:
static inline void blkcg_bio_issue_init(struct bio *bio)
{
- bio->issue_time_ns = blk_time_get_ns();
+ struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+
+ if (test_bit(QUEUE_FLAG_BIO_ISSUE, &q->queue_flags))
+ bio->issue_time_ns = blk_time_get_ns();
}
Given that this is called on a bio and called from generic code
and not blk-mq, the flag should in the gendisk and not the queue.
ok, will change to disk, and also change set/clear the flag to
enable/disable iolatency.
After careful consideration, I think it's better to delay
blkcg_bio_issue_init() to blk_mq_submit_bio():
- it's only used by iolatency, which can only be enabled for rq-based
disks;
- For bio that is submitted the first time, blk_cgroup_bio_start() is
called from submit_bio_no_acct_nocheck(), where q_usage_counter is not
grabbed yet, hence it's not safe to enable that flag while enabling
iolatency.
diff --git a/block/blk-core.c b/block/blk-core.c
index 4201504158a1..83c262a3dfd9 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -728,7 +728,6 @@ static void __submit_bio_noacct_mq(struct bio *bio)
void submit_bio_noacct_nocheck(struct bio *bio)
{
blk_cgroup_bio_start(bio);
- blkcg_bio_issue_init(bio);
if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
trace_block_bio_queue(bio);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 70d704615be5..5538356770a4 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -119,7 +119,6 @@ static struct bio *bio_submit_split(struct bio *bio,
int split_sectors)
goto error;
}
split->bi_opf |= REQ_NOMERGE;
- blkcg_bio_issue_init(split);
bio_chain(split, bio);
trace_block_split(split, bio->bi_iter.bi_sector);
WARN_ON_ONCE(bio_zone_write_plugging(bio));
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ba3a4b77f578..030937b129a2 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3108,7 +3108,7 @@ static bool bio_unaligned(const struct bio *bio,
struct request_queue *q)
* It will not queue the request if there is an error with the bio, or
at the
* request creation.
*/
-void blk_mq_submit_bio(struct bio *bio)
+void b k_mq_submit_bio(struct bio *bio)
{
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
struct blk_plug *plug = current->plug;
@@ -3168,6 +3168,9 @@ void blk_mq_submit_bio(struct bio *bio)
if (!bio_integrity_prep(bio))
goto queue_exit;
+ if (test_bit(QUEUE_FLAG_BIO_ISSUE, &q->queue_flags))
+ bio->issue_time_ns = blk_time_get_ns();
+
if (blk_mq_attempt_bio_merge(q, bio, nr_segs))
goto queue_exit;
Thanks,
Kuai
.
