Subsequent patches will split the single queue into separate bps and iops
queues. To prevent IO that has already passed through the bps queue at a
single tg level from being counted toward bps wait time again, we
introduce
"BIO_TG_BPS_THROTTLED" flag. Since throttle and QoS operate at different
levels, we reuse the value as "BIO_QOS_THROTTLED".
We set this flag when charge bps and clear it when charge iops, as the
bio
will move to the upper-level tg or be dispatched.
This patch does not involve functional changes.
Signed-off-by: Zizhi Wo <wozizhi@xxxxxxxxxx>
---
block/blk-throttle.c | 9 +++++++--
include/linux/blk_types.h | 5 +++++
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 91ee1c502b41..caae2e3b7534 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -741,12 +741,16 @@ static void throtl_charge_bps_bio(struct
throtl_grp *tg, struct bio *bio)
unsigned int bio_size = throtl_bio_data_size(bio);
/* Charge the bio to the group */
- if (!bio_flagged(bio, BIO_BPS_THROTTLED))
+ if (!bio_flagged(bio, BIO_BPS_THROTTLED) &&
+ !bio_flagged(bio, BIO_TG_BPS_THROTTLED)) {
+ bio_set_flag(bio, BIO_TG_BPS_THROTTLED);
tg->bytes_disp[bio_data_dir(bio)] += bio_size;
+ }
}
static void throtl_charge_iops_bio(struct throtl_grp *tg, struct bio
*bio)
{
+ bio_clear_flag(bio, BIO_TG_BPS_THROTTLED);
tg->io_disp[bio_data_dir(bio)]++;
}
@@ -772,7 +776,8 @@ static unsigned long tg_dispatch_bps_time(struct
throtl_grp *tg, struct bio *bio
/* no need to throttle if this bio's bytes have been accounted */
if (bps_limit == U64_MAX || tg->flags & THROTL_TG_CANCELING ||
- bio_flagged(bio, BIO_BPS_THROTTLED))
+ bio_flagged(bio, BIO_BPS_THROTTLED) ||
+ bio_flagged(bio, BIO_TG_BPS_THROTTLED))
return 0;
tg_update_slice(tg, rw);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index dce7615c35e7..f9d1230e27a7 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -296,6 +296,11 @@ enum {
* of this bio. */
BIO_CGROUP_ACCT, /* has been accounted to a cgroup */
BIO_QOS_THROTTLED, /* bio went through rq_qos throttle path */
+ /*
+ * This bio has undergone rate limiting at the single throtl_grp
level bps
+ * queue. Since throttle and QoS are not at the same level,
reused the value.
