On 12/5/23 16:42, Damien Le Moal wrote:
... when prio_aging_expire is set to 0. Right ? Otherwise, the sentence above
reads as if you are disabling IO priority for zoned devices...
Hi Damien,
I just noticed that I posted an old version of this patch (3/3). In the patch
below I/O priorities are ignored for zoned writes.
Thanks,
Bart.
Subject: [PATCH] block/mq-deadline: Disable I/O prioritization in certain cases
Fix the following two issues:
- Even with prio_aging_expire set to zero, I/O priorities still affect the
request order.
- Assigning I/O priorities with the ioprio cgroup policy breaks zoned
storage support in the mq-deadline scheduler.
This patch fixes both issues by disabling I/O prioritization for these
two cases.
Cc: Damien Le Moal <dlemoal@xxxxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
block/mq-deadline.c | 37 ++++++++++++++++++++++++-------------
1 file changed, 24 insertions(+), 13 deletions(-)
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index fe5da2ade953..310ff133ce20 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -119,18 +119,27 @@ deadline_rb_root(struct dd_per_prio *per_prio, struct request *rq)
return &per_prio->sort_list[rq_data_dir(rq)];
}
+static bool dd_use_io_priority(struct deadline_data *dd, enum req_op op)
+{
+ return dd->prio_aging_expire != 0 && !op_needs_zoned_write_locking(op);
+}
+
/*
* Returns the I/O priority class (IOPRIO_CLASS_*) that has been assigned to a
* request.
*/
-static u8 dd_rq_ioclass(struct request *rq)
+static u8 dd_rq_ioclass(struct deadline_data *dd, struct request *rq)
{
- return IOPRIO_PRIO_CLASS(req_get_ioprio(rq));
+ if (dd_use_io_priority(dd, req_op(rq)))
+ return IOPRIO_PRIO_CLASS(req_get_ioprio(rq));
+ return IOPRIO_CLASS_NONE;
}
-static u8 dd_bio_ioclass(struct bio *bio)
+static u8 dd_bio_ioclass(struct deadline_data *dd, struct bio *bio)
{
- return IOPRIO_PRIO_CLASS(bio->bi_ioprio);
+ if (dd_use_io_priority(dd, bio_op(bio)))
+ return IOPRIO_PRIO_CLASS(bio->bi_ioprio);
+ return IOPRIO_CLASS_NONE;
}
/*
@@ -233,7 +242,7 @@ static void dd_request_merged(struct request_queue *q, struct request *req,
enum elv_merge type)
{
struct deadline_data *dd = q->elevator->elevator_data;
- const u8 ioprio_class = dd_rq_ioclass(req);
+ const u8 ioprio_class = dd_rq_ioclass(dd, req);
const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
struct dd_per_prio *per_prio = &dd->per_prio[prio];
@@ -253,7 +262,7 @@ static void dd_merged_requests(struct request_queue *q, struct request *req,
struct request *next)
{
struct deadline_data *dd = q->elevator->elevator_data;
- const u8 ioprio_class = dd_rq_ioclass(next);
+ const u8 ioprio_class = dd_rq_ioclass(dd, next);
const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
lockdep_assert_held(&dd->lock);
@@ -550,7 +559,7 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd,
dd->batching++;
deadline_move_request(dd, per_prio, rq);
done:
- ioprio_class = dd_rq_ioclass(rq);
+ ioprio_class = dd_rq_ioclass(dd, rq);
prio = ioprio_class_to_prio[ioprio_class];
dd->per_prio[prio].latest_pos[data_dir] = blk_rq_pos(rq);
dd->per_prio[prio].stats.dispatched++;
@@ -606,9 +615,11 @@ static struct request *dd_dispatch_request(struct blk_mq_hw_ctx *hctx)
enum dd_prio prio;
spin_lock(&dd->lock);
- rq = dd_dispatch_prio_aged_requests(dd, now);
- if (rq)
- goto unlock;
+ if (dd->prio_aging_expire != 0) {
+ rq = dd_dispatch_prio_aged_requests(dd, now);
+ if (rq)
+ goto unlock;
+ }
/*
* Next, dispatch requests in priority order. Ignore lower priority
@@ -749,7 +760,7 @@ static int dd_request_merge(struct request_queue *q, struct request **rq,
struct bio *bio)
{
struct deadline_data *dd = q->elevator->elevator_data;
- const u8 ioprio_class = dd_bio_ioclass(bio);
+ const u8 ioprio_class = dd_bio_ioclass(dd, bio);
const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
struct dd_per_prio *per_prio = &dd->per_prio[prio];
sector_t sector = bio_end_sector(bio);
@@ -814,7 +825,7 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
*/
blk_req_zone_write_unlock(rq);
- prio = ioprio_class_to_prio[dd_rq_ioclass(rq)];
+ prio = ioprio_class_to_prio[dd_rq_ioclass(dd, rq)];
per_prio = &dd->per_prio[prio];
if (!rq->elv.priv[0]) {
per_prio->stats.inserted++;
@@ -923,7 +934,7 @@ static void dd_finish_request(struct request *rq)
{
struct request_queue *q = rq->q;
struct deadline_data *dd = q->elevator->elevator_data;
- const u8 ioprio_class = dd_rq_ioclass(rq);
+ const u8 ioprio_class = dd_rq_ioclass(dd, rq);
const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
struct dd_per_prio *per_prio = &dd->per_prio[prio];
