Re: [PATCH -next 5/8] md/raid10: switch to use md_account_bio() for io accounting

[Xiao Ni <xni@redhat.com>]

On Mon, Jun 19, 2023 at 8:50 PM Yu Kuai <yukuai1@huaweicloud.com> wrote:
>
> From: Yu Kuai <yukuai3@huawei.com>
>
> Make sure that 'active_io' will represent inflight io instead of io that
> is dispatching, and io accounting from all levels will be consistent.
>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> ---
>  drivers/md/raid10.c | 20 +++++++++-----------
>  drivers/md/raid10.h |  1 -
>  2 files changed, 9 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 79067769e44b..69f6d7b1e600 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -325,8 +325,6 @@ static void raid_end_bio_io(struct r10bio *r10_bio)
>         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
>                 bio->bi_status = BLK_STS_IOERR;
>
> -       if (r10_bio->start_time)
> -               bio_end_io_acct(bio, r10_bio->start_time);
>         bio_endio(bio);
>         /*
>          * Wake up any possible resync thread that waits for the device
> @@ -1172,7 +1170,7 @@ static bool regular_request_wait(struct mddev *mddev, struct r10conf *conf,
>  }
>
>  static void raid10_read_request(struct mddev *mddev, struct bio *bio,
> -                               struct r10bio *r10_bio)
> +                               struct r10bio *r10_bio, bool io_accounting)
>  {
>         struct r10conf *conf = mddev->private;
>         struct bio *read_bio;
> @@ -1243,9 +1241,10 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
>         }
>         slot = r10_bio->read_slot;
>
> -       if (!r10_bio->start_time &&
> -           blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
> -               r10_bio->start_time = bio_start_io_acct(bio);
> +       if (io_accounting) {
> +               md_account_bio(mddev, &bio);
> +               r10_bio->master_bio = bio;
> +       }
>         read_bio = bio_alloc_clone(rdev->bdev, bio, gfp, &mddev->bio_set);
>
>         r10_bio->devs[slot].bio = read_bio;
> @@ -1543,8 +1542,8 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
>                 r10_bio->master_bio = bio;
>         }
>
> -       if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
> -               r10_bio->start_time = bio_start_io_acct(bio);
> +       md_account_bio(mddev, &bio);
> +       r10_bio->master_bio = bio;
>         atomic_set(&r10_bio->remaining, 1);
>         md_bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
>
> @@ -1571,12 +1570,11 @@ static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
>         r10_bio->sector = bio->bi_iter.bi_sector;
>         r10_bio->state = 0;
>         r10_bio->read_slot = -1;
> -       r10_bio->start_time = 0;
>         memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) *
>                         conf->geo.raid_disks);
>
>         if (bio_data_dir(bio) == READ)
> -               raid10_read_request(mddev, bio, r10_bio);
> +               raid10_read_request(mddev, bio, r10_bio, true);
>         else
>                 raid10_write_request(mddev, bio, r10_bio);
>  }
> @@ -2985,7 +2983,7 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
>
>         rdev_dec_pending(rdev, mddev);
>         r10_bio->state = 0;
> -       raid10_read_request(mddev, r10_bio->master_bio, r10_bio);
> +       raid10_read_request(mddev, r10_bio->master_bio, r10_bio, false);
>         /*
>          * allow_barrier after re-submit to ensure no sync io
>          * can be issued while regular io pending.
> diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
> index 63e48b11b552..2e75e88d0802 100644
> --- a/drivers/md/raid10.h
> +++ b/drivers/md/raid10.h
> @@ -123,7 +123,6 @@ struct r10bio {
>         sector_t                sector; /* virtual sector number */
>         int                     sectors;
>         unsigned long           state;
> -       unsigned long           start_time;
>         struct mddev            *mddev;
>         /*
>          * original bio going to /dev/mdx
> --
> 2.39.2
>

Reviewed-by: Xiao Ni <xni@redhat.com>