lkml.org 
[lkml]   [2022]   [Jan]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.16 064/200] dm: properly fix redundant bio-based IO accounting
    Date
    From: Mike Snitzer <snitzer@redhat.com>

    commit b879f915bc48a18d4f4462729192435bb0f17052 upstream.

    Record the start_time for a bio but defer the starting block core's IO
    accounting until after IO is submitted using bio_start_io_acct_time().

    This approach avoids the need to mess around with any of the
    individual IO stats in response to a bio_split() that follows bio
    submission.

    Reported-by: Bud Brown <bubrown@redhat.com>
    Reviewed-by: Christoph Hellwig <hch@lst.de>
    Cc: stable@vger.kernel.org
    Depends-on: e45c47d1f94e ("block: add bio_start_io_acct_time() to control start_time")
    Signed-off-by: Mike Snitzer <snitzer@redhat.com>
    Link: https://lore.kernel.org/r/20220128155841.39644-4-snitzer@redhat.com
    Signed-off-by: Jens Axboe <axboe@kernel.dk>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/md/dm.c | 5 +++--
    1 file changed, 3 insertions(+), 2 deletions(-)

    --- a/drivers/md/dm.c
    +++ b/drivers/md/dm.c
    @@ -489,7 +489,7 @@ static void start_io_acct(struct dm_io *
    struct mapped_device *md = io->md;
    struct bio *bio = io->orig_bio;

    - io->start_time = bio_start_io_acct(bio);
    + bio_start_io_acct_time(bio, io->start_time);
    if (unlikely(dm_stats_used(&md->stats)))
    dm_stats_account_io(&md->stats, bio_data_dir(bio),
    bio->bi_iter.bi_sector, bio_sectors(bio),
    @@ -535,7 +535,7 @@ static struct dm_io *alloc_io(struct map
    io->md = md;
    spin_lock_init(&io->endio_lock);

    - start_io_acct(io);
    + io->start_time = jiffies;

    return io;
    }
    @@ -1550,6 +1550,7 @@ static void __split_and_process_bio(stru
    submit_bio_noacct(bio);
    }
    }
    + start_io_acct(ci.io);

    /* drop the extra reference count */
    dm_io_dec_pending(ci.io, errno_to_blk_status(error));

    \
     
     \ /
      Last update: 2022-01-31 13:09    [W:4.023 / U:0.024 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site