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 <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Cc: [email protected] Depends-on: 1073e8492f88 ("block: add bio_start_io_acct_time() to control start_time") Signed-off-by: Mike Snitzer <[email protected]> --- drivers/md/dm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 9849114b3c08..dcbd6d201619 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -489,7 +489,7 @@ static void start_io_acct(struct dm_io *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 mapped_device *md, struct bio *bio) io->md = md; spin_lock_init(&io->endio_lock); - start_io_acct(io); + io->start_time = jiffies; return io; } @@ -1482,6 +1482,7 @@ static void __split_and_process_bio(struct mapped_device *md, 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)); -- 2.15.0 -- dm-devel mailing list [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
