diff mbox series

[v2,10/14] block: add bio_start_io_acct_remapped for the benefit of DM

Message ID 20220211214057.40612-11-snitzer@redhat.com (mailing list archive)
State New, archived
Headers show
Series dm: improve bio-based IO accounting | expand

Commit Message

Mike Snitzer Feb. 11, 2022, 9:40 p.m. UTC 
DM needs the ability to account a clone bio's IO to the original
block_device. So add @orig_bdev argument to bio_start_io_acct_time.

Rename bio_start_io_acct_time to bio_start_io_acct_remapped.

Also, follow bio_end_io_acct and bio_end_io_acct_remapped pattern by
moving bio_start_io_acct to blkdev.h and have it call
bio_start_io_acct_remapped.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 block/blk-core.c       | 24 ++++++++----------------
 drivers/md/dm.c        |  3 ++-
 include/linux/blkdev.h | 16 ++++++++++++++--
 3 files changed, 24 insertions(+), 19 deletions(-)

Comments

Christoph Hellwig Feb. 14, 2022, 2:02 p.m. UTC | #1 
On Fri, Feb 11, 2022 at 04:40:53PM -0500, Mike Snitzer wrote:
> DM needs the ability to account a clone bio's IO to the original
> block_device. So add @orig_bdev argument to bio_start_io_acct_time.
> 
> Rename bio_start_io_acct_time to bio_start_io_acct_remapped.
> 
> Also, follow bio_end_io_acct and bio_end_io_acct_remapped pattern by
> moving bio_start_io_acct to blkdev.h and have it call
> bio_start_io_acct_remapped.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
Mike Snitzer Feb. 15, 2022, 2:40 a.m. UTC | #2 
On Mon, Feb 14 2022 at  9:02P -0500,
Christoph Hellwig <hch@infradead.org> wrote:

> On Fri, Feb 11, 2022 at 04:40:53PM -0500, Mike Snitzer wrote:
> > DM needs the ability to account a clone bio's IO to the original
> > block_device. So add @orig_bdev argument to bio_start_io_acct_time.
> > 
> > Rename bio_start_io_acct_time to bio_start_io_acct_remapped.
> > 
> > Also, follow bio_end_io_acct and bio_end_io_acct_remapped pattern by
> > moving bio_start_io_acct to blkdev.h and have it call
> > bio_start_io_acct_remapped.
> 
> Looks good:
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> 

Thanks.

But turns out I don't need this patch afterall.

DM can't account IO to the DM device in terms of clone bios because
they may not be simple remaps, the payload could change in size such
that the original vs clone varies widely.  Also, dmstats imposes the
additional constraint that the same bio be used for the
{start,end}_io_acct's calls to dm_stats_account_io().
diff mbox series

Patch

diff --git a/block/blk-core.c b/block/blk-core.c
index be8812f5489d..8f23be96c737 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1077,29 +1077,21 @@  static unsigned long __part_start_io_acct(struct block_device *part,
 }
 
 /**
- * bio_start_io_acct_time - start I/O accounting for bio based drivers
+ * bio_start_io_acct_remapped - start I/O accounting for bio based drivers
  * @bio:	bio to start account for
  * @start_time:	start time that should be passed back to bio_end_io_acct().
- */
-void bio_start_io_acct_time(struct bio *bio, unsigned long start_time)
-{
-	__part_start_io_acct(bio->bi_bdev, bio_sectors(bio),
-			     bio_op(bio), start_time);
-}
-EXPORT_SYMBOL_GPL(bio_start_io_acct_time);
-
-/**
- * bio_start_io_acct - start I/O accounting for bio based drivers
- * @bio:	bio to start account for
+ * @orig_bdev:	block device that I/O must be accounted to.
  *
  * Returns the start time that should be passed back to bio_end_io_acct().
  */
-unsigned long bio_start_io_acct(struct bio *bio)
+unsigned long bio_start_io_acct_remapped(struct bio *bio,
+				unsigned long start_time,
+				struct block_device *orig_bdev)
 {
-	return __part_start_io_acct(bio->bi_bdev, bio_sectors(bio),
-				    bio_op(bio), jiffies);
+	return __part_start_io_acct(orig_bdev, bio_sectors(bio),
+				    bio_op(bio), start_time);
 }
-EXPORT_SYMBOL_GPL(bio_start_io_acct);
+EXPORT_SYMBOL_GPL(bio_start_io_acct_remapped);
 
 unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
 				 unsigned int op)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 72686329f91e..c0177552b471 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -489,7 +489,8 @@  static void start_io_acct(struct dm_io *io)
 {
 	struct bio *bio = io->orig_bio;
 
-	bio_start_io_acct_time(bio, io->start_time);
+	bio_start_io_acct_remapped(bio, io->start_time,
+				   io->orig_bio->bi_bdev);
 
 	if (unlikely(dm_stats_used(&io->md->stats)))
 		dm_stats_account_io(&io->md->stats, bio_data_dir(bio),
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3bfc75a2a450..31d055d4a17e 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1512,11 +1512,23 @@  unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
 void disk_end_io_acct(struct gendisk *disk, unsigned int op,
 		unsigned long start_time);
 
-void bio_start_io_acct_time(struct bio *bio, unsigned long start_time);
-unsigned long bio_start_io_acct(struct bio *bio);
+unsigned long bio_start_io_acct_remapped(struct bio *bio,
+				unsigned long start_time,
+				struct block_device *orig_bdev);
 void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
 		struct block_device *orig_bdev);
 
+/**
+ * bio_start_io_acct - start I/O accounting for bio based drivers
+ * @bio:	bio to start account for
+ *
+ * Returns the start time that should be passed back to bio_end_io_acct().
+ */
+static inline unsigned long bio_start_io_acct(struct bio *bio)
+{
+	return bio_start_io_acct_remapped(bio, jiffies, bio->bi_bdev);
+}
+
 /**
  * bio_end_io_acct - end I/O accounting for bio based drivers
  * @bio:	bio to end account for