From: Li Nan <linan122@xxxxxxxxxx>
Commit bc59ba9468d9 ("block: add sysfs file for controlling io stats
accounting") allowed user to turn off disk stat accounting completely by
queue flag QUEUE_FLAG_IO_STAT. In dm, this flag is not set for BIO_BASED
device, io stats is continuously counted and cannot be turn off.
Support turning off io stat accounting for dm. Set QUEUE_FLAG_IO_STAT for
dm request_queue. When the io starts, we account the io using DM_IO_STAT
dm_io flag to avoid io stats disable in the middle of the io. DM statistics
is independent of block io stat and remains unchanged.
Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
---
v2:
- set QUEUE_FLAG_IO_STAT in dm_setup_md_queue()
- get request_queue by md->queue
---
drivers/md/dm-core.h | 3 ++-
drivers/md/dm.c | 16 +++++++++++-----
2 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index aecab0c0720f..8b0af3e1331a 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -307,7 +307,8 @@ struct dm_io {
*/
enum {
DM_IO_ACCOUNTED,
- DM_IO_WAS_SPLIT
+ DM_IO_WAS_SPLIT,
+ DM_IO_STAT
};
static inline bool dm_io_flagged(struct dm_io *io, unsigned int bit)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3b694ba3a106..fee27ae4129e 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -511,11 +511,14 @@ static void dm_io_acct(struct dm_io *io, bool end)
else
sectors = io->sectors;
- if (!end)
- bdev_start_io_acct(bio->bi_bdev, bio_op(bio), start_time);
- else
- bdev_end_io_acct(bio->bi_bdev, bio_op(bio), sectors,
- start_time);
+ if (dm_io_flagged(io, DM_IO_STAT)) {
+ if (!end)
+ bdev_start_io_acct(bio->bi_bdev, bio_op(bio),
+ start_time);
+ else
+ bdev_end_io_acct(bio->bi_bdev, bio_op(bio),
+ sectors, start_time);
+ }
if (static_branch_unlikely(&stats_enabled) &&
unlikely(dm_stats_used(&md->stats))) {
@@ -592,6 +595,8 @@ static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
spin_lock_init(&io->lock);
io->start_time = jiffies;
io->flags = 0;
+ if (blk_queue_io_stat(md->queue))
+ dm_io_set_flag(io, DM_IO_STAT);
if (static_branch_unlikely(&stats_enabled))
dm_stats_record_start(&md->stats, &io->stats_aux);
@@ -2341,6 +2346,7 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
break;
case DM_TYPE_BIO_BASED:
case DM_TYPE_DAX_BIO_BASED:
+ blk_queue_flag_set(QUEUE_FLAG_IO_STAT, md->queue);
break;
case DM_TYPE_NONE:
WARN_ON_ONCE(true);
--
2.39.2
--
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