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dm: simplify bio-based IO accounting further

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Now that io splitting is recorded prior to, or during, ->map IO
accounting can happen immediately rather than defer until after
bio splitting in dm_split_and_process_bio().

Remove the DM_IO_START_ACCT flag and also remove dm_io's map_task
member because there is no longer any need to wait for splitting to
occur before accounting.

Also move dm_io struct's 'flags' member to consolidate struct holes.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Mike Snitzer 2022-04-15 20:08:23 -04:00
parent ec211631ae
commit 9d20653fe8
2 changed files with 6 additions and 34 deletions
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6
drivers/md/dm-core.h
View file

@ -255,15 +255,12 @@ static inline bool dm_tio_is_normal(struct dm_target_io *tio)
#define DM_IO_MAGIC 19577 #define DM_IO_MAGIC 19577
struct dm_io { struct dm_io {
unsigned short magic; unsigned short magic;
blk_short_t flags;
spinlock_t lock; spinlock_t lock;
unsigned long start_time; unsigned long start_time;
void *data; void *data;
struct dm_io *next; struct dm_io *next;
struct task_struct *map_task;
struct dm_stats_aux stats_aux; struct dm_stats_aux stats_aux;
blk_short_t flags;
blk_status_t status; blk_status_t status;
atomic_t io_count; atomic_t io_count;
struct mapped_device *md; struct mapped_device *md;
@ -281,7 +278,6 @@ struct dm_io {
* dm_io flags * dm_io flags
*/ */
enum { enum {
DM_IO_START_ACCT,
DM_IO_ACCOUNTED, DM_IO_ACCOUNTED,
DM_IO_WAS_SPLIT DM_IO_WAS_SPLIT
}; };

32
drivers/md/dm.c
View file

@ -596,7 +596,6 @@ static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
this_cpu_inc(*md->pending_io); this_cpu_inc(*md->pending_io);
io->orig_bio = bio; io->orig_bio = bio;
io->md = md; io->md = md;
io->map_task = current;
spin_lock_init(&io->lock); spin_lock_init(&io->lock);
io->start_time = jiffies; io->start_time = jiffies;
io->flags = 0; io->flags = 0;
@ -1241,13 +1240,6 @@ void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
} }
EXPORT_SYMBOL_GPL(dm_accept_partial_bio); EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
static inline void __dm_submit_bio_remap(struct bio *clone,
dev_t dev, sector_t old_sector)
{
trace_block_bio_remap(clone, dev, old_sector);
submit_bio_noacct(clone);
}
/* /*
* @clone: clone bio that DM core passed to target's .map function * @clone: clone bio that DM core passed to target's .map function
* @tgt_clone: clone of @clone bio that target needs submitted * @tgt_clone: clone of @clone bio that target needs submitted
@ -1262,8 +1254,6 @@ void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)
struct dm_target_io *tio = clone_to_tio(clone); struct dm_target_io *tio = clone_to_tio(clone);
struct dm_io *io = tio->io; struct dm_io *io = tio->io;
WARN_ON_ONCE(!tio->ti->accounts_remapped_io);
/* establish bio that will get submitted */ /* establish bio that will get submitted */
if (!tgt_clone) if (!tgt_clone)
tgt_clone = clone; tgt_clone = clone;
@ -1272,15 +1262,11 @@ void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)
* Account io->origin_bio to DM dev on behalf of target * Account io->origin_bio to DM dev on behalf of target
* that took ownership of IO with DM_MAPIO_SUBMITTED. * that took ownership of IO with DM_MAPIO_SUBMITTED.
*/ */
if (io->map_task == current) {
/* Still in target's map function */
dm_io_set_flag(io, DM_IO_START_ACCT);
} else {
dm_start_io_acct(io, clone); dm_start_io_acct(io, clone);
}
__dm_submit_bio_remap(tgt_clone, disk_devt(io->md->disk), trace_block_bio_remap(tgt_clone, disk_devt(io->md->disk),
tio->old_sector); tio->old_sector);
submit_bio_noacct(tgt_clone);
} }
EXPORT_SYMBOL_GPL(dm_submit_bio_remap); EXPORT_SYMBOL_GPL(dm_submit_bio_remap);
@ -1340,16 +1326,10 @@ static void __map_bio(struct bio *clone)
case DM_MAPIO_SUBMITTED: case DM_MAPIO_SUBMITTED:
/* target has assumed ownership of this io */ /* target has assumed ownership of this io */
if (!ti->accounts_remapped_io) if (!ti->accounts_remapped_io)
dm_io_set_flag(io, DM_IO_START_ACCT); dm_start_io_acct(io, clone);
break; break;
case DM_MAPIO_REMAPPED: case DM_MAPIO_REMAPPED:
/* dm_submit_bio_remap(clone, NULL);
* the bio has been remapped so dispatch it, but defer
* dm_start_io_acct() until after possible bio_split().
*/
__dm_submit_bio_remap(clone, disk_devt(md->disk),
tio->old_sector);
dm_io_set_flag(io, DM_IO_START_ACCT);
break; break;
case DM_MAPIO_KILL: case DM_MAPIO_KILL:
case DM_MAPIO_REQUEUE: case DM_MAPIO_REQUEUE:
@ -1667,7 +1647,6 @@ static void dm_split_and_process_bio(struct mapped_device *md,
} }
error = __split_and_process_bio(&ci); error = __split_and_process_bio(&ci);
io->map_task = NULL;
if (error || !ci.sector_count) if (error || !ci.sector_count)
goto out; goto out;
/* /*
@ -1679,9 +1658,6 @@ static void dm_split_and_process_bio(struct mapped_device *md,
bio_inc_remaining(bio); bio_inc_remaining(bio);
submit_bio_noacct(bio); submit_bio_noacct(bio);
out: out:
if (dm_io_flagged(io, DM_IO_START_ACCT))
dm_start_io_acct(io, NULL);
/* /*
* Drop the extra reference count for non-POLLED bio, and hold one * Drop the extra reference count for non-POLLED bio, and hold one
* reference for POLLED bio, which will be released in dm_poll_bio * reference for POLLED bio, which will be released in dm_poll_bio