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dm: remove the pending IO accounting 

Remove the "pending" atomic counters, that duplicate block-core's
in_flight counters, and update md_in_flight() to look at percpu
in_flight counters.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Mikulas Patocka 2018-12-06 11:41:22 -05:00 committed by Jens Axboe
parent e016b78201
commit 6f75723190
2 changed files with 15 additions and 21 deletions
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2
drivers/md/dm-core.h
View File

@ -65,7 +65,6 @@ struct mapped_device {
*/
struct work_struct work;
wait_queue_head_t wait;
atomic_t pending[2];
spinlock_t deferred_lock;
struct bio_list deferred;
@ -119,7 +118,6 @@ struct mapped_device {
struct srcu_struct io_barrier;
};
int md_in_flight(struct mapped_device *md);
void disable_write_same(struct mapped_device *md);
void disable_write_zeroes(struct mapped_device *md);

34
drivers/md/dm.c
View File

@ -646,25 +646,30 @@ static void free_tio(struct dm_target_io *tio)
bio_put(&tio->clone);
}
int md_in_flight(struct mapped_device *md)
static bool md_in_flight(struct mapped_device *md)
{
return atomic_read(&md->pending[READ]) +
atomic_read(&md->pending[WRITE]);
int cpu;
struct hd_struct *part = &dm_disk(md)->part0;
for_each_possible_cpu(cpu) {
if (part_stat_local_read_cpu(part, in_flight[0], cpu) ||
part_stat_local_read_cpu(part, in_flight[1], cpu))
return true;
}
return false;
}
static void start_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
struct bio *bio = io->orig_bio;
int rw = bio_data_dir(bio);
io->start_time = jiffies;
generic_start_io_acct(md->queue, bio_op(bio), bio_sectors(bio),
&dm_disk(md)->part0);
atomic_inc(&md->pending[rw]);
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),
@ -676,8 +681,6 @@ static void end_io_acct(struct dm_io *io)
struct mapped_device *md = io->md;
struct bio *bio = io->orig_bio;
unsigned long duration = jiffies - io->start_time;
int pending;
int rw = bio_data_dir(bio);
generic_end_io_acct(md->queue, bio_op(bio), &dm_disk(md)->part0,
io->start_time);
@ -687,16 +690,11 @@ static void end_io_acct(struct dm_io *io)
bio->bi_iter.bi_sector, bio_sectors(bio),
true, duration, &io->stats_aux);
/*
* After this is decremented the bio must not be touched if it is
* a flush.
*/
pending = atomic_dec_return(&md->pending[rw]);
pending += atomic_read(&md->pending[rw^0x1]);
/* nudge anyone waiting on suspend queue */
if (!pending)
wake_up(&md->wait);
if (unlikely(waitqueue_active(&md->wait))) {
if (!md_in_flight(md))
wake_up(&md->wait);
}
}
/*
@ -1915,8 +1913,6 @@ static struct mapped_device *alloc_dev(int minor)
if (!md->disk)
goto bad;
atomic_set(&md->pending[0], 0);
atomic_set(&md->pending[1], 0);
init_waitqueue_head(&md->wait);
INIT_WORK(&md->work, dm_wq_work);
init_waitqueue_head(&md->eventq);