From 5b18b5a737600fd20ba2045f320d5926ebbf341a Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 6 Dec 2018 11:41:19 -0500 Subject: block: delete part_round_stats and switch to less precise counting We want to convert to per-cpu in_flight counters. The function part_round_stats needs the in_flight counter every jiffy, it would be too costly to sum all the percpu variables every jiffy, so it must be deleted. part_round_stats is used to calculate two counters - time_in_queue and io_ticks. time_in_queue can be calculated without part_round_stats, by adding the duration of the I/O when the I/O ends (the value is almost as exact as the previously calculated value, except that time for in-progress I/Os is not counted). io_ticks can be approximated by increasing the value when I/O is started or ended and the jiffies value has changed. If the I/Os take less than a jiffy, the value is as exact as the previously calculated value. If the I/Os take more than a jiffy, io_ticks can drift behind the previously calculated value. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Jens Axboe --- include/linux/genhd.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'include/linux/genhd.h') diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 1677cd2a4c4e..838c2a7a40c5 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -398,8 +398,7 @@ static inline void free_part_info(struct hd_struct *part) kfree(part->info); } -/* block/blk-core.c */ -extern void part_round_stats(struct request_queue *q, struct hd_struct *part); +void update_io_ticks(struct hd_struct *part, unsigned long now); /* block/genhd.c */ extern void device_add_disk(struct device *parent, struct gendisk *disk, -- cgit v1.2.3-59-g8ed1b