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authorMikulas Patocka <mpatocka@redhat.com>2018-12-06 19:41:19 +0300
committerJens Axboe <axboe@kernel.dk>2018-12-10 18:30:37 +0300
commit5b18b5a737600fd20ba2045f320d5926ebbf341a (patch)
treefe35e150bf36785dfe3ed8c845e3b043e56f9f90 /block/partition-generic.c
parent112f158f66cbe25fd561a5dfe9c3826e06abf757 (diff)
downloadlinux-5b18b5a737600fd20ba2045f320d5926ebbf341a.tar.xz
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 <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/partition-generic.c')
-rw-r--r--block/partition-generic.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/block/partition-generic.c b/block/partition-generic.c
index 7e663cfb1487..42d6138ac876 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -122,9 +122,6 @@ ssize_t part_stat_show(struct device *dev,
struct request_queue *q = part_to_disk(p)->queue;
unsigned int inflight[2];
- part_stat_lock();
- part_round_stats(q, p);
- part_stat_unlock();
part_in_flight(q, p, inflight);
return sprintf(buf,
"%8lu %8lu %8llu %8u "