block: Track DISCARD statistics and output them in stat and diskstat
Add tracking of REQ_OP_DISCARD ios to the partition statistics and
append them to the various stat files in /sys as well as
/proc/diskstats. These are tracked with the same four stats as reads
and writes:
Number of discard ios completed.
Number of discard ios merged
Number of discard sectors completed
Milliseconds spent on discard requests
This is done via adding a new STAT_DISCARD define to genhd.h and then
using it to index that stat field for discard requests.
tj: Refreshed on top of v4.17 and other previous updates.
Signed-off-by: Michael Callahan <michaelcallahan@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andy Newell <newella@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/genhd.c b/block/genhd.c
index 0711a80..8cc719a3 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1333,8 +1333,11 @@ static int diskstats_show(struct seq_file *seqf, void *v)
part_round_stats(gp->queue, cpu, hd);
part_stat_unlock();
part_in_flight(gp->queue, hd, inflight);
- seq_printf(seqf, "%4d %7d %s %lu %lu %lu "
- "%u %lu %lu %lu %u %u %u %u\n",
+ seq_printf(seqf, "%4d %7d %s "
+ "%lu %lu %lu %u "
+ "%lu %lu %lu %u "
+ "%u %u %u "
+ "%lu %lu %lu %u\n",
MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
disk_name(gp, hd->partno, buf),
part_stat_read(hd, ios[STAT_READ]),
@@ -1347,7 +1350,11 @@ static int diskstats_show(struct seq_file *seqf, void *v)
jiffies_to_msecs(part_stat_read(hd, ticks[STAT_WRITE])),
inflight[0],
jiffies_to_msecs(part_stat_read(hd, io_ticks)),
- jiffies_to_msecs(part_stat_read(hd, time_in_queue))
+ jiffies_to_msecs(part_stat_read(hd, time_in_queue)),
+ part_stat_read(hd, ios[STAT_DISCARD]),
+ part_stat_read(hd, merges[STAT_DISCARD]),
+ part_stat_read(hd, sectors[STAT_DISCARD]),
+ jiffies_to_msecs(part_stat_read(hd, ticks[STAT_DISCARD]))
);
}
disk_part_iter_exit(&piter);