diff options
| author | Nikanth Karthikesan <knikanth@suse.de> | 2009-10-06 22:16:55 +0400 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2009-10-06 22:16:55 +0400 |
| commit | 316d315bffa4026f28085f6b24ebcebede370ac7 (patch) | |
| tree | 10b6b057fec2382536371d2e14f9d4c0d6cf9eea /drivers/md | |
| parent | 23e018a1b083ecb4b8bb2fb43d58e7c19b5d7959 (diff) | |
| download | linux-316d315bffa4026f28085f6b24ebcebede370ac7.tar.xz | |
block: Seperate read and write statistics of in_flight requests v2
Commit a9327cac440be4d8333bba975cbbf76045096275 added seperate read
and write statistics of in_flight requests. And exported the number
of read and write requests in progress seperately through sysfs.
But Corrado Zoccolo <czoccolo@gmail.com> reported getting strange
output from "iostat -kx 2". Global values for service time and
utilization were garbage. For interval values, utilization was always
100%, and service time is higher than normal.
So this was reverted by commit 0f78ab9899e9d6acb09d5465def618704255963b
The problem was in part_round_stats_single(), I missed the following:
if (now == part->stamp)
return;
- if (part->in_flight) {
+ if (part_in_flight(part)) {
__part_stat_add(cpu, part, time_in_queue,
part_in_flight(part) * (now - part->stamp));
__part_stat_add(cpu, part, io_ticks, (now - part->stamp));
With this chunk included, the reported regression gets fixed.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
--
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 23e76fe0d359..376f1ab48a24 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -130,7 +130,7 @@ struct mapped_device { /* * A list of ios that arrived while we were suspended. */ - atomic_t pending; + atomic_t pending[2]; wait_queue_head_t wait; struct work_struct work; struct bio_list deferred; @@ -453,13 +453,14 @@ static void start_io_acct(struct dm_io *io) { struct mapped_device *md = io->md; int cpu; + int rw = bio_data_dir(io->bio); io->start_time = jiffies; cpu = part_stat_lock(); part_round_stats(cpu, &dm_disk(md)->part0); part_stat_unlock(); - dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending); + dm_disk(md)->part0.in_flight[rw] = atomic_inc_return(&md->pending[rw]); } static void end_io_acct(struct dm_io *io) @@ -479,8 +480,9 @@ static void end_io_acct(struct dm_io *io) * After this is decremented the bio must not be touched if it is * a barrier. */ - dm_disk(md)->part0.in_flight = pending = - atomic_dec_return(&md->pending); + dm_disk(md)->part0.in_flight[rw] = pending = + atomic_dec_return(&md->pending[rw]); + pending += atomic_read(&md->pending[rw^0x1]); /* nudge anyone waiting on suspend queue */ if (!pending) @@ -1785,7 +1787,8 @@ static struct mapped_device *alloc_dev(int minor) if (!md->disk) goto bad_disk; - atomic_set(&md->pending, 0); + 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); @@ -2088,7 +2091,8 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible) break; } spin_unlock_irqrestore(q->queue_lock, flags); - } else if (!atomic_read(&md->pending)) + } else if (!atomic_read(&md->pending[0]) && + !atomic_read(&md->pending[1])) break; if (interruptible == TASK_INTERRUPTIBLE && |