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authorNikanth Karthikesan <knikanth@suse.de>2009-09-11 09:18:54 +0200
committerJens Axboe <jens.axboe@oracle.com>2009-09-14 08:24:52 +0200
commita9327cac440be4d8333bba975cbbf76045096275 (patch)
tree83fd5dc45dc925c5b4eb0264c3add96cfaa4cae6 /drivers
parent18d8217bc441630c3c5ec7416c5a65c69e8a0979 (diff)
Seperate read and write statistics of in_flight requests
Currently, there is a single in_flight counter measuring the number of requests in the request_queue. But some monitoring tools would like to know how many read requests and write requests are in progress. Split the current in_flight counter into two seperate counters for read and write. This information is exported as a sysfs attribute, as changing the currently available stat files would break the existing tools. Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/dm.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ec012f03024..eee28fac210 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 &&