Commit 26308eab authored by Jerome Marchand's avatar Jerome Marchand Committed by Jens Axboe

block: fix inconsistency in I/O stat accounting code

This forces in_flight to be zero when turning off or on the I/O stat
accounting and stops updating I/O stats in attempt_merge() when
accounting is turned off.
Signed-off-by: default avatarJerome Marchand <jmarchan@redhat.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 6c7e8cee
......@@ -64,12 +64,11 @@ static struct workqueue_struct *kblockd_workqueue;
static void drive_stat_acct(struct request *rq, int new_io)
{
struct gendisk *disk = rq->rq_disk;
struct hd_struct *part;
int rw = rq_data_dir(rq);
int cpu;
if (!blk_fs_request(rq) || !disk || !blk_do_io_stat(disk->queue))
if (!blk_fs_request(rq) || !blk_do_io_stat(rq))
return;
cpu = part_stat_lock();
......@@ -1675,9 +1674,7 @@ EXPORT_SYMBOL(blkdev_dequeue_request);
static void blk_account_io_completion(struct request *req, unsigned int bytes)
{
struct gendisk *disk = req->rq_disk;
if (!disk || !blk_do_io_stat(disk->queue))
if (!blk_do_io_stat(req))
return;
if (blk_fs_request(req)) {
......@@ -1694,9 +1691,7 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
static void blk_account_io_done(struct request *req)
{
struct gendisk *disk = req->rq_disk;
if (!disk || !blk_do_io_stat(disk->queue))
if (!blk_do_io_stat(req))
return;
/*
......@@ -1711,7 +1706,7 @@ static void blk_account_io_done(struct request *req)
int cpu;
cpu = part_stat_lock();
part = disk_map_sector_rcu(disk, req->sector);
part = disk_map_sector_rcu(req->rq_disk, req->sector);
part_stat_inc(cpu, part, ios[rw]);
part_stat_add(cpu, part, ticks[rw], duration);
......
......@@ -338,6 +338,22 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
return 1;
}
static void blk_account_io_merge(struct request *req)
{
if (blk_do_io_stat(req)) {
struct hd_struct *part;
int cpu;
cpu = part_stat_lock();
part = disk_map_sector_rcu(req->rq_disk, req->sector);
part_round_stats(cpu, part);
part_dec_in_flight(part);
part_stat_unlock();
}
}
/*
* Has to be called with the request spinlock acquired
*/
......@@ -386,18 +402,7 @@ static int attempt_merge(struct request_queue *q, struct request *req,
elv_merge_requests(q, req, next);
if (req->rq_disk) {
struct hd_struct *part;
int cpu;
cpu = part_stat_lock();
part = disk_map_sector_rcu(req->rq_disk, req->sector);
part_round_stats(cpu, part);
part_dec_in_flight(part);
part_stat_unlock();
}
blk_account_io_merge(req);
req->ioprio = ioprio_best(req->ioprio, next->ioprio);
if (blk_rq_cpu_valid(next))
......
......@@ -209,10 +209,14 @@ static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
ssize_t ret = queue_var_store(&stats, page, count);
spin_lock_irq(q->queue_lock);
elv_quisce_start(q);
if (stats)
queue_flag_set(QUEUE_FLAG_IO_STAT, q);
else
queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
elv_quisce_end(q);
spin_unlock_irq(q->queue_lock);
return ret;
......
......@@ -112,12 +112,14 @@ static inline int blk_cpu_to_group(int cpu)
#endif
}
static inline int blk_do_io_stat(struct request_queue *q)
static inline int blk_do_io_stat(struct request *rq)
{
if (q)
return blk_queue_io_stat(q);
struct gendisk *disk = rq->rq_disk;
return 0;
if (!disk || !disk->queue)
return 0;
return blk_queue_io_stat(disk->queue) && (rq->cmd_flags & REQ_ELVPRIV);
}
#endif
......@@ -573,7 +573,7 @@ void elv_requeue_request(struct request_queue *q, struct request *rq)
elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE);
}
static void elv_drain_elevator(struct request_queue *q)
void elv_drain_elevator(struct request_queue *q)
{
static int printed;
while (q->elevator->ops->elevator_dispatch_fn(q, 1))
......
......@@ -116,6 +116,7 @@ extern void elv_abort_queue(struct request_queue *);
extern void elv_completed_request(struct request_queue *, struct request *);
extern int elv_set_request(struct request_queue *, struct request *, gfp_t);
extern void elv_put_request(struct request_queue *, struct request *);
extern void elv_drain_elevator(struct request_queue *);
/*
* io scheduler registration
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment