From 26308eab69aa193f7b3fb50764a64ae14544a39b Mon Sep 17 00:00:00 2001 From: Jerome Marchand Date: Fri, 27 Mar 2009 10:31:51 +0100 Subject: [PATCH] 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: Jerome Marchand Signed-off-by: Jens Axboe --- block/blk-core.c | 13 ++++--------- block/blk-merge.c | 29 +++++++++++++++++------------ block/blk-sysfs.c | 4 ++++ block/blk.h | 10 ++++++---- block/elevator.c | 2 +- include/linux/elevator.h | 1 + 6 files changed, 33 insertions(+), 26 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 25572802dac2..3688abff2430 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -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); diff --git a/block/blk-merge.c b/block/blk-merge.c index e39cb24b7679..63760ca3da0f 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -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)) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 3ff9bba3379a..73f36beff5cd 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -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; diff --git a/block/blk.h b/block/blk.h index 22043c2886c7..24fcaeeaf620 100644 --- a/block/blk.h +++ b/block/blk.h @@ -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 diff --git a/block/elevator.c b/block/elevator.c index c6744913ff4a..fb81bcc14a8c 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -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)) diff --git a/include/linux/elevator.h b/include/linux/elevator.h index 7a204256b155..c59b769f62b0 100644 --- a/include/linux/elevator.h +++ b/include/linux/elevator.h @@ -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