diff options
author | Jens Axboe <jens.axboe@oracle.com> | 2009-03-27 09:30:47 (GMT) |
---|---|---|
committer | Jens Axboe <jens.axboe@oracle.com> | 2009-04-07 06:12:37 (GMT) |
commit | 6c7e8cee6a9128eeb7f83c3ad1cb243f77f5cb16 (patch) | |
tree | f57ac6ab9e57a4e3317a54d04c39151d3bb942cf /block/elevator.c | |
parent | d508afb437daee7cf07da085b635c44a4ebf9b38 (diff) | |
download | linux-fsl-qoriq-6c7e8cee6a9128eeb7f83c3ad1cb243f77f5cb16.tar.xz |
block: elevator quiescing helpers
Simple helper functions to quiesce the request queue. These are
currently only used for switching IO schedulers on-the-fly, but
we can use them to properly switch IO accounting on and off as well.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/elevator.c')
-rw-r--r-- | block/elevator.c | 40 |
1 files changed, 27 insertions, 13 deletions
diff --git a/block/elevator.c b/block/elevator.c index ca6788a..c674491 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -587,6 +587,31 @@ static void elv_drain_elevator(struct request_queue *q) } } +/* + * Call with queue lock held, interrupts disabled + */ +void elv_quisce_start(struct request_queue *q) +{ + queue_flag_set(QUEUE_FLAG_ELVSWITCH, q); + + /* + * make sure we don't have any requests in flight + */ + elv_drain_elevator(q); + while (q->rq.elvpriv) { + blk_start_queueing(q); + spin_unlock_irq(q->queue_lock); + msleep(10); + spin_lock_irq(q->queue_lock); + elv_drain_elevator(q); + } +} + +void elv_quisce_end(struct request_queue *q) +{ + queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); +} + void elv_insert(struct request_queue *q, struct request *rq, int where) { struct list_head *pos; @@ -1101,18 +1126,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) * Turn on BYPASS and drain all requests w/ elevator private data */ spin_lock_irq(q->queue_lock); - - queue_flag_set(QUEUE_FLAG_ELVSWITCH, q); - - elv_drain_elevator(q); - - while (q->rq.elvpriv) { - blk_start_queueing(q); - spin_unlock_irq(q->queue_lock); - msleep(10); - spin_lock_irq(q->queue_lock); - elv_drain_elevator(q); - } + elv_quisce_start(q); /* * Remember old elevator. @@ -1136,7 +1150,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) */ elevator_exit(old_elevator); spin_lock_irq(q->queue_lock); - queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); + elv_quisce_end(q); spin_unlock_irq(q->queue_lock); blk_add_trace_msg(q, "elv switch: %s", e->elevator_type->elevator_name); |