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>
This commit is contained in:
Jens Axboe
2009-03-27 10:30:47 +01:00
parent d508afb437
commit 6c7e8cee6a
2 changed files with 31 additions and 13 deletions
+4
View File
@@ -70,6 +70,10 @@ void blk_queue_congestion_threshold(struct request_queue *q);
int blk_dev_init(void);
void elv_quisce_start(struct request_queue *q);
void elv_quisce_end(struct request_queue *q);
/*
* Return the threshold (number of used requests) at which the queue is
* considered to be congested. It include a little hysteresis to keep the