blk-throttle: process limit change only through one function

With the help of cgroup interface one can go and upate the bps/iops
limits of existing group. Once the limits are udpated, a thread is
woken up to see if some blocked group needs recalculation based on new
limits and needs to be requeued.

There was also a piece of code where I was checking for group limit
update when a fresh bio comes in. This patch gets rid of that piece of
code and keeps processing the limit change at one place
throtl_process_limit_change().  It just keeps the code simple and easy
to understand.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 061dee6..a29f092 100644 (file)
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1009,14 +1009,8 @@ int blk_throtl_bio(struct request_queue *q, struct bio **biop)
                /*
                 * There is already another bio queued in same dir. No
                 * need to update dispatch time.
-                * Still update the disptime if rate limits on this group
-                * were changed.
                 */
-               if (!tg->limits_changed)
-                       update_disptime = false;
-               else
-                       tg->limits_changed = false;
-
+               update_disptime = false;
                goto queue_bio;
        }