On Sat 14-05-22 17:05:21, Yu Kuai wrote:
It will only be called from bfq_bfqq_handle_idle_busy_switch() in
specific code branch, there is no need to precaculate
'bfqq_wants_to_preempt' each time bfq_bfqq_handle_idle_busy_switch()
is caleld.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Please see below:
@@ -1816,14 +1807,6 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd,...
(bfqq->bic || RQ_BIC(rq)->stably_merged) &&
(*interactive || soft_rt)));
- /*
- * Using the last flag, update budget and check whether bfqq
- * may want to preempt the in-service queue.
- */
- bfqq_wants_to_preempt =
- bfq_bfqq_update_budg_for_activation(bfqd, bfqq,
- arrived_in_time);
-
/*
* If bfqq happened to be activated in a burst, but has been
* idle for much more than an interactive queue, then we
@@ -1918,7 +1900,7 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd,
* (2) this switch of bfqq to busy changes the scenario.
*/
if (bfqd->in_service_queue &&
- ((bfqq_wants_to_preempt &&
+ ((bfq_bfqq_update_budg_for_activation(bfqd, bfqq) &&
bfqq->wr_coeff >= bfqd->in_service_queue->wr_coeff) ||
bfq_bfqq_higher_class_or_weight(bfqq, bfqd->in_service_queue) ||
!bfq_better_to_idle(bfqd->in_service_queue)) &&
So these changes are actually wrong because
bfq_bfqq_update_budg_for_activation() relies on
bfq_bfqq_non_blocking_wait_rq() but bfq_add_bfqq_busy() clears that. And
bfq_add_bfqq_busy() is called between the place where
bfq_bfqq_update_budg_for_activation() was called previously and now so your
patch breaks this logic.
Honza