* [PATCH] sched: deadline: Fix confusing comments about selection of top pi-waiter
@ 2017-02-23 4:09 Joel Fernandes
2017-02-28 11:15 ` Juri Lelli
2017-02-28 13:06 ` Daniel Bristot de Oliveira
0 siblings, 2 replies; 3+ messages in thread
From: Joel Fernandes @ 2017-02-23 4:09 UTC (permalink / raw)
To: linux-kernel; +Cc: Joel Fernandes, Juri Lelli, Ingo Molnar, Peter Zijlstra
This comment in the code is incomplete, and I believe it begs a definition of
dl_boosted to make sense of the condition that follows. Rewrite the comment and
also rearrange the condition that follows to reflect the first condition "we
have a top pi-waiter which is a SCHED_DEADLINE task" in that order. Also fix a
typo that follows.
Cc: Juri Lelli <Juri.Lelli@arm.com>
Signed-off-by: Joel Fernandes <joelaf@google.com>
---
kernel/sched/deadline.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 70ef2b1901e4..4b86abcef135 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -928,17 +928,19 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
struct sched_dl_entity *pi_se = &p->dl;
/*
- * Use the scheduling parameters of the top pi-waiter
- * task if we have one and its (absolute) deadline is
- * smaller than our one... OTW we keep our runtime and
- * deadline.
+ * Use the scheduling parameters of the top pi-waiter task if:
+ * - we have a top pi-waiter which is a SCHED_DEADLINE task AND
+ * - our dl_boosted is set (i.e. the pi-waiter's (absolute) deadline is
+ * smaller than our deadline OR we are a !SCHED_DEADLINE task getting
+ * boosted due to a SCHED_DEADLINE pi-waiter).
+ * Otherwise we keep our runtime and deadline.
*/
- if (pi_task && p->dl.dl_boosted && dl_prio(pi_task->normal_prio)) {
+ if (pi_task && dl_prio(pi_task->normal_prio) && p->dl.dl_boosted) {
pi_se = &pi_task->dl;
} else if (!dl_prio(p->normal_prio)) {
/*
* Special case in which we have a !SCHED_DEADLINE task
- * that is going to be deboosted, but exceedes its
+ * that is going to be deboosted, but exceeds its
* runtime while doing so. No point in replenishing
* it, as it's going to return back to its original
* scheduling class after this.
--
2.11.0.483.g087da7b7c-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] sched: deadline: Fix confusing comments about selection of top pi-waiter
2017-02-23 4:09 [PATCH] sched: deadline: Fix confusing comments about selection of top pi-waiter Joel Fernandes
@ 2017-02-28 11:15 ` Juri Lelli
2017-02-28 13:06 ` Daniel Bristot de Oliveira
1 sibling, 0 replies; 3+ messages in thread
From: Juri Lelli @ 2017-02-28 11:15 UTC (permalink / raw)
To: Joel Fernandes; +Cc: linux-kernel, Ingo Molnar, Peter Zijlstra
Hi,
On 22/02/17 20:09, Joel Fernandes wrote:
> This comment in the code is incomplete, and I believe it begs a definition of
> dl_boosted to make sense of the condition that follows. Rewrite the comment and
> also rearrange the condition that follows to reflect the first condition "we
> have a top pi-waiter which is a SCHED_DEADLINE task" in that order. Also fix a
> typo that follows.
>
> Cc: Juri Lelli <Juri.Lelli@arm.com>
> Signed-off-by: Joel Fernandes <joelaf@google.com>
Looks good to me.
Acked-by: Juri Lelli <juri.lelli@arm.com>
Thanks,
- Juri
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] sched: deadline: Fix confusing comments about selection of top pi-waiter
2017-02-23 4:09 [PATCH] sched: deadline: Fix confusing comments about selection of top pi-waiter Joel Fernandes
2017-02-28 11:15 ` Juri Lelli
@ 2017-02-28 13:06 ` Daniel Bristot de Oliveira
1 sibling, 0 replies; 3+ messages in thread
From: Daniel Bristot de Oliveira @ 2017-02-28 13:06 UTC (permalink / raw)
To: Joel Fernandes, linux-kernel; +Cc: Juri Lelli, Ingo Molnar, Peter Zijlstra
On 02/23/2017 05:09 AM, Joel Fernandes wrote:
> This comment in the code is incomplete, and I believe it begs a definition of
> dl_boosted to make sense of the condition that follows. Rewrite the comment and
> also rearrange the condition that follows to reflect the first condition "we
> have a top pi-waiter which is a SCHED_DEADLINE task" in that order. Also fix a
> typo that follows.
>
> Cc: Juri Lelli <Juri.Lelli@arm.com>
> Signed-off-by: Joel Fernandes <joelaf@google.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
-- Daniel
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-02-23 4:09 [PATCH] sched: deadline: Fix confusing comments about selection of top pi-waiter Joel Fernandes
2017-02-28 11:15 ` Juri Lelli
2017-02-28 13:06 ` Daniel Bristot de Oliveira
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