sched: deadline: Fix confusing comments about selection of top pi-waiter
PATCH RESEND 1/1 sched: deadline: Fix confusing comments about selection of top pi-waiter
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 Peter Zijlstra <[email protected]>
Signed-off-by Joel Fernandes <[email protected]>
Acked-by Juri Lelli <[email protected]>
Reviewed-by Daniel Bristot de Oliveira <[email protected]>
--- kernel/sched/deadline.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
kernel/sched/deadline.c +8 -6
@@ -970,17 +970,19 @@ 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.
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2.13.2.932.g7449e964c-goog
tip-bot for Joel Fernandes
merge bot[tip:sched/urgent] sched/deadline: Fix confusing comments about selection of top pi-waiter
sched/deadline: Fix confusing comments about selection of top pi-waiter
Commit-ID: 193be41e33168a3a06eb9d356d9e39c69de161d2 Gitweb: http://git.kernel.org/tip/193be41e33168a3a06eb9d356d9e39c69de161d2 Author: Joel Fernandes <[email protected]> AuthorDate: Wed, 12 Jul 2017 19:24:29 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 14 Jul 2017 10:35:16 +0200
sched/deadline: Fix confusing comments about selection of top pi-waiter
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.
Signed-off-by Joel Fernandes <[email protected]>
Reviewed-by Daniel Bristot de Oliveira <[email protected]>
Acked-by Juri Lelli <[email protected]>
Cc Linus Torvalds <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Thomas Gleixner <[email protected]>
Signed-off-by Ingo Molnar <[email protected]>
--- kernel/sched/deadline.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
kernel/sched/deadline.c +8 -6
@@ -1392,17 +1392,19 @@ 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.