Messages in this thread Patch in this message | | | From | Sebastian Andrzej Siewior <> | Subject | [RFC PATCH 1/3] sched/core: Provide a method to check if a task is PI-boosted. | Date | Fri, 4 Aug 2023 13:30:37 +0200 |
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Provide a method to check if a task inherited the priority from another task. This happens if a task owns a lock which is requested by a task with higher priority. This can be used as a hint to add a preemption point to the critical section.
Provide a function which reports true if the task is PI-boosted.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- include/linux/sched.h | 1 + kernel/sched/core.c | 15 +++++++++++++++ 2 files changed, 16 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 609bde814cb06..77fd274133750 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1887,6 +1887,7 @@ static inline int dl_task_check_affinity(struct task_struct *p, const struct cpu } #endif +extern bool task_is_pi_boosted(const struct task_struct *p); extern int yield_to(struct task_struct *p, bool preempt); extern void set_user_nice(struct task_struct *p, long nice); extern int task_prio(const struct task_struct *p); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index c52c2eba7c739..132f06522efa0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8886,6 +8886,21 @@ static inline void preempt_dynamic_init(void) { } #endif /* #ifdef CONFIG_PREEMPT_DYNAMIC */ +/* + * task_is_pi_boosted - Check if task has been PI boosted. + * @p: Task to check. + * + * Return true if task is subject to priority inheritance. + */ +bool task_is_pi_boosted(const struct task_struct *p) +{ + int prio = p->prio; + + if (!rt_prio(prio)) + return false; + return prio != p->normal_prio; +} + /** * yield - yield the current processor to other threads. * -- 2.40.1
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