55 lines
1.7 KiB
Diff
55 lines
1.7 KiB
Diff
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Fri, 4 Aug 2023 13:30:37 +0200
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Subject: [PATCH 1/3] sched/core: Provide a method to check if a task is
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PI-boosted.
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.11/older/patches-6.11-rt7.tar.xz
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Provide a method to check if a task inherited the priority from another
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task. This happens if a task owns a lock which is requested by a task
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with higher priority. This can be used as a hint to add a preemption
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point to the critical section.
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Provide a function which reports true if the task is PI-boosted.
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Link: https://lore.kernel.org/r/20230804113039.419794-2-bigeasy@linutronix.de
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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include/linux/sched.h | 1 +
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kernel/sched/core.c | 15 +++++++++++++++
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2 files changed, 16 insertions(+)
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--- a/include/linux/sched.h
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+++ b/include/linux/sched.h
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@@ -1814,6 +1814,7 @@ static inline int dl_task_check_affinity
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}
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#endif
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+extern bool task_is_pi_boosted(const struct task_struct *p);
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extern int yield_to(struct task_struct *p, bool preempt);
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extern void set_user_nice(struct task_struct *p, long nice);
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extern int task_prio(const struct task_struct *p);
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--- a/kernel/sched/core.c
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+++ b/kernel/sched/core.c
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@@ -7362,6 +7362,21 @@ static inline void preempt_dynamic_init(
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#endif /* CONFIG_PREEMPT_DYNAMIC */
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+/*
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+ * task_is_pi_boosted - Check if task has been PI boosted.
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+ * @p: Task to check.
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+ *
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+ * Return true if task is subject to priority inheritance.
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+ */
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+bool task_is_pi_boosted(const struct task_struct *p)
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+{
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+ int prio = p->prio;
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+
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+ if (!rt_prio(prio))
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+ return false;
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+ return prio != p->normal_prio;
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+}
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+
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int io_schedule_prepare(void)
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{
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int old_iowait = current->in_iowait;
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