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rt_task() checks if a task has RT priority. But depends on your dictionary, this could mean it belongs to RT class, or is a 'realtime' task, which includes RT and DL classes. Since this has caused some confusion already on discussion [1], it seemed a clean up is due. I define the usage of rt_task() to be tasks that belong to RT class. Make sure that it returns true only for RT class and audit the users and replace the ones required the old behavior with the new realtime_task() which returns true for RT and DL classes. Introduce similar realtime_prio() to create similar distinction to rt_prio() and update the users that required the old behavior to use the new function. Move MAX_DL_PRIO to prio.h so it can be used in the new definitions. Document the functions to make it more obvious what is the difference between them. PI-boosted tasks is a factor that must be taken into account when choosing which function to use. Rename task_is_realtime() to realtime_task_policy() as the old name is confusing against the new realtime_task(). No functional changes were intended. [1] https://lore.kernel.org/lkml/20240506100509.GL40213@noisy.programming.kicks-ass.net/ Signed-off-by: Qais Yousef <qyousef@layalina.io> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Phil Auld <pauld@redhat.com> Reviewed-by: "Steven Rostedt (Google)" <rostedt@goodmis.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/20240610192018.1567075-2-qyousef@layalina.io
47 lines
1.1 KiB
C
47 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SCHED_PRIO_H
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#define _LINUX_SCHED_PRIO_H
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#define MAX_NICE 19
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#define MIN_NICE -20
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#define NICE_WIDTH (MAX_NICE - MIN_NICE + 1)
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/*
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* Priority of a process goes from 0..MAX_PRIO-1, valid RT
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* priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
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* tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
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* values are inverted: lower p->prio value means higher priority.
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*/
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#define MAX_RT_PRIO 100
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#define MAX_DL_PRIO 0
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#define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
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#define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
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/*
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* Convert user-nice values [ -20 ... 0 ... 19 ]
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* to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
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* and back.
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*/
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#define NICE_TO_PRIO(nice) ((nice) + DEFAULT_PRIO)
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#define PRIO_TO_NICE(prio) ((prio) - DEFAULT_PRIO)
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/*
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* Convert nice value [19,-20] to rlimit style value [1,40].
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*/
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static inline long nice_to_rlimit(long nice)
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{
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return (MAX_NICE - nice + 1);
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}
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/*
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* Convert rlimit style value [1,40] to nice value [-20, 19].
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*/
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static inline long rlimit_to_nice(long prio)
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{
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return (MAX_NICE - prio + 1);
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}
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#endif /* _LINUX_SCHED_PRIO_H */
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