From 130fd056dd82b02db9a661c013071af35309be1a Mon Sep 17 00:00:00 2001 From: Qais Yousef Date: Mon, 10 Jun 2024 20:20:16 +0100 Subject: sched/rt: Clean up usage of rt_task() 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 Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Phil Auld Reviewed-by: "Steven Rostedt (Google)" Reviewed-by: Sebastian Andrzej Siewior Link: https://lore.kernel.org/r/20240610192018.1567075-2-qyousef@layalina.io --- include/linux/sched/deadline.h | 6 ++++-- include/linux/sched/prio.h | 1 + include/linux/sched/rt.h | 27 ++++++++++++++++++++++++++- 3 files changed, 31 insertions(+), 3 deletions(-) (limited to 'include/linux/sched') diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h index df3aca89d4f5..5cb88b748ad6 100644 --- a/include/linux/sched/deadline.h +++ b/include/linux/sched/deadline.h @@ -10,8 +10,6 @@ #include -#define MAX_DL_PRIO 0 - static inline int dl_prio(int prio) { if (unlikely(prio < MAX_DL_PRIO)) @@ -19,6 +17,10 @@ static inline int dl_prio(int prio) return 0; } +/* + * Returns true if a task has a priority that belongs to DL class. PI-boosted + * tasks will return true. Use dl_policy() to ignore PI-boosted tasks. + */ static inline int dl_task(struct task_struct *p) { return dl_prio(p->prio); diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h index ab83d85e1183..6ab43b4f72f9 100644 --- a/include/linux/sched/prio.h +++ b/include/linux/sched/prio.h @@ -14,6 +14,7 @@ */ #define MAX_RT_PRIO 100 +#define MAX_DL_PRIO 0 #define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH) #define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2) diff --git a/include/linux/sched/rt.h b/include/linux/sched/rt.h index b2b9e6eb9683..a055dd68a77c 100644 --- a/include/linux/sched/rt.h +++ b/include/linux/sched/rt.h @@ -7,18 +7,43 @@ struct task_struct; static inline int rt_prio(int prio) +{ + if (unlikely(prio < MAX_RT_PRIO && prio >= MAX_DL_PRIO)) + return 1; + return 0; +} + +static inline int realtime_prio(int prio) { if (unlikely(prio < MAX_RT_PRIO)) return 1; return 0; } +/* + * Returns true if a task has a priority that belongs to RT class. PI-boosted + * tasks will return true. Use rt_policy() to ignore PI-boosted tasks. + */ static inline int rt_task(struct task_struct *p) { return rt_prio(p->prio); } -static inline bool task_is_realtime(struct task_struct *tsk) +/* + * Returns true if a task has a priority that belongs to RT or DL classes. + * PI-boosted tasks will return true. Use realtime_task_policy() to ignore + * PI-boosted tasks. + */ +static inline int realtime_task(struct task_struct *p) +{ + return realtime_prio(p->prio); +} + +/* + * Returns true if a task has a policy that belongs to RT or DL classes. + * PI-boosted tasks will return false. + */ +static inline bool realtime_task_policy(struct task_struct *tsk) { int policy = tsk->policy; -- cgit v1.2.3 From b166af3db70fdcecf125662a2360471bb20be203 Mon Sep 17 00:00:00 2001 From: Qais Yousef Date: Mon, 10 Jun 2024 20:20:17 +0100 Subject: sched/rt, dl: Convert functions to return bool {rt, realtime, dl}_{task, prio}() functions' return value is actually a bool. Convert their return type to reflect that. Suggested-by: "Steven Rostedt (Google)" Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Sebastian Andrzej Siewior Reviewed-by: "Steven Rostedt (Google)" Reviewed-by: Metin Kaya Link: https://lore.kernel.org/r/20240610192018.1567075-3-qyousef@layalina.io --- include/linux/sched/deadline.h | 8 +++----- include/linux/sched/rt.h | 16 ++++++---------- 2 files changed, 9 insertions(+), 15 deletions(-) (limited to 'include/linux/sched') diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h index 5cb88b748ad6..3a912ab42bb5 100644 --- a/include/linux/sched/deadline.h +++ b/include/linux/sched/deadline.h @@ -10,18 +10,16 @@ #include -static inline int dl_prio(int prio) +static inline bool dl_prio(int prio) { - if (unlikely(prio < MAX_DL_PRIO)) - return 1; - return 0; + return unlikely(prio < MAX_DL_PRIO); } /* * Returns true if a task has a priority that belongs to DL class. PI-boosted * tasks will return true. Use dl_policy() to ignore PI-boosted tasks. */ -static inline int dl_task(struct task_struct *p) +static inline bool dl_task(struct task_struct *p) { return dl_prio(p->prio); } diff --git a/include/linux/sched/rt.h b/include/linux/sched/rt.h index a055dd68a77c..91ef1ef2019f 100644 --- a/include/linux/sched/rt.h +++ b/include/linux/sched/rt.h @@ -6,25 +6,21 @@ struct task_struct; -static inline int rt_prio(int prio) +static inline bool rt_prio(int prio) { - if (unlikely(prio < MAX_RT_PRIO && prio >= MAX_DL_PRIO)) - return 1; - return 0; + return unlikely(prio < MAX_RT_PRIO && prio >= MAX_DL_PRIO); } -static inline int realtime_prio(int prio) +static inline bool realtime_prio(int prio) { - if (unlikely(prio < MAX_RT_PRIO)) - return 1; - return 0; + return unlikely(prio < MAX_RT_PRIO); } /* * Returns true if a task has a priority that belongs to RT class. PI-boosted * tasks will return true. Use rt_policy() to ignore PI-boosted tasks. */ -static inline int rt_task(struct task_struct *p) +static inline bool rt_task(struct task_struct *p) { return rt_prio(p->prio); } @@ -34,7 +30,7 @@ static inline int rt_task(struct task_struct *p) * PI-boosted tasks will return true. Use realtime_task_policy() to ignore * PI-boosted tasks. */ -static inline int realtime_task(struct task_struct *p) +static inline bool realtime_task(struct task_struct *p) { return realtime_prio(p->prio); } -- cgit v1.2.3 From ae04f69de0bef93c7086cf2983dbc8e8fd624ebe Mon Sep 17 00:00:00 2001 From: Qais Yousef Date: Mon, 10 Jun 2024 20:20:18 +0100 Subject: sched/rt: Rename realtime_{prio, task}() to rt_or_dl_{prio, task}() Some find the name realtime overloaded. Use rt_or_dl() as an alternative, hopefully better, name. Suggested-by: Daniel Bristot de Oliveira Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20240610192018.1567075-4-qyousef@layalina.io --- include/linux/sched/rt.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include/linux/sched') diff --git a/include/linux/sched/rt.h b/include/linux/sched/rt.h index 91ef1ef2019f..4e3338103654 100644 --- a/include/linux/sched/rt.h +++ b/include/linux/sched/rt.h @@ -11,7 +11,7 @@ static inline bool rt_prio(int prio) return unlikely(prio < MAX_RT_PRIO && prio >= MAX_DL_PRIO); } -static inline bool realtime_prio(int prio) +static inline bool rt_or_dl_prio(int prio) { return unlikely(prio < MAX_RT_PRIO); } @@ -27,19 +27,19 @@ static inline bool rt_task(struct task_struct *p) /* * Returns true if a task has a priority that belongs to RT or DL classes. - * PI-boosted tasks will return true. Use realtime_task_policy() to ignore + * PI-boosted tasks will return true. Use rt_or_dl_task_policy() to ignore * PI-boosted tasks. */ -static inline bool realtime_task(struct task_struct *p) +static inline bool rt_or_dl_task(struct task_struct *p) { - return realtime_prio(p->prio); + return rt_or_dl_prio(p->prio); } /* * Returns true if a task has a policy that belongs to RT or DL classes. * PI-boosted tasks will return false. */ -static inline bool realtime_task_policy(struct task_struct *tsk) +static inline bool rt_or_dl_task_policy(struct task_struct *tsk) { int policy = tsk->policy; -- cgit v1.2.3