Messages in this thread Patch in this message | | | Date | Thu, 19 Dec 2019 16:44:54 -0500 | From | Steven Rostedt <> | Subject | [RFC][PATCH 3/4] sched: Remove struct sched_class next field |
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From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Now that the sched_class descriptors are defined in order via the linker script vmlinux.lds.h, there's no reason to have a "next" pointer to the previous priroity structure. The order of the sturctures can be aligned as an array, and used to index and find the next sched_class descriptor.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> --- include/asm-generic/vmlinux.lds.h | 1 + kernel/sched/deadline.c | 1 - kernel/sched/fair.c | 1 - kernel/sched/idle.c | 1 - kernel/sched/rt.c | 1 - kernel/sched/sched.h | 6 +++--- kernel/sched/stop_task.c | 1 - 7 files changed, 4 insertions(+), 8 deletions(-)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 1c14c4ddf785..f4d480c4f7c6 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -128,6 +128,7 @@ */ #define SCHED_DATA \ STRUCT_ALIGN(); \ + __start_sched_classes = .; \ *(__idle_sched_class) \ *(__fair_sched_class) \ *(__rt_sched_class) \ diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 5abdbe569f93..9c232214fe63 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2430,7 +2430,6 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p, const struct sched_class dl_sched_class __attribute__((section("__dl_sched_class"))) = { - .next = &rt_sched_class, .enqueue_task = enqueue_task_dl, .dequeue_task = dequeue_task_dl, .yield_task = yield_task_dl, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e745fe0e0cd3..52f2a7b06d9b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10747,7 +10747,6 @@ static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task */ const struct sched_class fair_sched_class __attribute__((section("__fair_sched_class"))) = { - .next = &idle_sched_class, .enqueue_task = enqueue_task_fair, .dequeue_task = dequeue_task_fair, .yield_task = yield_task_fair, diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 700a9c826f0e..f0871a9b8c98 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -456,7 +456,6 @@ static void update_curr_idle(struct rq *rq) */ const struct sched_class idle_sched_class __attribute__((section("__idle_sched_class"))) = { - /* .next is NULL */ /* no enqueue/yield_task for idle tasks */ /* dequeue is not valid, we print a debug message there: */ diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 5d3f9bcddaeb..d6b330b72c60 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -2356,7 +2356,6 @@ static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task) const struct sched_class rt_sched_class __attribute__((section("__rt_sched_class"))) = { - .next = &fair_sched_class, .enqueue_task = enqueue_task_rt, .dequeue_task = dequeue_task_rt, .yield_task = yield_task_rt, diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 0554c588ad85..30a4615cf480 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1700,7 +1700,6 @@ extern const u32 sched_prio_to_wmult[40]; #define RETRY_TASK ((void *)-1UL) struct sched_class { - const struct sched_class *next; #ifdef CONFIG_UCLAMP_TASK int uclamp_enabled; @@ -1773,12 +1772,13 @@ static inline void set_next_task(struct rq *rq, struct task_struct *next) /* Defined in include/asm-generic/vmlinux.lds.h */ extern struct sched_class sched_class_highest; +extern struct sched_class __start_sched_classes; #define for_class_range(class, _from, _to) \ - for (class = (_from); class != (_to); class = class->next) + for (class = (_from); class > (_to); class--) #define for_each_class(class) \ - for_class_range(class, &sched_class_highest, NULL) + for_class_range(class, &sched_class_highest, (&__start_sched_classes) - 1) extern const struct sched_class stop_sched_class; extern const struct sched_class dl_sched_class; diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c index 03bc7530ff75..0f88eec8d4da 100644 --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -117,7 +117,6 @@ static void update_curr_stop(struct rq *rq) */ const struct sched_class stop_sched_class __attribute__((section("__stop_sched_class"))) = { - .next = &dl_sched_class, .enqueue_task = enqueue_task_stop, .dequeue_task = dequeue_task_stop, -- 2.24.0
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