Messages in this thread Patch in this message | | | Date | Wed, 2 Aug 2017 12:28:18 -0400 (EDT) | From | Nicolas Pitre <> | Subject | [PATCH] sched/deadline: make it configurable |
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On most small systems, the deadline scheduler class is a luxury that rarely gets used if at all. It is preferable to have the ability to configure it out to reduce the kernel size in that case.
Before:
$ size -t kernel/sched/built-in.o text data bss dec hex filename [...] 24435 3452 108 27995 6d5b (TOTALS)
With CONFIG_SCHED_DL=n:
$ size -t kernel/sched/built-in.o text data bss dec hex filename [...] 18336 3388 92 21816 5538 (TOTALS)
Signed-off-by: Nicolas Pitre <nico@linaro.org> --- include/linux/sched.h | 2 ++ include/linux/sched/deadline.h | 8 +++++++- init/Kconfig | 8 ++++++++ kernel/locking/rtmutex.c | 6 +++--- kernel/sched/Makefile | 5 +++-- kernel/sched/core.c | 15 ++++++++------ kernel/sched/cpudeadline.h | 7 ++++++- kernel/sched/debug.c | 4 ++++ kernel/sched/rt.c | 13 +++++++----- kernel/sched/sched.h | 38 +++++++++++++++++++++++++++++------- kernel/sched/stop_task.c | 4 ++++ 11 files changed, 85 insertions(+), 25 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 8337e2db0b..5240f8c0d3 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -565,7 +565,9 @@ struct task_struct { #ifdef CONFIG_CGROUP_SCHED struct task_group *sched_task_group; #endif +#ifdef CONFIG_SCHED_DL struct sched_dl_entity dl; +#endif #ifdef CONFIG_PREEMPT_NOTIFIERS /* List of struct preempt_notifier: */ diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h index 975be862e0..8f191a17dd 100644 --- a/include/linux/sched/deadline.h +++ b/include/linux/sched/deadline.h @@ -13,7 +13,7 @@ static inline int dl_prio(int prio) { - if (unlikely(prio < MAX_DL_PRIO)) + if (IS_ENABLED(CONFIG_SCHED_DL) && unlikely(prio < MAX_DL_PRIO)) return 1; return 0; } @@ -28,4 +28,10 @@ static inline bool dl_time_before(u64 a, u64 b) return (s64)(a - b) < 0; } +#ifdef CONFIG_SCHED_DL +#define dl_deadline(tsk) (tsk)->dl.deadline +#else +#define dl_deadline(tsk) 0 +#endif + #endif /* _LINUX_SCHED_DEADLINE_H */ diff --git a/init/Kconfig b/init/Kconfig index 5f0ef850e8..8a430de9f4 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -959,6 +959,14 @@ config SCHED_AUTOGROUP desktop applications. Task group autogeneration is currently based upon task session. +config SCHED_DL + bool "Deadline Task Scheduling" if EXPERT + default y + help + This adds the sched_dl scheduling class to the kernel providing + support for the SCHED_DEADLINE policy. You might want to disable + this to reduce the kernel size. If unsure say y. + config SYSFS_DEPRECATED bool "Enable deprecated sysfs features to support old userspace tools" depends on SYSFS diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 649dc9d395..ebc7c3a610 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -228,7 +228,7 @@ static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock, * Only use with rt_mutex_waiter_{less,equal}() */ #define task_to_waiter(p) \ - &(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline } + &(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = dl_deadline(p) } static inline int rt_mutex_waiter_less(struct rt_mutex_waiter *left, @@ -692,7 +692,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, * the values of the node being removed. */ waiter->prio = task->prio; - waiter->deadline = task->dl.deadline; + waiter->deadline = dl_deadline(task); rt_mutex_enqueue(lock, waiter); @@ -966,7 +966,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock, waiter->task = task; waiter->lock = lock; waiter->prio = task->prio; - waiter->deadline = task->dl.deadline; + waiter->deadline = dl_deadline(task); /* Get the top priority waiter on the lock */ if (rt_mutex_has_waiters(lock)) diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile index 53f0164ed3..6ba5664cfb 100644 --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -16,9 +16,10 @@ CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer endif obj-y += core.o loadavg.o clock.o cputime.o -obj-y += idle_task.o fair.o rt.o deadline.o +obj-y += idle_task.o fair.o rt.o obj-y += wait.o wait_bit.o swait.o completion.o idle.o -obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o topology.o stop_task.o +obj-$(CONFIG_SCHED_DL) += deadline.o $(if $(CONFIG_SMP),cpudeadline.o) +obj-$(CONFIG_SMP) += cpupri.o topology.o stop_task.o obj-$(CONFIG_SCHED_AUTOGROUP) += autogroup.o obj-$(CONFIG_SCHEDSTATS) += stats.o obj-$(CONFIG_SCHED_DEBUG) += debug.o diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0869b20fba..2fc053f06a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -636,7 +636,7 @@ bool sched_can_stop_tick(struct rq *rq) int fifo_nr_running; /* Deadline tasks, even if single, need the tick */ - if (rq->dl.dl_nr_running) + if (dl_nr_running(rq)) return false; /* @@ -2166,10 +2166,12 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) memset(&p->se.statistics, 0, sizeof(p->se.statistics)); #endif +#ifdef CONFIG_SCHED_DL RB_CLEAR_NODE(&p->dl.rb_node); init_dl_task_timer(&p->dl); init_dl_inactive_task_timer(&p->dl); __dl_clear_params(p); +#endif INIT_LIST_HEAD(&p->rt.run_list); p->rt.timeout = 0; @@ -3695,20 +3697,20 @@ void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task) if (dl_prio(prio)) { if (!dl_prio(p->normal_prio) || (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) { - p->dl.dl_boosted = 1; + dl_boosted(p) = 1; queue_flag |= ENQUEUE_REPLENISH; } else - p->dl.dl_boosted = 0; + dl_boosted(p) = 0; p->sched_class = &dl_sched_class; } else if (rt_prio(prio)) { if (dl_prio(oldprio)) - p->dl.dl_boosted = 0; + dl_boosted(p) = 0; if (oldprio < prio) queue_flag |= ENQUEUE_HEAD; p->sched_class = &rt_sched_class; } else { if (dl_prio(oldprio)) - p->dl.dl_boosted = 0; + dl_boosted(p) = 0; if (rt_prio(oldprio)) p->rt.timeout = 0; p->sched_class = &fair_sched_class; @@ -5260,7 +5262,8 @@ int cpuset_cpumask_can_shrink(const struct cpumask *cur, if (!cpumask_weight(cur)) return ret; - ret = dl_cpuset_cpumask_can_shrink(cur, trial); + if (IS_ENABLED(CONFIG_SCHED_DL)) + ret = dl_cpuset_cpumask_can_shrink(cur, trial); return ret; } diff --git a/kernel/sched/cpudeadline.h b/kernel/sched/cpudeadline.h index f7da8c55bb..5f4c10f837 100644 --- a/kernel/sched/cpudeadline.h +++ b/kernel/sched/cpudeadline.h @@ -25,10 +25,15 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p, struct cpumask *later_mask); void cpudl_set(struct cpudl *cp, int cpu, u64 dl); void cpudl_clear(struct cpudl *cp, int cpu); -int cpudl_init(struct cpudl *cp); void cpudl_set_freecpu(struct cpudl *cp, int cpu); void cpudl_clear_freecpu(struct cpudl *cp, int cpu); +#ifdef CONFIG_SCHED_DL +int cpudl_init(struct cpudl *cp); void cpudl_cleanup(struct cpudl *cp); +#else +#define cpudl_init(cp) 0 +#define cpudl_cleanup(cp) do { } while (0) +#endif #endif /* CONFIG_SMP */ #endif /* _LINUX_CPUDL_H */ diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 4fa66de52b..f144d50da4 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -659,7 +659,9 @@ do { \ spin_lock_irqsave(&sched_debug_lock, flags); print_cfs_stats(m, cpu); print_rt_stats(m, cpu); +#ifdef CONFIG_SCHED_DL print_dl_stats(m, cpu); +#endif print_rq(m, rq, cpu); spin_unlock_irqrestore(&sched_debug_lock, flags); @@ -967,10 +969,12 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m) #endif P(policy); P(prio); +#ifdef CONFIG_SCHED_DL if (p->policy == SCHED_DEADLINE) { P(dl.runtime); P(dl.deadline); } +#endif #undef PN_SCHEDSTAT #undef PN #undef __PN diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 45caf937ef..d48e75a4a8 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1556,7 +1556,7 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) * to re-start task selection. */ if (unlikely((rq->stop && task_on_rq_queued(rq->stop)) || - rq->dl.dl_nr_running)) + dl_nr_running(rq))) return RETRY_TASK; } @@ -2716,16 +2716,19 @@ int sched_rt_handler(struct ctl_table *table, int write, if (ret) goto undo; - ret = sched_dl_global_validate(); - if (ret) - goto undo; + if (IS_ENABLED(CONFIG_SCHED_DL)) { + ret = sched_dl_global_validate(); + if (ret) + goto undo; + } ret = sched_rt_global_constraints(); if (ret) goto undo; sched_rt_do_global(); - sched_dl_do_global(); + if (IS_ENABLED(CONFIG_SCHED_DL)) + sched_dl_do_global(); } if (0) { undo: diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index eeef1a3086..e4427c8a8b 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -137,7 +137,7 @@ static inline int rt_policy(int policy) static inline int dl_policy(int policy) { - return policy == SCHED_DEADLINE; + return IS_ENABLED(CONFIG_SCHED_DL) && policy == SCHED_DEADLINE; } static inline bool valid_policy(int policy) { @@ -158,11 +158,15 @@ static inline int task_has_dl_policy(struct task_struct *p) /* * Tells if entity @a should preempt entity @b. */ +#ifdef CONFIG_SCHED_DL static inline bool dl_entity_preempt(struct sched_dl_entity *a, struct sched_dl_entity *b) { return dl_time_before(a->deadline, b->deadline); } +#else +#define dl_entity_preempt(a, b) false +#endif /* * This is the priority-queue data structure of the RT scheduling class: @@ -247,7 +251,6 @@ bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw) } void dl_change_utilization(struct task_struct *p, u64 new_bw); -extern void init_dl_bw(struct dl_bw *dl_b); extern int sched_dl_global_validate(void); extern void sched_dl_do_global(void); extern int sched_dl_overflow(struct task_struct *p, int policy, @@ -261,7 +264,27 @@ extern int dl_task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed); extern int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial); +extern struct dl_bandwidth def_dl_bandwidth; + +struct dl_rq; + +#ifdef CONFIG_SCHED_DL +#define dl_nr_running(rq) (rq)->dl.dl_nr_running +#define dl_boosted(tsk) (tsk)->dl.dl_boosted extern bool dl_cpu_busy(unsigned int cpu); +extern void init_dl_bw(struct dl_bw *dl_b); +extern void init_sched_dl_class(void); +extern void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime); +extern void init_dl_rq(struct dl_rq *dl_rq); +#else +#define dl_nr_running(rq) 0 +#define dl_boosted(tsk) (*(int *)0) +#define dl_cpu_busy(cpu) false +#define init_dl_bw(dl_b) do { } while (0) +#define init_sched_dl_class() do { } while (0) +#define init_dl_bandwidth(...) do { } while (0) +#define init_dl_rq(dl_rq) do { } while (0) +#endif #ifdef CONFIG_CGROUP_SCHED @@ -697,7 +720,9 @@ struct rq { struct cfs_rq cfs; struct rt_rq rt; +#ifdef CONFIG_SCHED_DL struct dl_rq dl; +#endif #ifdef CONFIG_FAIR_GROUP_SCHED /* list of leaf cfs_rq on this cpu: */ @@ -1471,9 +1496,12 @@ static inline void set_curr_task(struct rq *rq, struct task_struct *curr) #ifdef CONFIG_SMP #define sched_class_highest (&stop_sched_class) -#else +#elif defined(CONFIG_SCHED_DL) #define sched_class_highest (&dl_sched_class) +#else +#define sched_class_highest (&rt_sched_class) #endif + #define for_each_class(class) \ for (class = sched_class_highest; class; class = class->next) @@ -1524,7 +1552,6 @@ extern void sysrq_sched_debug_show(void); extern void sched_init_granularity(void); extern void update_max_interval(void); -extern void init_sched_dl_class(void); extern void init_sched_rt_class(void); extern void init_sched_fair_class(void); @@ -1534,8 +1561,6 @@ extern void resched_cpu(int cpu); extern struct rt_bandwidth def_rt_bandwidth; extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime); -extern struct dl_bandwidth def_dl_bandwidth; -extern void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime); extern void init_dl_task_timer(struct sched_dl_entity *dl_se); extern void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se); extern void init_dl_rq_bw_ratio(struct dl_rq *dl_rq); @@ -1966,7 +1991,6 @@ print_numa_stats(struct seq_file *m, int node, unsigned long tsf, extern void init_cfs_rq(struct cfs_rq *cfs_rq); extern void init_rt_rq(struct rt_rq *rt_rq); -extern void init_dl_rq(struct dl_rq *dl_rq); extern void cfs_bandwidth_usage_inc(void); extern void cfs_bandwidth_usage_dec(void); diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c index 9f69fb6308..5632dc3e63 100644 --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -110,7 +110,11 @@ static void update_curr_stop(struct rq *rq) * Simple, special scheduling class for the per-CPU stop tasks: */ const struct sched_class stop_sched_class = { +#ifdef CONFIG_SCHED_DL .next = &dl_sched_class, +#else + .next = &rt_sched_class, +#endif .enqueue_task = enqueue_task_stop, .dequeue_task = dequeue_task_stop,
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