Messages in this thread | | | Date | Thu, 17 Aug 2017 03:35:03 -0400 (EDT) | From | Nicolas Pitre <> | Subject | Re: [PATCH v2] sched/deadline: make it configurable |
| |
Ping.
On Thu, 3 Aug 2017, Nicolas Pitre wrote:
> 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> > --- > > Changes from v1: > > - fix for a compilation error found by kbuild test robot > > 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 | 44 ++++++++++++++++++++++++++++++++++-------- > kernel/sched/stop_task.c | 4 ++++ > 11 files changed, 90 insertions(+), 26 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..33a3391943 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); > @@ -1985,7 +2009,11 @@ static inline void nohz_balance_exit_idle(unsigned int cpu) { } > #endif > > > -#ifdef CONFIG_SMP > +#if !defined(CONFIG_SCHED_DL) > +void __dl_update(struct dl_bw *dl_b, s64 bw) > +{ > +} > +#elif defined(CONFIG_SMP) > static inline > void __dl_update(struct dl_bw *dl_b, s64 bw) > { > 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, >
| |