[v2,6/8] sched/deadline: make it configurable

Message ID 20170606232450.30278-7-nicolas.pitre@linaro.org
State Superseded
Headers show
Series
  • scheduler tinification
Related show

Commit Message

Nicolas Pitre June 6, 2017, 11:24 p.m.
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.

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(-)

-- 
2.9.4

Patch

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2b69fc6502..ba0c203669 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -522,7 +522,9 @@  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 ad91724f75..43e6ae3414 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1303,6 +1303,14 @@  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 28cd09e635..1deabf9ebd 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);
 
@@ -967,7 +967,7 @@  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 5e4c2e7a63..3bd6a7c1cc 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 += wait.o swait.o completion.o idle.o
-obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o topology.o stop_task.o
+obj-y += idle_task.o fair.o rt.o
+obj-$(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 9923c4b742..30138033b7 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -635,7 +635,7 @@  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;
 
 	/*
@@ -2174,9 +2174,11 @@  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);
 	__dl_clear_params(p);
+#endif
 
 	INIT_LIST_HEAD(&p->rt.run_list);
 	p->rt.timeout		= 0;
@@ -3702,20 +3704,20 @@  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;
@@ -5266,7 +5268,8 @@  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 38f019324f..84f80a81ab 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -646,7 +646,9 @@  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);
@@ -954,10 +956,12 @@  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 29c48a6cfb..02ac9b336f 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1545,7 +1545,7 @@  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;
 	}
 
@@ -2705,16 +2705,19 @@  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 84ab1be493..c05cc33848 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:
@@ -244,7 +248,6 @@  bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw)
 	       dl_b->bw * cpus < dl_b->total_bw - old_bw + 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,
@@ -258,7 +261,27 @@  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
 
@@ -672,7 +695,9 @@  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: */
@@ -1443,9 +1468,12 @@  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)
 
@@ -1496,7 +1524,6 @@  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);
 
@@ -1506,8 +1533,6 @@  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);
 
 unsigned long to_ratio(u64 period, u64 runtime);
@@ -1933,7 +1958,6 @@  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,