[PATCH 46/89] sched/headers: Move the NOHZ APIs from <linux/sched.h> to <linux/sched/nohz.h>

[Ingo Molnar]

There's a number of NOHZ/dyntics related functionality in <linux/sched.h>,
but only a handful of timer files are making use of them.

Move them into their own header. This better documents these APIs
and unclutters <linux/sched.h>.

Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 include/linux/sched.h      | 35 -----------------------------------
 include/linux/sched/nohz.h | 43 +++++++++++++++++++++++++++++++++++++++++++
 kernel/sched/sched.h       |  1 +
 kernel/time/hrtimer.c      |  1 +
 kernel/time/tick-sched.c   |  1 +
 kernel/time/timer.c        |  1 +
 6 files changed, 47 insertions(+), 35 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2a05f8d6d9f1..947d4033b019 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -38,14 +38,6 @@ struct nameidata;
 struct signal_struct;
 struct sighand_struct;
 
-#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
-extern void cpu_load_update_nohz_start(void);
-extern void cpu_load_update_nohz_stop(void);
-#else
-static inline void cpu_load_update_nohz_start(void) { }
-static inline void cpu_load_update_nohz_stop(void) { }
-#endif
-
 extern void dump_cpu_task(int cpu);
 
 struct seq_file;
@@ -199,15 +191,6 @@ extern cpumask_var_t cpu_isolated_map;
 
 extern int runqueue_is_locked(int cpu);
 
-#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
-extern void nohz_balance_enter_idle(int cpu);
-extern void set_cpu_sd_state_idle(void);
-extern int get_nohz_timer_target(void);
-#else
-static inline void nohz_balance_enter_idle(int cpu) { }
-static inline void set_cpu_sd_state_idle(void) { }
-#endif
-
 /*
  * Only dump TASK_* tasks. (0 for all tasks)
  */
@@ -1532,14 +1515,6 @@ static inline int set_cpus_allowed_ptr(struct task_struct *p,
 }
 #endif
 
-#ifdef CONFIG_NO_HZ_COMMON
-void calc_load_enter_idle(void);
-void calc_load_exit_idle(void);
-#else
-static inline void calc_load_enter_idle(void) { }
-static inline void calc_load_exit_idle(void) { }
-#endif /* CONFIG_NO_HZ_COMMON */
-
 #ifndef cpu_relax_yield
 #define cpu_relax_yield() cpu_relax()
 #endif
@@ -1560,16 +1535,6 @@ extern void idle_task_exit(void);
 static inline void idle_task_exit(void) {}
 #endif
 
-#if defined(CONFIG_NO_HZ_COMMON) && defined(CONFIG_SMP)
-extern void wake_up_nohz_cpu(int cpu);
-#else
-static inline void wake_up_nohz_cpu(int cpu) { }
-#endif
-
-#ifdef CONFIG_NO_HZ_FULL
-extern u64 scheduler_tick_max_deferment(void);
-#endif
-
 extern int yield_to(struct task_struct *p, bool preempt);
 extern void set_user_nice(struct task_struct *p, long nice);
 extern int task_prio(const struct task_struct *p);
diff --git a/include/linux/sched/nohz.h b/include/linux/sched/nohz.h
new file mode 100644
index 000000000000..4995b717500b
--- /dev/null
+++ b/include/linux/sched/nohz.h
@@ -0,0 +1,43 @@
+#ifndef _LINUX_SCHED_NOHZ_H
+#define _LINUX_SCHED_NOHZ_H
+
+/*
+ * This is the interface between the scheduler and nohz/dyntics:
+ */
+
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+extern void cpu_load_update_nohz_start(void);
+extern void cpu_load_update_nohz_stop(void);
+#else
+static inline void cpu_load_update_nohz_start(void) { }
+static inline void cpu_load_update_nohz_stop(void) { }
+#endif
+
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+extern void nohz_balance_enter_idle(int cpu);
+extern void set_cpu_sd_state_idle(void);
+extern int get_nohz_timer_target(void);
+#else
+static inline void nohz_balance_enter_idle(int cpu) { }
+static inline void set_cpu_sd_state_idle(void) { }
+#endif
+
+#ifdef CONFIG_NO_HZ_COMMON
+void calc_load_enter_idle(void);
+void calc_load_exit_idle(void);
+#else
+static inline void calc_load_enter_idle(void) { }
+static inline void calc_load_exit_idle(void) { }
+#endif /* CONFIG_NO_HZ_COMMON */
+
+#if defined(CONFIG_NO_HZ_COMMON) && defined(CONFIG_SMP)
+extern void wake_up_nohz_cpu(int cpu);
+#else
+static inline void wake_up_nohz_cpu(int cpu) { }
+#endif
+
+#ifdef CONFIG_NO_HZ_FULL
+extern u64 scheduler_tick_max_deferment(void);
+#endif
+
+#endif /* _LINUX_SCHED_NOHZ_H */
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 6c8a1db44dde..5979f47c422c 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -10,6 +10,7 @@
 #include <linux/sched/mm.h>
 #include <linux/sched/cpufreq.h>
 #include <linux/sched/stat.h>
+#include <linux/sched/nohz.h>
 #include <linux/u64_stats_sync.h>
 #include <linux/sched/deadline.h>
 #include <linux/kernel_stat.h>
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 6e36467b678f..301323221d2c 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -47,6 +47,7 @@
 #include <linux/sched/sysctl.h>
 #include <linux/sched/rt.h>
 #include <linux/sched/deadline.h>
+#include <linux/sched/nohz.h>
 #include <linux/timer.h>
 #include <linux/freezer.h>
 
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 52abe90b590d..8b084c5a2962 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -22,6 +22,7 @@
 #include <linux/sched/signal.h>
 #include <linux/sched/clock.h>
 #include <linux/sched/stat.h>
+#include <linux/sched/nohz.h>
 #include <linux/module.h>
 #include <linux/irq_work.h>
 #include <linux/posix-timers.h>
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index c78f2b3e076e..bf69e770e303 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -40,6 +40,7 @@
 #include <linux/irq_work.h>
 #include <linux/sched/signal.h>
 #include <linux/sched/sysctl.h>
+#include <linux/sched/nohz.h>
 #include <linux/slab.h>
 #include <linux/compat.h>
 
-- 
2.7.4