sched/headers: Move idle polling methods to <linux/sched/idle.h>

Further reduce the size of <linux/sched.h> by moving these APIs:

	tsk_is_polling()
	__current_set_polling()
	current_set_polling_and_test()
	__current_clr_polling()
	current_clr_polling_and_test()
	current_clr_polling()

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/sched.h

@@ -3176,82 +3176,6 @@ static inline int spin_needbreak(spinlock_t *lock)
 #endif
 }
 
-/*
- * Idle thread specific functions to determine the need_resched
- * polling state.
- */
-#ifdef TIF_POLLING_NRFLAG
-static inline int tsk_is_polling(struct task_struct *p)
-{
-	return test_tsk_thread_flag(p, TIF_POLLING_NRFLAG);
-}
-
-static inline void __current_set_polling(void)
-{
-	set_thread_flag(TIF_POLLING_NRFLAG);
-}
-
-static inline bool __must_check current_set_polling_and_test(void)
-{
-	__current_set_polling();
-
-	/*
-	 * Polling state must be visible before we test NEED_RESCHED,
-	 * paired by resched_curr()
-	 */
-	smp_mb__after_atomic();
-
-	return unlikely(tif_need_resched());
-}
-
-static inline void __current_clr_polling(void)
-{
-	clear_thread_flag(TIF_POLLING_NRFLAG);
-}
-
-static inline bool __must_check current_clr_polling_and_test(void)
-{
-	__current_clr_polling();
-
-	/*
-	 * Polling state must be visible before we test NEED_RESCHED,
-	 * paired by resched_curr()
-	 */
-	smp_mb__after_atomic();
-
-	return unlikely(tif_need_resched());
-}
-
-#else
-static inline int tsk_is_polling(struct task_struct *p) { return 0; }
-static inline void __current_set_polling(void) { }
-static inline void __current_clr_polling(void) { }
-
-static inline bool __must_check current_set_polling_and_test(void)
-{
-	return unlikely(tif_need_resched());
-}
-static inline bool __must_check current_clr_polling_and_test(void)
-{
-	return unlikely(tif_need_resched());
-}
-#endif
-
-static inline void current_clr_polling(void)
-{
-	__current_clr_polling();
-
-	/*
-	 * Ensure we check TIF_NEED_RESCHED after we clear the polling bit.
-	 * Once the bit is cleared, we'll get IPIs with every new
-	 * TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also
-	 * fold.
-	 */
-	smp_mb(); /* paired with resched_curr() */
-
-	preempt_fold_need_resched();
-}
-
 static __always_inline bool need_resched(void)
 {
 	return unlikely(tif_need_resched());

include/linux/sched/idle.h

@@ -12,4 +12,80 @@ enum cpu_idle_type {
 
 extern void wake_up_if_idle(int cpu);
 
+/*
+ * Idle thread specific functions to determine the need_resched
+ * polling state.
+ */
+#ifdef TIF_POLLING_NRFLAG
+static inline int tsk_is_polling(struct task_struct *p)
+{
+	return test_tsk_thread_flag(p, TIF_POLLING_NRFLAG);
+}
+
+static inline void __current_set_polling(void)
+{
+	set_thread_flag(TIF_POLLING_NRFLAG);
+}
+
+static inline bool __must_check current_set_polling_and_test(void)
+{
+	__current_set_polling();
+
+	/*
+	 * Polling state must be visible before we test NEED_RESCHED,
+	 * paired by resched_curr()
+	 */
+	smp_mb__after_atomic();
+
+	return unlikely(tif_need_resched());
+}
+
+static inline void __current_clr_polling(void)
+{
+	clear_thread_flag(TIF_POLLING_NRFLAG);
+}
+
+static inline bool __must_check current_clr_polling_and_test(void)
+{
+	__current_clr_polling();
+
+	/*
+	 * Polling state must be visible before we test NEED_RESCHED,
+	 * paired by resched_curr()
+	 */
+	smp_mb__after_atomic();
+
+	return unlikely(tif_need_resched());
+}
+
+#else
+static inline int tsk_is_polling(struct task_struct *p) { return 0; }
+static inline void __current_set_polling(void) { }
+static inline void __current_clr_polling(void) { }
+
+static inline bool __must_check current_set_polling_and_test(void)
+{
+	return unlikely(tif_need_resched());
+}
+static inline bool __must_check current_clr_polling_and_test(void)
+{
+	return unlikely(tif_need_resched());
+}
+#endif
+
+static inline void current_clr_polling(void)
+{
+	__current_clr_polling();
+
+	/*
+	 * Ensure we check TIF_NEED_RESCHED after we clear the polling bit.
+	 * Once the bit is cleared, we'll get IPIs with every new
+	 * TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also
+	 * fold.
+	 */
+	smp_mb(); /* paired with resched_curr() */
+
+	preempt_fold_need_resched();
+}
+
 #endif /* _LINUX_SCHED_IDLE_H */