hrtimer: Make the hrtimer_cpu_base::hres_active field unconditional, to simplify the code

The hrtimer_cpu_base::hres_active_member field depends on CONFIG_HIGH_RES_TIMERS=y
currently, and all related functions to this member are conditional as well.

To simplify the code make it unconditional and set it to zero during initialization.

(This will also help with the upcoming softirq based hrtimers code.)

The conditional code sections can be avoided by adding IS_ENABLED(HIGHRES)
conditionals into common functions, which ensures dead code elimination.

There is no functional change.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: keescook@chromium.org
Link: http://lkml.kernel.org/r/20171221104205.7269-14-anna-maria@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 8 insertions, 12 deletions

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 56e56bcb6f0f..22627b3a33fe 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -161,8 +161,8 @@ enum  hrtimer_base_type {
  * @cpu:                cpu number
  * @active_bases:       Bitfield to mark bases with active timers
  * @clock_was_set_seq:  Sequence counter of clock was set events
- * @in_hrtirq:          hrtimer_interrupt() is currently executing
  * @hres_active:        State of high resolution mode
+ * @in_hrtirq:          hrtimer_interrupt() is currently executing
  * @hang_detected:      The last hrtimer interrupt detected a hang
  * @expires_next:       absolute time of the next event, is required for remote
  *                      hrtimer enqueue
@@ -182,9 +182,9 @@ struct hrtimer_cpu_base {
         unsigned int                    cpu;
         unsigned int                    active_bases;
         unsigned int                    clock_was_set_seq;
+        unsigned int                    hres_active     : 1;
 #ifdef CONFIG_HIGH_RES_TIMERS
         unsigned int                    in_hrtirq       : 1,
-                                        hres_active     : 1,
                                         hang_detected   : 1;
         ktime_t                         expires_next;
         struct hrtimer                  *next_timer;
@@ -266,16 +266,17 @@ static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
         return timer->base->get_time();
 }
 
+static inline int hrtimer_is_hres_active(struct hrtimer *timer)
+{
+        return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
+                timer->base->cpu_base->hres_active : 0;
+}
+
 #ifdef CONFIG_HIGH_RES_TIMERS
 struct clock_event_device;
 
 extern void hrtimer_interrupt(struct clock_event_device *dev);
 
-static inline int hrtimer_is_hres_active(struct hrtimer *timer)
-{
-        return timer->base->cpu_base->hres_active;
-}
-
 /*
  * The resolution of the clocks. The resolution value is returned in
  * the clock_getres() system call to give application programmers an
@@ -298,11 +299,6 @@ extern unsigned int hrtimer_resolution;
 
 #define hrtimer_resolution      (unsigned int)LOW_RES_NSEC
 
-static inline int hrtimer_is_hres_active(struct hrtimer *timer)
-{
-        return 0;
-}
-
 static inline void clock_was_set_delayed(void) { }
 
 #endif