hrtimer: Get rid of softirq time

The softirq time field in the clock bases is an optimization from the
early days of hrtimers. It provides a coarse "jiffies" like time
mostly for self rearming timers.

But that comes with a price:
    - Larger code size
    - Extra storage space
    - Duplicated functions with really small differences
   
The benefit of this is optimization is marginal for contemporary
systems.

Consolidate everything on the high resolution timer
implementation. This makes further optimizations possible.

Text size reduction:
       x8664 -95, i386 -356, ARM -148, ARM64 -40, power64 -16

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20150414203501.039977424@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 5 insertions, 19 deletions

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index d39f2847754c..e292830b58f0 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -138,7 +138,6 @@ struct hrtimer_sleeper {
  * @clockid:		clock id for per_cpu support
  * @active:		red black tree root node for the active timers
  * @get_time:		function to retrieve the current time of the clock
- * @softirq_time:	the time when running the hrtimer queue in the softirq
  * @offset:		offset of this clock to the monotonic base
  */
 struct hrtimer_clock_base {
@@ -147,7 +146,6 @@ struct hrtimer_clock_base {
 	clockid_t		clockid;
 	struct timerqueue_head	active;
 	ktime_t			(*get_time)(void);
-	ktime_t			softirq_time;
 	ktime_t			offset;
 };
 
@@ -260,19 +258,16 @@ static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
 	return ktime_sub(timer->node.expires, timer->base->get_time());
 }
 
-#ifdef CONFIG_HIGH_RES_TIMERS
-struct clock_event_device;
-
-extern void hrtimer_interrupt(struct clock_event_device *dev);
-
-/*
- * In high resolution mode the time reference must be read accurate
- */
 static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
 {
 	return timer->base->get_time();
 }
 
+#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;
@@ -304,15 +299,6 @@ extern unsigned int hrtimer_resolution;
 
 static inline void hrtimer_peek_ahead_timers(void) { }
 
-/*
- * In non high resolution mode the time reference is taken from
- * the base softirq time variable.
- */
-static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
-{
-	return timer->base->softirq_time;
-}
-
 static inline int hrtimer_is_hres_active(struct hrtimer *timer)
 {
 	return 0;