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Groups > linux.kernel > #1625448

[patch V2 10/10] timer: Always queue timers on the local CPU

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The timer pull model is in place so we can remove the heuristics which try
to guess the best target CPU at enqueue/modification time.

All non pinned timers are queued on the local cpu in the seperate storage
and eventually pulled at expiry time to a remote cpu.

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 kernel/time/timer.c |   20 +-------------------
 1 file changed, 1 insertion(+), 19 deletions(-)

--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -857,18 +857,6 @@ static inline struct timer_base *get_tim
 }
 
 #ifdef CONFIG_NO_HZ_COMMON
-static inline struct timer_base *
-get_target_base(struct timer_base *base, unsigned tflags)
-{
-#ifdef CONFIG_SMP
-	if ((tflags & TIMER_PINNED) || !base->migration_enabled)
-		return get_timer_this_cpu_base(tflags);
-	return get_timer_cpu_base(tflags, get_nohz_timer_target());
-#else
-	return get_timer_this_cpu_base(tflags);
-#endif
-}
-
 static inline void forward_timer_base(struct timer_base *base)
 {
 	unsigned long jnow = READ_ONCE(jiffies);
@@ -890,12 +878,6 @@ static inline void forward_timer_base(st
 		base->clk = base->next_expiry;
 }
 #else
-static inline struct timer_base *
-get_target_base(struct timer_base *base, unsigned tflags)
-{
-	return get_timer_this_cpu_base(tflags);
-}
-
 static inline void forward_timer_base(struct timer_base *base) { }
 #endif
 
@@ -985,7 +967,7 @@ static inline int
 	if (!ret && pending_only)
 		goto out_unlock;
 
-	new_base = get_target_base(base, timer->flags);
+	new_base = get_timer_this_cpu_base(timer->flags);
 
 	if (base != new_base) {
 		/*

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[patch V2 00/10] timer: Move from a push remote at enqueue to a pull  at expiry model Thomas Gleixner <tglx@linutronix.de> - 2017-04-18 18:50 +0200
  [patch V2 06/10] timer: Restructure internal locking Thomas Gleixner <tglx@linutronix.de> - 2017-04-18 18:50 +0200
    Re: [patch V2 06/10] timer: Restructure internal locking Peter Zijlstra <peterz@infradead.org> - 2017-04-19 09:10 +0200
  [patch V2 10/10] timer: Always queue timers on the local CPU Thomas Gleixner <tglx@linutronix.de> - 2017-04-18 18:50 +0200
  [patch V2 07/10] tick/sched: Split out jiffies update helper function Thomas Gleixner <tglx@linutronix.de> - 2017-04-18 18:50 +0200
  [patch V2 08/10] timer: Implement the hierarchical pull model Thomas Gleixner <tglx@linutronix.de> - 2017-04-18 18:50 +0200
    Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 09:30 +0200
    Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 09:30 +0200
    Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 09:40 +0200
    Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 09:40 +0200
    Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 10:20 +0200
      Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 10:40 +0200
        Re: [patch V2 08/10] timer: Implement the hierarchical pull model Thomas Gleixner <tglx@linutronix.de> - 2017-04-19 11:10 +0200
      Re: [patch V2 08/10] timer: Implement the hierarchical pull model Thomas Gleixner <tglx@linutronix.de> - 2017-04-19 10:40 +0200
    Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 11:00 +0200
    Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 11:10 +0200
      Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 11:50 +0200
        Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 12:00 +0200
      Re: [patch V2 08/10] timer: Implement the hierarchical pull model Thomas Gleixner <tglx@linutronix.de> - 2017-04-19 11:50 +0200
        Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 12:00 +0200
    Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 11:30 +0200
    Re: [patch V2 08/10] timer: Implement the hierarchical pull model Peter Zijlstra <peterz@infradead.org> - 2017-04-19 12:30 +0200
  [patch V2 05/10] timer: Retrieve next expiry of pinned/non-pinned  timers seperately Thomas Gleixner <tglx@linutronix.de> - 2017-04-18 18:50 +0200
    Re: [patch V2 05/10] timer: Retrieve next expiry of  pinned/non-pinned timers seperately Peter Zijlstra <peterz@infradead.org> - 2017-04-19 09:10 +0200
      Re: [patch V2 05/10] timer: Retrieve next expiry of pinned/non-pinned  timers seperately Thomas Gleixner <tglx@linutronix.de> - 2017-04-19 12:00 +0200
  [patch V2 04/10] timer: Keep the pinned timers separate from the  others Thomas Gleixner <tglx@linutronix.de> - 2017-04-18 18:50 +0200
  Re: [patch V2 00/10] timer: Move from a push remote at enqueue to a  pull at expiry model "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-21 21:30 +0200

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