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Commit 6201b4d6 authored by Viresh Kumar's avatar Viresh Kumar Committed by Thomas Gleixner
Browse files

timer: Remove code redundancy while calling get_nohz_timer_target() 



There are only two users of get_nohz_timer_target(): timer and hrtimer. Both
call it under same circumstances, i.e.

	#ifdef CONFIG_NO_HZ_COMMON
	       if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
	               return get_nohz_timer_target();
	#endif

So, it makes more sense to get all this as part of get_nohz_timer_target()
instead of duplicating code at two places. For this another parameter is
required to be passed to this routine, pinned.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: fweisbec@gmail.com
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1e1b53537217d58d48c2d7a222a9c3ac47d5b64c.1395140107.git.viresh.kumar@linaro.org


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent e2e680fb

include/linux/sched.h

+5 −1
Original line number Diff line number Diff line
@@ -291,10 +291,14 @@ 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);

extern int get_nohz_timer_target(int pinned);

#else

static inline void nohz_balance_enter_idle(int cpu) { }

static inline void set_cpu_sd_state_idle(void) { }

static inline int get_nohz_timer_target(int pinned)

{

	return smp_processor_id();

}

#endif



/*

kernel/hrtimer.c

+1 −14
Original line number Diff line number Diff line
@@ -168,19 +168,6 @@ struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer, 
	}

}





/*

 * Get the preferred target CPU for NOHZ

 */

static int hrtimer_get_target(int this_cpu, int pinned)

{

#ifdef CONFIG_NO_HZ_COMMON

	if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))

		return get_nohz_timer_target();

#endif

	return this_cpu;

}



/*

 * With HIGHRES=y we do not migrate the timer when it is expiring

 * before the next event on the target cpu because we cannot reprogram
@@ -214,7 +201,7 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base, 
	struct hrtimer_clock_base *new_base;

	struct hrtimer_cpu_base *new_cpu_base;

	int this_cpu = smp_processor_id();

	int cpu = hrtimer_get_target(this_cpu, pinned);

	int cpu = get_nohz_timer_target(pinned);

	int basenum = base->index;



again:

kernel/sched/core.c

+4 −1
Original line number Diff line number Diff line
@@ -555,12 +555,15 @@ void resched_cpu(int cpu) 
 * selecting an idle cpu will add more delays to the timers than intended

 * (as that cpu's timer base may not be uptodate wrt jiffies etc).

 */

int get_nohz_timer_target(void)

int get_nohz_timer_target(int pinned)

{

	int cpu = smp_processor_id();

	int i;

	struct sched_domain *sd;



	if (pinned || !get_sysctl_timer_migration() || !idle_cpu(cpu))

		return cpu;



	rcu_read_lock();

	for_each_domain(cpu, sd) {

		for_each_cpu(i, sched_domain_span(sd)) {

kernel/timer.c

+1 −6
Original line number Diff line number Diff line
@@ -760,12 +760,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, 


	debug_activate(timer, expires);



	cpu = smp_processor_id();



#if defined(CONFIG_NO_HZ_COMMON) && defined(CONFIG_SMP)

	if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu))

		cpu = get_nohz_timer_target();

#endif

	cpu = get_nohz_timer_target(pinned);

	new_base = per_cpu(tvec_bases, cpu);



	if (base != new_base) {