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timer: Remove code redundancy while calling get_nohz_timer_target()

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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: Viresh 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: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Viresh Kumar 2014-03-18 16:26:07 +05:30 committed by Thomas Gleixner
parent e2e680fb75
commit 6201b4d61f
4 changed files with 11 additions and 22 deletions
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6
include/linux/sched.h
View File

@ -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
/*

15
kernel/hrtimer.c
View File

@ -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:

5
kernel/sched/core.c
View File

@ -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)) {

7
kernel/timer.c
View File

@ -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) {