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.ku...@linaro.org>
---
include/linux/sched.h | 6 +++++-
kernel/hrtimer.c | 15 +--------------
kernel/sched/core.c | 5 ++++-
kernel/timer.c | 7 +------
4 files changed, 11 insertions(+), 22 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6dbb9e5..9819f93 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -299,10 +299,14 @@ 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
/*
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index f60dce8..7eef615 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -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:
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 6fde755..a58e24d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -556,12 +556,15 @@ 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)) {
diff --git a/kernel/timer.c b/kernel/timer.c
index e6868bf..2cf8616 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -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) {
--
1.7.12.rc2.18.g61b472e
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