* [PATCH v2] few functions clean up
@ 2012-09-14 5:47 Alex Shi
2012-09-14 5:47 ` [PATCH v2 1/3] nohz: clean up select_nohz_load_balancer() Alex Shi
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Alex Shi @ 2012-09-14 5:47 UTC (permalink / raw)
To: mingo, peterz, tglx, suresh.b.siddha, venki; +Cc: linux-kernel
Changed according to Peter and Suresh suggestion.
Thanks
[PATCH v2 1/3] nohz: clean up select_nohz_load_balancer()
[PATCH v2 2/3] sched:nohz rename clear_nohz_tick_stopped as
[PATCH v2 3/3] sched/balance: remove on_null_domain() in
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2 1/3] nohz: clean up select_nohz_load_balancer()
2012-09-14 5:47 [PATCH v2] few functions clean up Alex Shi
@ 2012-09-14 5:47 ` Alex Shi
2012-09-14 5:47 ` [PATCH v2 2/3] sched:nohz rename clear_nohz_tick_stopped as nohz_balance_exit_idle Alex Shi
2012-09-14 5:47 ` [PATCH v2 3/3] sched/balance: remove on_null_domain() in trigger_load_balance Alex Shi
2 siblings, 0 replies; 4+ messages in thread
From: Alex Shi @ 2012-09-14 5:47 UTC (permalink / raw)
To: mingo, peterz, tglx, suresh.b.siddha, venki; +Cc: linux-kernel
There is no load_balancer to be selected now. It just set state of
nohz tick stopping.
So rename the function as nohz_balance_enter_idle according to Peter's
suggestion, pass the 'cpu' from parameter and then
remove the useless calling from tick_nohz_restart_sched_tick().
Signed-off-by: Alex Shi <alex.shi@intel.com>
---
include/linux/sched.h | 4 ++--
kernel/sched/fair.c | 19 +++++++------------
kernel/time/tick-sched.c | 3 +--
3 files changed, 10 insertions(+), 16 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b8c8664..e723a4b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -273,11 +273,11 @@ extern void init_idle_bootup_task(struct task_struct *idle);
extern int runqueue_is_locked(int cpu);
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
-extern void select_nohz_load_balancer(int stop_tick);
+extern void nohz_balance_enter_idle(int cpu);
extern void set_cpu_sd_state_idle(void);
extern int get_nohz_timer_target(void);
#else
-static inline void select_nohz_load_balancer(int stop_tick) { }
+static inline void nohz_balance_enter_idle(int cpu) { }
static inline void set_cpu_sd_state_idle(void) { }
#endif
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c219bf8..b681941 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4674,28 +4674,23 @@ void set_cpu_sd_state_idle(void)
}
/*
- * This routine will record that this cpu is going idle with tick stopped.
+ * This routine will record that the cpu is going idle with tick stopped.
* This info will be used in performing idle load balancing in the future.
*/
-void select_nohz_load_balancer(int stop_tick)
+void nohz_balance_enter_idle(int cpu)
{
- int cpu = smp_processor_id();
-
/*
* If this cpu is going down, then nothing needs to be done.
*/
if (!cpu_active(cpu))
return;
- if (stop_tick) {
- if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))
- return;
+ if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))
+ return;
- cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
- atomic_inc(&nohz.nr_cpus);
- set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
- }
- return;
+ cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
+ atomic_inc(&nohz.nr_cpus);
+ set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
}
static int __cpuinit sched_ilb_notifier(struct notifier_block *nfb,
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 024540f..0e6a945 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -372,7 +372,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
* the scheduler tick in nohz_restart_sched_tick.
*/
if (!ts->tick_stopped) {
- select_nohz_load_balancer(1);
+ nohz_balance_enter_idle(cpu);
calc_load_enter_idle();
ts->last_tick = hrtimer_get_expires(&ts->sched_timer);
@@ -569,7 +569,6 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
{
/* Update jiffies first */
- select_nohz_load_balancer(0);
tick_do_update_jiffies64(now);
update_cpu_load_nohz();
--
1.7.12
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 2/3] sched:nohz rename clear_nohz_tick_stopped as nohz_balance_exit_idle
2012-09-14 5:47 [PATCH v2] few functions clean up Alex Shi
2012-09-14 5:47 ` [PATCH v2 1/3] nohz: clean up select_nohz_load_balancer() Alex Shi
@ 2012-09-14 5:47 ` Alex Shi
2012-09-14 5:47 ` [PATCH v2 3/3] sched/balance: remove on_null_domain() in trigger_load_balance Alex Shi
2 siblings, 0 replies; 4+ messages in thread
From: Alex Shi @ 2012-09-14 5:47 UTC (permalink / raw)
To: mingo, peterz, tglx, suresh.b.siddha, venki; +Cc: linux-kernel
This patch just rename the function clear_nohz_tick_stopped() to
nohz_balance_exit_idle(), that align with nohz_balance_enter_idle.
no function changes.
Signed-off-by: Alex Shi <alex.shi@intel.com>
---
kernel/sched/fair.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b681941..60d5505 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4634,7 +4634,7 @@ static void nohz_balancer_kick(int cpu)
return;
}
-static inline void clear_nohz_tick_stopped(int cpu)
+static inline void nohz_balance_exit_idle(int cpu)
{
if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) {
cpumask_clear_cpu(cpu, nohz.idle_cpus_mask);
@@ -4698,7 +4698,7 @@ static int __cpuinit sched_ilb_notifier(struct notifier_block *nfb,
{
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DYING:
- clear_nohz_tick_stopped(smp_processor_id());
+ nohz_balance_exit_idle(smp_processor_id());
return NOTIFY_OK;
default:
return NOTIFY_DONE;
@@ -4858,7 +4858,7 @@ static inline int nohz_kick_needed(struct rq *rq, int cpu)
* busy tick after returning from idle, we will update the busy stats.
*/
set_cpu_sd_state_busy();
- clear_nohz_tick_stopped(cpu);
+ nohz_balance_exit_idle(cpu);
/*
* None are in tickless mode and hence no need for NOHZ idle load
--
1.7.12
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 3/3] sched/balance: remove on_null_domain() in trigger_load_balance
2012-09-14 5:47 [PATCH v2] few functions clean up Alex Shi
2012-09-14 5:47 ` [PATCH v2 1/3] nohz: clean up select_nohz_load_balancer() Alex Shi
2012-09-14 5:47 ` [PATCH v2 2/3] sched:nohz rename clear_nohz_tick_stopped as nohz_balance_exit_idle Alex Shi
@ 2012-09-14 5:47 ` Alex Shi
2 siblings, 0 replies; 4+ messages in thread
From: Alex Shi @ 2012-09-14 5:47 UTC (permalink / raw)
To: mingo, peterz, tglx, suresh.b.siddha, venki; +Cc: linux-kernel
According to Suresh's inverstigation, the first on_null_domain in
trigger_load_balance is for avoiding unnecessary loadbalances(from
softirq) when a SMP kernel running on UP machine.
The second on_null_domain is not needed, since nohz_kick_needed()
will return 0 in this scenario.
So, remove the 2nd on_null_domain calling.
Signed-off-by: Alex Shi <alex.shi@intel.com>
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 60d5505..1ae2c66 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4938,7 +4938,7 @@ void trigger_load_balance(struct rq *rq, int cpu)
likely(!on_null_domain(cpu)))
raise_softirq(SCHED_SOFTIRQ);
#ifdef CONFIG_NO_HZ
- if (nohz_kick_needed(rq, cpu) && likely(!on_null_domain(cpu)))
+ if (nohz_kick_needed(rq, cpu))
nohz_balancer_kick(cpu);
#endif
}
--
1.7.12
^ permalink raw reply related [flat|nested] 4+ messages in thread
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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2012-09-14 5:47 [PATCH v2] few functions clean up Alex Shi
2012-09-14 5:47 ` [PATCH v2 1/3] nohz: clean up select_nohz_load_balancer() Alex Shi
2012-09-14 5:47 ` [PATCH v2 2/3] sched:nohz rename clear_nohz_tick_stopped as nohz_balance_exit_idle Alex Shi
2012-09-14 5:47 ` [PATCH v2 3/3] sched/balance: remove on_null_domain() in trigger_load_balance Alex Shi
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