[PATCH] sched: use this_rq() helper

[PATCH] sched: use this_rq() helper

[Nathan Zimmer]

It is a few instructions more efficent to and slightly more readable to use
this_rq()-> instead of cpu_rq(smp_processor_id()->

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org> 
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
---
 kernel/sched/fair.c | 6 ++----
 kernel/sched/rt.c   | 2 +-
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c61a614..f2c9c0c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5418,10 +5418,9 @@ static inline void nohz_balance_exit_idle(int cpu)
 static inline void set_cpu_sd_state_busy(void)
 {
 	struct sched_domain *sd;
-	int cpu = smp_processor_id();
 
 	rcu_read_lock();
-	sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd);
+	sd = rcu_dereference_check_sched_domain(this_rq()->sd);
 
 	if (!sd || !sd->nohz_idle)
 		goto unlock;
@@ -5436,10 +5435,9 @@ unlock:
 void set_cpu_sd_state_idle(void)
 {
 	struct sched_domain *sd;
-	int cpu = smp_processor_id();
 
 	rcu_read_lock();
-	sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd);
+	sd = rcu_dereference_check_sched_domain(this_rq()->sd);
 
 	if (!sd || sd->nohz_idle)
 		goto unlock;
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 127a2c4..7aced2e 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -472,7 +472,7 @@ static int rt_se_boosted(struct sched_rt_entity *rt_se)
 #ifdef CONFIG_SMP
 static inline const struct cpumask *sched_rt_period_mask(void)
 {
-	return cpu_rq(smp_processor_id())->rd->span;
+	return this_rq()->rd->span;
 }
 #else
 static inline const struct cpumask *sched_rt_period_mask(void)
-- 
1.8.2.1

Re: [PATCH] sched: use this_rq() helper

[Peter Zijlstra]

On Thu, May 09, 2013 at 11:24:03AM -0500, Nathan Zimmer wrote:
> It is a few instructions more efficent to and slightly more readable to use
> this_rq()-> instead of cpu_rq(smp_processor_id()->

If you've taken the trouble of actually measuring this, including the
measurement results is appreciated.

But yes, it also makes the code slightly smaller.

Thanks!

Acked-by: Peter Zijlstra <peterz@infradead.org> 

[tip:sched/core] sched: Use this_rq() helper

[tip-bot for Nathan Zimmer]

Commit-ID:  424c93fe4cbe719e7fd7169248d2b648c493b68d
Gitweb:     http://git.kernel.org/tip/424c93fe4cbe719e7fd7169248d2b648c493b68d
Author:     Nathan Zimmer <nzimmer@sgi.com>
AuthorDate: Thu, 9 May 2013 11:24:03 -0500
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 10 May 2013 10:35:56 +0200

sched: Use this_rq() helper

It is a few instructions more efficent to and slightly more
readable to use this_rq()-> instead of cpu_rq(smp_processor_id())-> .

Size comparison of kernel/sched/fair.o:

   text    data     bss     dec     hex filename
  27972     122      26   28120    6dd8 fair.o.before
  27956     122      26   28104    6dc8 fair.o.after

Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1368116643-87971-1-git-send-email-nzimmer@sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/fair.c | 6 ++----
 kernel/sched/rt.c   | 2 +-
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c61a614..f2c9c0c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5418,10 +5418,9 @@ static inline void nohz_balance_exit_idle(int cpu)
 static inline void set_cpu_sd_state_busy(void)
 {
 	struct sched_domain *sd;
-	int cpu = smp_processor_id();
 
 	rcu_read_lock();
-	sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd);
+	sd = rcu_dereference_check_sched_domain(this_rq()->sd);
 
 	if (!sd || !sd->nohz_idle)
 		goto unlock;
@@ -5436,10 +5435,9 @@ unlock:
 void set_cpu_sd_state_idle(void)
 {
 	struct sched_domain *sd;
-	int cpu = smp_processor_id();
 
 	rcu_read_lock();
-	sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd);
+	sd = rcu_dereference_check_sched_domain(this_rq()->sd);
 
 	if (!sd || sd->nohz_idle)
 		goto unlock;
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 127a2c4..7aced2e 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -472,7 +472,7 @@ static int rt_se_boosted(struct sched_rt_entity *rt_se)
 #ifdef CONFIG_SMP
 static inline const struct cpumask *sched_rt_period_mask(void)
 {
-	return cpu_rq(smp_processor_id())->rd->span;
+	return this_rq()->rd->span;
 }
 #else
 static inline const struct cpumask *sched_rt_period_mask(void)