[PATCH] Optimise tick_nohz_stop_sched_tick() a bit

From: Karsten Wiese
Date: Thu Feb 28 2008 - 09:11:17 EST



Call
ts = &per_cpu(tick_cpu_sched, cpu);
and
cpu = smp_processor_id();
once instead of twice.

No functional change done, as changed code runs with local irq off.
Reduces source lines and text size (20bytes on x86_64).

Signed-off-by: Karsten Wiese <fzu@xxxxxxxxxxxxxxxxxxxxx>
---
kernel/time/tick-sched.c | 6 ++----
1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 686da82..851a852 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -158,9 +158,8 @@ void tick_nohz_stop_idle(int cpu)
}
}

-static ktime_t tick_nohz_start_idle(int cpu)
+static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts)
{
- struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
ktime_t now, delta;

now = ktime_get();
@@ -201,8 +200,8 @@ void tick_nohz_stop_sched_tick(void)
local_irq_save(flags);

cpu = smp_processor_id();
- now = tick_nohz_start_idle(cpu);
ts = &per_cpu(tick_cpu_sched, cpu);
+ now = tick_nohz_start_idle(cpu, ts);

/*
* If this cpu is offline and it is the one which updates
@@ -222,7 +221,6 @@ void tick_nohz_stop_sched_tick(void)
if (need_resched())
goto end;

- cpu = smp_processor_id();
if (unlikely(local_softirq_pending())) {
static int ratelimit;

--
1.5.3.3
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