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Subject[PATCH 4/4] nohz: Convert a few places to use local per cpu accesses
Date
A few functions use remote per CPU access APIs when they
deal with local values.

Just to the right conversion to improve performance, code
readability and debug checks.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Fernando Luis Vazquez Cao <fernando_b1@lab.ntt.co.jp>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
---
kernel/time/tick-sched.c | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 017bec2..11d64e2 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -395,11 +395,9 @@ __setup("nohz=", setup_tick_nohz);
*/
static void tick_nohz_update_jiffies(ktime_t now)
{
- int cpu = smp_processor_id();
- struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
unsigned long flags;

- ts->idle_waketime = now;
+ __this_cpu_write(tick_cpu_sched.idle_waketime, now);

local_irq_save(flags);
tick_do_update_jiffies64(now);
@@ -410,7 +408,7 @@ static void tick_nohz_update_jiffies(ktime_t now)

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

/* Updates the per cpu time idle statistics counters */
@@ -901,7 +899,7 @@ static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
void tick_nohz_idle_exit(void)
{
int cpu = smp_processor_id();
- struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+ struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
ktime_t now;

local_irq_disable();
@@ -1020,7 +1018,7 @@ static void tick_nohz_kick_tick(int cpu, ktime_t now)

static inline void tick_check_nohz(int cpu)
{
- struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+ struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
ktime_t now;

if (!ts->idle_active && !ts->tick_stopped)
--
1.7.5.4


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