[POWERPC] Timer interrupt: use a struct for two per_cpu varables
timer_interrupt() was calculating per_cpu_offset several times, having to
start from the toc because of potential aliasing issues.
Placing both decrementer per_cpu varables in a struct and calculating
the address once with __get_cpu_var results in better code on both 32
and 64 bit.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 888c657..5cf3940 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -116,8 +116,12 @@
.features = CLOCK_EVT_FEAT_ONESHOT,
};
-static DEFINE_PER_CPU(struct clock_event_device, decrementers);
-static DEFINE_PER_CPU(u64, decrementer_next_tb);
+struct decrementer_clock {
+ struct clock_event_device event;
+ u64 next_tb;
+};
+
+static DEFINE_PER_CPU(struct decrementer_clock, decrementers);
#ifdef CONFIG_PPC_ISERIES
static unsigned long __initdata iSeries_recal_titan;
@@ -555,8 +559,8 @@
void timer_interrupt(struct pt_regs * regs)
{
struct pt_regs *old_regs;
- int cpu = smp_processor_id();
- struct clock_event_device *evt = &per_cpu(decrementers, cpu);
+ struct decrementer_clock *decrementer = &__get_cpu_var(decrementers);
+ struct clock_event_device *evt = &decrementer->event;
u64 now;
/* Ensure a positive value is written to the decrementer, or else
@@ -569,9 +573,9 @@
#endif
now = get_tb_or_rtc();
- if (now < per_cpu(decrementer_next_tb, cpu)) {
+ if (now < decrementer->next_tb) {
/* not time for this event yet */
- now = per_cpu(decrementer_next_tb, cpu) - now;
+ now = decrementer->next_tb - now;
if (now <= DECREMENTER_MAX)
set_dec((int)now);
return;
@@ -810,7 +814,7 @@
static int decrementer_set_next_event(unsigned long evt,
struct clock_event_device *dev)
{
- __get_cpu_var(decrementer_next_tb) = get_tb_or_rtc() + evt;
+ __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt;
set_dec(evt);
return 0;
}
@@ -824,7 +828,7 @@
static void register_decrementer_clockevent(int cpu)
{
- struct clock_event_device *dec = &per_cpu(decrementers, cpu);
+ struct clock_event_device *dec = &per_cpu(decrementers, cpu).event;
*dec = decrementer_clockevent;
dec->cpumask = cpumask_of_cpu(cpu);