decrementer_check_overflow is called from arch_local_irq_restore so
we want to make it as light weight as possible. As such, turn
decrementer_check_overflow into an inline function.
To avoid a circular mess of includes, separate out the two components
of struct decrementer_clock and keep the struct clock_event_device
part local to time.c.
The fast path improves from:
arch_local_irq_restore
0: mflr r0
4: std r0,16(r1)
8: stdu r1,-112(r1)
c: stb r3,578(r13)
10: cmpdi cr7,r3,0
14: beq- cr7,24 <.arch_local_irq_restore+0x24>
...
24: addi r1,r1,112
28: ld r0,16(r1)
2c: mtlr r0
30: blr
to:
arch_local_irq_restore
0: std r30,-16(r1)
4: ld r30,0(r2)
8: stb r3,578(r13)
c: cmpdi cr7,r3,0
10: beq- cr7,6c <.arch_local_irq_restore+0x6c>
...
6c: ld r30,-16(r1)
70: blr
Unfortunately we still setup a local TOC (due to -mminimal-toc). Yet
another sign we should be moving to -mcmodel=medium.
Signed-off-by: Anton Blanchard <an...@samba.org>
---
Index: linux-build/arch/powerpc/kernel/time.c
===================================================================
--- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-17 13:07:26.638774436
+1100
+++ linux-build/arch/powerpc/kernel/time.c 2011-11-17 13:13:22.409001783
+1100
@@ -114,12 +114,8 @@ static struct clock_event_device decreme
.features = CLOCK_EVT_FEAT_ONESHOT,
};
-struct decrementer_clock {
- struct clock_event_device event;
- u64 next_tb;
-};
-
-static DEFINE_PER_CPU(struct decrementer_clock, decrementers);
+DEFINE_PER_CPU(u64, decrementers_next_tb);
+static DEFINE_PER_CPU(struct clock_event_device, decrementers);
#ifdef CONFIG_PPC_ISERIES
static unsigned long __initdata iSeries_recal_titan;
@@ -570,8 +566,8 @@ void arch_irq_work_raise(void)
void timer_interrupt(struct pt_regs * regs)
{
struct pt_regs *old_regs;
- struct decrementer_clock *decrementer = &__get_cpu_var(decrementers);
- struct clock_event_device *evt = &decrementer->event;
+ u64 *next_tb = &__get_cpu_var(decrementers_next_tb);
+ struct clock_event_device *evt = &__get_cpu_var(decrementers);
/* Ensure a positive value is written to the decrementer, or else
* some CPUs will continue to take decrementer exceptions.
@@ -606,7 +602,7 @@ void timer_interrupt(struct pt_regs * re
get_lppaca()->int_dword.fields.decr_int = 0;
#endif
- decrementer->next_tb = ~(u64)0;
+ *next_tb = ~(u64)0;
if (evt->event_handler)
evt->event_handler(evt);
@@ -872,19 +868,10 @@ static void __init clocksource_init(void
clock->name, clock->mult, clock->shift);
}
-void decrementer_check_overflow(void)
-{
- u64 now = get_tb_or_rtc();
- struct decrementer_clock *decrementer = &__get_cpu_var(decrementers);
-
- if (now >= decrementer->next_tb)
- set_dec(1);
-}
-
static int decrementer_set_next_event(unsigned long evt,
struct clock_event_device *dev)
{
- __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt;
+ __get_cpu_var(decrementers_next_tb) = get_tb_or_rtc() + evt;
set_dec(evt);
return 0;
}
@@ -898,7 +885,7 @@ static void decrementer_set_mode(enum cl
static void register_decrementer_clockevent(int cpu)
{
- struct clock_event_device *dec = &per_cpu(decrementers, cpu).event;
+ struct clock_event_device *dec = &per_cpu(decrementers, cpu);
*dec = decrementer_clockevent;
dec->cpumask = cpumask_of(cpu);
Index: linux-build/arch/powerpc/include/asm/time.h
===================================================================
--- linux-build.orig/arch/powerpc/include/asm/time.h 2011-11-17
13:07:30.438840750 +1100
+++ linux-build/arch/powerpc/include/asm/time.h 2011-11-17 13:13:05.492705459
+1100
@@ -219,7 +219,7 @@ DECLARE_PER_CPU(struct cpu_usage, cpu_us
extern void secondary_cpu_time_init(void);
extern void iSeries_time_init_early(void);
-extern void decrementer_check_overflow(void);
+DECLARE_PER_CPU(u64, decrementers_next_tb);
#endif /* __KERNEL__ */
#endif /* __POWERPC_TIME_H */
Index: linux-build/arch/powerpc/kernel/irq.c
===================================================================
--- linux-build.orig/arch/powerpc/kernel/irq.c 2011-11-17 13:07:26.662774855
+1100
+++ linux-build/arch/powerpc/kernel/irq.c 2011-11-17 13:15:02.038747391
+1100
@@ -115,6 +115,15 @@ static inline notrace void set_soft_enab
: : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
}
+static inline notrace void decrementer_check_overflow(void)
+{
+ u64 now = get_tb_or_rtc();
+ u64 *next_tb = &__get_cpu_var(decrementers_next_tb);
+
+ if (now >= *next_tb)
+ set_dec(1);
+}
+
notrace void arch_local_irq_restore(unsigned long en)
{
/*
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