On Mon, 2012-02-20 at 10:04 +0400, Dmitry Antipov wrote:
Generalize CONFIG_IRQ_TIME_ACCOUNTING between X86 and ARM, move "noirqtime=" option to common debugging code. For a bit of backward compatibility, X86-specific option "tsc=noirqtime" is preserved, but issues a warning.
Suggested-by: Yong Zhang yong.zhang0@gmail.com Suggested-by: Russell King rmk+kernel@arm.linux.org.uk Suggested-by: Ingo Molnar mingo@elte.hu Acked-by: Venkatesh Pallipadi venki@google.com Signed-off-by: Dmitry Antipov dmitry.antipov@linaro.org
Thanks for Cc'ing me (maintainer) and Venki (original author of the stuff) :-)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 7d379a6..9b13f79 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1961,13 +1961,16 @@ extern void sched_clock_idle_wakeup_event(u64 delta_ns); #endif #ifdef CONFIG_IRQ_TIME_ACCOUNTING -/*
- An i/f to runtime opt-in for irq time accounting based off of sched_clock.
- The reason for this explicit opt-in is not to have perf penalty with
- slow sched_clocks.
- */
-extern void enable_sched_clock_irqtime(void); -extern void disable_sched_clock_irqtime(void); +extern int sched_clock_irqtime; +static inline void enable_sched_clock_irqtime(void) +{
- if (sched_clock_irqtime == -1)
sched_clock_irqtime = 1;
+} +static inline void disable_sched_clock_irqtime(void) +{
- sched_clock_irqtime = 0;
+} #else static inline void enable_sched_clock_irqtime(void) {} static inline void disable_sched_clock_irqtime(void) {}
Please keep them out-of-line, its not a fast path and it avoids having to expose the state variable.
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5255c9d..4e7a197 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -757,18 +757,21 @@ static DEFINE_PER_CPU(u64, cpu_hardirq_time); static DEFINE_PER_CPU(u64, cpu_softirq_time); static DEFINE_PER_CPU(u64, irq_start_time); -static int sched_clock_irqtime; -void enable_sched_clock_irqtime(void) -{
- sched_clock_irqtime = 1;
-} +/*
- -1 if not initialized, 0 if disabled with "noirqtime" kernel option
- or after unstable clock was detected, 1 if enabled and active.
- */
You forgot to explain what you need the tri-state for.
+__read_mostly int sched_clock_irqtime = -1; -void disable_sched_clock_irqtime(void) +static int __init irqtime_setup(char *str) { sched_clock_irqtime = 0;
- return 1;
} +__setup("noirqtime", irqtime_setup);
#ifndef CONFIG_64BIT static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
Other than that no real objections.. I guess.