Re: [PATCH 1/3] lockup_detector: convert per_cpu to __get_cpu_var for readability

[Frederic Weisbecker <fweisbec@gmail.com>]

On Mon, May 17, 2010 at 06:06:04PM -0400, Don Zickus wrote:
> Just a bunch of conversions as suggested by Frederic W.
> 
> Signed-off-by: Don Zickus <dzickus@redhat.com>
> ---


I'm taking this one,

Thanks.



>  kernel/watchdog.c |   35 +++++++++++++++++------------------
>  1 files changed, 17 insertions(+), 18 deletions(-)
> 
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index e53622c..91b0b26 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -115,7 +115,7 @@ static unsigned long get_sample_period(void)
>  /* Commands for resetting the watchdog */
>  static void __touch_watchdog(void)
>  {
> -	int this_cpu = raw_smp_processor_id();
> +	int this_cpu = smp_processor_id();
>  
>  	__get_cpu_var(watchdog_touch_ts) = get_timestamp(this_cpu);
>  }
> @@ -157,21 +157,21 @@ void touch_softlockup_watchdog_sync(void)
>  
>  #ifdef CONFIG_HARDLOCKUP_DETECTOR
>  /* watchdog detector functions */
> -static int is_hardlockup(int cpu)
> +static int is_hardlockup(void)
>  {
> -	unsigned long hrint = per_cpu(hrtimer_interrupts, cpu);
> +	unsigned long hrint = __get_cpu_var(hrtimer_interrupts);
>  
> -	if (per_cpu(hrtimer_interrupts_saved, cpu) == hrint)
> +	if (__get_cpu_var(hrtimer_interrupts_saved) == hrint)
>  		return 1;
>  
> -	per_cpu(hrtimer_interrupts_saved, cpu) = hrint;
> +	__get_cpu_var(hrtimer_interrupts_saved) = hrint;
>  	return 0;
>  }
>  #endif
>  
> -static int is_softlockup(unsigned long touch_ts, int cpu)
> +static int is_softlockup(unsigned long touch_ts)
>  {
> -	unsigned long now = get_timestamp(cpu);
> +	unsigned long now = get_timestamp(smp_processor_id());
>  
>  	/* Warn about unreasonable delays: */
>  	if (time_after(now, touch_ts + softlockup_thresh))
> @@ -206,8 +206,6 @@ void watchdog_overflow_callback(struct perf_event *event, int nmi,
>  		 struct perf_sample_data *data,
>  		 struct pt_regs *regs)
>  {
> -	int this_cpu = smp_processor_id();
> -
>  	if (__get_cpu_var(watchdog_nmi_touch) == true) {
>  		__get_cpu_var(watchdog_nmi_touch) = false;
>  		return;
> @@ -219,7 +217,9 @@ void watchdog_overflow_callback(struct perf_event *event, int nmi,
>  	 * fired multiple times before we overflow'd.  If it hasn't
>  	 * then this is a good indication the cpu is stuck
>  	 */
> -	if (is_hardlockup(this_cpu)) {
> +	if (is_hardlockup()) {
> +		int this_cpu = smp_processor_id();
> +
>  		/* only print hardlockups once */
>  		if (__get_cpu_var(hard_watchdog_warn) == true)
>  			return;
> @@ -247,7 +247,6 @@ static inline void watchdog_interrupt_count(void) { return; }
>  /* watchdog kicker functions */
>  static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
>  {
> -	int this_cpu = smp_processor_id();
>  	unsigned long touch_ts = __get_cpu_var(watchdog_touch_ts);
>  	struct pt_regs *regs = get_irq_regs();
>  	int duration;
> @@ -262,12 +261,12 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
>  	hrtimer_forward_now(hrtimer, ns_to_ktime(get_sample_period()));
>  
>  	if (touch_ts == 0) {
> -		if (unlikely(per_cpu(softlockup_touch_sync, this_cpu))) {
> +		if (unlikely(__get_cpu_var(softlockup_touch_sync))) {
>  			/*
>  			 * If the time stamp was touched atomically
>  			 * make sure the scheduler tick is up to date.
>  			 */
> -			per_cpu(softlockup_touch_sync, this_cpu) = false;
> +			__get_cpu_var(softlockup_touch_sync) = false;
>  			sched_clock_tick();
>  		}
>  		__touch_watchdog();
> @@ -280,14 +279,14 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
>  	 * indicate it is getting cpu time.  If it hasn't then
>  	 * this is a good indication some task is hogging the cpu
>  	 */
> -	duration = is_softlockup(touch_ts, this_cpu);
> +	duration = is_softlockup(touch_ts);
>  	if (unlikely(duration)) {
>  		/* only warn once */
>  		if (__get_cpu_var(soft_watchdog_warn) == true)
>  			return HRTIMER_RESTART;
>  
>  		printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
> -			this_cpu, duration,
> +			smp_processor_id(), duration,
>  			current->comm, task_pid_nr(current));
>  		print_modules();
>  		print_irqtrace_events(current);
> @@ -309,10 +308,10 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
>  /*
>   * The watchdog thread - touches the timestamp.
>   */
> -static int watchdog(void *__bind_cpu)
> +static int watchdog(void *unused)
>  {
>  	struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
> -	struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, (unsigned long)__bind_cpu);
> +	struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
>  
>  	sched_setscheduler(current, SCHED_FIFO, &param);
>  
> @@ -328,7 +327,7 @@ static int watchdog(void *__bind_cpu)
>  	/*
>  	 * Run briefly once per second to reset the softlockup timestamp.
>  	 * If this gets delayed for more than 60 seconds then the
> -	 * debug-printout triggers in softlockup_tick().
> +	 * debug-printout triggers in watchdog_timer_fn().
>  	 */
>  	while (!kthread_should_stop()) {
>  		__touch_watchdog();
> -- 
> 1.7.0.1
>