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Message-ID: <20100519084703.GI5704@nowhere>
Date: Wed, 19 May 2010 10:47:05 +0200
From: Frederic Weisbecker <fweisbec@...il.com>
To: Don Zickus <dzickus@...hat.com>
Cc: mingo@...e.hu, a.p.zijlstra@...llo.nl, gorcunov@...il.com,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] lockup_detector: convert per_cpu to __get_cpu_var
for readability
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@...hat.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, ¶m);
>
> @@ -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
>
--
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