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sched: fix sched_clock_cpu()

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Make sched_clock_cpu() return 0 before it has been initialized and avoid
corrupting its state due to doing so.

This fixes the weird printk timestamp jump reported.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
This commit is contained in:
Peter Zijlstra 2008-05-29 10:07:15 +02:00 committed by Ingo Molnar
parent 6363ca57c7
commit a381759d6a
1 changed files with 14 additions and 4 deletions
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18
kernel/sched_clock.c
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@ -59,22 +59,26 @@ static inline struct sched_clock_data *cpu_sdc(int cpu)
return &per_cpu(sched_clock_data, cpu);
}
static __read_mostly int sched_clock_running;
void sched_clock_init(void)
{
u64 ktime_now = ktime_to_ns(ktime_get());
u64 now = 0;
unsigned long now_jiffies = jiffies;
int cpu;
for_each_possible_cpu(cpu) {
struct sched_clock_data *scd = cpu_sdc(cpu);
scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
scd->prev_jiffies = jiffies;
scd->prev_raw = now;
scd->tick_raw = now;
scd->prev_jiffies = now_jiffies;
scd->prev_raw = 0;
scd->tick_raw = 0;
scd->tick_gtod = ktime_now;
scd->clock = ktime_now;
}
sched_clock_running = 1;
}
/*
@ -136,6 +140,9 @@ u64 sched_clock_cpu(int cpu)
struct sched_clock_data *scd = cpu_sdc(cpu);
u64 now, clock;
if (unlikely(!sched_clock_running))
return 0ull;
WARN_ON_ONCE(!irqs_disabled());
now = sched_clock();
@ -174,6 +181,9 @@ void sched_clock_tick(void)
struct sched_clock_data *scd = this_scd();
u64 now, now_gtod;
if (unlikely(!sched_clock_running))
return;
WARN_ON_ONCE(!irqs_disabled());
now = sched_clock();