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Commit a381759d authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: fix sched_clock_cpu() 



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: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
parent 6363ca57

kernel/sched_clock.c

+14 −4
Original line number Diff line number Diff line
@@ -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();