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-rw-r--r--kernel/sched_clock.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index 9c597e37f7d..ce05271219a 100644
--- a/kernel/sched_clock.c
+++ b/kernel/sched_clock.c
@@ -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();