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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-05-29 10:07:15 +0200
committerIngo Molnar <mingo@elte.hu>2008-05-29 11:29:19 +0200
commita381759d6ad5c5dea5a981918e0b4493e9b66ac7 (patch)
tree059df197fe2974c655fc098e3aaf6968a3cc2a3c /kernel/sched_clock.c
parent6363ca57c76b7b83639ca8c83fc285fa26a7880e (diff)
downloadlinux-stericsson-a381759d6ad5c5dea5a981918e0b4493e9b66ac7.tar.gz
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: Peter Zijlstra <a.p.zijlstra@chello.nl>
Diffstat (limited to 'kernel/sched_clock.c')
-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 9c597e37f7de..ce05271219ab 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();