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author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-05-29 08:07:15 (GMT) |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-05-29 09:29:19 (GMT) |
commit | a381759d6ad5c5dea5a981918e0b4493e9b66ac7 (patch) | |
tree | 059df197fe2974c655fc098e3aaf6968a3cc2a3c | |
parent | 6363ca57c76b7b83639ca8c83fc285fa26a7880e (diff) | |
download | linux-fsl-qoriq-a381759d6ad5c5dea5a981918e0b4493e9b66ac7.tar.xz |
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>
-rw-r--r-- | kernel/sched_clock.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index 9c597e3..ce05271 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(); |