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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-05-29 04:07:15 -0400
committerIngo Molnar <mingo@elte.hu>2008-05-29 05:29:19 -0400
commita381759d6ad5c5dea5a981918e0b4493e9b66ac7 (patch)
tree059df197fe2974c655fc098e3aaf6968a3cc2a3c /kernel
parent6363ca57c76b7b83639ca8c83fc285fa26a7880e (diff)
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')
-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)
59 return &per_cpu(sched_clock_data, cpu); 59 return &per_cpu(sched_clock_data, cpu);
60} 60}
61 61
62static __read_mostly int sched_clock_running;
63
62void sched_clock_init(void) 64void sched_clock_init(void)
63{ 65{
64 u64 ktime_now = ktime_to_ns(ktime_get()); 66 u64 ktime_now = ktime_to_ns(ktime_get());
65 u64 now = 0; 67 unsigned long now_jiffies = jiffies;
66 int cpu; 68 int cpu;
67 69
68 for_each_possible_cpu(cpu) { 70 for_each_possible_cpu(cpu) {
69 struct sched_clock_data *scd = cpu_sdc(cpu); 71 struct sched_clock_data *scd = cpu_sdc(cpu);
70 72
71 scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; 73 scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
72 scd->prev_jiffies = jiffies; 74 scd->prev_jiffies = now_jiffies;
73 scd->prev_raw = now; 75 scd->prev_raw = 0;
74 scd->tick_raw = now; 76 scd->tick_raw = 0;
75 scd->tick_gtod = ktime_now; 77 scd->tick_gtod = ktime_now;
76 scd->clock = ktime_now; 78 scd->clock = ktime_now;
77 } 79 }
80
81 sched_clock_running = 1;
78} 82}
79 83
80/* 84/*
@@ -136,6 +140,9 @@ u64 sched_clock_cpu(int cpu)
136 struct sched_clock_data *scd = cpu_sdc(cpu); 140 struct sched_clock_data *scd = cpu_sdc(cpu);
137 u64 now, clock; 141 u64 now, clock;
138 142
143 if (unlikely(!sched_clock_running))
144 return 0ull;
145
139 WARN_ON_ONCE(!irqs_disabled()); 146 WARN_ON_ONCE(!irqs_disabled());
140 now = sched_clock(); 147 now = sched_clock();
141 148
@@ -174,6 +181,9 @@ void sched_clock_tick(void)
174 struct sched_clock_data *scd = this_scd(); 181 struct sched_clock_data *scd = this_scd();
175 u64 now, now_gtod; 182 u64 now, now_gtod;
176 183
184 if (unlikely(!sched_clock_running))
185 return;
186
177 WARN_ON_ONCE(!irqs_disabled()); 187 WARN_ON_ONCE(!irqs_disabled());
178 188
179 now = sched_clock(); 189 now = sched_clock();