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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-08-11 08:59:03 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-08-11 08:59:03 +0200 |
| commit | c1955a3d4762e7a9bf84035eb3c4886a900f0d15 (patch) | |
| tree | a00dcd1736c612017df7094a91d8a6435b7a49c9 /kernel/sched_clock.c | |
| parent | 4a273f209cc95d148f79b4c96d3d03997b44ffda (diff) | |
| download | lwn-c1955a3d4762e7a9bf84035eb3c4886a900f0d15.tar.gz lwn-c1955a3d4762e7a9bf84035eb3c4886a900f0d15.zip | |
sched_clock: delay using sched_clock()
Some arch's can't handle sched_clock() being called too early - delay
this until sched_clock_init() has been called.
Reported-by: Bill Gatliff <bgat@billgatliff.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Nishanth Aravamudan <nacc@us.ibm.com>
CC: Russell King - ARM Linux <linux@arm.linux.org.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_clock.c')
| -rw-r--r-- | kernel/sched_clock.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index 074edc989379..204991a0bfa7 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -42,6 +42,8 @@ unsigned long long __attribute__((weak)) sched_clock(void) return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ); } +static __read_mostly int sched_clock_running; + #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK struct sched_clock_data { @@ -70,8 +72,6 @@ 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()); @@ -248,6 +248,21 @@ void sched_clock_idle_wakeup_event(u64 delta_ns) } EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); +#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */ + +void sched_clock_init(void) +{ + sched_clock_running = 1; +} + +u64 sched_clock_cpu(int cpu) +{ + if (unlikely(!sched_clock_running)) + return 0; + + return sched_clock(); +} + #endif unsigned long long cpu_clock(int cpu) |