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sched: sched_clock() lockdep fix

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Sitsofe Wheeler bisected the following commit to cause a lockdep to
warn about itself and turn itself off:

> commit c6531cce6e
> Author: Ingo Molnar <mingo@elte.hu>
> Date:   Mon May 12 21:21:14 2008 +0200
>
>     sched: do not trace sched_clock

do not use raw irq flags in cpu_clock() as it causes lockdep to lose
track of the true state of the IRQ flag.

Reported-and-bisected-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Ingo Molnar
2008-06-09 01:45:29 -07:00
parent 34078a5e44
commit 040ec23d07
1 changed files with 2 additions and 2 deletions
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4
kernel/sched.c
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@@ -889,7 +889,7 @@ unsigned long long notrace cpu_clock(int cpu)
unsigned long long prev_cpu_time, time, delta_time; unsigned long long prev_cpu_time, time, delta_time;
unsigned long flags; unsigned long flags;
raw_local_irq_save(flags); local_irq_save(flags);
prev_cpu_time = per_cpu(prev_cpu_time, cpu); prev_cpu_time = per_cpu(prev_cpu_time, cpu);
time = __cpu_clock(cpu) + per_cpu(time_offset, cpu); time = __cpu_clock(cpu) + per_cpu(time_offset, cpu);
delta_time = time-prev_cpu_time; delta_time = time-prev_cpu_time;
@@ -898,7 +898,7 @@ unsigned long long notrace cpu_clock(int cpu)
time = __sync_cpu_clock(time, cpu); time = __sync_cpu_clock(time, cpu);
per_cpu(prev_cpu_time, cpu) = time; per_cpu(prev_cpu_time, cpu) = time;
} }
raw_local_irq_restore(flags); local_irq_restore(flags);
return time; return time;
} }