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[CPUFREQ] Don't take semaphore in cpufreq_quick_get() 

I don't see any reason to take an expensive lock in cpufreq_quick_get()
Reading policy->cur is a single atomic operation and after
the lock is dropped again the state could change any time anyways.

So don't take the lock in the first place.

This also makes this function interrupt safe which is useful
for some code of mine.

Signed-off-by: Andi Kleen <ak@suse.de>
Cc: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
This commit is contained in:
Andi Kleen 2007-10-10 02:18:27 +02:00 committed by Dave Jones
parent 562d94d98f
commit 9eb59573d4
1 changed files with 0 additions and 5 deletions
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5
drivers/cpufreq/cpufreq.c
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@ -1111,12 +1111,7 @@ unsigned int cpufreq_quick_get(unsigned int cpu)
unsigned int ret_freq = 0;
if (policy) {
if (unlikely(lock_policy_rwsem_read(cpu)))
return ret_freq;
ret_freq = policy->cur;
unlock_policy_rwsem_read(cpu);
cpufreq_cpu_put(policy);
}