Commit 9eb59573 authored Oct 10, 2007 by Andi Kleen Committed by Dave Jones Oct 09, 2007

[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>

parent 562d94d9

drivers/cpufreq/cpufreq.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -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);
		}