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Commit b9111b7b authored by Dave Jones's avatar Dave Jones
Browse files

[CPUFREQ] Remove preempt_disable from powernow-k8 



Via reading the code, my understanding is that powernow-k8 uses
preempt_disable to ensure that driver->target doesn't migrate across cpus
whilst it's accessing per processor registers, however set_cpus_allowed
will provide this for us.  Additionally, remove schedule() calls from
set_cpus_allowed as set_cpus_allowed ensures that you're executing on the
target processor on return.

Signed-off-by: default avatarZwane Mwaikambo <zwane@arm.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent df8b59be

arch/i386/kernel/cpu/cpufreq/powernow-k8.c

+2 −14
Original line number Original line Diff line number Diff line
@@ -453,7 +453,6 @@ static int check_supported_cpu(unsigned int cpu) 




	oldmask = current->cpus_allowed;

	oldmask = current->cpus_allowed;

	set_cpus_allowed(current, cpumask_of_cpu(cpu));

	set_cpus_allowed(current, cpumask_of_cpu(cpu));

	schedule();





	if (smp_processor_id() != cpu) {

	if (smp_processor_id() != cpu) {

		printk(KERN_ERR "limiting to cpu %u failed\n", cpu);

		printk(KERN_ERR "limiting to cpu %u failed\n", cpu);
@@ -488,9 +487,7 @@ static int check_supported_cpu(unsigned int cpu) 




out:

out:

	set_cpus_allowed(current, oldmask);

	set_cpus_allowed(current, oldmask);

	schedule();

	return rc;

	return rc;



}

}





static int check_pst_table(struct powernow_k8_data *data, struct pst_s *pst, u8 maxvid)

static int check_pst_table(struct powernow_k8_data *data, struct pst_s *pst, u8 maxvid)
@@ -904,7 +901,6 @@ static int powernowk8_target(struct cpufreq_policy *pol, unsigned targfreq, unsi 
	/* only run on specific CPU from here on */

	/* only run on specific CPU from here on */

	oldmask = current->cpus_allowed;

	oldmask = current->cpus_allowed;

	set_cpus_allowed(current, cpumask_of_cpu(pol->cpu));

	set_cpus_allowed(current, cpumask_of_cpu(pol->cpu));

	schedule();





	if (smp_processor_id() != pol->cpu) {

	if (smp_processor_id() != pol->cpu) {

		printk(KERN_ERR "limiting to cpu %u failed\n", pol->cpu);

		printk(KERN_ERR "limiting to cpu %u failed\n", pol->cpu);
@@ -959,8 +955,6 @@ static int powernowk8_target(struct cpufreq_policy *pol, unsigned targfreq, unsi 




err_out:

err_out:

	set_cpus_allowed(current, oldmask);

	set_cpus_allowed(current, oldmask);

	schedule();



	return ret;

	return ret;

}

}
@@ -1017,7 +1011,6 @@ static int __init powernowk8_cpu_init(struct cpufreq_policy *pol) 
	/* only run on specific CPU from here on */

	/* only run on specific CPU from here on */

	oldmask = current->cpus_allowed;

	oldmask = current->cpus_allowed;

	set_cpus_allowed(current, cpumask_of_cpu(pol->cpu));

	set_cpus_allowed(current, cpumask_of_cpu(pol->cpu));

	schedule();





	if (smp_processor_id() != pol->cpu) {

	if (smp_processor_id() != pol->cpu) {

		printk(KERN_ERR "limiting to cpu %u failed\n", pol->cpu);

		printk(KERN_ERR "limiting to cpu %u failed\n", pol->cpu);
@@ -1036,7 +1029,6 @@ static int __init powernowk8_cpu_init(struct cpufreq_policy *pol) 




	/* run on any CPU again */

	/* run on any CPU again */

	set_cpus_allowed(current, oldmask);

	set_cpus_allowed(current, oldmask);

	schedule();





	pol->governor = CPUFREQ_DEFAULT_GOVERNOR;

	pol->governor = CPUFREQ_DEFAULT_GOVERNOR;

	pol->cpus = cpu_core_map[pol->cpu];

	pol->cpus = cpu_core_map[pol->cpu];
@@ -1071,7 +1063,6 @@ static int __init powernowk8_cpu_init(struct cpufreq_policy *pol) 




err_out:

err_out:

	set_cpus_allowed(current, oldmask);

	set_cpus_allowed(current, oldmask);

	schedule();

	powernow_k8_cpu_exit_acpi(data);

	powernow_k8_cpu_exit_acpi(data);





	kfree(data);

	kfree(data);
@@ -1107,7 +1098,6 @@ static unsigned int powernowk8_get (unsigned int cpu) 
		set_cpus_allowed(current, oldmask);

		set_cpus_allowed(current, oldmask);

		return 0;

		return 0;

	}

	}

	preempt_disable();





	if (query_current_values_with_pending_wait(data))

	if (query_current_values_with_pending_wait(data))

		goto out;

		goto out;
@@ -1115,9 +1105,7 @@ static unsigned int powernowk8_get (unsigned int cpu) 
	khz = find_khz_freq_from_fid(data->currfid);

	khz = find_khz_freq_from_fid(data->currfid);





out:

out:

	preempt_enable_no_resched();

	set_cpus_allowed(current, oldmask);

	set_cpus_allowed(current, oldmask);



	return khz;

	return khz;

}

}