[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: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>
diff --git a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
index ab6e061..e2e03ee 100644
--- a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
@@ -453,7 +453,6 @@
oldmask = current->cpus_allowed;
set_cpus_allowed(current, cpumask_of_cpu(cpu));
- schedule();
if (smp_processor_id() != cpu) {
printk(KERN_ERR "limiting to cpu %u failed\n", cpu);
@@ -488,9 +487,7 @@
out:
set_cpus_allowed(current, oldmask);
- schedule();
return rc;
-
}
static int check_pst_table(struct powernow_k8_data *data, struct pst_s *pst, u8 maxvid)
@@ -904,7 +901,6 @@
/* only run on specific CPU from here on */
oldmask = current->cpus_allowed;
set_cpus_allowed(current, cpumask_of_cpu(pol->cpu));
- schedule();
if (smp_processor_id() != pol->cpu) {
printk(KERN_ERR "limiting to cpu %u failed\n", pol->cpu);
@@ -959,8 +955,6 @@
err_out:
set_cpus_allowed(current, oldmask);
- schedule();
-
return ret;
}
@@ -1017,7 +1011,6 @@
/* only run on specific CPU from here on */
oldmask = current->cpus_allowed;
set_cpus_allowed(current, cpumask_of_cpu(pol->cpu));
- schedule();
if (smp_processor_id() != pol->cpu) {
printk(KERN_ERR "limiting to cpu %u failed\n", pol->cpu);
@@ -1036,7 +1029,6 @@
/* run on any CPU again */
set_cpus_allowed(current, oldmask);
- schedule();
pol->governor = CPUFREQ_DEFAULT_GOVERNOR;
pol->cpus = cpu_core_map[pol->cpu];
@@ -1071,7 +1063,6 @@
err_out:
set_cpus_allowed(current, oldmask);
- schedule();
powernow_k8_cpu_exit_acpi(data);
kfree(data);
@@ -1107,17 +1098,14 @@
set_cpus_allowed(current, oldmask);
return 0;
}
- preempt_disable();
-
+
if (query_current_values_with_pending_wait(data))
goto out;
khz = find_khz_freq_from_fid(data->currfid);
- out:
- preempt_enable_no_resched();
+out:
set_cpus_allowed(current, oldmask);
-
return khz;
}