On Friday, August 10, 2012, Shawn Guo wrote:
> From: Richard Zhao <richard.zhao@xxxxxxxxxx>
>
> If CONFIG_SMP, cpufreq skips loops_per_jiffy update, because different
> arch has different per-cpu loops_per_jiffy definition.
>
> Signed-off-by: Richard Zhao <richard.zhao@xxxxxxxxxx>
> Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
> Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
Applied to the linux-next branch of the linux-pm.git tree as v3.7 material.
Thanks,
Rafael
> ---
> arch/arm/kernel/smp.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 54 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> index ebd8ad2..8e03567 100644
> --- a/arch/arm/kernel/smp.c
> +++ b/arch/arm/kernel/smp.c
> @@ -25,6 +25,7 @@
> #include <linux/percpu.h>
> #include <linux/clockchips.h>
> #include <linux/completion.h>
> +#include <linux/cpufreq.h>
>
> #include <linux/atomic.h>
> #include <asm/cacheflush.h>
> @@ -584,3 +585,56 @@ int setup_profiling_timer(unsigned int multiplier)
> {
> return -EINVAL;
> }
> +
> +#ifdef CONFIG_CPU_FREQ
> +
> +static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
> +static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
> +static unsigned long global_l_p_j_ref;
> +static unsigned long global_l_p_j_ref_freq;
> +
> +static int cpufreq_callback(struct notifier_block *nb,
> + unsigned long val, void *data)
> +{
> + struct cpufreq_freqs *freq = data;
> + int cpu = freq->cpu;
> +
> + if (freq->flags & CPUFREQ_CONST_LOOPS)
> + return NOTIFY_OK;
> +
> + if (!per_cpu(l_p_j_ref, cpu)) {
> + per_cpu(l_p_j_ref, cpu) =
> + per_cpu(cpu_data, cpu).loops_per_jiffy;
> + per_cpu(l_p_j_ref_freq, cpu) = freq->old;
> + if (!global_l_p_j_ref) {
> + global_l_p_j_ref = loops_per_jiffy;
> + global_l_p_j_ref_freq = freq->old;
> + }
> + }
> +
> + if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
> + (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
> + (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
> + loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
> + global_l_p_j_ref_freq,
> + freq->new);
> + per_cpu(cpu_data, cpu).loops_per_jiffy =
> + cpufreq_scale(per_cpu(l_p_j_ref, cpu),
> + per_cpu(l_p_j_ref_freq, cpu),
> + freq->new);
> + }
> + return NOTIFY_OK;
> +}
> +
> +static struct notifier_block cpufreq_notifier = {
> + .notifier_call = cpufreq_callback,
> +};
> +
> +static int __init register_cpufreq_notifier(void)
> +{
> + return cpufreq_register_notifier(&cpufreq_notifier,
> + CPUFREQ_TRANSITION_NOTIFIER);
> +}
> +core_initcall(register_cpufreq_notifier);
> +
> +#endif
>
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