[PATCH v3 1/3] ARM: add cpufreq transiton notifier to adjust loops_per_jiffy for smp
From: Shawn Guo <hidden>
Date: 2012-08-10 05:37:23
Also in:
linux-arm-kernel
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
From: Richard Zhao <redacted> 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 <redacted> Acked-by: Russell King <redacted> Acked-by: Santosh Shilimkar <redacted> Signed-off-by: Shawn Guo <redacted> --- 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
--
1.7.5.4