linux-kernel - [PATCH] ondemand governor restructure the work callback

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Message-ID: <20061229133450.B12358@unix-os.sc.intel.com>
Date:	Fri, 29 Dec 2006 13:34:50 -0800
From:	Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>
To:	Dave Jones <davej@...hat.com>,
	Dominik Brodowski <linux@...inikbrodowski.net>,
	Andrew Morton <akpm@...l.org>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	Gautham R Shenoy <ego@...ibm.com>
Subject: [PATCH] ondemand governor restructure the work callback


Restructure the delayed_work callback in ondemand.

This eliminates the need for smp_processor_id in the callback function and also
helps in proper locking and avoiding flush_workqueue when stopping the governor
(done in subsequent patch).

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>

Index: linux-2.6.20-rc-mm/drivers/cpufreq/cpufreq_ondemand.c
===================================================================
--- linux-2.6.20-rc-mm.orig/drivers/cpufreq/cpufreq_ondemand.c
+++ linux-2.6.20-rc-mm/drivers/cpufreq/cpufreq_ondemand.c
@@ -52,19 +52,20 @@ static unsigned int def_sampling_rate;
 static void do_dbs_timer(struct work_struct *work);
 
 /* Sampling types */
-enum dbs_sample {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
+enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
 
 struct cpu_dbs_info_s {
 	cputime64_t prev_cpu_idle;
 	cputime64_t prev_cpu_wall;
 	struct cpufreq_policy *cur_policy;
  	struct delayed_work work;
-	enum dbs_sample sample_type;
-	unsigned int enable;
 	struct cpufreq_frequency_table *freq_table;
 	unsigned int freq_lo;
 	unsigned int freq_lo_jiffies;
 	unsigned int freq_hi_jiffies;
+	int cpu;
+	unsigned int enable:1,
+	             sample_type:1;
 };
 static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
 
@@ -402,7 +403,7 @@ static void dbs_check_cpu(struct cpu_dbs
 	if (load < (dbs_tuners_ins.up_threshold - 10)) {
 		unsigned int freq_next, freq_cur;
 
-		freq_cur = cpufreq_driver_getavg(policy);
+		freq_cur = __cpufreq_driver_getavg(policy);
 		if (!freq_cur)
 			freq_cur = policy->cur;
 
@@ -423,9 +424,11 @@ static void dbs_check_cpu(struct cpu_dbs
 
 static void do_dbs_timer(struct work_struct *work)
 {
-	unsigned int cpu = smp_processor_id();
-	struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
-	enum dbs_sample sample_type = dbs_info->sample_type;
+	struct cpu_dbs_info_s *dbs_info =
+		container_of(work, struct cpu_dbs_info_s, work.work);
+	unsigned int cpu = dbs_info->cpu;
+	int sample_type = dbs_info->sample_type;
+
 	/* We want all CPUs to do sampling nearly on same jiffy */
 	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
 
@@ -454,17 +457,17 @@ static void do_dbs_timer(struct work_str
 	queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
 }
 
-static inline void dbs_timer_init(unsigned int cpu)
+static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
 {
-	struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
 	/* We want all CPUs to do sampling nearly on same jiffy */
 	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
 	delay -= jiffies % delay;
 
 	ondemand_powersave_bias_init();
-	INIT_DELAYED_WORK_NAR(&dbs_info->work, do_dbs_timer);
 	dbs_info->sample_type = DBS_NORMAL_SAMPLE;
-	queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
+	INIT_DELAYED_WORK_NAR(&dbs_info->work, do_dbs_timer);
+	queue_delayed_work_on(dbs_info->cpu, kondemand_wq, &dbs_info->work,
+	                      delay);
 }
 
 static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
@@ -528,6 +531,7 @@ static int cpufreq_governor_dbs(struct c
 			j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
 			j_dbs_info->prev_cpu_wall = get_jiffies_64();
 		}
+		this_dbs_info->cpu = cpu;
 		this_dbs_info->enable = 1;
 		/*
 		 * Start the timerschedule work, when this governor
@@ -548,7 +552,7 @@ static int cpufreq_governor_dbs(struct c
 
 			dbs_tuners_ins.sampling_rate = def_sampling_rate;
 		}
-		dbs_timer_init(policy->cpu);
+		dbs_timer_init(this_dbs_info);
 
 		mutex_unlock(&dbs_mutex);
 		break;
-
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