Make vm statistics update interval configurable

[linux-2.6] / mm / vmstat.c

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 6c488d6ac425d948b7b77d78a6cac899be16af6a..006eb7621869946141d7e159372d9661939f07a7 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -640,6 +640,24 @@ const struct seq_operations vmstat_op = {
 #endif /* CONFIG_PROC_FS */
 
 #ifdef CONFIG_SMP
+static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
+int sysctl_stat_interval __read_mostly = HZ;
+
+static void vmstat_update(struct work_struct *w)
+{
+       refresh_cpu_vm_stats(smp_processor_id());
+       schedule_delayed_work(&__get_cpu_var(vmstat_work),
+               sysctl_stat_interval);
+}
+
+static void __devinit start_cpu_timer(int cpu)
+{
+       struct delayed_work *vmstat_work = &per_cpu(vmstat_work, cpu);
+
+       INIT_DELAYED_WORK(vmstat_work, vmstat_update);
+       schedule_delayed_work_on(cpu, vmstat_work, HZ + cpu);
+}
+
 /*
  * Use the cpu notifier to insure that the thresholds are recalculated
  * when necessary.
@@ -648,10 +666,24 @@ static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
                unsigned long action,
                void *hcpu)
 {
+       long cpu = (long)hcpu;
+
        switch (action) {
-       case CPU_UP_PREPARE:
-       case CPU_UP_CANCELED:
+       case CPU_ONLINE:
+       case CPU_ONLINE_FROZEN:
+               start_cpu_timer(cpu);
+               break;
+       case CPU_DOWN_PREPARE:
+       case CPU_DOWN_PREPARE_FROZEN:
+               cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu));
+               per_cpu(vmstat_work, cpu).work.func = NULL;
+               break;
+       case CPU_DOWN_FAILED:
+       case CPU_DOWN_FAILED_FROZEN:
+               start_cpu_timer(cpu);
+               break;
        case CPU_DEAD:
+       case CPU_DEAD_FROZEN:
                refresh_zone_stat_thresholds();
                break;
        default:
@@ -665,8 +697,13 @@ static struct notifier_block __cpuinitdata vmstat_notifier =
 
 int __init setup_vmstat(void)
 {
+       int cpu;
+
        refresh_zone_stat_thresholds();
        register_cpu_notifier(&vmstat_notifier);
+
+       for_each_online_cpu(cpu)
+               start_cpu_timer(cpu);
        return 0;
 }
 module_init(setup_vmstat)