time: Fix accumulation bug triggered by long delay.
[linux-2.6.git] / kernel / time / timer_stats.c
index fa3d380..2f3b585 100644 (file)
@@ -26,7 +26,7 @@
  * the pid and cmdline from the owner process if applicable.
  *
  * Start/stop data collection:
- * # echo 1[0] >/proc/timer_stats
+ * # echo [1|0] >/proc/timer_stats
  *
  * Display the information collected so far:
  * # cat /proc/timer_stats
@@ -68,6 +68,7 @@ struct entry {
         * Number of timeout events:
         */
        unsigned long           count;
+       unsigned int            timer_flag;
 
        /*
         * We save the command-line string to preserve
@@ -85,7 +86,7 @@ static DEFINE_SPINLOCK(table_lock);
 /*
  * Per-CPU lookup locks for fast hash lookup:
  */
-static DEFINE_PER_CPU(spinlock_t, lookup_lock);
+static DEFINE_PER_CPU(raw_spinlock_t, tstats_lookup_lock);
 
 /*
  * Mutex to serialize state changes with show-stats activities:
@@ -95,7 +96,7 @@ static DEFINE_MUTEX(show_mutex);
 /*
  * Collection status, active/inactive:
  */
-static int __read_mostly active;
+int __read_mostly timer_stats_active;
 
 /*
  * Beginning/end timestamps of measurement:
@@ -231,22 +232,29 @@ static struct entry *tstat_lookup(struct entry *entry, char *comm)
  * incremented. Otherwise the timer is registered in a free slot.
  */
 void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
-                             void *timerf, char * comm)
+                             void *timerf, char *comm,
+                             unsigned int timer_flag)
 {
        /*
         * It doesnt matter which lock we take:
         */
-       spinlock_t *lock = &per_cpu(lookup_lock, raw_smp_processor_id());
+       raw_spinlock_t *lock;
        struct entry *entry, input;
        unsigned long flags;
 
+       if (likely(!timer_stats_active))
+               return;
+
+       lock = &per_cpu(tstats_lookup_lock, raw_smp_processor_id());
+
        input.timer = timer;
        input.start_func = startf;
        input.expire_func = timerf;
        input.pid = pid;
+       input.timer_flag = timer_flag;
 
-       spin_lock_irqsave(lock, flags);
-       if (!active)
+       raw_spin_lock_irqsave(lock, flags);
+       if (!timer_stats_active)
                goto out_unlock;
 
        entry = tstat_lookup(&input, comm);
@@ -256,12 +264,12 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
                atomic_inc(&overflow_count);
 
  out_unlock:
-       spin_unlock_irqrestore(lock, flags);
+       raw_spin_unlock_irqrestore(lock, flags);
 }
 
 static void print_name_offset(struct seq_file *m, unsigned long addr)
 {
-       char symname[KSYM_NAME_LEN+1];
+       char symname[KSYM_NAME_LEN];
 
        if (lookup_symbol_name(addr, symname) < 0)
                seq_printf(m, "<%p>", (void *)addr);
@@ -282,7 +290,7 @@ static int tstats_show(struct seq_file *m, void *v)
        /*
         * If still active then calculate up to now:
         */
-       if (active)
+       if (timer_stats_active)
                time_stop = ktime_get();
 
        time = ktime_sub(time_stop, time_start);
@@ -290,7 +298,7 @@ static int tstats_show(struct seq_file *m, void *v)
        period = ktime_to_timespec(time);
        ms = period.tv_nsec / 1000000;
 
-       seq_puts(m, "Timer Stats Version: v0.1\n");
+       seq_puts(m, "Timer Stats Version: v0.2\n");
        seq_printf(m, "Sample period: %ld.%03ld s\n", period.tv_sec, ms);
        if (atomic_read(&overflow_count))
                seq_printf(m, "Overflow: %d entries\n",
@@ -298,8 +306,13 @@ static int tstats_show(struct seq_file *m, void *v)
 
        for (i = 0; i < nr_entries; i++) {
                entry = entries + i;
-               seq_printf(m, "%4lu, %5d %-16s ",
+               if (entry->timer_flag & TIMER_STATS_FLAG_DEFERRABLE) {
+                       seq_printf(m, "%4luD, %5d %-16s ",
                                entry->count, entry->pid, entry->comm);
+               } else {
+                       seq_printf(m, " %4lu, %5d %-16s ",
+                               entry->count, entry->pid, entry->comm);
+               }
 
                print_name_offset(m, (unsigned long)entry->start_func);
                seq_puts(m, " (");
@@ -314,8 +327,9 @@ static int tstats_show(struct seq_file *m, void *v)
                ms = 1;
 
        if (events && period.tv_sec)
-               seq_printf(m, "%ld total events, %ld.%ld events/sec\n", events,
-                          events / period.tv_sec, events * 1000 / ms);
+               seq_printf(m, "%ld total events, %ld.%03ld events/sec\n",
+                          events, events * 1000 / ms,
+                          (events * 1000000 / ms) % 1000);
        else
                seq_printf(m, "%ld total events\n", events);
 
@@ -334,9 +348,11 @@ static void sync_access(void)
        int cpu;
 
        for_each_online_cpu(cpu) {
-               spin_lock_irqsave(&per_cpu(lookup_lock, cpu), flags);
+               raw_spinlock_t *lock = &per_cpu(tstats_lookup_lock, cpu);
+
+               raw_spin_lock_irqsave(lock, flags);
                /* nothing */
-               spin_unlock_irqrestore(&per_cpu(lookup_lock, cpu), flags);
+               raw_spin_unlock_irqrestore(lock, flags);
        }
 }
 
@@ -354,18 +370,18 @@ static ssize_t tstats_write(struct file *file, const char __user *buf,
        mutex_lock(&show_mutex);
        switch (ctl[0]) {
        case '0':
-               if (active) {
-                       active = 0;
+               if (timer_stats_active) {
+                       timer_stats_active = 0;
                        time_stop = ktime_get();
                        sync_access();
                }
                break;
        case '1':
-               if (!active) {
+               if (!timer_stats_active) {
                        reset_entries();
                        time_start = ktime_get();
                        smp_mb();
-                       active = 1;
+                       timer_stats_active = 1;
                }
                break;
        default:
@@ -381,12 +397,12 @@ static int tstats_open(struct inode *inode, struct file *filp)
        return single_open(filp, tstats_show, NULL);
 }
 
-static struct file_operations tstats_fops = {
+static const struct file_operations tstats_fops = {
        .open           = tstats_open,
        .read           = seq_read,
        .write          = tstats_write,
        .llseek         = seq_lseek,
-       .release        = seq_release,
+       .release        = single_release,
 };
 
 void __init init_timer_stats(void)
@@ -394,19 +410,16 @@ void __init init_timer_stats(void)
        int cpu;
 
        for_each_possible_cpu(cpu)
-               spin_lock_init(&per_cpu(lookup_lock, cpu));
+               raw_spin_lock_init(&per_cpu(tstats_lookup_lock, cpu));
 }
 
 static int __init init_tstats_procfs(void)
 {
        struct proc_dir_entry *pe;
 
-       pe = create_proc_entry("timer_stats", 0644, NULL);
+       pe = proc_create("timer_stats", 0644, NULL, &tstats_fops);
        if (!pe)
                return -ENOMEM;
-
-       pe->proc_fops = &tstats_fops;
-
        return 0;
 }
 __initcall(init_tstats_procfs);