clocksource: Cleanup clocksource selection
[linux-2.6.git] / kernel / time / timer_stats.c
index 868f1bceb07ff60bfb87ec2be8d5729a70ece0bd..4cde8b9c716f39b778ab7dfe5ead8985c0eb2c97 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
@@ -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:
@@ -117,21 +118,6 @@ static struct entry entries[MAX_ENTRIES];
 
 static atomic_t overflow_count;
 
-static void reset_entries(void)
-{
-       nr_entries = 0;
-       memset(entries, 0, sizeof(entries));
-       atomic_set(&overflow_count, 0);
-}
-
-static struct entry *alloc_entry(void)
-{
-       if (nr_entries >= MAX_ENTRIES)
-               return NULL;
-
-       return entries + nr_entries++;
-}
-
 /*
  * The entries are in a hash-table, for fast lookup:
  */
@@ -149,6 +135,22 @@ static struct entry *alloc_entry(void)
 
 static struct entry *tstat_hash_table[TSTAT_HASH_SIZE] __read_mostly;
 
+static void reset_entries(void)
+{
+       nr_entries = 0;
+       memset(entries, 0, sizeof(entries));
+       memset(tstat_hash_table, 0, sizeof(tstat_hash_table));
+       atomic_set(&overflow_count, 0);
+}
+
+static struct entry *alloc_entry(void)
+{
+       if (nr_entries >= MAX_ENTRIES)
+               return NULL;
+
+       return entries + nr_entries++;
+}
+
 static int match_entries(struct entry *entry1, struct entry *entry2)
 {
        return entry1->timer       == entry2->timer       &&
@@ -202,12 +204,15 @@ static struct entry *tstat_lookup(struct entry *entry, char *comm)
        if (curr) {
                *curr = *entry;
                curr->count = 0;
+               curr->next = NULL;
                memcpy(curr->comm, comm, TASK_COMM_LEN);
+
+               smp_mb(); /* Ensure that curr is initialized before insert */
+
                if (prev)
                        prev->next = curr;
                else
                        *head = curr;
-               curr->next = NULL;
        }
  out_unlock:
        spin_unlock(&table_lock);
@@ -227,22 +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());
+       spinlock_t *lock;
        struct entry *entry, input;
        unsigned long flags;
 
+       if (likely(!timer_stats_active))
+               return;
+
+       lock = &per_cpu(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)
+       if (!timer_stats_active)
                goto out_unlock;
 
        entry = tstat_lookup(&input, comm);
@@ -257,7 +269,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
 
 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);
@@ -278,7 +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);
@@ -286,7 +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",
@@ -294,8 +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, " (");
@@ -310,8 +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);
 
@@ -350,17 +368,18 @@ 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();
-                       active = 1;
+                       smp_mb();
+                       timer_stats_active = 1;
                }
                break;
        default:
@@ -381,7 +400,7 @@ static struct file_operations tstats_fops = {
        .read           = seq_read,
        .write          = tstats_write,
        .llseek         = seq_lseek,
-       .release        = seq_release,
+       .release        = single_release,
 };
 
 void __init init_timer_stats(void)
@@ -396,12 +415,9 @@ 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);