Add a flag to indicate deferrable timers in /proc/timer_stats

Add a flag in /proc/timer_stats to indicate deferrable timers.  This will
let developers/users to differentiate between types of tiemrs in
/proc/timer_stats.

Deferrable timer and normal timer will appear in /proc/timer_stats as below.
  10D,     1 swapper          queue_delayed_work_on (delayed_work_timer_fn)
   10,     1 swapper          queue_delayed_work_on (delayed_work_timer_fn)

Also version of timer_stats changes from v0.1 to v0.2

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 25 insertions, 3 deletions

diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c
index 321693724ad7..9b8a826236dd 100644
--- a/kernel/time/timer_stats.c
+++ b/kernel/time/timer_stats.c
@@ -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
@@ -231,7 +232,8 @@ 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:
@@ -249,6 +251,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
         input.start_func = startf;
         input.expire_func = timerf;
         input.pid = pid;
+        input.timer_flag = timer_flag;
 
         spin_lock_irqsave(lock, flags);
         if (!active)
@@ -295,7 +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",
@@ -303,8 +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, " (");
diff --git a/kernel/timer.c b/kernel/timer.c
index 1ab3106a2b5d..1258371e0d2b 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -305,6 +305,20 @@ void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
         memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
         timer->start_pid = current->pid;
 }
+
+static void timer_stats_account_timer(struct timer_list *timer)
+{
+        unsigned int flag = 0;
+
+        if (unlikely(tbase_get_deferrable(timer->base)))
+                flag |= TIMER_STATS_FLAG_DEFERRABLE;
+
+        timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
+                                 timer->function, timer->start_comm, flag);
+}
+
+#else
+static void timer_stats_account_timer(struct timer_list *timer) {}
 #endif
 
 /**