freezer: measure freezing time

Measure the time of the freezing of tasks, even if it doesn't fail.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/power/process.c b/kernel/power/process.c
index 3d98d7f..6533923 100644 (file)
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -168,6 +168,11 @@ static int try_to_freeze_tasks(int freeze_user_space)
        struct task_struct *g, *p;
        unsigned long end_time;
        unsigned int todo;
+       struct timeval start, end;
+       s64 elapsed_csecs64;
+       unsigned int elapsed_csecs;
+
+       do_gettimeofday(&start);
 
        end_time = jiffies + TIMEOUT;
        do {
@@ -194,6 +199,11 @@ static int try_to_freeze_tasks(int freeze_user_space)
                        break;
        } while (todo);
 
+       do_gettimeofday(&end);
+       elapsed_csecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);
+       do_div(elapsed_csecs64, NSEC_PER_SEC / 100);
+       elapsed_csecs = elapsed_csecs64;
+
        if (todo) {
                /* This does not unfreeze processes that are already frozen
                 * (we have slightly ugly calling convention in that respect,
@@ -201,10 +211,9 @@ static int try_to_freeze_tasks(int freeze_user_space)
                 * but it cleans up leftover PF_FREEZE requests.
                 */
                printk("\n");
-               printk(KERN_ERR "Freezing of %s timed out after %d seconds "
+               printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds "
                                "(%d tasks refusing to freeze):\n",
-                               freeze_user_space ? "user space " : "tasks ",
-                               TIMEOUT / HZ, todo);
+                               elapsed_csecs / 100, elapsed_csecs % 100, todo);
                show_state();
                read_lock(&tasklist_lock);
                do_each_thread(g, p) {
@@ -215,6 +224,9 @@ static int try_to_freeze_tasks(int freeze_user_space)
                        task_unlock(p);
                } while_each_thread(g, p);
                read_unlock(&tasklist_lock);
+       } else {
+               printk("(elapsed %d.%02d seconds) ", elapsed_csecs / 100,
+                       elapsed_csecs % 100);
        }
 
        return todo ? -EBUSY : 0;