oprofile: convert oprofile from timer_hook to hrtimer

Oprofile is currently broken on systems running with NOHZ enabled.
A maximum of 1 tick is accounted via the timer_hook if a cpu sleeps
for a longer period of time. This does bad things to the percentages
in the profiler output. To solve this problem convert oprofile to
use a restarting hrtimer instead of the timer_hook.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c
index dc8a0428260d..b336cd9ee7a1 100644
--- a/drivers/oprofile/oprof.c
+++ b/drivers/oprofile/oprof.c
@@ -253,22 +253,26 @@ static int __init oprofile_init(void)
         int err;
 
         err = oprofile_arch_init(&oprofile_ops);
-
         if (err < 0 || timer) {
                 printk(KERN_INFO "oprofile: using timer interrupt.\n");
-                oprofile_timer_init(&oprofile_ops);
+                err = oprofile_timer_init(&oprofile_ops);
+                if (err)
+                        goto out_arch;
         }
-
         err = oprofilefs_register();
         if (err)
-                oprofile_arch_exit();
+                goto out_arch;
+        return 0;
 
+out_arch:
+        oprofile_arch_exit();
         return err;
 }
 
 
 static void __exit oprofile_exit(void)
 {
+        oprofile_timer_exit();
         oprofilefs_unregister();
         oprofile_arch_exit();
 }