cputime: Use accessors to read task cputime stats

This is in preparation for the full dynticks feature. While
remotely reading the cputime of a task running in a full
dynticks CPU, we'll need to do some extra-computation. This
way we can account the time it spent tickless in userspace
since its last cputime snapshot.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 6 insertions, 4 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index b4df21937216..7dd20408707c 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -85,6 +85,7 @@ static void __exit_signal(struct task_struct *tsk)
         bool group_dead = thread_group_leader(tsk);
         struct sighand_struct *sighand;
         struct tty_struct *uninitialized_var(tty);
+        cputime_t utime, stime;
 
         sighand = rcu_dereference_check(tsk->sighand,
                                         lockdep_tasklist_lock_is_held());
@@ -123,9 +124,10 @@ static void __exit_signal(struct task_struct *tsk)
                  * We won't ever get here for the group leader, since it
                  * will have been the last reference on the signal_struct.
                  */
-                sig->utime += tsk->utime;
-                sig->stime += tsk->stime;
-                sig->gtime += tsk->gtime;
+                task_cputime(tsk, &utime, &stime);
+                sig->utime += utime;
+                sig->stime += stime;
+                sig->gtime += task_gtime(tsk);
                 sig->min_flt += tsk->min_flt;
                 sig->maj_flt += tsk->maj_flt;
                 sig->nvcsw += tsk->nvcsw;
@@ -1092,7 +1094,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
                 sig = p->signal;
                 psig->cutime += tgutime + sig->cutime;
                 psig->cstime += tgstime + sig->cstime;
-                psig->cgtime += p->gtime + sig->gtime + sig->cgtime;
+                psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
                 psig->cmin_flt +=
                         p->min_flt + sig->min_flt + sig->cmin_flt;
                 psig->cmaj_flt +=