sched, cputime: Cleanups related to task_times()

- Remove if({u,s}t)s because no one call it with NULL now.
- Use cputime_{add,sub}().
- Add ifndef-endif for prev_{u,s}time since they are used
  only when !VIRT_CPU_ACCOUNTING.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Spencer Candland <spencer@bluehost.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
LKML-Reference: <4B1624C7.7040302@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 166b8c49257c..ad7cb6d1193c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1066,8 +1066,10 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         p->gtime = cputime_zero;
         p->utimescaled = cputime_zero;
         p->stimescaled = cputime_zero;
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING
         p->prev_utime = cputime_zero;
         p->prev_stime = cputime_zero;
+#endif
 
         p->default_timer_slack_ns = current->timer_slack_ns;