From: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Date: Wed, 2 Dec 2009 08:26:47 +0000 (+0900)
Subject: sched, cputime: Cleanups related to task_times()
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=d99ca3b977fc5a93141304f571475c2af9e6c1c5;p=openwrt%2Fstaging%2Fblogic.git

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>
---

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0395b0f4df3a..dff85e58264e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1331,7 +1331,9 @@ struct task_struct {
 
 	cputime_t utime, stime, utimescaled, stimescaled;
 	cputime_t gtime;
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING
 	cputime_t prev_utime, prev_stime;
+#endif
 	unsigned long nvcsw, nivcsw; /* context switch counts */
 	struct timespec start_time; 		/* monotonic time */
 	struct timespec real_start_time;	/* boot based time */
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;
 
diff --git a/kernel/sched.c b/kernel/sched.c
index 4883fee99314..17e2c1db2bde 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5184,10 +5184,8 @@ void account_idle_ticks(unsigned long ticks)
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
 {
-	if (ut)
-		*ut = p->utime;
-	if (st)
-		*st = p->stime;
+	*ut = p->utime;
+	*st = p->stime;
 }
 #else
 
@@ -5197,7 +5195,7 @@ void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
 
 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
 {
-	cputime_t rtime, utime = p->utime, total = utime + p->stime;
+	cputime_t rtime, utime = p->utime, total = cputime_add(utime, p->stime);
 
 	/*
 	 * Use CFS's precise accounting:
@@ -5217,12 +5215,10 @@ void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
 	 * Compare with previous values, to keep monotonicity:
 	 */
 	p->prev_utime = max(p->prev_utime, utime);
-	p->prev_stime = max(p->prev_stime, rtime - p->prev_utime);
+	p->prev_stime = max(p->prev_stime, cputime_sub(rtime, p->prev_utime));
 
-	if (ut)
-		*ut = p->prev_utime;
-	if (st)
-		*st = p->prev_stime;
+	*ut = p->prev_utime;
+	*st = p->prev_stime;
 }
 #endif