sched/cputime, powerpc, s390: Make scaled cputime arch specific

Only s390 and powerpc have hardware facilities allowing to measure
cputimes scaled by frequency. On all other architectures
utimescaled/stimescaled are equal to utime/stime (however they are
accounted separately).

Remove {u,s}timescaled accounting on all architectures except
powerpc and s390, where those values are explicitly accounted
in the proper places.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161031162143.GB12646@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 17 insertions, 46 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 997ac1d584f7..600e93b5e539 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1551,7 +1551,9 @@ static __latent_entropy struct task_struct *copy_process(
 	init_sigpending(&p->pending);
 
 	p->utime = p->stime = p->gtime = 0;
+#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
 	p->utimescaled = p->stimescaled = 0;
+#endif
 	prev_cputime_init(&p->prev_cputime);
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 3229c7244fdd..ba55ebf77f9a 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -128,16 +128,13 @@ static inline void task_group_account_field(struct task_struct *p, int index,
  * Account user cpu time to a process.
  * @p: the process that the cpu time gets accounted to
  * @cputime: the cpu time spent in user space since the last update
- * @cputime_scaled: cputime scaled by cpu frequency
  */
-void account_user_time(struct task_struct *p, cputime_t cputime,
-		       cputime_t cputime_scaled)
+void account_user_time(struct task_struct *p, cputime_t cputime)
 {
 	int index;
 
 	/* Add user time to process. */
 	p->utime += cputime;
-	p->utimescaled += cputime_scaled;
 	account_group_user_time(p, cputime);
 
 	index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
@@ -153,16 +150,13 @@ void account_user_time(struct task_struct *p, cputime_t cputime,
  * Account guest cpu time to a process.
  * @p: the process that the cpu time gets accounted to
  * @cputime: the cpu time spent in virtual machine since the last update
- * @cputime_scaled: cputime scaled by cpu frequency
  */
-static void account_guest_time(struct task_struct *p, cputime_t cputime,
-			       cputime_t cputime_scaled)
+static void account_guest_time(struct task_struct *p, cputime_t cputime)
 {
 	u64 *cpustat = kcpustat_this_cpu->cpustat;
 
 	/* Add guest time to process. */
 	p->utime += cputime;
-	p->utimescaled += cputime_scaled;
 	account_group_user_time(p, cputime);
 	p->gtime += cputime;
 
@@ -180,16 +174,13 @@ static void account_guest_time(struct task_struct *p, cputime_t cputime,
  * Account system cpu time to a process and desired cpustat field
  * @p: the process that the cpu time gets accounted to
  * @cputime: the cpu time spent in kernel space since the last update
- * @cputime_scaled: cputime scaled by cpu frequency
- * @target_cputime64: pointer to cpustat field that has to be updated
+ * @index: pointer to cpustat field that has to be updated
  */
 static inline
-void __account_system_time(struct task_struct *p, cputime_t cputime,
-			cputime_t cputime_scaled, int index)
+void __account_system_time(struct task_struct *p, cputime_t cputime, int index)
 {
 	/* Add system time to process. */
 	p->stime += cputime;
-	p->stimescaled += cputime_scaled;
 	account_group_system_time(p, cputime);
 
 	/* Add system time to cpustat. */
@@ -204,15 +195,14 @@ void __account_system_time(struct task_struct *p, cputime_t cputime,
  * @p: the process that the cpu time gets accounted to
  * @hardirq_offset: the offset to subtract from hardirq_count()
  * @cputime: the cpu time spent in kernel space since the last update
- * @cputime_scaled: cputime scaled by cpu frequency
  */
 void account_system_time(struct task_struct *p, int hardirq_offset,
-			 cputime_t cputime, cputime_t cputime_scaled)
+			 cputime_t cputime)
 {
 	int index;
 
 	if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
-		account_guest_time(p, cputime, cputime_scaled);
+		account_guest_time(p, cputime);
 		return;
 	}
 
@@ -223,7 +213,7 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
 	else
 		index = CPUTIME_SYSTEM;
 
-	__account_system_time(p, cputime, cputime_scaled, index);
+	__account_system_time(p, cputime, index);
 }
 
 /*
@@ -410,15 +400,15 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
 		 * So, we have to handle it separately here.
 		 * Also, p->stime needs to be updated for ksoftirqd.
 		 */
-		__account_system_time(p, cputime, cputime, CPUTIME_SOFTIRQ);
+		__account_system_time(p, cputime, CPUTIME_SOFTIRQ);
 	} else if (user_tick) {
-		account_user_time(p, cputime, cputime);
+		account_user_time(p, cputime);
 	} else if (p == rq->idle) {
 		account_idle_time(cputime);
 	} else if (p->flags & PF_VCPU) { /* System time or guest time */
-		account_guest_time(p, cputime, cputime);
+		account_guest_time(p, cputime);
 	} else {
-		__account_system_time(p, cputime, cputime, CPUTIME_SYSTEM);
+		__account_system_time(p, cputime, CPUTIME_SYSTEM);
 	}
 }
 
@@ -521,9 +511,9 @@ void account_process_tick(struct task_struct *p, int user_tick)
 	cputime -= steal;
 
 	if (user_tick)
-		account_user_time(p, cputime, cputime);
+		account_user_time(p, cputime);
 	else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
-		account_system_time(p, HARDIRQ_OFFSET, cputime, cputime);
+		account_system_time(p, HARDIRQ_OFFSET, cputime);
 	else
 		account_idle_time(cputime);
 }
@@ -744,7 +734,7 @@ static void __vtime_account_system(struct task_struct *tsk)
 {
 	cputime_t delta_cpu = get_vtime_delta(tsk);
 
-	account_system_time(tsk, irq_count(), delta_cpu, delta_cpu);
+	account_system_time(tsk, irq_count(), delta_cpu);
 }
 
 void vtime_account_system(struct task_struct *tsk)
@@ -765,7 +755,7 @@ void vtime_account_user(struct task_struct *tsk)
 	tsk->vtime_snap_whence = VTIME_SYS;
 	if (vtime_delta(tsk)) {
 		delta_cpu = get_vtime_delta(tsk);
-		account_user_time(tsk, delta_cpu, delta_cpu);
+		account_user_time(tsk, delta_cpu);
 	}
 	write_seqcount_end(&tsk->vtime_seqcount);
 }
@@ -921,25 +911,4 @@ void task_cputime(struct task_struct *t, cputime_t *utime, cputime_t *stime)
 	if (stime)
 		*stime += sdelta;
 }
-
-void task_cputime_scaled(struct task_struct *t,
-			 cputime_t *utimescaled, cputime_t *stimescaled)
-{
-	cputime_t udelta, sdelta;
-
-	if (!vtime_accounting_enabled()) {
-		if (utimescaled)
-			*utimescaled = t->utimescaled;
-		if (stimescaled)
-			*stimescaled = t->stimescaled;
-		return;
-	}
-
-	fetch_task_cputime(t, utimescaled, stimescaled,
-			   &t->utimescaled, &t->stimescaled, &udelta, &sdelta);
-	if (utimescaled)
-		*utimescaled += udelta;
-	if (stimescaled)
-		*stimescaled += sdelta;
-}
 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */