sched/cputime: Push time to account_idle_time() in nsecs

This is one more step toward converting cputime accounting to pure nsecs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1485832191-26889-24-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/ia64/kernel/time.c

@@ -73,7 +73,7 @@ void vtime_flush(struct task_struct *tsk)
 		account_guest_time(tsk, cycle_to_cputime(ti->gtime));
 
 	if (ti->idle_time)
-		account_idle_time(cycle_to_cputime(ti->idle_time));
+		account_idle_time(cputime_to_nsecs(cycle_to_cputime(ti->idle_time)));
 
 	if (ti->stime) {
 		delta = cycle_to_cputime(ti->stime);

arch/powerpc/kernel/time.c

@@ -405,7 +405,7 @@ void vtime_flush(struct task_struct *tsk)
 		account_steal_time(cputime_to_nsecs(acct->steal_time));
 
 	if (acct->idle_time)
-		account_idle_time(acct->idle_time);
+		account_idle_time(cputime_to_nsecs(acct->idle_time));
 
 	if (acct->stime)
 		account_system_index_time(tsk, acct->stime, CPUTIME_SYSTEM);

arch/s390/kernel/idle.c

@@ -43,7 +43,7 @@ void enabled_wait(void)
 	idle->clock_idle_enter = idle->clock_idle_exit = 0ULL;
 	idle->idle_time += idle_time;
 	idle->idle_count++;
-	account_idle_time(idle_time);
+	account_idle_time(cputime_to_nsecs(idle_time));
 	write_seqcount_end(&idle->seqcount);
 }
 NOKPROBE_SYMBOL(enabled_wait);

include/linux/kernel_stat.h

@@ -84,7 +84,7 @@ extern void account_system_time(struct task_struct *, int, cputime_t);
 extern void account_system_index_time(struct task_struct *, cputime_t,
 				      enum cpu_usage_stat);
 extern void account_steal_time(u64);
-extern void account_idle_time(cputime_t);
+extern void account_idle_time(u64);
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 static inline void account_process_tick(struct task_struct *tsk, int user)

kernel/sched/cputime.c

@@ -218,15 +218,15 @@ void account_steal_time(u64 cputime)
  * Account for idle time.
  * @cputime: the cpu time spent in idle wait
  */
-void account_idle_time(cputime_t cputime)
+void account_idle_time(u64 cputime)
 {
 	u64 *cpustat = kcpustat_this_cpu->cpustat;
 	struct rq *rq = this_rq();
 
 	if (atomic_read(&rq->nr_iowait) > 0)
-		cpustat[CPUTIME_IOWAIT] += cputime_to_nsecs(cputime);
+		cpustat[CPUTIME_IOWAIT] += cputime;
 	else
-		cpustat[CPUTIME_IDLE] += cputime_to_nsecs(cputime);
+		cpustat[CPUTIME_IDLE] += cputime;
 }
 
 /*
@@ -392,7 +392,7 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
 	} else if (user_tick) {
 		account_user_time(p, cputime);
 	} else if (p == rq->idle) {
-		account_idle_time(old_cputime);
+		account_idle_time(cputime);
 	} else if (p->flags & PF_VCPU) { /* System time or guest time */
 
 		account_guest_time(p, old_cputime);
@@ -504,7 +504,7 @@ void account_process_tick(struct task_struct *p, int user_tick)
 	else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
 		account_system_time(p, HARDIRQ_OFFSET, old_cputime);
 	else
-		account_idle_time(old_cputime);
+		account_idle_time(cputime);
 }
 
 /*
@@ -513,15 +513,15 @@ void account_process_tick(struct task_struct *p, int user_tick)
  */
 void account_idle_ticks(unsigned long ticks)
 {
-	cputime_t cputime, steal;
+	u64 cputime, steal;
 
 	if (sched_clock_irqtime) {
 		irqtime_account_idle_ticks(ticks);
 		return;
 	}
 
-	cputime = jiffies_to_cputime(ticks);
-	steal = steal_account_process_time(ULONG_MAX);
+	cputime = ticks * TICK_NSEC;
+	steal = cputime_to_nsecs(steal_account_process_time(ULONG_MAX));
 
 	if (steal >= cputime)
 		return;
@@ -787,7 +787,7 @@ void vtime_account_idle(struct task_struct *tsk)
 {
 	cputime_t delta_cpu = get_vtime_delta(tsk);
 
-	account_idle_time(delta_cpu);
+	account_idle_time(cputime_to_nsecs(delta_cpu));
 }
 
 void arch_vtime_task_switch(struct task_struct *prev)