sched/cputime: Push time to account_user_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/1485832191-26889-22-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/ia64/kernel/time.c

@@ -67,7 +67,7 @@ void vtime_flush(struct task_struct *tsk)
 	cputime_t delta;
 
 	if (ti->utime)
-		account_user_time(tsk, cycle_to_cputime(ti->utime));
+		account_user_time(tsk, cputime_to_nsecs(cycle_to_cputime(ti->utime)));
 
 	if (ti->gtime)
 		account_guest_time(tsk, cycle_to_cputime(ti->gtime));

arch/powerpc/kernel/time.c

@@ -393,7 +393,7 @@ void vtime_flush(struct task_struct *tsk)
 	struct cpu_accounting_data *acct = get_accounting(tsk);
 
 	if (acct->utime)
-		account_user_time(tsk, acct->utime);
+		account_user_time(tsk, cputime_to_nsecs(acct->utime));
 
 	if (acct->utime_scaled)
 		tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled);

arch/s390/kernel/vtime.c

@@ -166,7 +166,7 @@ static int do_account_vtime(struct task_struct *tsk)
 
 	/* Push account value */
 	if (user) {
-		account_user_time(tsk, user);
+		account_user_time(tsk, cputime_to_nsecs(user));
 		tsk->utimescaled += cputime_to_nsecs(scale_vtime(user));
 	}
 

include/linux/kernel_stat.h

@@ -78,7 +78,7 @@ static inline unsigned int kstat_cpu_irqs_sum(unsigned int cpu)
 	return kstat_cpu(cpu).irqs_sum;
 }
 
-extern void account_user_time(struct task_struct *, cputime_t);
+extern void account_user_time(struct task_struct *, u64);
 extern void account_guest_time(struct task_struct *, cputime_t);
 extern void account_system_time(struct task_struct *, int, cputime_t);
 extern void account_system_index_time(struct task_struct *, cputime_t,

kernel/sched/cputime.c

@@ -116,18 +116,18 @@ static inline void task_group_account_field(struct task_struct *p, int index,
  * @p: the process that the cpu time gets accounted to
  * @cputime: the cpu time spent in user space since the last update
  */
-void account_user_time(struct task_struct *p, cputime_t cputime)
+void account_user_time(struct task_struct *p, u64 cputime)
 {
 	int index;
 
 	/* Add user time to process. */
-	p->utime += cputime_to_nsecs(cputime);
-	account_group_user_time(p, cputime_to_nsecs(cputime));
+	p->utime += cputime;
+	account_group_user_time(p, cputime);
 
 	index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
 
 	/* Add user time to cpustat. */
-	task_group_account_field(p, index, cputime_to_nsecs(cputime));
+	task_group_account_field(p, index, cputime);
 
 	/* Account for user time used */
 	acct_account_cputime(p);
@@ -363,8 +363,9 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
 					 struct rq *rq, int ticks)
 {
-	u64 cputime = (__force u64) cputime_one_jiffy * ticks;
+	u64 old_cputime = (__force u64) cputime_one_jiffy * ticks;
 	cputime_t other;
+	u64 cputime;
 
 	/*
 	 * When returning from idle, many ticks can get accounted at
@@ -374,9 +375,11 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
 	 * other time can exceed ticks occasionally.
 	 */
 	other = account_other_time(ULONG_MAX);
-	if (other >= cputime)
+	if (other >= old_cputime)
 		return;
-	cputime -= other;
+
+	old_cputime -= other;
+	cputime = cputime_to_nsecs(old_cputime);
 
 	if (this_cpu_ksoftirqd() == p) {
 		/*
@@ -384,15 +387,16 @@ 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_index_time(p, cputime, CPUTIME_SOFTIRQ);
+		account_system_index_time(p, old_cputime, CPUTIME_SOFTIRQ);
 	} else if (user_tick) {
 		account_user_time(p, cputime);
 	} else if (p == rq->idle) {
-		account_idle_time(cputime);
+		account_idle_time(old_cputime);
 	} else if (p->flags & PF_VCPU) { /* System time or guest time */
-		account_guest_time(p, cputime);
+
+		account_guest_time(p, old_cputime);
 	} else {
-		account_system_index_time(p, cputime, CPUTIME_SYSTEM);
+		account_system_index_time(p, old_cputime, CPUTIME_SYSTEM);
 	}
 }
 
@@ -473,7 +477,8 @@ void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
  */
 void account_process_tick(struct task_struct *p, int user_tick)
 {
-	cputime_t cputime, steal;
+	cputime_t old_cputime, steal;
+	u64 cputime;
 	struct rq *rq = this_rq();
 
 	if (vtime_accounting_cpu_enabled())
@@ -484,20 +489,21 @@ void account_process_tick(struct task_struct *p, int user_tick)
 		return;
 	}
 
-	cputime = cputime_one_jiffy;
+	old_cputime = cputime_one_jiffy;
 	steal = steal_account_process_time(ULONG_MAX);
 
-	if (steal >= cputime)
+	if (steal >= old_cputime)
 		return;
 
-	cputime -= steal;
+	old_cputime -= steal;
+	cputime = cputime_to_nsecs(old_cputime);
 
 	if (user_tick)
 		account_user_time(p, cputime);
 	else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
-		account_system_time(p, HARDIRQ_OFFSET, cputime);
+		account_system_time(p, HARDIRQ_OFFSET, old_cputime);
 	else
-		account_idle_time(cputime);
+		account_idle_time(old_cputime);
 }
 
 /*
@@ -736,7 +742,7 @@ 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);
+		account_user_time(tsk, cputime_to_nsecs(delta_cpu));
 	}
 	write_seqcount_end(&tsk->vtime_seqcount);
 }