[PATCH 22/36] cputime: Push time to account_user_time() in nsecs

[Frederic Weisbecker <fweisbec@gmail.com>]

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

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 arch/ia64/kernel/time.c     |  5 +++--
 arch/powerpc/kernel/time.c  |  2 +-
 arch/s390/kernel/vtime.c    |  2 +-
 include/linux/kernel_stat.h |  2 +-
 kernel/sched/cputime.c      | 42 ++++++++++++++++++++++++------------------
 5 files changed, 30 insertions(+), 23 deletions(-)

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 021f44a..ce6bf09 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -63,11 +63,12 @@ extern cputime_t cycle_to_cputime(u64 cyc);
 
 void vtime_account_user(struct task_struct *tsk)
 {
-	cputime_t delta_utime;
+	u64 delta_utime;
 	struct thread_info *ti = task_thread_info(tsk);
 
 	if (ti->ac_utime) {
-		delta_utime = cycle_to_cputime(ti->ac_utime);
+		/* TODO: cycle_to_ns */
+		delta_utime = cputime_to_nsecs(cycle_to_cputime(ti->ac_utime));
 		account_user_time(tsk, delta_utime);
 		ti->ac_utime = 0;
 	}
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 19361fb..9b372b1 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -392,7 +392,7 @@ void vtime_account_user(struct task_struct *tsk)
 	acct->user_time = 0;
 	acct->user_time_scaled = 0;
 	acct->utime_sspurr = 0;
-	account_user_time(tsk, utime);
+	account_user_time(tsk, cputime_to_nsecs(utime));
 	tsk->utimescaled += cputime_to_nsecs(utimescaled);
 }
 
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 4905e8c..0ac0d4c 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -137,7 +137,7 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
 		user_scaled = (user_scaled * mult) / div;
 		system_scaled = (system_scaled * mult) / div;
 	}
-	account_user_time(tsk, user);
+	account_user_time(tsk, cputime_to_nsecs(user));
 	tsk->utimescaled += cputime_to_nsecs(user_scaled);
 	account_system_time(tsk, hardirq_offset, system);
 	tsk->stimescaled += cputime_to_nsecs(system_scaled);
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 00f7768..6831734 100644
--- a/include/linux/kernel_stat.h
+++ b/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_system_time(struct task_struct *, int, cputime_t);
 extern void account_steal_time(cputime_t);
 extern void account_idle_time(cputime_t);
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 31c457f..f5318d9 100644
--- a/kernel/sched/cputime.c
+++ b/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_time(p, cputime, CPUTIME_SOFTIRQ);
+		__account_system_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_time(p, cputime, CPUTIME_SYSTEM);
+		__account_system_time(p, old_cputime, CPUTIME_SYSTEM);
 	}
 }
 
@@ -475,7 +479,8 @@ 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())
@@ -486,20 +491,21 @@ 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);
 }
 
 /*
@@ -738,7 +744,7 @@ 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);
 }
-- 
2.7.4