sched/cputime: Convert task/group cputime to nsecs

Now that most cputime readers use the transition API which return the
task cputime in old style cputime_t, we can safely store the cputime in
nsecs. This will eventually make cputime statistics less opaque and more
granular. Back and forth convertions between cputime_t and nsecs in order
to deal with cputime_t random granularity won't be needed anymore.

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/1485832191-26889-8-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

4 files changed, 10 insertions, 9 deletions

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index 0f92438d736b..82ccb43b795b 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -1163,8 +1163,8 @@ SYSCALL_DEFINE2(osf_getrusage, int, who, struct rusage32 __user *, ru)
 		r.ru_majflt = current->maj_flt;
 		break;
 	case RUSAGE_CHILDREN:
-		utime_jiffies = cputime_to_jiffies(current->signal->cutime);
-		stime_jiffies = cputime_to_jiffies(current->signal->cstime);
+		utime_jiffies = nsecs_to_jiffies(current->signal->cutime);
+		stime_jiffies = nsecs_to_jiffies(current->signal->cstime);
 		jiffies_to_timeval32(utime_jiffies, &r.ru_utime);
 		jiffies_to_timeval32(stime_jiffies, &r.ru_stime);
 		r.ru_minflt = current->signal->cmin_flt;
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 02e97305d22b..3cca82e065c9 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -396,7 +396,7 @@ void vtime_flush(struct task_struct *tsk)
 		account_user_time(tsk, acct->utime);
 
 	if (acct->utime_scaled)
-		tsk->utimescaled += acct->utime_scaled;
+		tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled);
 
 	if (acct->gtime)
 		account_guest_time(tsk, acct->gtime);
@@ -411,7 +411,7 @@ void vtime_flush(struct task_struct *tsk)
 		account_system_index_time(tsk, acct->stime, CPUTIME_SYSTEM);
 
 	if (acct->stime_scaled)
-		tsk->stimescaled += acct->stime_scaled;
+		tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled);
 
 	if (acct->hardirq_time)
 		account_system_index_time(tsk, acct->hardirq_time, CPUTIME_IRQ);
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 0a9e5d67547d..f2fc27491604 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -114,7 +114,7 @@ static void account_system_index_scaled(struct task_struct *p,
 					cputime_t cputime, cputime_t scaled,
 					enum cpu_usage_stat index)
 {
-	p->stimescaled += scaled;
+	p->stimescaled += cputime_to_nsecs(scaled);
 	account_system_index_time(p, cputime, index);
 }
 
@@ -167,12 +167,12 @@ static int do_account_vtime(struct task_struct *tsk)
 	/* Push account value */
 	if (user) {
 		account_user_time(tsk, user);
-		tsk->utimescaled += scale_vtime(user);
+		tsk->utimescaled += cputime_to_nsecs(scale_vtime(user));
 	}
 
 	if (guest) {
 		account_guest_time(tsk, guest);
-		tsk->utimescaled += scale_vtime(guest);
+		tsk->utimescaled += cputime_to_nsecs(scale_vtime(guest));
 	}
 
 	if (system)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 1572c35b4f1a..2ecd7dab4631 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -964,10 +964,11 @@ static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
 /* Calculate cpu time spent by current task in 100ns units */
 static u64 current_task_runtime_100ns(void)
 {
-	cputime_t utime, stime;
+	u64 utime, stime;
 
 	task_cputime_adjusted(current, &utime, &stime);
-	return div_u64(cputime_to_nsecs(utime + stime), 100);
+
+	return div_u64(utime + stime, 100);
 }
 
 static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)