[tip:sched/core] sched/cputime: Push time to account_steal_time() in nsecs

[tip-bot for Frederic Weisbecker]

Commit-ID:  be9095ed4fb3cf69e9fdf64e28ff6b5bd0ec7215
Gitweb:     http://git.kernel.org/tip/be9095ed4fb3cf69e9fdf64e28ff6b5bd0ec7215
Author:     Frederic Weisbecker <fweisbec@xxxxxxxxx>
AuthorDate: Tue, 31 Jan 2017 04:09:38 +0100
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 1 Feb 2017 09:13:57 +0100

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

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

Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1485832191-26889-23-git-send-email-fweisbec@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/powerpc/kernel/time.c  |  2 +-
 arch/s390/kernel/vtime.c    |  2 +-
 include/linux/kernel_stat.h |  2 +-
 kernel/sched/cputime.c      | 11 ++++++-----
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index c3931d8..53e5982 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -402,7 +402,7 @@ void vtime_flush(struct task_struct *tsk)
 		account_guest_time(tsk, acct->gtime);
 
 	if (acct->steal_time)
-		account_steal_time(acct->steal_time);
+		account_steal_time(cputime_to_nsecs(acct->steal_time));
 
 	if (acct->idle_time)
 		account_idle_time(acct->idle_time);
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index ca206d1..1e7023c 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -188,7 +188,7 @@ static int do_account_vtime(struct task_struct *tsk)
 	steal = S390_lowcore.steal_timer;
 	if ((s64) steal > 0) {
 		S390_lowcore.steal_timer = 0;
-		account_steal_time(steal);
+		account_steal_time(cputime_to_nsecs(steal));
 	}
 
 	return virt_timer_forward(user + guest + system + hardirq + softirq);
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index b716001..1d55d10 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -83,7 +83,7 @@ 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,
 				      enum cpu_usage_stat);
-extern void account_steal_time(cputime_t);
+extern void account_steal_time(u64);
 extern void account_idle_time(cputime_t);
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 55d31c3..9a80287 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -207,11 +207,11 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
  * Account for involuntary wait time.
  * @cputime: the cpu time spent in involuntary wait
  */
-void account_steal_time(cputime_t cputime)
+void account_steal_time(u64 cputime)
 {
 	u64 *cpustat = kcpustat_this_cpu->cpustat;
 
-	cpustat[CPUTIME_STEAL] += cputime_to_nsecs(cputime);
+	cpustat[CPUTIME_STEAL] += cputime;
 }
 
 /*
@@ -239,14 +239,15 @@ static __always_inline cputime_t steal_account_process_time(cputime_t maxtime)
 #ifdef CONFIG_PARAVIRT
 	if (static_key_false(&paravirt_steal_enabled)) {
 		cputime_t steal_cputime;
-		u64 steal;
+		u64 steal, rounded;
 
 		steal = paravirt_steal_clock(smp_processor_id());
 		steal -= this_rq()->prev_steal_time;
 
 		steal_cputime = min(nsecs_to_cputime(steal), maxtime);
-		account_steal_time(steal_cputime);
-		this_rq()->prev_steal_time += cputime_to_nsecs(steal_cputime);
+		rounded = cputime_to_nsecs(steal_cputime);
+		account_steal_time(rounded);
+		this_rq()->prev_steal_time += rounded;
 
 		return steal_cputime;
 	}