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>

1 files changed, 34 insertions, 21 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9cc722f77799..b7ccc54b35cc 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -585,8 +585,8 @@ struct cpu_itimer {
  */
 struct prev_cputime {
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
-	cputime_t utime;
-	cputime_t stime;
+	u64 utime;
+	u64 stime;
 	raw_spinlock_t lock;
 #endif
 };
@@ -601,8 +601,8 @@ static inline void prev_cputime_init(struct prev_cputime *prev)
 
 /**
  * struct task_cputime - collected CPU time counts
- * @utime:		time spent in user mode, in &cputime_t units
- * @stime:		time spent in kernel mode, in &cputime_t units
+ * @utime:		time spent in user mode, in nanoseconds
+ * @stime:		time spent in kernel mode, in nanoseconds
  * @sum_exec_runtime:	total time spent on the CPU, in nanoseconds
  *
  * This structure groups together three kinds of CPU time that are tracked for
@@ -610,8 +610,8 @@ static inline void prev_cputime_init(struct prev_cputime *prev)
  * these counts together and treat all three of them in parallel.
  */
 struct task_cputime {
-	cputime_t utime;
-	cputime_t stime;
+	u64 utime;
+	u64 stime;
 	unsigned long long sum_exec_runtime;
 };
 
@@ -780,7 +780,7 @@ struct signal_struct {
 	 * in __exit_signal, except for the group leader.
 	 */
 	seqlock_t stats_lock;
-	cputime_t utime, stime, cutime, cstime;
+	u64 utime, stime, cutime, cstime;
 	u64 gtime;
 	u64 cgtime;
 	struct prev_cputime prev_cputime;
@@ -1661,9 +1661,9 @@ struct task_struct {
 	int __user *set_child_tid;		/* CLONE_CHILD_SETTID */
 	int __user *clear_child_tid;		/* CLONE_CHILD_CLEARTID */
 
-	cputime_t utime, stime;
+	u64 utime, stime;
 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
-	cputime_t utimescaled, stimescaled;
+	u64 utimescaled, stimescaled;
 #endif
 	u64 gtime;
 	struct prev_cputime prev_cputime;
@@ -2260,11 +2260,11 @@ struct task_struct *try_get_task_struct(struct task_struct **ptask);
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
 extern void task_cputime(struct task_struct *t,
-			 cputime_t *utime, cputime_t *stime);
+			 u64 *utime, u64 *stime);
 extern u64 task_gtime(struct task_struct *t);
 #else
 static inline void task_cputime(struct task_struct *t,
-				cputime_t *utime, cputime_t *stime)
+				u64 *utime, u64 *stime)
 {
 	*utime = t->utime;
 	*stime = t->stime;
@@ -2278,16 +2278,16 @@ static inline u64 task_gtime(struct task_struct *t)
 
 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
 static inline void task_cputime_scaled(struct task_struct *t,
-				       cputime_t *utimescaled,
-				       cputime_t *stimescaled)
+				       u64 *utimescaled,
+				       u64 *stimescaled)
 {
 	*utimescaled = t->utimescaled;
 	*stimescaled = t->stimescaled;
 }
 #else
 static inline void task_cputime_scaled(struct task_struct *t,
-				       cputime_t *utimescaled,
-				       cputime_t *stimescaled)
+				       u64 *utimescaled,
+				       u64 *stimescaled)
 {
 	task_cputime(t, utimescaled, stimescaled);
 }
@@ -2296,18 +2296,26 @@ static inline void task_cputime_scaled(struct task_struct *t,
 static inline void task_cputime_t(struct task_struct *t,
 				  cputime_t *utime, cputime_t *stime)
 {
-	task_cputime(t, utime, stime);
+	u64 ut, st;
+
+	task_cputime(t, &ut, &st);
+	*utime = nsecs_to_cputime(ut);
+	*stime = nsecs_to_cputime(st);
 }
 
 static inline void task_cputime_t_scaled(struct task_struct *t,
 					 cputime_t *utimescaled,
 					 cputime_t *stimescaled)
 {
-	task_cputime_scaled(t, utimescaled, stimescaled);
+	u64 ut, st;
+
+	task_cputime_scaled(t, &ut, &st);
+	*utimescaled = nsecs_to_cputime(ut);
+	*stimescaled = nsecs_to_cputime(st);
 }
 
-extern void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
-extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
+extern void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st);
+extern void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st);
 
 /*
  * Per process flags
@@ -3522,9 +3530,14 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times);
 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime_t *times);
 
 static inline void thread_group_cputime_t(struct task_struct *tsk,
-					  struct task_cputime_t *times)
+					  struct task_cputime_t *cputime)
 {
-	thread_group_cputime(tsk, (struct task_cputime *)times);
+	struct task_cputime times;
+
+	thread_group_cputime(tsk, &times);
+	cputime->utime = nsecs_to_cputime(times.utime);
+	cputime->stime = nsecs_to_cputime(times.stime);
+	cputime->sum_exec_runtime = times.sum_exec_runtime;
 }
 
 /*