sched/cputime: Convert guest time accounting to nsecs (u64)

cputime_t is being obsolete and replaced by nsecs units in order to make
internal timestamps less opaque and more granular.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1485832191-26889-6-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

fs/proc/array.c

@@ -402,7 +402,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 	unsigned long cmin_flt = 0, cmaj_flt = 0;
 	unsigned long  min_flt = 0,  maj_flt = 0;
 	cputime_t cutime, cstime, utime, stime;
-	cputime_t cgtime, gtime;
+	u64 cgtime, gtime;
 	unsigned long rsslim = 0;
 	char tcomm[sizeof(task->comm)];
 	unsigned long flags;
@@ -542,8 +542,8 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 	seq_put_decimal_ull(m, " ", task->rt_priority);
 	seq_put_decimal_ull(m, " ", task->policy);
 	seq_put_decimal_ull(m, " ", delayacct_blkio_ticks(task));
-	seq_put_decimal_ull(m, " ", cputime_to_clock_t(gtime));
-	seq_put_decimal_ll(m, " ", cputime_to_clock_t(cgtime));
+	seq_put_decimal_ull(m, " ", nsec_to_clock_t(gtime));
+	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cgtime));
 
 	if (mm && permitted) {
 		seq_put_decimal_ull(m, " ", mm->start_data);

include/linux/sched.h

@@ -774,8 +774,8 @@ struct signal_struct {
 	 */
 	seqlock_t stats_lock;
 	cputime_t utime, stime, cutime, cstime;
-	cputime_t gtime;
-	cputime_t cgtime;
+	u64 gtime;
+	u64 cgtime;
 	struct prev_cputime prev_cputime;
 	unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
 	unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
@@ -1658,7 +1658,7 @@ struct task_struct {
 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
 	cputime_t utimescaled, stimescaled;
 #endif
-	cputime_t gtime;
+	u64 gtime;
 	struct prev_cputime prev_cputime;
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
 	seqcount_t vtime_seqcount;
@@ -2254,7 +2254,7 @@ 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);
-extern cputime_t task_gtime(struct task_struct *t);
+extern u64 task_gtime(struct task_struct *t);
 #else
 static inline void task_cputime(struct task_struct *t,
 				cputime_t *utime, cputime_t *stime)
@@ -2263,7 +2263,7 @@ static inline void task_cputime(struct task_struct *t,
 	*stime = t->stime;
 }
 
-static inline cputime_t task_gtime(struct task_struct *t)
+static inline u64 task_gtime(struct task_struct *t)
 {
 	return t->gtime;
 }

kernel/sched/cputime.c

@@ -158,7 +158,7 @@ void account_guest_time(struct task_struct *p, cputime_t cputime)
 	/* Add guest time to process. */
 	p->utime += cputime;
 	account_group_user_time(p, cputime);
-	p->gtime += cputime;
+	p->gtime += cputime_to_nsecs(cputime);
 
 	/* Add guest time to cpustat. */
 	if (task_nice(p) > 0) {
@@ -824,10 +824,10 @@ void vtime_init_idle(struct task_struct *t, int cpu)
 	local_irq_restore(flags);
 }
 
-cputime_t task_gtime(struct task_struct *t)
+u64 task_gtime(struct task_struct *t)
 {
 	unsigned int seq;
-	cputime_t gtime;
+	u64 gtime;
 
 	if (!vtime_accounting_enabled())
 		return t->gtime;
@@ -837,7 +837,7 @@ cputime_t task_gtime(struct task_struct *t)
 
 		gtime = t->gtime;
 		if (t->vtime_snap_whence == VTIME_SYS && t->flags & PF_VCPU)
-			gtime += vtime_delta(t);
+			gtime += cputime_to_nsecs(vtime_delta(t));
 
 	} while (read_seqcount_retry(&t->vtime_seqcount, seq));