sched/cputime: Rename vtime_account_system() to vtime_account_kernel()

vtime_account_system() decides if we need to account the time to the
system (__vtime_account_system()) or to the guest (vtime_account_guest()).

So this function is a misnomer as we are on a higher level than
"system". All we know when we call that function is that we are
accounting kernel cputime. Whether it belongs to guest or system time
is a lower level detail.

Rename this function to vtime_account_kernel(). This will clarify things
and avoid too many underscored vtime_account_system() versions.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Link: https://lkml.kernel.org/r/20191003161745.28464-2-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/ia64/kernel/time.c

@@ -132,7 +132,7 @@ static __u64 vtime_delta(struct task_struct *tsk)
 	return delta_stime;
 }
 
-void vtime_account_system(struct task_struct *tsk)
+void vtime_account_kernel(struct task_struct *tsk)
 {
 	struct thread_info *ti = task_thread_info(tsk);
 	__u64 stime = vtime_delta(tsk);
@@ -146,7 +146,7 @@ void vtime_account_system(struct task_struct *tsk)
 	else
 		ti->stime += stime;
 }
-EXPORT_SYMBOL_GPL(vtime_account_system);
+EXPORT_SYMBOL_GPL(vtime_account_kernel);
 
 void vtime_account_idle(struct task_struct *tsk)
 {

arch/powerpc/kernel/time.c

@@ -338,7 +338,7 @@ static unsigned long vtime_delta(struct task_struct *tsk,
 	return stime;
 }
 
-void vtime_account_system(struct task_struct *tsk)
+void vtime_account_kernel(struct task_struct *tsk)
 {
 	unsigned long stime, stime_scaled, steal_time;
 	struct cpu_accounting_data *acct = get_accounting(tsk);
@@ -366,7 +366,7 @@ void vtime_account_system(struct task_struct *tsk)
 #endif
 	}
 }
-EXPORT_SYMBOL_GPL(vtime_account_system);
+EXPORT_SYMBOL_GPL(vtime_account_kernel);
 
 void vtime_account_idle(struct task_struct *tsk)
 {
@@ -395,7 +395,7 @@ static void vtime_flush_scaled(struct task_struct *tsk,
 /*
  * Account the whole cputime accumulated in the paca
  * Must be called with interrupts disabled.
- * Assumes that vtime_account_system/idle() has been called
+ * Assumes that vtime_account_kernel/idle() has been called
  * recently (i.e. since the last entry from usermode) so that
  * get_paca()->user_time_scaled is up to date.
  */

arch/s390/kernel/vtime.c

@@ -247,9 +247,9 @@ void vtime_account_irq_enter(struct task_struct *tsk)
 }
 EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
 
-void vtime_account_system(struct task_struct *tsk)
+void vtime_account_kernel(struct task_struct *tsk)
 __attribute__((alias("vtime_account_irq_enter")));
-EXPORT_SYMBOL_GPL(vtime_account_system);
+EXPORT_SYMBOL_GPL(vtime_account_kernel);
 
 /*
  * Sorted add to a list. List is linear searched until first bigger

include/linux/context_tracking.h

@@ -141,15 +141,15 @@ static inline void guest_enter_irqoff(void)
 	 * to assume that it's the stime pending cputime
 	 * to flush.
 	 */
-	vtime_account_system(current);
+	vtime_account_kernel(current);
 	current->flags |= PF_VCPU;
 	rcu_virt_note_context_switch(smp_processor_id());
 }
 
 static inline void guest_exit_irqoff(void)
 {
 	/* Flush the guest cputime we spent on the guest */
-	vtime_account_system(current);
+	vtime_account_kernel(current);
 	current->flags &= ~PF_VCPU;
 }
 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */

include/linux/vtime.h

@@ -57,13 +57,13 @@ static inline void vtime_task_switch(struct task_struct *prev)
 }
 #endif /* __ARCH_HAS_VTIME_TASK_SWITCH */
 
-extern void vtime_account_system(struct task_struct *tsk);
+extern void vtime_account_kernel(struct task_struct *tsk);
 extern void vtime_account_idle(struct task_struct *tsk);
 
 #else /* !CONFIG_VIRT_CPU_ACCOUNTING */
 
 static inline void vtime_task_switch(struct task_struct *prev) { }
-static inline void vtime_account_system(struct task_struct *tsk) { }
+static inline void vtime_account_kernel(struct task_struct *tsk) { }
 #endif /* !CONFIG_VIRT_CPU_ACCOUNTING */
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
@@ -86,7 +86,7 @@ extern void vtime_account_irq_enter(struct task_struct *tsk);
 static inline void vtime_account_irq_exit(struct task_struct *tsk)
 {
 	/* On hard|softirq exit we always account to hard|softirq cputime */
-	vtime_account_system(tsk);
+	vtime_account_kernel(tsk);
 }
 extern void vtime_flush(struct task_struct *tsk);
 #else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */

kernel/sched/cputime.c

@@ -412,7 +412,7 @@ void vtime_common_task_switch(struct task_struct *prev)
 	if (is_idle_task(prev))
 		vtime_account_idle(prev);
 	else
-		vtime_account_system(prev);
+		vtime_account_kernel(prev);
 
 	vtime_flush(prev);
 	arch_vtime_task_switch(prev);
@@ -425,7 +425,7 @@ void vtime_common_task_switch(struct task_struct *prev)
 /*
  * Archs that account the whole time spent in the idle task
  * (outside irq) as idle time can rely on this and just implement
- * vtime_account_system() and vtime_account_idle(). Archs that
+ * vtime_account_kernel() and vtime_account_idle(). Archs that
  * have other meaning of the idle time (s390 only includes the
  * time spent by the CPU when it's in low power mode) must override
  * vtime_account().
@@ -436,7 +436,7 @@ void vtime_account_irq_enter(struct task_struct *tsk)
 	if (!in_interrupt() && is_idle_task(tsk))
 		vtime_account_idle(tsk);
 	else
-		vtime_account_system(tsk);
+		vtime_account_kernel(tsk);
 }
 EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
 #endif /* __ARCH_HAS_VTIME_ACCOUNT */
@@ -711,8 +711,8 @@ static u64 get_vtime_delta(struct vtime *vtime)
 	return delta - other;
 }
 
-static void __vtime_account_system(struct task_struct *tsk,
-				   struct vtime *vtime)
+static void vtime_account_system(struct task_struct *tsk,
+				 struct vtime *vtime)
 {
 	vtime->stime += get_vtime_delta(vtime);
 	if (vtime->stime >= TICK_NSEC) {
@@ -731,7 +731,7 @@ static void vtime_account_guest(struct task_struct *tsk,
 	}
 }
 
-void vtime_account_system(struct task_struct *tsk)
+void vtime_account_kernel(struct task_struct *tsk)
 {
 	struct vtime *vtime = &tsk->vtime;
 
@@ -743,7 +743,7 @@ void vtime_account_system(struct task_struct *tsk)
 	if (tsk->flags & PF_VCPU)
 		vtime_account_guest(tsk, vtime);
 	else
-		__vtime_account_system(tsk, vtime);
+		vtime_account_system(tsk, vtime);
 	write_seqcount_end(&vtime->seqcount);
 }
 
@@ -752,7 +752,7 @@ void vtime_user_enter(struct task_struct *tsk)
 	struct vtime *vtime = &tsk->vtime;
 
 	write_seqcount_begin(&vtime->seqcount);
-	__vtime_account_system(tsk, vtime);
+	vtime_account_system(tsk, vtime);
 	vtime->state = VTIME_USER;
 	write_seqcount_end(&vtime->seqcount);
 }
@@ -782,7 +782,7 @@ void vtime_guest_enter(struct task_struct *tsk)
 	 * that can thus safely catch up with a tickless delta.
 	 */
 	write_seqcount_begin(&vtime->seqcount);
-	__vtime_account_system(tsk, vtime);
+	vtime_account_system(tsk, vtime);
 	tsk->flags |= PF_VCPU;
 	write_seqcount_end(&vtime->seqcount);
 }