3 files changed, 43 insertions, 11 deletions

diff --git a/include/linux/vtime.h b/include/linux/vtime.h
index 21ef703d1b25..5368af9bdf06 100644
--- a/include/linux/vtime.h
+++ b/include/linux/vtime.h
@@ -10,12 +10,20 @@ extern void vtime_account_system_irqsafe(struct task_struct *tsk);
 extern void vtime_account_idle(struct task_struct *tsk);
 extern void vtime_account_user(struct task_struct *tsk);
 extern void vtime_account(struct task_struct *tsk);
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+extern bool vtime_accounting_enabled(void);
 #else
+static inline bool vtime_accounting_enabled(void) { return true; }
+#endif
+
+#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_system_irqsafe(struct task_struct *tsk) { }
 static inline void vtime_account_user(struct task_struct *tsk) { }
 static inline void vtime_account(struct task_struct *tsk) { }
+static inline bool vtime_accounting_enabled(void) { return false; }
 #endif
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 1c964eced92c..e1939d38bf73 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -317,8 +317,6 @@ out:
         rcu_read_unlock();
 }
 
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
-
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
 /*
  * Account a tick to a process and cpustat
@@ -383,11 +381,12 @@ static void irqtime_account_idle_ticks(int ticks)
                 irqtime_account_process_tick(current, 0, rq);
 }
 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
-static void irqtime_account_idle_ticks(int ticks) {}
-static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
+static inline void irqtime_account_idle_ticks(int ticks) {}
+static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
                                                 struct rq *rq) {}
 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
 
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 /*
  * Account a single tick of cpu time.
  * @p: the process that the cpu time gets accounted to
@@ -398,6 +397,9 @@ void account_process_tick(struct task_struct *p, int user_tick)
         cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
         struct rq *rq = this_rq();
 
+        if (vtime_accounting_enabled())
+                return;
+
         if (sched_clock_irqtime) {
                 irqtime_account_process_tick(p, user_tick, rq);
                 return;
@@ -439,8 +441,7 @@ void account_idle_ticks(unsigned long ticks)
 
         account_idle_time(jiffies_to_cputime(ticks));
 }
-
-#endif
+#endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
 /*
  * Use precise platform statistics if available:
@@ -475,6 +476,9 @@ EXPORT_SYMBOL_GPL(vtime_account_system_irqsafe);
 #ifndef __ARCH_HAS_VTIME_TASK_SWITCH
 void vtime_task_switch(struct task_struct *prev)
 {
+        if (!vtime_accounting_enabled())
+                return;
+
         if (is_idle_task(prev))
                 vtime_account_idle(prev);
         else
@@ -498,6 +502,9 @@ void vtime_task_switch(struct task_struct *prev)
 #ifndef __ARCH_HAS_VTIME_ACCOUNT
 void vtime_account(struct task_struct *tsk)
 {
+        if (!vtime_accounting_enabled())
+                return;
+
         if (!in_interrupt()) {
                 /*
                  * If we interrupted user, context_tracking_in_user()
@@ -520,7 +527,7 @@ void vtime_account(struct task_struct *tsk)
 EXPORT_SYMBOL_GPL(vtime_account);
 #endif /* __ARCH_HAS_VTIME_ACCOUNT */
 
-#else
+#else /* !CONFIG_VIRT_CPU_ACCOUNTING */
 
 static cputime_t scale_utime(cputime_t utime, cputime_t rtime, cputime_t total)
 {
@@ -599,7 +606,7 @@ void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime
         thread_group_cputime(p, &cputime);
         cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
 }
-#endif
+#endif /* !CONFIG_VIRT_CPU_ACCOUNTING */
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
 static DEFINE_PER_CPU(unsigned long long, cputime_snap);
@@ -617,14 +624,23 @@ static cputime_t get_vtime_delta(void)
 
 void vtime_account_system(struct task_struct *tsk)
 {
-        cputime_t delta_cpu = get_vtime_delta();
+        cputime_t delta_cpu;
+
+        if (!vtime_accounting_enabled())
+                return;
 
+        delta_cpu = get_vtime_delta();
         account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
 }
 
 void vtime_account_user(struct task_struct *tsk)
 {
-        cputime_t delta_cpu = get_vtime_delta();
+        cputime_t delta_cpu;
+
+        if (!vtime_accounting_enabled())
+                return;
+
+        delta_cpu = get_vtime_delta();
 
         account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu));
 }
@@ -635,4 +651,9 @@ void vtime_account_idle(struct task_struct *tsk)
 
         account_idle_time(delta_cpu);
 }
+
+bool vtime_accounting_enabled(void)
+{
+        return context_tracking_active();
+}
 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index d58e552d9fd1..46dfb6d94b1c 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -631,8 +631,11 @@ static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
 
 static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
 {
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
         unsigned long ticks;
+
+        if (vtime_accounting_enabled())
+                return;
         /*
          * We stopped the tick in idle. Update process times would miss the
          * time we slept as update_process_times does only a 1 tick