5 files changed, 73 insertions, 30 deletions

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 16bb6eda879d..01cd43e491cd 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -116,29 +116,32 @@ void vtime_task_switch(struct task_struct *prev)
  * Account time for a transition between system, hard irq or soft irq state.
  * Note that this function is called with interrupts enabled.
  */
-void vtime_account(struct task_struct *tsk)
+static cputime_t vtime_delta(struct task_struct *tsk)
 {
         struct thread_info *ti = task_thread_info(tsk);
-        unsigned long flags;
         cputime_t delta_stime;
         __u64 now;
 
-        local_irq_save(flags);
-
         now = ia64_get_itc();
 
         delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp));
-        if (irq_count() || idle_task(smp_processor_id()) != tsk)
-                account_system_time(tsk, 0, delta_stime, delta_stime);
-        else
-                account_idle_time(delta_stime);
         ti->ac_stime = 0;
-
         ti->ac_stamp = now;
 
-        local_irq_restore(flags);
+        return delta_stime;
+}
+
+void vtime_account_system(struct task_struct *tsk)
+{
+        cputime_t delta = vtime_delta(tsk);
+
+        account_system_time(tsk, 0, delta, delta);
+}
+
+void vtime_account_idle(struct task_struct *tsk)
+{
+        account_idle_time(vtime_delta(tsk));
 }
-EXPORT_SYMBOL_GPL(vtime_account);
 
 /*
  * Called from the timer interrupt handler to charge accumulated user time
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 39899d7ebda0..29b6d3e1ea28 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -291,13 +291,12 @@ static inline u64 calculate_stolen_time(u64 stop_tb)
  * Account time for a transition between system, hard irq
  * or soft irq state.
  */
-void vtime_account(struct task_struct *tsk)
+static u64 vtime_delta(struct task_struct *tsk,
+                        u64 *sys_scaled, u64 *stolen)
 {
-        u64 now, nowscaled, delta, deltascaled;
-        unsigned long flags;
-        u64 stolen, udelta, sys_scaled, user_scaled;
+        u64 now, nowscaled, deltascaled;
+        u64 udelta, delta, user_scaled;
 
-        local_irq_save(flags);
         now = mftb();
         nowscaled = read_spurr(now);
         get_paca()->system_time += now - get_paca()->starttime;
@@ -305,7 +304,7 @@ void vtime_account(struct task_struct *tsk)
         deltascaled = nowscaled - get_paca()->startspurr;
         get_paca()->startspurr = nowscaled;
 
-        stolen = calculate_stolen_time(now);
+        *stolen = calculate_stolen_time(now);
 
         delta = get_paca()->system_time;
         get_paca()->system_time = 0;
@@ -322,28 +321,38 @@ void vtime_account(struct task_struct *tsk)
          * the user ticks get saved up in paca->user_time_scaled to be
          * used by account_process_tick.
          */
-        sys_scaled = delta;
+        *sys_scaled = delta;
         user_scaled = udelta;
         if (deltascaled != delta + udelta) {
                 if (udelta) {
-                        sys_scaled = deltascaled * delta / (delta + udelta);
-                        user_scaled = deltascaled - sys_scaled;
+                        *sys_scaled = deltascaled * delta / (delta + udelta);
+                        user_scaled = deltascaled - *sys_scaled;
                 } else {
-                        sys_scaled = deltascaled;
+                        *sys_scaled = deltascaled;
                 }
         }
         get_paca()->user_time_scaled += user_scaled;
 
-        if (in_interrupt() || idle_task(smp_processor_id()) != tsk) {
-                account_system_time(tsk, 0, delta, sys_scaled);
-                if (stolen)
-                        account_steal_time(stolen);
-        } else {
-                account_idle_time(delta + stolen);
-        }
-        local_irq_restore(flags);
+        return delta;
+}
+
+void vtime_account_system(struct task_struct *tsk)
+{
+        u64 delta, sys_scaled, stolen;
+
+        delta = vtime_delta(tsk, &sys_scaled, &stolen);
+        account_system_time(tsk, 0, delta, sys_scaled);
+        if (stolen)
+                account_steal_time(stolen);
+}
+
+void vtime_account_idle(struct task_struct *tsk)
+{
+        u64 delta, sys_scaled, stolen;
+
+        delta = vtime_delta(tsk, &sys_scaled, &stolen);
+        account_idle_time(delta + stolen);
 }
-EXPORT_SYMBOL_GPL(vtime_account);
 
 /*
  * Transfer the user and system times accumulated in the paca
diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h
index 8709bdef233c..023d5ae24482 100644
--- a/arch/s390/include/asm/cputime.h
+++ b/arch/s390/include/asm/cputime.h
@@ -12,6 +12,9 @@
 #include <linux/spinlock.h>
 #include <asm/div64.h>
 
+
+#define __ARCH_HAS_VTIME_ACCOUNT
+
 /* We want to use full resolution of the CPU timer: 2**-12 micro-seconds. */
 
 typedef unsigned long long __nocast cputime_t;
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index ca0944b92f4a..36d12f0884c3 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -132,6 +132,8 @@ extern void account_idle_ticks(unsigned long ticks);
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 extern void vtime_task_switch(struct task_struct *prev);
+extern void vtime_account_system(struct task_struct *tsk);
+extern void vtime_account_idle(struct task_struct *tsk);
 #else
 static inline void vtime_task_switch(struct task_struct *prev) { }
 #endif
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 53f5b12f2821..81b763ba58a6 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -432,6 +432,32 @@ void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
         *ut = cputime.utime;
         *st = cputime.stime;
 }
+
+/*
+ * 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
+ * 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().
+ */
+#ifndef __ARCH_HAS_VTIME_ACCOUNT
+void vtime_account(struct task_struct *tsk)
+{
+        unsigned long flags;
+
+        local_irq_save(flags);
+
+        if (in_interrupt() || !is_idle_task(tsk))
+                vtime_account_system(tsk);
+        else
+                vtime_account_idle(tsk);
+
+        local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(vtime_account);
+#endif /* __ARCH_HAS_VTIME_ACCOUNT */
+
 #else
 
 #ifndef nsecs_to_cputime