[PATCH] fix scaled & unscaled cputime accounting

The utimescaled / stimescaled fields in the task structure and the
global cpustat should be set on all architectures. On s390 the calls
to account_user_time_scaled and account_system_time_scaled never have
been added. In addition system time that is accounted as guest time
to the user time of a process is accounted to the scaled system time
instead of the scaled user time.
To fix the bugs and to prevent future forgetfulness this patch merges
account_system_time_scaled into account_system_time and
account_user_time_scaled into account_user_time.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Michael Neuling <mikey@neuling.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

7 files changed, 37 insertions, 56 deletions

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 65c10a42c88f..4ee367817049 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -93,13 +93,11 @@ void ia64_account_on_switch(struct task_struct *prev, struct task_struct *next)
         now = ia64_get_itc();
 
         delta_stime = cycle_to_cputime(pi->ac_stime + (now - pi->ac_stamp));
-        account_system_time(prev, 0, delta_stime);
-        account_system_time_scaled(prev, delta_stime);
+        account_system_time(prev, 0, delta_stime, delta_stime);
 
         if (pi->ac_utime) {
                 delta_utime = cycle_to_cputime(pi->ac_utime);
-                account_user_time(prev, delta_utime);
-                account_user_time_scaled(prev, delta_utime);
+                account_user_time(prev, delta_utime, delta_utime);
         }
 
         pi->ac_stamp = ni->ac_stamp = now;
@@ -122,8 +120,7 @@ void account_system_vtime(struct task_struct *tsk)
         now = ia64_get_itc();
 
         delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp));
-        account_system_time(tsk, 0, delta_stime);
-        account_system_time_scaled(tsk, delta_stime);
+        account_system_time(tsk, 0, delta_stime, delta_stime);
         ti->ac_stime = 0;
 
         ti->ac_stamp = now;
@@ -143,8 +140,7 @@ void account_process_tick(struct task_struct *p, int user_tick)
 
         if (ti->ac_utime) {
                 delta_utime = cycle_to_cputime(ti->ac_utime);
-                account_user_time(p, delta_utime);
-                account_user_time_scaled(p, delta_utime);
+                account_user_time(p, delta_utime, delta_utime);
                 ti->ac_utime = 0;
         }
 }
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index e1f3a5140429..92650ccad2e1 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -256,8 +256,7 @@ void account_system_vtime(struct task_struct *tsk)
                 delta += sys_time;
                 get_paca()->system_time = 0;
         }
-        account_system_time(tsk, 0, delta);
-        account_system_time_scaled(tsk, deltascaled);
+        account_system_time(tsk, 0, delta, deltascaled);
         per_cpu(cputime_last_delta, smp_processor_id()) = delta;
         per_cpu(cputime_scaled_last_delta, smp_processor_id()) = deltascaled;
         local_irq_restore(flags);
@@ -275,10 +274,8 @@ void account_process_tick(struct task_struct *tsk, int user_tick)
 
         utime = get_paca()->user_time;
         get_paca()->user_time = 0;
-        account_user_time(tsk, utime);
-
         utimescaled = cputime_to_scaled(utime);
-        account_user_time_scaled(tsk, utimescaled);
+        account_user_time(tsk, utime, utimescaled);
 }
 
 /*
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 75a6e62ea973..07283aea2e56 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -50,12 +50,12 @@ void account_process_tick(struct task_struct *tsk, int user_tick)
         rcu_user_flag = cputime != 0;
         S390_lowcore.user_timer -= cputime << 12;
         S390_lowcore.steal_clock -= cputime << 12;
-        account_user_time(tsk, cputime);
+        account_user_time(tsk, cputime, cputime);
 
         cputime =  S390_lowcore.system_timer >> 12;
         S390_lowcore.system_timer -= cputime << 12;
         S390_lowcore.steal_clock -= cputime << 12;
-        account_system_time(tsk, HARDIRQ_OFFSET, cputime);
+        account_system_time(tsk, HARDIRQ_OFFSET, cputime, cputime);
 
         cputime = S390_lowcore.steal_clock;
         if ((__s64) cputime > 0) {
@@ -82,12 +82,12 @@ void account_vtime(struct task_struct *tsk)
         cputime = S390_lowcore.user_timer >> 12;
         S390_lowcore.user_timer -= cputime << 12;
         S390_lowcore.steal_clock -= cputime << 12;
-        account_user_time(tsk, cputime);
+        account_user_time(tsk, cputime, cputime);
 
         cputime =  S390_lowcore.system_timer >> 12;
         S390_lowcore.system_timer -= cputime << 12;
         S390_lowcore.steal_clock -= cputime << 12;
-        account_system_time(tsk, 0, cputime);
+        account_system_time(tsk, 0, cputime, cputime);
 }
 
 /*
@@ -107,7 +107,7 @@ void account_system_vtime(struct task_struct *tsk)
         cputime =  S390_lowcore.system_timer >> 12;
         S390_lowcore.system_timer -= cputime << 12;
         S390_lowcore.steal_clock -= cputime << 12;
-        account_system_time(tsk, 0, cputime);
+        account_system_time(tsk, 0, cputime, cputime);
 }
 EXPORT_SYMBOL_GPL(account_system_vtime);
 
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 4ee4b3d2316f..c78a459662a6 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -79,10 +79,8 @@ static inline unsigned int kstat_irqs(unsigned int irq)
 }
 
 extern unsigned long long task_delta_exec(struct task_struct *);
-extern void account_user_time(struct task_struct *, cputime_t);
-extern void account_user_time_scaled(struct task_struct *, cputime_t);
-extern void account_system_time(struct task_struct *, int, cputime_t);
-extern void account_system_time_scaled(struct task_struct *, cputime_t);
+extern void account_user_time(struct task_struct *, cputime_t, cputime_t);
+extern void account_system_time(struct task_struct *, int, cputime_t, cputime_t);
 extern void account_steal_time(struct task_struct *, cputime_t);
 
 #endif /* _LINUX_KERNEL_STAT_H */
diff --git a/kernel/sched.c b/kernel/sched.c
index fff1c4a20b65..5b03679ff712 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4080,13 +4080,17 @@ unsigned long long task_delta_exec(struct task_struct *p)
  * Account user cpu time to a process.
  * @p: the process that the cpu time gets accounted to
  * @cputime: the cpu time spent in user space since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
  */
-void account_user_time(struct task_struct *p, cputime_t cputime)
+void account_user_time(struct task_struct *p, cputime_t cputime,
+                       cputime_t cputime_scaled)
 {
         struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
         cputime64_t tmp;
 
+        /* Add user time to process. */
         p->utime = cputime_add(p->utime, cputime);
+        p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
         account_group_user_time(p, cputime);
 
         /* Add user time to cpustat. */
@@ -4103,51 +4107,49 @@ void account_user_time(struct task_struct *p, cputime_t cputime)
  * Account guest cpu time to a process.
  * @p: the process that the cpu time gets accounted to
  * @cputime: the cpu time spent in virtual machine since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
  */
-static void account_guest_time(struct task_struct *p, cputime_t cputime)
+static void account_guest_time(struct task_struct *p, cputime_t cputime,
+                               cputime_t cputime_scaled)
 {
         cputime64_t tmp;
         struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
 
         tmp = cputime_to_cputime64(cputime);
 
+        /* Add guest time to process. */
         p->utime = cputime_add(p->utime, cputime);
+        p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
         account_group_user_time(p, cputime);
         p->gtime = cputime_add(p->gtime, cputime);
 
+        /* Add guest time to cpustat. */
         cpustat->user = cputime64_add(cpustat->user, tmp);
         cpustat->guest = cputime64_add(cpustat->guest, tmp);
 }
 
 /*
- * Account scaled user cpu time to a process.
- * @p: the process that the cpu time gets accounted to
- * @cputime: the cpu time spent in user space since the last update
- */
-void account_user_time_scaled(struct task_struct *p, cputime_t cputime)
-{
-        p->utimescaled = cputime_add(p->utimescaled, cputime);
-}
-
-/*
  * Account system cpu time to a process.
  * @p: the process that the cpu time gets accounted to
  * @hardirq_offset: the offset to subtract from hardirq_count()
  * @cputime: the cpu time spent in kernel space since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
  */
 void account_system_time(struct task_struct *p, int hardirq_offset,
-                         cputime_t cputime)
+                         cputime_t cputime, cputime_t cputime_scaled)
 {
         struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
         struct rq *rq = this_rq();
         cputime64_t tmp;
 
         if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
-                account_guest_time(p, cputime);
+                account_guest_time(p, cputime, cputime_scaled);
                 return;
         }
 
+        /* Add system time to process. */
         p->stime = cputime_add(p->stime, cputime);
+        p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
         account_group_system_time(p, cputime);
 
         /* Add system time to cpustat. */
@@ -4167,17 +4169,6 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
 }
 
 /*
- * Account scaled system cpu time to a process.
- * @p: the process that the cpu time gets accounted to
- * @hardirq_offset: the offset to subtract from hardirq_count()
- * @cputime: the cpu time spent in kernel space since the last update
- */
-void account_system_time_scaled(struct task_struct *p, cputime_t cputime)
-{
-        p->stimescaled = cputime_add(p->stimescaled, cputime);
-}
-
-/*
  * Account for involuntary wait time.
  * @p: the process from which the cpu time has been stolen
  * @steal: the cpu time spent in involuntary wait
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 8f3fc2582d38..1f2fce2479fe 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -420,6 +420,7 @@ void tick_nohz_restart_sched_tick(void)
         int cpu = smp_processor_id();
         struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
         unsigned long ticks;
+        cputime_t cputime;
         ktime_t now;
 
         local_irq_disable();
@@ -452,8 +453,8 @@ void tick_nohz_restart_sched_tick(void)
          */
         if (ticks && ticks < LONG_MAX) {
                 add_preempt_count(HARDIRQ_OFFSET);
-                account_system_time(current, HARDIRQ_OFFSET,
-                                    jiffies_to_cputime(ticks));
+                cputime = jiffies_to_cputime(ticks);
+                account_system_time(current, HARDIRQ_OFFSET, cputime, cputime);
                 sub_preempt_count(HARDIRQ_OFFSET);
         }
 
diff --git a/kernel/timer.c b/kernel/timer.c
index 566257d1dc10..b5efb528aa1d 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1023,13 +1023,11 @@ void account_process_tick(struct task_struct *p, int user_tick)
 {
         cputime_t one_jiffy = jiffies_to_cputime(1);
 
-        if (user_tick) {
-                account_user_time(p, one_jiffy);
-                account_user_time_scaled(p, cputime_to_scaled(one_jiffy));
-        } else {
-                account_system_time(p, HARDIRQ_OFFSET, one_jiffy);
-                account_system_time_scaled(p, cputime_to_scaled(one_jiffy));
-        }
+        if (user_tick)
+                account_user_time(p, one_jiffy, cputime_to_scaled(one_jiffy));
+        else
+                account_system_time(p, HARDIRQ_OFFSET, one_jiffy,
+                                    cputime_to_scaled(one_jiffy));
 }
 #endif