sched/cputime, powerpc, s390: Make scaled cputime arch specific

Only s390 and powerpc have hardware facilities allowing to measure
cputimes scaled by frequency. On all other architectures
utimescaled/stimescaled are equal to utime/stime (however they are
accounted separately).

Remove {u,s}timescaled accounting on all architectures except
powerpc and s390, where those values are explicitly accounted
in the proper places.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161031162143.GB12646@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

10 files changed, 53 insertions, 61 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 659bdd079277..abab6590f08f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -512,6 +512,9 @@ config HAVE_CONTEXT_TRACKING
 config HAVE_VIRT_CPU_ACCOUNTING
         bool
 
+config ARCH_HAS_SCALED_CPUTIME
+        bool
+
 config HAVE_VIRT_CPU_ACCOUNTING_GEN
         bool
         default y if 64BIT
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 6f892b94e906..021f44ab4bfb 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -68,7 +68,7 @@ void vtime_account_user(struct task_struct *tsk)
 
         if (ti->ac_utime) {
                 delta_utime = cycle_to_cputime(ti->ac_utime);
-                account_user_time(tsk, delta_utime, delta_utime);
+                account_user_time(tsk, delta_utime);
                 ti->ac_utime = 0;
         }
 }
@@ -112,7 +112,7 @@ void vtime_account_system(struct task_struct *tsk)
 {
         cputime_t delta = vtime_delta(tsk);
 
-        account_system_time(tsk, 0, delta, delta);
+        account_system_time(tsk, 0, delta);
 }
 EXPORT_SYMBOL_GPL(vtime_account_system);
 
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 65fba4c34cd7..c7f120aaa98f 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -160,6 +160,7 @@ config PPC
         select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS
         select GENERIC_CPU_AUTOPROBE
         select HAVE_VIRT_CPU_ACCOUNTING
+        select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE
         select HAVE_ARCH_HARDENED_USERCOPY
         select HAVE_KERNEL_GZIP
 
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 81051986739c..be9751f1cb2a 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -358,7 +358,8 @@ void vtime_account_system(struct task_struct *tsk)
         unsigned long delta, sys_scaled, stolen;
 
         delta = vtime_delta(tsk, &sys_scaled, &stolen);
-        account_system_time(tsk, 0, delta, sys_scaled);
+        account_system_time(tsk, 0, delta);
+        tsk->stimescaled += sys_scaled;
         if (stolen)
                 account_steal_time(stolen);
 }
@@ -391,7 +392,8 @@ void vtime_account_user(struct task_struct *tsk)
         acct->user_time = 0;
         acct->user_time_scaled = 0;
         acct->utime_sspurr = 0;
-        account_user_time(tsk, utime, utimescaled);
+        account_user_time(tsk, utime);
+        tsk->utimescaled += utimescaled;
 }
 
 #ifdef CONFIG_PPC32
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 426481d4cc86..028f97be5bae 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -171,6 +171,7 @@ config S390
         select SYSCTL_EXCEPTION_TRACE
         select TTY
         select VIRT_CPU_ACCOUNTING
+        select ARCH_HAS_SCALED_CPUTIME
         select VIRT_TO_BUS
         select HAVE_NMI
 
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 856e30d8463f..1bd5dde2d5a9 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -137,8 +137,10 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
                 user_scaled = (user_scaled * mult) / div;
                 system_scaled = (system_scaled * mult) / div;
         }
-        account_user_time(tsk, user, user_scaled);
-        account_system_time(tsk, hardirq_offset, system, system_scaled);
+        account_user_time(tsk, user);
+        tsk->utimescaled += user_scaled;
+        account_system_time(tsk, hardirq_offset, system);
+        tsk->stimescaled += system_scaled;
 
         steal = S390_lowcore.steal_timer;
         if ((s64) steal > 0) {
@@ -202,7 +204,8 @@ void vtime_account_irq_enter(struct task_struct *tsk)
 
                 system_scaled = (system_scaled * mult) / div;
         }
-        account_system_time(tsk, 0, system, system_scaled);
+        account_system_time(tsk, 0, system);
+        tsk->stimescaled += system_scaled;
 
         virt_timer_forward(system);
 }
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 44fda64ad434..00f776816aa3 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -78,8 +78,8 @@ static inline unsigned int kstat_cpu_irqs_sum(unsigned int cpu)
         return kstat_cpu(cpu).irqs_sum;
 }
 
-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_user_time(struct task_struct *, cputime_t);
+extern void account_system_time(struct task_struct *, int, cputime_t);
 extern void account_steal_time(cputime_t);
 extern void account_idle_time(cputime_t);
 
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 3762fe4e3a80..f72e81395dac 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1647,7 +1647,10 @@ struct task_struct {
         int __user *set_child_tid;              /* CLONE_CHILD_SETTID */
         int __user *clear_child_tid;            /* CLONE_CHILD_CLEARTID */
 
-        cputime_t utime, stime, utimescaled, stimescaled;
+        cputime_t utime, stime;
+#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
+        cputime_t utimescaled, stimescaled;
+#endif
         cputime_t gtime;
         struct prev_cputime prev_cputime;
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
@@ -2240,8 +2243,6 @@ 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 void task_cputime_scaled(struct task_struct *t,
-                                cputime_t *utimescaled, cputime_t *stimescaled);
 extern cputime_t task_gtime(struct task_struct *t);
 #else
 static inline void task_cputime(struct task_struct *t,
@@ -2253,6 +2254,13 @@ static inline void task_cputime(struct task_struct *t,
                 *stime = t->stime;
 }
 
+static inline cputime_t task_gtime(struct task_struct *t)
+{
+        return t->gtime;
+}
+#endif
+
+#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
 static inline void task_cputime_scaled(struct task_struct *t,
                                        cputime_t *utimescaled,
                                        cputime_t *stimescaled)
@@ -2262,12 +2270,15 @@ static inline void task_cputime_scaled(struct task_struct *t,
         if (stimescaled)
                 *stimescaled = t->stimescaled;
 }
-
-static inline cputime_t task_gtime(struct task_struct *t)
+#else
+static inline void task_cputime_scaled(struct task_struct *t,
+                                       cputime_t *utimescaled,
+                                       cputime_t *stimescaled)
 {
-        return t->gtime;
+        task_cputime(t, utimescaled, stimescaled);
 }
 #endif
+
 extern void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
 extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
 
diff --git a/kernel/fork.c b/kernel/fork.c
index 997ac1d584f7..600e93b5e539 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1551,7 +1551,9 @@ static __latent_entropy struct task_struct *copy_process(
         init_sigpending(&p->pending);
 
         p->utime = p->stime = p->gtime = 0;
+#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
         p->utimescaled = p->stimescaled = 0;
+#endif
         prev_cputime_init(&p->prev_cputime);
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 3229c7244fdd..ba55ebf77f9a 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -128,16 +128,13 @@ static inline void task_group_account_field(struct task_struct *p, int index,
  * 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,
-                       cputime_t cputime_scaled)
+void account_user_time(struct task_struct *p, cputime_t cputime)
 {
         int index;
 
         /* Add user time to process. */
         p->utime += cputime;
-        p->utimescaled += cputime_scaled;
         account_group_user_time(p, cputime);
 
         index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
@@ -153,16 +150,13 @@ 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,
-                               cputime_t cputime_scaled)
+static void account_guest_time(struct task_struct *p, cputime_t cputime)
 {
         u64 *cpustat = kcpustat_this_cpu->cpustat;
 
         /* Add guest time to process. */
         p->utime += cputime;
-        p->utimescaled += cputime_scaled;
         account_group_user_time(p, cputime);
         p->gtime += cputime;
 
@@ -180,16 +174,13 @@ static void account_guest_time(struct task_struct *p, cputime_t cputime,
  * Account system cpu time to a process and desired cpustat field
  * @p: the process that the cpu time gets accounted to
  * @cputime: the cpu time spent in kernel space since the last update
- * @cputime_scaled: cputime scaled by cpu frequency
- * @target_cputime64: pointer to cpustat field that has to be updated
+ * @index: pointer to cpustat field that has to be updated
  */
 static inline
-void __account_system_time(struct task_struct *p, cputime_t cputime,
-                        cputime_t cputime_scaled, int index)
+void __account_system_time(struct task_struct *p, cputime_t cputime, int index)
 {
         /* Add system time to process. */
         p->stime += cputime;
-        p->stimescaled += cputime_scaled;
         account_group_system_time(p, cputime);
 
         /* Add system time to cpustat. */
@@ -204,15 +195,14 @@ void __account_system_time(struct task_struct *p, cputime_t cputime,
  * @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_scaled)
+                         cputime_t cputime)
 {
         int index;
 
         if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
-                account_guest_time(p, cputime, cputime_scaled);
+                account_guest_time(p, cputime);
                 return;
         }
 
@@ -223,7 +213,7 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
         else
                 index = CPUTIME_SYSTEM;
 
-        __account_system_time(p, cputime, cputime_scaled, index);
+        __account_system_time(p, cputime, index);
 }
 
 /*
@@ -410,15 +400,15 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
                  * So, we have to handle it separately here.
                  * Also, p->stime needs to be updated for ksoftirqd.
                  */
-                __account_system_time(p, cputime, cputime, CPUTIME_SOFTIRQ);
+                __account_system_time(p, cputime, CPUTIME_SOFTIRQ);
         } else if (user_tick) {
-                account_user_time(p, cputime, cputime);
+                account_user_time(p, cputime);
         } else if (p == rq->idle) {
                 account_idle_time(cputime);
         } else if (p->flags & PF_VCPU) { /* System time or guest time */
-                account_guest_time(p, cputime, cputime);
+                account_guest_time(p, cputime);
         } else {
-                __account_system_time(p, cputime, cputime, CPUTIME_SYSTEM);
+                __account_system_time(p, cputime, CPUTIME_SYSTEM);
         }
 }
 
@@ -521,9 +511,9 @@ void account_process_tick(struct task_struct *p, int user_tick)
         cputime -= steal;
 
         if (user_tick)
-                account_user_time(p, cputime, cputime);
+                account_user_time(p, cputime);
         else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
-                account_system_time(p, HARDIRQ_OFFSET, cputime, cputime);
+                account_system_time(p, HARDIRQ_OFFSET, cputime);
         else
                 account_idle_time(cputime);
 }
@@ -744,7 +734,7 @@ static void __vtime_account_system(struct task_struct *tsk)
 {
         cputime_t delta_cpu = get_vtime_delta(tsk);
 
-        account_system_time(tsk, irq_count(), delta_cpu, delta_cpu);
+        account_system_time(tsk, irq_count(), delta_cpu);
 }
 
 void vtime_account_system(struct task_struct *tsk)
@@ -765,7 +755,7 @@ void vtime_account_user(struct task_struct *tsk)
         tsk->vtime_snap_whence = VTIME_SYS;
         if (vtime_delta(tsk)) {
                 delta_cpu = get_vtime_delta(tsk);
-                account_user_time(tsk, delta_cpu, delta_cpu);
+                account_user_time(tsk, delta_cpu);
         }
         write_seqcount_end(&tsk->vtime_seqcount);
 }
@@ -921,25 +911,4 @@ void task_cputime(struct task_struct *t, cputime_t *utime, cputime_t *stime)
         if (stime)
                 *stime += sdelta;
 }
-
-void task_cputime_scaled(struct task_struct *t,
-                         cputime_t *utimescaled, cputime_t *stimescaled)
-{
-        cputime_t udelta, sdelta;
-
-        if (!vtime_accounting_enabled()) {
-                if (utimescaled)
-                        *utimescaled = t->utimescaled;
-                if (stimescaled)
-                        *stimescaled = t->stimescaled;
-                return;
-        }
-
-        fetch_task_cputime(t, utimescaled, stimescaled,
-                           &t->utimescaled, &t->stimescaled, &udelta, &sdelta);
-        if (utimescaled)
-                *utimescaled += udelta;
-        if (stimescaled)
-                *stimescaled += sdelta;
-}
 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */