[S390] /proc/stat idle field for idle cpus
The cpu idle field in the output of /proc/stat is too small for cpus
that have been idle for more than a tick. Add the architecture hook
arch_idle_time that allows to add the not accounted idle time of a
sleeping cpu without waking the cpu.
The s390 implementation of arch_idle_time uses the already existing
s390_idle_data per_cpu variable to find the sleep time of a neighboring
idle cpu.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h
index 95b0f7d..941384f 100644
--- a/arch/s390/include/asm/cputime.h
+++ b/arch/s390/include/asm/cputime.h
@@ -174,4 +174,8 @@
return __div(cputime, 4096000000ULL / USER_HZ);
}
+cputime64_t s390_get_idle_time(int cpu);
+
+#define arch_idle_time(cpu) s390_get_idle_time(cpu)
+
#endif /* _S390_CPUTIME_H */
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 38ea92f..c87f59b 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -240,6 +240,22 @@
}
}
+cputime64_t s390_get_idle_time(int cpu)
+{
+ struct s390_idle_data *idle;
+ unsigned long long now, idle_time, idle_enter;
+
+ idle = &per_cpu(s390_idle, cpu);
+ spin_lock(&idle->lock);
+ now = get_clock();
+ idle_time = 0;
+ idle_enter = idle->idle_enter;
+ if (idle_enter != 0ULL && idle_enter < now)
+ idle_time = now - idle_enter;
+ spin_unlock(&idle->lock);
+ return idle_time;
+}
+
/*
* Sorted add to a list. List is linear searched until first bigger
* element is found.