diff options
Diffstat (limited to 'arch/s390/kernel/vtime.c')
| -rw-r--r-- | arch/s390/kernel/vtime.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c index ade17e771f0..c41bb0d416e 100644 --- a/arch/s390/kernel/vtime.c +++ b/arch/s390/kernel/vtime.c @@ -27,9 +27,7 @@ static DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer); -DEFINE_PER_CPU(struct s390_idle_data, s390_idle) = { - .lock = __SPIN_LOCK_UNLOCKED(s390_idle.lock) -}; +DEFINE_PER_CPU(struct s390_idle_data, s390_idle); static inline __u64 get_vtimer(void) { @@ -151,11 +149,13 @@ void vtime_start_cpu(void) vq->elapsed -= vq->idle - S390_lowcore.async_enter_timer; } - spin_lock(&idle->lock); + idle->sequence++; + smp_wmb(); idle->idle_time += idle_time; idle->idle_enter = 0ULL; idle->idle_count++; - spin_unlock(&idle->lock); + smp_wmb(); + idle->sequence++; } void vtime_stop_cpu(void) @@ -242,15 +242,23 @@ cputime64_t s390_get_idle_time(int cpu) { struct s390_idle_data *idle; unsigned long long now, idle_time, idle_enter; + unsigned int sequence; idle = &per_cpu(s390_idle, cpu); - spin_lock(&idle->lock); + now = get_clock(); +repeat: + sequence = idle->sequence; + smp_rmb(); + if (sequence & 1) + goto repeat; idle_time = 0; idle_enter = idle->idle_enter; if (idle_enter != 0ULL && idle_enter < now) idle_time = now - idle_enter; - spin_unlock(&idle->lock); + smp_rmb(); + if (idle->sequence != sequence) + goto repeat; return idle_time; } |