diff options
Diffstat (limited to 'arch/s390/kernel/smp.c')
| -rw-r--r-- | arch/s390/kernel/smp.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index fd8e3111a4e..2270730f535 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -856,13 +856,20 @@ static ssize_t show_idle_count(struct sys_device *dev, { struct s390_idle_data *idle; unsigned long long idle_count; + unsigned int sequence; idle = &per_cpu(s390_idle, dev->id); - spin_lock(&idle->lock); +repeat: + sequence = idle->sequence; + smp_rmb(); + if (sequence & 1) + goto repeat; idle_count = idle->idle_count; if (idle->idle_enter) idle_count++; - spin_unlock(&idle->lock); + smp_rmb(); + if (idle->sequence != sequence) + goto repeat; return sprintf(buf, "%llu\n", idle_count); } static SYSDEV_ATTR(idle_count, 0444, show_idle_count, NULL); @@ -872,15 +879,22 @@ static ssize_t show_idle_time(struct sys_device *dev, { struct s390_idle_data *idle; unsigned long long now, idle_time, idle_enter; + unsigned int sequence; idle = &per_cpu(s390_idle, dev->id); - spin_lock(&idle->lock); now = get_clock(); +repeat: + sequence = idle->sequence; + smp_rmb(); + if (sequence & 1) + goto repeat; idle_time = idle->idle_time; 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 sprintf(buf, "%llu\n", idle_time >> 12); } static SYSDEV_ATTR(idle_time_us, 0444, show_idle_time, NULL); @@ -908,11 +922,7 @@ static int __cpuinit smp_cpu_notify(struct notifier_block *self, case CPU_ONLINE: case CPU_ONLINE_FROZEN: idle = &per_cpu(s390_idle, cpu); - spin_lock_irq(&idle->lock); - idle->idle_enter = 0; - idle->idle_time = 0; - idle->idle_count = 0; - spin_unlock_irq(&idle->lock); + memset(idle, 0, sizeof(struct s390_idle_data)); if (sysfs_create_group(&s->kobj, &cpu_online_attr_group)) return NOTIFY_BAD; break; |