diff options
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 49 |
1 files changed, 23 insertions, 26 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index d7f07a2da5a..deff2e69376 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -306,8 +306,28 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) __func__, cpu); goto out_release; } + + /* + * By now we've cleared cpu_active_mask, wait for all preempt-disabled + * and RCU users of this state to go away such that all new such users + * will observe it. + * + * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might + * not imply sync_sched(), so explicitly call both. + * + * Do sync before park smpboot threads to take care the rcu boost case. + */ +#ifdef CONFIG_PREEMPT + synchronize_sched(); +#endif + synchronize_rcu(); + smpboot_park_threads(cpu); + /* + * So now all preempt/rcu users must observe !cpu_active(). + */ + err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu)); if (err) { /* CPU didn't die: tell everyone. Can't complain. */ @@ -420,11 +440,6 @@ int cpu_up(unsigned int cpu) { int err = 0; -#ifdef CONFIG_MEMORY_HOTPLUG - int nid; - pg_data_t *pgdat; -#endif - if (!cpu_possible(cpu)) { printk(KERN_ERR "can't online cpu %d because it is not " "configured as may-hotadd at boot time\n", cpu); @@ -435,27 +450,9 @@ int cpu_up(unsigned int cpu) return -EINVAL; } -#ifdef CONFIG_MEMORY_HOTPLUG - nid = cpu_to_node(cpu); - if (!node_online(nid)) { - err = mem_online_node(nid); - if (err) - return err; - } - - pgdat = NODE_DATA(nid); - if (!pgdat) { - printk(KERN_ERR - "Can't online cpu %d due to NULL pgdat\n", cpu); - return -ENOMEM; - } - - if (pgdat->node_zonelists->_zonerefs->zone == NULL) { - mutex_lock(&zonelists_mutex); - build_all_zonelists(NULL, NULL); - mutex_unlock(&zonelists_mutex); - } -#endif + err = try_online_node(cpu_to_node(cpu)); + if (err) + return err; cpu_maps_update_begin(); |