diff options
| -rw-r--r-- | include/linux/smpboot.h | 5 | ||||
| -rw-r--r-- | kernel/smpboot.c | 59 |
2 files changed, 63 insertions, 1 deletions
diff --git a/include/linux/smpboot.h b/include/linux/smpboot.h index d600afb21926..da3c593f9845 100644 --- a/include/linux/smpboot.h +++ b/include/linux/smpboot.h @@ -27,6 +27,8 @@ struct smpboot_thread_data; * @pre_unpark: Optional unpark function, called before the thread is * unparked (cpu online). This is not guaranteed to be * called on the target cpu of the thread. Careful! + * @cpumask: Internal state. To update which threads are unparked, + * call smpboot_update_cpumask_percpu_thread(). * @selfparking: Thread is not parked by the park function. * @thread_comm: The base name of the thread */ @@ -41,11 +43,14 @@ struct smp_hotplug_thread { void (*park)(unsigned int cpu); void (*unpark)(unsigned int cpu); void (*pre_unpark)(unsigned int cpu); + cpumask_var_t cpumask; bool selfparking; const char *thread_comm; }; int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread); void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread); +int smpboot_update_cpumask_percpu_thread(struct smp_hotplug_thread *plug_thread, + const struct cpumask *); #endif diff --git a/kernel/smpboot.c b/kernel/smpboot.c index c697f73d82d6..5e46c2a75d59 100644 --- a/kernel/smpboot.c +++ b/kernel/smpboot.c @@ -232,7 +232,8 @@ void smpboot_unpark_threads(unsigned int cpu) mutex_lock(&smpboot_threads_lock); list_for_each_entry(cur, &hotplug_threads, list) - smpboot_unpark_thread(cur, cpu); + if (cpumask_test_cpu(cpu, cur->cpumask)) + smpboot_unpark_thread(cur, cpu); mutex_unlock(&smpboot_threads_lock); } @@ -258,6 +259,15 @@ static void smpboot_destroy_threads(struct smp_hotplug_thread *ht) { unsigned int cpu; + /* Unpark any threads that were voluntarily parked. */ + for_each_cpu_not(cpu, ht->cpumask) { + if (cpu_online(cpu)) { + struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu); + if (tsk) + kthread_unpark(tsk); + } + } + /* We need to destroy also the parked threads of offline cpus */ for_each_possible_cpu(cpu) { struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu); @@ -281,6 +291,10 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread) unsigned int cpu; int ret = 0; + if (!alloc_cpumask_var(&plug_thread->cpumask, GFP_KERNEL)) + return -ENOMEM; + cpumask_copy(plug_thread->cpumask, cpu_possible_mask); + get_online_cpus(); mutex_lock(&smpboot_threads_lock); for_each_online_cpu(cpu) { @@ -313,9 +327,52 @@ void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread) smpboot_destroy_threads(plug_thread); mutex_unlock(&smpboot_threads_lock); put_online_cpus(); + free_cpumask_var(plug_thread->cpumask); } EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread); +/** + * smpboot_update_cpumask_percpu_thread - Adjust which per_cpu hotplug threads stay parked + * @plug_thread: Hotplug thread descriptor + * @new: Revised mask to use + * + * The cpumask field in the smp_hotplug_thread must not be updated directly + * by the client, but only by calling this function. + */ +int smpboot_update_cpumask_percpu_thread(struct smp_hotplug_thread *plug_thread, + const struct cpumask *new) +{ + struct cpumask *old = plug_thread->cpumask; + cpumask_var_t tmp; + unsigned int cpu; + + if (!alloc_cpumask_var(&tmp, GFP_KERNEL)) + return -ENOMEM; + + get_online_cpus(); + mutex_lock(&smpboot_threads_lock); + + /* Park threads that were exclusively enabled on the old mask. */ + cpumask_andnot(tmp, old, new); + for_each_cpu_and(cpu, tmp, cpu_online_mask) + smpboot_park_thread(plug_thread, cpu); + + /* Unpark threads that are exclusively enabled on the new mask. */ + cpumask_andnot(tmp, new, old); + for_each_cpu_and(cpu, tmp, cpu_online_mask) + smpboot_unpark_thread(plug_thread, cpu); + + cpumask_copy(old, new); + + mutex_unlock(&smpboot_threads_lock); + put_online_cpus(); + + free_cpumask_var(tmp); + + return 0; +} +EXPORT_SYMBOL_GPL(smpboot_update_cpumask_percpu_thread); + static DEFINE_PER_CPU(atomic_t, cpu_hotplug_state) = ATOMIC_INIT(CPU_POST_DEAD); /* |