Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

[sfrench/cifs-2.6.git] / kernel / smpboot.c

diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index c697f73d82d6a4157a15ef9b0039b007083f7857..7c434c39f02a250f4721475910e881b43b603313 100644 (file)
--- 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 +327,53 @@ 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.
+ * This function can only be called on a registered smp_hotplug_thread.
+ */
+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);
 
 /*