sched: fix nohz load balancer on cpu offline

[safe/jmp/linux-2.6] / kernel / kthread.c

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 0ac8878..4fbc456 100644 (file)
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -13,7 +13,7 @@
 #include <linux/file.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
-#include <asm/semaphore.h>
+#include <trace/sched.h>
 
 #define KTHREAD_NICE_LEVEL (-5)
 
@@ -21,6 +21,9 @@ static DEFINE_SPINLOCK(kthread_create_lock);
 static LIST_HEAD(kthread_create_list);
 struct task_struct *kthreadd_task;
 
+DEFINE_TRACE(sched_kthread_stop);
+DEFINE_TRACE(sched_kthread_stop_ret);
+
 struct kthread_create_info
 {
        /* Information passed to kthread() from kthreadd. */
@@ -99,7 +102,7 @@ static void create_kthread(struct kthread_create_info *create)
                struct sched_param param = { .sched_priority = 0 };
                wait_for_completion(&create->started);
                read_lock(&tasklist_lock);
-               create->result = find_task_by_pid(pid);
+               create->result = find_task_by_pid_ns(pid, &init_pid_ns);
                read_unlock(&tasklist_lock);
                /*
                 * root may have changed our (kthreadd's) priority or CPU mask.
@@ -107,7 +110,7 @@ static void create_kthread(struct kthread_create_info *create)
                 */
                sched_setscheduler(create->result, SCHED_NORMAL, &param);
                set_user_nice(create->result, KTHREAD_NICE_LEVEL);
-               set_cpus_allowed(create->result, CPU_MASK_ALL);
+               set_cpus_allowed_ptr(create->result, CPU_MASK_ALL_PTR);
        }
        complete(&create->done);
 }
@@ -145,9 +148,9 @@ struct task_struct *kthread_create(int (*threadfn)(void *data),
 
        spin_lock(&kthread_create_lock);
        list_add_tail(&create.list, &kthread_create_list);
-       wake_up_process(kthreadd_task);
        spin_unlock(&kthread_create_lock);
 
+       wake_up_process(kthreadd_task);
        wait_for_completion(&create.done);
 
        if (!IS_ERR(create.result)) {
@@ -172,14 +175,15 @@ EXPORT_SYMBOL(kthread_create);
  */
 void kthread_bind(struct task_struct *k, unsigned int cpu)
 {
-       if (k->state != TASK_UNINTERRUPTIBLE) {
+       /* Must have done schedule() in kthread() before we set_task_cpu */
+       if (!wait_task_inactive(k, TASK_UNINTERRUPTIBLE)) {
                WARN_ON(1);
                return;
        }
-       /* Must have done schedule() in kthread() before we set_task_cpu */
-       wait_task_inactive(k);
        set_task_cpu(k, cpu);
        k->cpus_allowed = cpumask_of_cpu(cpu);
+       k->rt.nr_cpus_allowed = 1;
+       k->flags |= PF_THREAD_BOUND;
 }
 EXPORT_SYMBOL(kthread_bind);
 
@@ -205,6 +209,8 @@ int kthread_stop(struct task_struct *k)
        /* It could exit after stop_info.k set, but before wake_up_process. */
        get_task_struct(k);
 
+       trace_sched_kthread_stop(k);
+
        /* Must init completion *before* thread sees kthread_stop_info.k */
        init_completion(&kthread_stop_info.done);
        smp_wmb();
@@ -220,6 +226,8 @@ int kthread_stop(struct task_struct *k)
        ret = kthread_stop_info.err;
        mutex_unlock(&kthread_stop_lock);
 
+       trace_sched_kthread_stop_ret(ret);
+
        return ret;
 }
 EXPORT_SYMBOL(kthread_stop);
@@ -232,9 +240,9 @@ int kthreadd(void *unused)
        set_task_comm(tsk, "kthreadd");
        ignore_signals(tsk);
        set_user_nice(tsk, KTHREAD_NICE_LEVEL);
-       set_cpus_allowed(tsk, CPU_MASK_ALL);
+       set_cpus_allowed_ptr(tsk, CPU_MASK_ALL_PTR);
 
-       current->flags |= PF_NOFREEZE;
+       current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG;
 
        for (;;) {
                set_current_state(TASK_INTERRUPTIBLE);