Merge 'Linux v3.0' into Litmus

Some notes:
* Litmus^RT scheduling class is the topmost scheduling class
  (above stop_sched_class).
* scheduler_ipi() function (e.g., in smp_reschedule_interrupt())
  may increase IPI latencies.
* Added path into schedule() to quickly re-evaluate scheduling
  decision without becoming preemptive again. This used to be
  a standard path before the removal of BKL.

Conflicts:
	Makefile
	arch/arm/kernel/calls.S
	arch/arm/kernel/smp.c
	arch/x86/include/asm/unistd_32.h
	arch/x86/kernel/smp.c
	arch/x86/kernel/syscall_table_32.S
	include/linux/hrtimer.h
	kernel/printk.c
	kernel/sched.c
	kernel/sched_fair.c

1 files changed, 12 insertions, 8 deletions

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 4372ccb25127..e3516b29076c 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -262,7 +262,7 @@ repeat:
                 cpu_stop_fn_t fn = work->fn;
                 void *arg = work->arg;
                 struct cpu_stop_done *done = work->done;
-                char ksym_buf[KSYM_NAME_LEN];
+                char ksym_buf[KSYM_NAME_LEN] __maybe_unused;
 
                 __set_current_state(TASK_RUNNING);
 
@@ -287,11 +287,12 @@ repeat:
         goto repeat;
 }
 
+extern void sched_set_stop_task(int cpu, struct task_struct *stop);
+
 /* manage stopper for a cpu, mostly lifted from sched migration thread mgmt */
 static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb,
                                            unsigned long action, void *hcpu)
 {
-        struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
         unsigned int cpu = (unsigned long)hcpu;
         struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
         struct task_struct *p;
@@ -300,17 +301,19 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb,
         case CPU_UP_PREPARE:
                 BUG_ON(stopper->thread || stopper->enabled ||
                        !list_empty(&stopper->works));
-                p = kthread_create(cpu_stopper_thread, stopper, "migration/%d",
-                                   cpu);
+                p = kthread_create_on_node(cpu_stopper_thread,
+                                           stopper,
+                                           cpu_to_node(cpu),
+                                           "migration/%d", cpu);
                 if (IS_ERR(p))
-                        return NOTIFY_BAD;
-                sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
+                        return notifier_from_errno(PTR_ERR(p));
                 get_task_struct(p);
+                kthread_bind(p, cpu);
+                sched_set_stop_task(cpu, p);
                 stopper->thread = p;
                 break;
 
         case CPU_ONLINE:
-                kthread_bind(stopper->thread, cpu);
                 /* strictly unnecessary, as first user will wake it */
                 wake_up_process(stopper->thread);
                 /* mark enabled */
@@ -325,6 +328,7 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb,
         {
                 struct cpu_stop_work *work;
 
+                sched_set_stop_task(cpu, NULL);
                 /* kill the stopper */
                 kthread_stop(stopper->thread);
                 /* drain remaining works */
@@ -370,7 +374,7 @@ static int __init cpu_stop_init(void)
         /* start one for the boot cpu */
         err = cpu_stop_cpu_callback(&cpu_stop_cpu_notifier, CPU_UP_PREPARE,
                                     bcpu);
-        BUG_ON(err == NOTIFY_BAD);
+        BUG_ON(err != NOTIFY_OK);
         cpu_stop_cpu_callback(&cpu_stop_cpu_notifier, CPU_ONLINE, bcpu);
         register_cpu_notifier(&cpu_stop_cpu_notifier);