stop_machine: Move 'cpu_stopper_task' and 'stop_cpus_work' into 'struct cpu_stopper'

Multpiple DEFINE_PER_CPU's do not make sense, move all the per-cpu
variables into 'struct cpu_stopper'.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: der.herr@hofr.at
Cc: paulmck@linux.vnet.ibm.com
Cc: riel@redhat.com
Cc: viro@ZenIV.linux.org.uk
Link: http://lkml.kernel.org/r/20150630012944.GA23924@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index fd643d8c4b424f858e3c6d7e0996bbb919a555e7..6e677b003164fa9e0997cbe4ce59665aaee8aea3 100644 (file)
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -35,13 +35,16 @@ struct cpu_stop_done {
 
 /* the actual stopper, one per every possible cpu, enabled on online cpus */
 struct cpu_stopper {
+       struct task_struct      *thread;
+
        spinlock_t              lock;
        bool                    enabled;        /* is this stopper enabled? */
        struct list_head        works;          /* list of pending works */
+
+       struct cpu_stop_work    stop_work;      /* for stop_cpus */
 };
 
 static DEFINE_PER_CPU(struct cpu_stopper, cpu_stopper);
-static DEFINE_PER_CPU(struct task_struct *, cpu_stopper_task);
 static bool stop_machine_initialized = false;
 
 /*
@@ -74,7 +77,6 @@ static void cpu_stop_signal_done(struct cpu_stop_done *done, bool executed)
 static void cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
 {
        struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
-       struct task_struct *p = per_cpu(cpu_stopper_task, cpu);
 
        unsigned long flags;
 
@@ -82,7 +84,7 @@ static void cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
 
        if (stopper->enabled) {
                list_add_tail(&work->list, &stopper->works);
-               wake_up_process(p);
+               wake_up_process(stopper->thread);
        } else
                cpu_stop_signal_done(work->done, false);
 
@@ -293,7 +295,6 @@ void stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
 
 /* static data for stop_cpus */
 static DEFINE_MUTEX(stop_cpus_mutex);
-static DEFINE_PER_CPU(struct cpu_stop_work, stop_cpus_work);
 
 static void queue_stop_cpus_work(const struct cpumask *cpumask,
                                 cpu_stop_fn_t fn, void *arg,
@@ -304,7 +305,7 @@ static void queue_stop_cpus_work(const struct cpumask *cpumask,
 
        /* initialize works and done */
        for_each_cpu(cpu, cpumask) {
-               work = &per_cpu(stop_cpus_work, cpu);
+               work = &per_cpu(cpu_stopper.stop_work, cpu);
                work->fn = fn;
                work->arg = arg;
                work->done = done;
@@ -317,7 +318,7 @@ static void queue_stop_cpus_work(const struct cpumask *cpumask,
         */
        lg_global_lock(&stop_cpus_lock);
        for_each_cpu(cpu, cpumask)
-               cpu_stop_queue_work(cpu, &per_cpu(stop_cpus_work, cpu));
+               cpu_stop_queue_work(cpu, &per_cpu(cpu_stopper.stop_work, cpu));
        lg_global_unlock(&stop_cpus_lock);
 }
 
@@ -458,7 +459,7 @@ extern void sched_set_stop_task(int cpu, struct task_struct *stop);
 
 static void cpu_stop_create(unsigned int cpu)
 {
-       sched_set_stop_task(cpu, per_cpu(cpu_stopper_task, cpu));
+       sched_set_stop_task(cpu, per_cpu(cpu_stopper.thread, cpu));
 }
 
 static void cpu_stop_park(unsigned int cpu)
@@ -485,7 +486,7 @@ static void cpu_stop_unpark(unsigned int cpu)
 }
 
 static struct smp_hotplug_thread cpu_stop_threads = {
-       .store                  = &cpu_stopper_task,
+       .store                  = &cpu_stopper.thread,
        .thread_should_run      = cpu_stop_should_run,
        .thread_fn              = cpu_stopper_thread,
        .thread_comm            = "migration/%u",