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authorThomas Gleixner <tglx@linutronix.de>2013-01-31 12:11:13 +0000
committerThomas Gleixner <tglx@linutronix.de>2013-02-14 15:29:37 +0100
commit860a0ffaa3e1a9cf0ebb5f43d6a2a2ce67463e93 (patch)
tree004c5b928e59605276609459d92db21bb41204e3 /kernel
parent7d7e499f7333f68b7e7f67d14b9c1480913b4afb (diff)
stop_machine: Store task reference in a separate per cpu variable
To allow the stopper thread being managed by the smpboot thread infrastructure separate out the task storage from the stopper data structure. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Arjan van de Veen <arjan@infradead.org> Cc: Paul Turner <pjt@google.com> Cc: Richard Weinberger <rw@linutronix.de> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130131120741.626690384@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/stop_machine.c32
1 files changed, 16 insertions, 16 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 2f194e965715..aaac68c5c3be 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -37,10 +37,10 @@ struct cpu_stopper {
spinlock_t lock;
bool enabled; /* is this stopper enabled? */
struct list_head works; /* list of pending works */
- struct task_struct *thread; /* stopper thread */
};
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;
static void cpu_stop_init_done(struct cpu_stop_done *done, unsigned int nr_todo)
@@ -62,16 +62,18 @@ static void cpu_stop_signal_done(struct cpu_stop_done *done, bool executed)
}
/* queue @work to @stopper. if offline, @work is completed immediately */
-static void cpu_stop_queue_work(struct cpu_stopper *stopper,
- struct cpu_stop_work *work)
+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;
spin_lock_irqsave(&stopper->lock, flags);
if (stopper->enabled) {
list_add_tail(&work->list, &stopper->works);
- wake_up_process(stopper->thread);
+ wake_up_process(p);
} else
cpu_stop_signal_done(work->done, false);
@@ -108,7 +110,7 @@ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg)
struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = &done };
cpu_stop_init_done(&done, 1);
- cpu_stop_queue_work(&per_cpu(cpu_stopper, cpu), &work);
+ cpu_stop_queue_work(cpu, &work);
wait_for_completion(&done.completion);
return done.executed ? done.ret : -ENOENT;
}
@@ -130,7 +132,7 @@ void stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
struct cpu_stop_work *work_buf)
{
*work_buf = (struct cpu_stop_work){ .fn = fn, .arg = arg, };
- cpu_stop_queue_work(&per_cpu(cpu_stopper, cpu), work_buf);
+ cpu_stop_queue_work(cpu, work_buf);
}
/* static data for stop_cpus */
@@ -159,8 +161,7 @@ static void queue_stop_cpus_work(const struct cpumask *cpumask,
*/
preempt_disable();
for_each_cpu(cpu, cpumask)
- cpu_stop_queue_work(&per_cpu(cpu_stopper, cpu),
- &per_cpu(stop_cpus_work, cpu));
+ cpu_stop_queue_work(cpu, &per_cpu(stop_cpus_work, cpu));
preempt_enable();
}
@@ -304,12 +305,11 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb,
{
unsigned int cpu = (unsigned long)hcpu;
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
- struct task_struct *p;
+ struct task_struct *p = per_cpu(cpu_stopper_task, cpu);
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_UP_PREPARE:
- BUG_ON(stopper->thread || stopper->enabled ||
- !list_empty(&stopper->works));
+ BUG_ON(p || stopper->enabled || !list_empty(&stopper->works));
p = kthread_create_on_node(cpu_stopper_thread,
stopper,
cpu_to_node(cpu),
@@ -319,12 +319,12 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb,
get_task_struct(p);
kthread_bind(p, cpu);
sched_set_stop_task(cpu, p);
- stopper->thread = p;
+ per_cpu(cpu_stopper_task, cpu) = p;
break;
case CPU_ONLINE:
/* strictly unnecessary, as first user will wake it */
- wake_up_process(stopper->thread);
+ wake_up_process(p);
/* mark enabled */
spin_lock_irq(&stopper->lock);
stopper->enabled = true;
@@ -339,7 +339,7 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb,
sched_set_stop_task(cpu, NULL);
/* kill the stopper */
- kthread_stop(stopper->thread);
+ kthread_stop(p);
/* drain remaining works */
spin_lock_irq(&stopper->lock);
list_for_each_entry(work, &stopper->works, list)
@@ -347,8 +347,8 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb,
stopper->enabled = false;
spin_unlock_irq(&stopper->lock);
/* release the stopper */
- put_task_struct(stopper->thread);
- stopper->thread = NULL;
+ put_task_struct(p);
+ per_cpu(cpu_stopper_task, cpu) = NULL;
break;
}
#endif