On Thu, Jan 31, 2013 at 12:11:13PM -0000, Thomas Gleixner wrote: > 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 <[email protected]>
Reviewed-by: Paul E. McKenney <[email protected]> > --- > kernel/stop_machine.c | 32 ++++++++++++++++---------------- > 1 file changed, 16 insertions(+), 16 deletions(-) > > Index: linux-2.6/kernel/stop_machine.c > =================================================================== > --- linux-2.6.orig/kernel/stop_machine.c > +++ linux-2.6/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 > } > > /* 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_s > 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 cp > 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 s > */ > 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_callba > { > 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_callba > 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_callba > > 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_callba > 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 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
