On Wed, Jun 04, 2014 at 04:25:15PM +0800, Lai Jiangshan wrote: > I think the following code works. (inspirited from the sched_ttwu_pending() > in migration_call().) > > if p->on_rq == 0 && p->state == TASK_WAKING in __migrate_task() after this > patch, > it means the cpuallowed is changed before __migrate_task() along with other > scheduler > movements happens between sched_ttwu_pending() and __migrate_task().
Yes, this is better. Can you send a full patch with the below comment in
as well, then I can apply.
Thanks!
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 268a45e..277f3bc 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -4530,7 +4530,7 @@ int set_cpus_allowed_ptr(struct task_struct *p, const
> struct cpumask *new_mask)
> goto out;
>
> dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
> - if (p->on_rq) {
> + if (p->on_rq || p->state == TASK_WAKING) {
> struct migration_arg arg = { p, dest_cpu };
> /* Need help from migration thread: drop lock and wait. */
> task_rq_unlock(rq, p, &flags);
> @@ -4656,6 +4656,7 @@ static int migration_cpu_stop(void *data)
> * be on another cpu but it doesn't matter.
> */
> local_irq_disable();
/*
* We need to explicitly wake pending tasks before running
* __migrate_task() such that we will not miss enforcing
* cpus_allowed during wakeups, see set_cpus_allowed_ptr()'s
* TASK_WAKING test.
*/
> + sched_ttwu_pending();
> __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
> local_irq_enable();
> return 0;
pgp4cWfrdef6y.pgp
Description: PGP signature
