Hey Will,
On Friday 13 Nov 2020 at 09:37:12 (+0000), Will Deacon wrote:
> -static int __set_cpus_allowed_ptr(struct task_struct *p,
> - const struct cpumask *new_mask, bool check)
> +static int __set_cpus_allowed_ptr_locked(struct task_struct *p,
> + const struct cpumask *new_mask,
> + bool check,
> + struct rq *rq,
> + struct rq_flags *rf)
> {
> const struct cpumask *cpu_valid_mask = cpu_active_mask;
> unsigned int dest_cpu;
> - struct rq_flags rf;
> - struct rq *rq;
> int ret = 0;
Should we have a lockdep assertion here?
> - rq = task_rq_lock(p, &rf);
> update_rq_clock(rq);
>
> if (p->flags & PF_KTHREAD) {
> @@ -1929,7 +1923,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
> if (task_running(rq, p) || 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, &rf);
> + task_rq_unlock(rq, p, rf);
> stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
> return 0;
> } else if (task_on_rq_queued(p)) {
> @@ -1937,20 +1931,69 @@ static int __set_cpus_allowed_ptr(struct task_struct
> *p,
> * OK, since we're going to drop the lock immediately
> * afterwards anyway.
> */
> - rq = move_queued_task(rq, &rf, p, dest_cpu);
> + rq = move_queued_task(rq, rf, p, dest_cpu);
> }
> out:
> - task_rq_unlock(rq, p, &rf);
> + task_rq_unlock(rq, p, rf);
And that's a little odd to have here no? Can we move it back on the
caller's side?
> return ret;
> }
Thanks,
Quentin
