Messages in this thread Patch in this message | | | Date | Thu, 19 Nov 2020 09:18:20 +0000 | From | Quentin Perret <> | Subject | Re: [PATCH v3 07/14] sched: Introduce restrict_cpus_allowed_ptr() to limit task CPU affinity |
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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
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