On Mon, Oct 26, 2020 at 02:52:13PM +0800, [email protected] wrote: > @@ -737,8 +741,11 @@ __kthread_create_worker(int cpu, unsigned int flags, > if (IS_ERR(task)) > goto fail_task; > > - if (cpu >= 0) > + if (cpu >= 0) { > kthread_bind(task, cpu); > + worker->bind_cpu = cpu; > + cpuhp_state_add_instance_nocalls(kworker_online, > &worker->cpuhp_node); > + } > > worker->flags = flags; > worker->task = task; ... > +static int kworker_cpu_online(unsigned int cpu, struct hlist_node *node) > +{ > + struct kthread_worker *worker = hlist_entry(node, struct > kthread_worker, cpuhp_node); > + struct task_struct *task = worker->task; > + > + if (cpu == worker->bind_cpu) > + WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpumask_of(cpu)) < 0); > + return 0; > +}
I don't think this works. The kthread may have changed its binding while running using set_cpus_allowed_ptr() as you're doing above. Besides, when a cpu goes offline, the bound kthread can fall back to other cpus but its cpu mask isn't cleared, is it? Thanks. -- tejun
