On Fri, 2 Apr 2021 12:16:32 Dan Schatzberg wrote:
> +queue_work:
> + if (worker) {
> + /*
> + * We need to remove from the idle list here while
> + * holding the lock so that the idle timer doesn't
> + * free the worker
> + */
> + if (!list_empty(&worker->idle_list))
> + list_del_init(&worker->idle_list);
Nit, only queue work if the worker is inactive - otherwise it is taking
care of the cmd_list.
> + work = &worker->work;
> + cmd_list = &worker->cmd_list;
> + } else {
> + work = &lo->rootcg_work;
> + cmd_list = &lo->rootcg_cmd_list;
> + }
> + list_add_tail(&cmd->list_entry, cmd_list);
> + queue_work(lo->workqueue, work);
> + spin_unlock_irq(&lo->lo_work_lock);
> }
[...]
> + /*
> + * We only add to the idle list if there are no pending cmds
> + * *and* the worker will not run again which ensures that it
> + * is safe to free any worker on the idle list
> + */
> + if (worker && !work_pending(&worker->work)) {
The empty cmd_list is a good enough reason for worker to become idle.
> + worker->last_ran_at = jiffies;
> + list_add_tail(&worker->idle_list, &lo->idle_worker_list);
> + loop_set_timer(lo);
> + }
> + spin_unlock_irq(&lo->lo_work_lock);
> + current->flags = orig_flags;
> +}
