On Sat, Jan 29, 2022 at 4:13 AM Hillf Danton <hdanton@xxxxxxxx> wrote:
>
> On Fri, 28 Jan 2022 05:09:53 -0800 Michel Lespinasse wrote:
> > +
> > +static LIST_HEAD(destroy_list);
> > +static DEFINE_SPINLOCK(destroy_list_lock);
>
> static bool destroyer_running;
>
> > +
> > +static void destroy_list_workfn(struct work_struct *work)
> > +{
> > + struct percpu_rw_semaphore *sem, *sem2;
> > + LIST_HEAD(to_destroy);
> > +
>
> again:
>
> > + spin_lock(&destroy_list_lock);
>
> if (list_empty(&destroy_list)) {
> destroyer_running = false;
> spin_unlock(&destroy_list_lock);
> return;
> }
> destroyer_running = true;
>
> > + list_splice_init(&destroy_list, &to_destroy);
> > + spin_unlock(&destroy_list_lock);
> > +
> > + if (list_empty(&to_destroy))
> > + return;
> > +
> > + list_for_each_entry_safe(sem, sem2, &to_destroy, destroy_list_entry) {
>
> list_del(&sem->destroy_list_entry);
>
> > + percpu_free_rwsem(sem);
> > + kfree(sem);
> > + }
>
> goto again;
> > +}
> > +
> > +static DECLARE_WORK(destroy_list_work, destroy_list_workfn);
> > +
> > +void percpu_rwsem_async_destroy(struct percpu_rw_semaphore *sem)
> > +{
> > + spin_lock(&destroy_list_lock);
> > + list_add_tail(&sem->destroy_list_entry, &destroy_list);
> > + spin_unlock(&destroy_list_lock);
> > + schedule_work(&destroy_list_work);
>
> Nits
> spin_lock(&destroy_list_lock);
> 1/ /* LIFO */
> list_add(&sem->destroy_list_entry, &destroy_list);
> 2/ /* spawn worker if it is idle */
> if (!destroyer_running)
> 3/ /* this is not critical work */
> queue_work(system_unbound_wq, &destroy_list_work);
> spin_unlock(&destroy_list_lock);
Thanks for the review! Just to clarify, are you suggesting
simplifications to the current patch or do you see a function issue?
> > +}
> > --
> > 2.20.1
>
