On Mon, Jun 22, 2020 at 5:06 PM Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
>
> From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
>
> Implement acpi_os_unmap_deferred() and
> acpi_os_release_unused_mappings() and set ACPI_USE_DEFERRED_UNMAPPING
> to allow ACPICA to use deferred unmapping of memory in
> acpi_ex_system_memory_space_handler() so as to avoid RCU-related
> performance issues with memory opregions.
...
> +static bool acpi_os_drop_map_ref(struct acpi_ioremap *map, bool defer)
> {
> - unsigned long refcount = --map->refcount;
> + if (--map->track.refcount)
> + return true;
>
> - if (!refcount)
> - list_del_rcu(&map->list);
> - return refcount;
> + list_del_rcu(&map->list);
> +
> + if (defer) {
> + INIT_LIST_HEAD(&map->track.gc);
> + list_add_tail(&map->track.gc, &unused_mappings);
> + return true;
> + }
> +
> + return false;
A nit:
Effectively it returns a value of defer.
return defer;
> }
...
> @@ -416,26 +421,102 @@ void __ref acpi_os_unmap_iomem(void __iomem *virt, acpi_size size)
> }
>
> mutex_lock(&acpi_ioremap_lock);
> +
> map = acpi_map_lookup_virt(virt, size);
A nit: should it be somewhere else (I mean in another patch)?
> if (!map) {
...
> + /* Release the unused mappings in the list. */
> + while (!list_empty(&list)) {
> + struct acpi_ioremap *map;
> +
> + map = list_entry(list.next, struct acpi_ioremap, track.gc);
A nt: if __acpi_os_map_cleanup() (actually acpi_unmap() according to
the code) has no side effects, can we use list_for_each_entry_safe()
here?
> + list_del(&map->track.gc);
> + __acpi_os_map_cleanup(map);
> + }
> +}
...
> @@ -472,16 +552,18 @@ void acpi_os_unmap_generic_address(struct acpi_generic_address *gas)
> return;
>
> mutex_lock(&acpi_ioremap_lock);
> +
> map = acpi_map_lookup(addr, gas->bit_width / 8);
A nit: should it be somewhere else (I mean in another patch)?
--
With Best Regards,
Andy Shevchenko
