On 11.07.22 16:00, Matthew Wilcox wrote:
> On Mon, Jul 11, 2022 at 03:35:42PM +0200, David Hildenbrand wrote:
>>> + /*
>>> + * Device coherent pages are managed by a driver and should not
>>> + * be pinned indefinitely as it prevents the driver moving the
>>> + * page. So when trying to pin with FOLL_LONGTERM instead try
>>> + * to migrate the page out of device memory.
>>> + */
>>> + if (folio_is_device_coherent(folio)) {
>>> + WARN_ON_ONCE(PageCompound(&folio->page));
>>
>> Maybe that belongs into migrate_device_page()?
>
> ... and should be simply WARN_ON_ONCE(folio_test_large(folio)).
> No need to go converting it back into a page in order to test things
> that can't possibly be true.
>
Good point.
--
Thanks,
David / dhildenb
