On 8/27/22 17:31, John Hubbard wrote:
> On 8/27/22 17:12, Andrew Morton wrote:
>> On Sat, 27 Aug 2022 16:59:32 -0700 John Hubbard <jhubbard@xxxxxxxxxx> wrote:
>>
>>> Anyway, I'll change my patch locally for now, to this:
>>>
>>> static inline void dio_w_unpin_user_pages(struct page **pages,
>>> unsigned long npages)
>>> {
>>> /* Careful, release_pages() uses a smaller integer type for npages: */
>>> if (WARN_ON_ONCE(npages > (unsigned long)INT_MAX))
>>> return;
>>>
>>> release_pages(pages, (int)npages);
>>> }
>>
>> Well, it might be slower. release_pages() has a ton of fluff.
>>
>> As mentioned, the above might be faster if the pages tend
>> to have page_count()==1??
>>
>
> I don't think we can know the answer to that. This code is called
To clarify: I mean, I don't think we can know whether or not these pages
usually have page_count()==1.
thanks,
--
John Hubbard
NVIDIA
