Re: [RFC PATCH 0/7] block, fs: convert Direct IO to FOLL_PIN

[John Hubbard]

On 2/25/22 05:12, David Hildenbrand wrote:
> vmsplice is another candidate that uses iov_iter_get_pages() and should

Yes.

> be converted to FOLL_PIN. For that particular user, we have to also pass
> FOLL_LONGTERM -- vmsplice as it stands can block memory hotunplug / CMA
> / ... for all eternity.

Oh, thanks for pointing that out. I was thinking about Direct IO, and
would have overlooked that vmsplice need FOLL_LONGTERM.

I'm still quite vague about which parts of vmsplice are in pipe buffers
(and therefore will *not* get FOLL_PIN pages) and which are in user space
buffers. Just haven't spent enough time with vmsplice yet, hopefully it
will clear up with some study of the code.


thanks,
--
John Hubbard
NVIDIA