Re: [PATCH RFC 5/5] non-mm: discourage the usage of __GFP_NOFAIL and encourage GFP_NOFAIL

Christoph Hellwig
2024-07-24T14:41:45Z

On Wed, Jul 24, 2024 at 04:39:11PM +0200, Vlastimil Babka wrote:
> On 7/24/24 3:55 PM, Christoph Hellwig wrote:
> > On Wed, Jul 24, 2024 at 03:47:46PM +0200, Michal Hocko wrote:
> >> OK, now it makes more sense ;) I have absolutely no objections to
> >> prefering scoped NO{FS,IO} interfaces of course. And that would indeed
> >> eliminate a need for defining GFP_NO{FS,IO}_NOFAIL alternatives.
> >
> > Yes. My proposal would be:
> >
> > GFP_NOFAIL without any modifiers it the only valid nofail API.
>
> Where GFP_NOFAIL is GFP_KERNEL | __GFP_NOFAIL (and not the more limited one
> as defined in patch 4/5).

Yes.

> > File systems / drivers can combine іt with the scoped nofs/noio if
> > needed.
>
> Sounds good, how quickly we can convert existing __GFP_NOFAIL users remains
> to be seen...

I took a quick look at the file system ones and they look pretty easy. I
think it would be good to a quick scriped run for everything that does
GFP_KERNEL | __GFP_NOFAIL right now, and then spend a little time on
the rest.