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

Michal Hocko
2024-07-24T13:47:56Z

On Wed 24-07-24 06:38:41, Christoph Hellwig wrote:
> On Wed, Jul 24, 2024 at 03:33:19PM +0200, Vlastimil Babka wrote:
> > > I do not see this a problem. There is no real reason to have a NOWAIT
> > > allocation down the stack that has a different fallback strategy.
> > > I am not saying that this is the current practice because I do not know
> > > that but I am saying that this is not impossible to imagine and it makes
> > > scoped NOFAIL context subtle and error prone.
> >
> > I don't think Christoph proposed scoped NOFAIL, just use scoped NOFS/NOIO
> > together with GFP_KERNEL_NOFAIL intead of introducing GFP_NOFS_NOFAIL.
>
> Yes, exactly.
>
> And I didn't think Michal thought I meant something different, maybe
> that's why it felt really confusing.

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.

Thanks for the clarification.
--
Michal Hocko
SUSE Labs