Re: [PATCH v2 05/34] mm: add utility functions for ptdesc

Mike Rapoport
2023-05-25T20:26:15Z

On Thu, May 25, 2023 at 11:04:28AM -0700, Vishal Moola wrote:
> On Thu, May 25, 2023 at 2:10 AM Mike Rapoport <rppt@kernel.org> wrote:
> > > +
> > > +static inline struct ptdesc *ptdesc_alloc(gfp_t gfp, unsigned int order)
> > > +{
> > > + struct page *page = alloc_pages(gfp | __GFP_COMP, order);
> > > +
> > > + return page_ptdesc(page);
> > > +}
> > > +
> > > +static inline void ptdesc_free(struct ptdesc *pt)
> > > +{
> > > + struct page *page = ptdesc_page(pt);
> > > +
> > > + __free_pages(page, compound_order(page));
> > > +}
> >
> > The ptdesc_{alloc,free} API does not sound right to me. The name
> > ptdesc_alloc() implies the allocation of the ptdesc itself, rather than
> > allocation of page table page. The same goes for free.
>
> I'm not sure I see the difference. Could you elaborate?

I read ptdesc_alloc() as "allocate a ptdesc" rather than as "allocate a
page for page table and return ptdesc pointing to that page". Seems very
confusing to me already and it will be even more confusion when we'll start
allocating actual ptdescs.

--
Sincerely yours,
Mike.