Re: [PATCH v3 4/6] mm/thp: add THP allocation helper

[Ralph Campbell]

On 11/6/20 12:01 AM, Christoph Hellwig wrote:
> > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> > +extern struct page *alloc_transhugepage(struct vm_area_struct *vma,
> > +					unsigned long addr);
>
> No need for the extern.  And also here: do we actually need the stub,
> or can the caller make sure (using IS_ENABLED and similar) that the
> compiler knows the code is dead?

Same problem as with prep_transhuge_device_private_page(), since
alloc_hugepage_direct_gfpmask() and alloc_hugepage_vma() are not
EXPORT_SYMBOL_GPL.

> > +struct page *alloc_transhugepage(struct vm_area_struct *vma,
> > +				 unsigned long haddr)
> > +{
> > +	gfp_t gfp;
> > +	struct page *page;
> > +
> > +	gfp = alloc_hugepage_direct_gfpmask(vma);
> > +	page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER);
> > +	if (page)
> > +		prep_transhuge_page(page);
> > +	return page;
>
> I think do_huge_pmd_anonymous_page should be switched to use this
> helper as well.

Sure, I'll do that for v4.