Re: [PATCH 04/17] mm/mm_init: skip initializing shared vmemmap tail pages

[Mike Rapoport]

On Wed, Jul 15, 2026 at 05:11:21PM +0800, Muchun Song wrote:
> > On Jul 15, 2026, at 13:08, Mike Rapoport <rppt@xxxxxxxxxx> wrote:
> > 
> >> --- a/mm/internal.h
> >> +++ b/mm/internal.h
> >> @@ -1002,10 +1002,26 @@ static inline void sparse_init(void) {}
> >>  */
> >> #ifdef CONFIG_SPARSEMEM_VMEMMAP
> >> void sparse_init_subsection_map(void);
> >> +
> >> +static inline bool page_vmemmap_optimizable(const struct page *page, unsigned int order)
> >> +{
> >> + 	const unsigned long pfn = page_to_pfn(page);
> >> + 	const unsigned long nr_pages = 1UL << order;
> >> +
> > 
> > Don't you want to gate it on HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON?
> 
> You mean HUGETLB_PAGE_OPTIMIZE_VMEMMAP, right? HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON
> could be off when user enable HVO via cmdline.

Yes

-- 
Sincerely yours,
Mike.