Re: [External] Re: [PATCH v5 21/21] mm/hugetlb: Disable freeing vmemmap if struct page size is not power of two

[Muchun Song]

On Fri, Nov 20, 2020 at 5:16 PM David Hildenbrand <david@xxxxxxxxxx> wrote:
>
> On 20.11.20 07:43, Muchun Song wrote:
> > We only can free the unused vmemmap to the buddy system when the
> > size of struct page is a power of two.
> >
> > Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> > ---
> >   mm/hugetlb_vmemmap.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
> > index c3b3fc041903..7bb749a3eea2 100644
> > --- a/mm/hugetlb_vmemmap.c
> > +++ b/mm/hugetlb_vmemmap.c
> > @@ -671,7 +671,8 @@ void __init hugetlb_vmemmap_init(struct hstate *h)
> >       unsigned int order = huge_page_order(h);
> >       unsigned int vmemmap_pages;
> >
> > -     if (hugetlb_free_vmemmap_disabled) {
> > +     if (hugetlb_free_vmemmap_disabled ||
> > +         !is_power_of_2(sizeof(struct page))) {
> >               pr_info("disable free vmemmap pages for %s\n", h->name);
> >               return;
> >       }
> >
>
> This patch should be merged into the original patch that introduced
> vmemmap freeing.

Oh, yeah. Will do.

>
> --
> Thanks,
>
> David / dhildenb
>


-- 
Yours,
Muchun