Re: [External] Re: [PATCH v9 10/11] mm/hugetlb: Gather discrete indexes of tail page

[Muchun Song]

On Wed, Dec 16, 2020 at 10:03 PM Oscar Salvador <osalvador@xxxxxxx> wrote:
>
> On Sun, Dec 13, 2020 at 11:45:33PM +0800, Muchun Song wrote:
> > For HugeTLB page, there are more metadata to save in the struct page.
> > But the head struct page cannot meet our needs, so we have to abuse
> > other tail struct page to store the metadata. In order to avoid
> > conflicts caused by subsequent use of more tail struct pages, we can
> > gather these discrete indexes of tail struct page. In this case, it
> > will be easier to add a new tail page index later.
> >
> > There are only (RESERVE_VMEMMAP_SIZE / sizeof(struct page)) struct
> > page structs can be used when CONFIG_HUGETLB_PAGE_FREE_VMEMMAP, so
> "that can be..."

Thanks.

>
> > add a BUILD_BUG_ON to catch invalid usage of the tail struct page.
> >
> > Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
>
> I think this makes the current situation with metadata usage in sub-pages
> easier to track.

Agree.

>
> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>

Thank you.

>
> --
> Oscar Salvador
> SUSE L3



-- 
Yours,
Muchun