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
