Introduce PageHuge(), which identifies huge/gigantic pages by their dedicated compound destructor functions. Signed-off-by: Wu Fengguang --- include/linux/mm.h | 24 ++++++++++++++++++++++++ mm/hugetlb.c | 2 +- mm/page_alloc.c | 11 ++++++++++- 3 files changed, 35 insertions(+), 2 deletions(-) --- mm.orig/mm/page_alloc.c +++ mm/mm/page_alloc.c @@ -299,13 +299,22 @@ void prep_compound_page(struct page *pag } #ifdef CONFIG_HUGETLBFS +/* + * This (duplicated) destructor function distinguishes gigantic pages from + * normal compound pages. + */ +void free_gigantic_page(struct page *page) +{ + __free_pages_ok(page, compound_order(page)); +} + void prep_compound_gigantic_page(struct page *page, unsigned long order) { int i; int nr_pages = 1 << order; struct page *p = page + 1; - set_compound_page_dtor(page, free_compound_page); + set_compound_page_dtor(page, free_gigantic_page); set_compound_order(page, order); __SetPageHead(page); for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { --- mm.orig/mm/hugetlb.c +++ mm/mm/hugetlb.c @@ -550,7 +550,7 @@ struct hstate *size_to_hstate(unsigned l return NULL; } -static void free_huge_page(struct page *page) +void free_huge_page(struct page *page) { /* * Can't pass hstate in here because it is called from the --- mm.orig/include/linux/mm.h +++ mm/include/linux/mm.h @@ -355,6 +355,30 @@ static inline void set_compound_order(st page[1].lru.prev = (void *)order; } +#ifdef CONFIG_HUGETLBFS +void free_huge_page(struct page *page); +void free_gigantic_page(struct page *page); + +static inline int PageHuge(struct page *page) +{ + compound_page_dtor *dtor; + + if (!PageCompound(page)) + return 0; + + page = compound_head(page); + dtor = get_compound_page_dtor(page); + + return dtor == free_huge_page || + dtor == free_gigantic_page; +} +#else +static inline int PageHuge(struct page *page) +{ + return 0; +} +#endif + /* * Multiple processes may "see" the same page. E.g. for untouched * mappings of /dev/null, all processes see the same page full of -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/