@@ -911,12 +911,15 @@ static inline int compound_pincount(struct page *page)
static inline void set_compound_order(struct page *page, unsigned int order)
{
page[1].compound_order = order;
+ page[1].compound_nr = 1U << order;
}
/* Returns the number of pages in this potentially compound page. */
static inline unsigned long compound_nr(struct page *page)
{
- return 1UL << compound_order(page);
+ if (!PageHead(page))
+ return 1;
+ return page[1].compound_nr;
}
/* Returns the number of bytes in this potentially compound page. */
@@ -134,6 +134,7 @@ struct page {
unsigned char compound_dtor;
unsigned char compound_order;
atomic_t compound_mapcount;
+ unsigned int compound_nr; /* 1 << compound_order */
};
struct { /* Second tail page of compound page */
unsigned long _compound_pad_1; /* compound_head */
@@ -673,8 +673,6 @@ void prep_compound_page(struct page *page, unsigned int order)
int i;
int nr_pages = 1 << order;
- set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
- set_compound_order(page, order);
__SetPageHead(page);
for (i = 1; i < nr_pages; i++) {
struct page *p = page + i;
@@ -682,6 +680,9 @@ void prep_compound_page(struct page *page, unsigned int order)
p->mapping = TAIL_MAPPING;
set_compound_head(p, page);
}
+
+ set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
+ set_compound_order(page, order);
atomic_set(compound_mapcount_ptr(page), -1);
if (hpage_pincount_available(page))
atomic_set(compound_pincount_ptr(page), 0);