Split the utility function prep_compound_page() into head and tail
counterparts, and use them accordingly.
This is in preparation for sharing the storage for / deduplicating
compound page metadata.
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
---
mm/page_alloc.c | 32 +++++++++++++++++++++-----------
1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8836e54721ae..95967ce55829 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -741,24 +741,34 @@ void free_compound_page(struct page *page)
free_the_page(page, compound_order(page));
}
+static void prep_compound_head(struct page *page, unsigned int order)
+{
+ 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);
+}
+
+static void prep_compound_tail(struct page *head, int tail_idx)
+{
+ struct page *p = head + tail_idx;
+
+ set_page_count(p, 0);
+ p->mapping = TAIL_MAPPING;
+ set_compound_head(p, head);
+}
+
void prep_compound_page(struct page *page, unsigned int order)
{
int i;
int nr_pages = 1 << order;
__SetPageHead(page);
- for (i = 1; i < nr_pages; i++) {
- struct page *p = page + i;
- set_page_count(p, 0);
- p->mapping = TAIL_MAPPING;
- set_compound_head(p, page);
- }
+ for (i = 1; i < nr_pages; i++)
+ prep_compound_tail(page, i);
- 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);
+ prep_compound_head(page, order);
}
#ifdef CONFIG_DEBUG_PAGEALLOC
--
2.17.1
