@@ -506,6 +506,8 @@ extern struct page *alloc_pages_vma(gfp_t gfp_mask, int order,
extern void free_hot_cold_page_list(struct list_head *list, bool cold);
struct page_frag_cache;
+extern void __page_frag_drain(struct page *page, unsigned int order,
+ unsigned int count);
extern void *__alloc_page_frag(struct page_frag_cache *nc,
unsigned int fragsz, gfp_t gfp_mask);
extern void __free_page_frag(void *addr);
@@ -3883,6 +3883,20 @@ static struct page *__page_frag_refill(struct page_frag_cache *nc,
return page;
}
+void __page_frag_drain(struct page *page, unsigned int order,
+ unsigned int count)
+{
+ VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
+
+ if (page_ref_sub_and_test(page, count)) {
+ if (order == 0)
+ free_hot_cold_page(page, false);
+ else
+ __free_pages_ok(page, order);
+ }
+}
+EXPORT_SYMBOL(__page_frag_drain);
+
void *__alloc_page_frag(struct page_frag_cache *nc,
unsigned int fragsz, gfp_t gfp_mask)
{
This patch adds a function that allows us to batch free a page that has multiple references outstanding. Specifically this function can be used to drop a page being used in the page frag alloc cache. With this drivers can make use of functionality similar to the page frag alloc cache without having to do any workarounds for the fact that there is no function that frees multiple references. Cc: linux-mm@kvack.org Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> --- include/linux/gfp.h | 2 ++ mm/page_alloc.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+)