From 2be0ffe2b29bd31d3debd0877797892ff2d91f4c Mon Sep 17 00:00:00 2001 From: Timur Tabi Date: Wed, 23 Jul 2008 21:28:11 -0700 Subject: mm: add alloc_pages_exact() and free_pages_exact() alloc_pages_exact() is similar to alloc_pages(), except that it allocates the minimum number of pages to fulfill the request. This is useful if you want to allocate a very large buffer that is slightly larger than an even power-of-two number of pages. In that case, alloc_pages() will waste a lot of memory. I have a video driver that wants to allocate a 5MB buffer. alloc_pages() wiill waste 3MB of physically-contiguous memory. Signed-off-by: Timur Tabi Cc: Andi Kleen Acked-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/gfp.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/gfp.h b/include/linux/gfp.h index f640ed241422..e8003afeffba 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -228,6 +228,9 @@ extern struct page *alloc_page_vma(gfp_t gfp_mask, extern unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order); extern unsigned long get_zeroed_page(gfp_t gfp_mask); +void *alloc_pages_exact(size_t size, gfp_t gfp_mask); +void free_pages_exact(void *virt, size_t size); + #define __get_free_page(gfp_mask) \ __get_free_pages((gfp_mask),0) -- cgit v1.2.3