The patch titled
mm: add alloc_pages_exact() and free_pages_exact()
has been removed from the -mm tree. Its filename was
mm-add-alloc_pages_exact-and-free_pages_exact.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mm: add alloc_pages_exact() and free_pages_exact()
From: Timur Tabi <timur@xxxxxxxxxxxxx>
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 <timur@xxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Acked-by: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/gfp.h | 3 ++
mm/page_alloc.c | 53 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 56 insertions(+)
diff -puN include/linux/gfp.h~mm-add-alloc_pages_exact-and-free_pages_exact include/linux/gfp.h
--- a/include/linux/gfp.h~mm-add-alloc_pages_exact-and-free_pages_exact
+++ a/include/linux/gfp.h
@@ -228,6 +228,9 @@ extern struct page *alloc_page_vma(gfp_t
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)
diff -puN mm/page_alloc.c~mm-add-alloc_pages_exact-and-free_pages_exact mm/page_alloc.c
--- a/mm/page_alloc.c~mm-add-alloc_pages_exact-and-free_pages_exact
+++ a/mm/page_alloc.c
@@ -1697,6 +1697,59 @@ void free_pages(unsigned long addr, unsi
EXPORT_SYMBOL(free_pages);
+/**
+ * alloc_pages_exact - allocate an exact number physically-contiguous pages.
+ * @size: the number of bytes to allocate
+ * @gfp_mask: GFP flags for the allocation
+ *
+ * This function is similar to alloc_pages(), except that it allocates the
+ * minimum number of pages to satisfy the request. alloc_pages() can only
+ * allocate memory in power-of-two pages.
+ *
+ * This function is also limited by MAX_ORDER.
+ *
+ * Memory allocated by this function must be released by free_pages_exact().
+ */
+void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
+{
+ unsigned int order = get_order(size);
+ unsigned long addr;
+
+ addr = __get_free_pages(gfp_mask, order);
+ if (addr) {
+ unsigned long alloc_end = addr + (PAGE_SIZE << order);
+ unsigned long used = addr + PAGE_ALIGN(size);
+
+ split_page(virt_to_page(addr), order);
+ while (used < alloc_end) {
+ free_page(used);
+ used += PAGE_SIZE;
+ }
+ }
+
+ return (void *)addr;
+}
+EXPORT_SYMBOL(alloc_pages_exact);
+
+/**
+ * free_pages_exact - release memory allocated via alloc_pages_exact()
+ * @virt: the value returned by alloc_pages_exact.
+ * @size: size of allocation, same value as passed to alloc_pages_exact().
+ *
+ * Release the memory allocated by a previous call to alloc_pages_exact.
+ */
+void free_pages_exact(void *virt, size_t size)
+{
+ unsigned long addr = (unsigned long)virt;
+ unsigned long end = addr + PAGE_ALIGN(size);
+
+ while (addr < end) {
+ free_page(addr);
+ addr += PAGE_SIZE;
+ }
+}
+EXPORT_SYMBOL(free_pages_exact);
+
static unsigned int nr_free_zone_pages(int offset)
{
struct zoneref *z;
_
Patches currently in -mm which might be from timur@xxxxxxxxxxxxx are
origin.patch
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