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authorMel Gorman <mel@csn.ul.ie>2007-07-17 04:03:05 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-17 10:22:59 -0700
commit769848c03895b63e5662eb7e4ec8c4866f7d0183 (patch)
tree8911c7c312c8b8b172795fa2874c8162e1d3d15a /include/linux/highmem.h
parenta32ea1e1f925399e0d81ca3f7394a44a6dafa12c (diff)
downloadop-kernel-dev-769848c03895b63e5662eb7e4ec8c4866f7d0183.zip
op-kernel-dev-769848c03895b63e5662eb7e4ec8c4866f7d0183.tar.gz
Add __GFP_MOVABLE for callers to flag allocations from high memory that may be migrated
It is often known at allocation time whether a page may be migrated or not. This patch adds a flag called __GFP_MOVABLE and a new mask called GFP_HIGH_MOVABLE. Allocations using the __GFP_MOVABLE can be either migrated using the page migration mechanism or reclaimed by syncing with backing storage and discarding. An API function very similar to alloc_zeroed_user_highpage() is added for __GFP_MOVABLE allocations called alloc_zeroed_user_highpage_movable(). The flags used by alloc_zeroed_user_highpage() are not changed because it would change the semantics of an existing API. After this patch is applied there are no in-kernel users of alloc_zeroed_user_highpage() so it probably should be marked deprecated if this patch is merged. Note that this patch includes a minor cleanup to the use of __GFP_ZERO in shmem.c to keep all flag modifications to inode->mapping in the shmem_dir_alloc() helper function. This clean-up suggestion is courtesy of Hugh Dickens. Additional credit goes to Christoph Lameter and Linus Torvalds for shaping the concept. Credit to Hugh Dickens for catching issues with shmem swap vector and ramfs allocations. [akpm@linux-foundation.org: build fix] [hugh@veritas.com: __GFP_ZERO cleanup] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/highmem.h')
-rw-r--r--include/linux/highmem.h51
1 files changed, 49 insertions, 2 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 98e2cce..12c5e4e 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -73,10 +73,27 @@ static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
}
#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
+/**
+ * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
+ * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
+ * @vma: The VMA the page is to be allocated for
+ * @vaddr: The virtual address the page will be inserted into
+ *
+ * This function will allocate a page for a VMA but the caller is expected
+ * to specify via movableflags whether the page will be movable in the
+ * future or not
+ *
+ * An architecture may override this function by defining
+ * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
+ * implementation.
+ */
static inline struct page *
-alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
+__alloc_zeroed_user_highpage(gfp_t movableflags,
+ struct vm_area_struct *vma,
+ unsigned long vaddr)
{
- struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
+ struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
+ vma, vaddr);
if (page)
clear_user_highpage(page, vaddr);
@@ -85,6 +102,36 @@ alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
}
#endif
+/**
+ * alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA
+ * @vma: The VMA the page is to be allocated for
+ * @vaddr: The virtual address the page will be inserted into
+ *
+ * This function will allocate a page for a VMA that the caller knows will
+ * not be able to move in the future using move_pages() or reclaim. If it
+ * is known that the page can move, use alloc_zeroed_user_highpage_movable
+ */
+static inline struct page *
+alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
+{
+ return __alloc_zeroed_user_highpage(0, vma, vaddr);
+}
+
+/**
+ * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
+ * @vma: The VMA the page is to be allocated for
+ * @vaddr: The virtual address the page will be inserted into
+ *
+ * This function will allocate a page for a VMA that the caller knows will
+ * be able to migrate in the future using move_pages() or reclaimed
+ */
+static inline struct page *
+alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
+ unsigned long vaddr)
+{
+ return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
+}
+
static inline void clear_highpage(struct page *page)
{
void *kaddr = kmap_atomic(page, KM_USER0);
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