Commit 769848c0 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
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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: default avatarMel Gorman <mel@csn.ul.ie>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a32ea1e1

fs/buffer.c

+1 −1
Original line number Diff line number Diff line
@@ -982,7 +982,7 @@ grow_dev_page(struct block_device *bdev, sector_t block, 
	struct buffer_head *bh;



	page = find_or_create_page(inode->i_mapping, index,

		mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);

		(mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE);

	if (!page)

		return NULL;

fs/inode.c

+8 −2
Original line number Diff line number Diff line
@@ -145,7 +145,7 @@ static struct inode *alloc_inode(struct super_block *sb) 
		mapping->a_ops = &empty_aops;

 		mapping->host = inode;

		mapping->flags = 0;

		mapping_set_gfp_mask(mapping, GFP_HIGHUSER);

		mapping_set_gfp_mask(mapping, GFP_HIGHUSER_PAGECACHE);

		mapping->assoc_mapping = NULL;

		mapping->backing_dev_info = &default_backing_dev_info;
@@ -519,7 +519,13 @@ repeat: 
 *	new_inode 	- obtain an inode

 *	@sb: superblock

 *

 *	Allocates a new inode for given superblock.

 *	Allocates a new inode for given superblock. The default gfp_mask

 *	for allocations related to inode->i_mapping is GFP_HIGHUSER_PAGECACHE.

 *	If HIGHMEM pages are unsuitable or it is known that pages allocated

 *	for the page cache are not reclaimable or migratable,

 *	mapping_set_gfp_mask() must be called with suitable flags on the

 *	newly created inode's mapping

 *

 */

struct inode *new_inode(struct super_block *sb)

{

fs/ramfs/inode.c

+1 −0
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ struct inode *ramfs_get_inode(struct super_block *sb, int mode, dev_t dev) 
		inode->i_blocks = 0;

		inode->i_mapping->a_ops = &ramfs_aops;

		inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info;

		mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);

		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;

		switch (mode & S_IFMT) {

		default:

include/asm-alpha/page.h

+2 −1
Original line number Diff line number Diff line
@@ -17,7 +17,8 @@ 
extern void clear_page(void *page);

#define clear_user_page(page, vaddr, pg)	clear_page(page)



#define alloc_zeroed_user_highpage(vma, vaddr) alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO, vma, vmaddr)

#define __alloc_zeroed_user_highpage(movableflags, vma, vaddr) \

	alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vmaddr)

#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE



extern void copy_page(void * _to, void * _from);

include/asm-cris/page.h

+2 −1
Original line number Diff line number Diff line
@@ -20,7 +20,8 @@ 
#define clear_user_page(page, vaddr, pg)    clear_page(page)

#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)



#define alloc_zeroed_user_highpage(vma, vaddr) alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO, vma, vaddr)

#define __alloc_zeroed_user_highpage(movableflags, vma, vaddr) \

	alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vaddr)

#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE



/*

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