[PATCH 5/5] Mark page cache pages as __GFP_PAGECACHE instead of __GFP_MOVABLE

[Mel Gorman]

This patch marks page cache allocations as __GFP_PAGECACHE instead of
__GFP_MOVABLE. To make code easier to read, a set of three GFP flags are
added called GFP_PAGECACHE, GFP_NOFS_PAGECACHE and GFP_HIGHUSER_PAGECACHE.

grow_dev_page() is changed to use GFP_NOFS_PAGECACHE instead of
__GFP_RECLAIMABLE. Marking them as __GFP_RECLAIMABLE was a mistake as
they should be grouped with other pagecache pages. bdget() no longer uses
mobility flags after this patch because it is does not appear that any pages
allocated on behalf of the mapping are movable so it needs to be revisited
separately. The allocations required for radix trees are still treated as
RECLAIMABLE after this patch is applied.

Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Acked-by: Andy Whitcroft <apw@xxxxxxxxxxxx>
Acked-by: Christoph Lameter <clameter@xxxxxxx>
---

 fs/block_dev.c      |    2 +-
 fs/buffer.c         |    2 +-
 fs/inode.c          |    4 ++--
 include/linux/gfp.h |    6 ++++++
 4 files changed, 10 insertions(+), 4 deletions(-)

diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.22-rc1-mm1-025_gfphighuser/fs/block_dev.c linux-2.6.22-rc1-mm1-030_pagecache_mark/fs/block_dev.c
--- linux-2.6.22-rc1-mm1-025_gfphighuser/fs/block_dev.c	2007-05-16 10:54:18.000000000 +0100
+++ linux-2.6.22-rc1-mm1-030_pagecache_mark/fs/block_dev.c	2007-05-16 23:07:30.000000000 +0100
@@ -576,7 +576,7 @@ struct block_device *bdget(dev_t dev)
 		inode->i_rdev = dev;
 		inode->i_bdev = bdev;
 		inode->i_data.a_ops = &def_blk_aops;
-		mapping_set_gfp_mask(&inode->i_data, GFP_USER|__GFP_MOVABLE);
+		mapping_set_gfp_mask(&inode->i_data, GFP_USER);
 		inode->i_data.backing_dev_info = &default_backing_dev_info;
 		spin_lock(&bdev_lock);
 		list_add(&bdev->bd_list, &all_bdevs);
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.22-rc1-mm1-025_gfphighuser/fs/buffer.c linux-2.6.22-rc1-mm1-030_pagecache_mark/fs/buffer.c
--- linux-2.6.22-rc1-mm1-025_gfphighuser/fs/buffer.c	2007-05-16 22:55:50.000000000 +0100
+++ linux-2.6.22-rc1-mm1-030_pagecache_mark/fs/buffer.c	2007-05-16 23:07:30.000000000 +0100
@@ -1009,7 +1009,7 @@ grow_dev_page(struct block_device *bdev,
 	struct buffer_head *bh;
 
 	page = find_or_create_page(inode->i_mapping, index,
-					GFP_NOFS|__GFP_RECLAIMABLE);
+					GFP_NOFS_PAGECACHE);
 	if (!page)
 		return NULL;
 
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.22-rc1-mm1-025_gfphighuser/fs/inode.c linux-2.6.22-rc1-mm1-030_pagecache_mark/fs/inode.c
--- linux-2.6.22-rc1-mm1-025_gfphighuser/fs/inode.c	2007-05-16 23:05:45.000000000 +0100
+++ linux-2.6.22-rc1-mm1-030_pagecache_mark/fs/inode.c	2007-05-16 23:07:30.000000000 +0100
@@ -154,7 +154,7 @@ static struct inode *alloc_inode(struct 
 		mapping->a_ops = &empty_aops;
  		mapping->host = inode;
 		mapping->flags = 0;
-		mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
+		mapping_set_gfp_mask(mapping, GFP_HIGHUSER_PAGECACHE);
 		mapping->assoc_mapping = NULL;
 		mapping->backing_dev_info = &default_backing_dev_info;
 
@@ -535,7 +535,7 @@ repeat:
  *	@sb: superblock
  *
  *	Allocates a new inode for given superblock. The default gfp_mask
- *	for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
+ *	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
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.22-rc1-mm1-025_gfphighuser/include/linux/gfp.h linux-2.6.22-rc1-mm1-030_pagecache_mark/include/linux/gfp.h
--- linux-2.6.22-rc1-mm1-025_gfphighuser/include/linux/gfp.h	2007-05-16 23:05:45.000000000 +0100
+++ linux-2.6.22-rc1-mm1-030_pagecache_mark/include/linux/gfp.h	2007-05-16 23:07:30.000000000 +0100
@@ -79,6 +79,12 @@ struct vm_area_struct;
 #define GFP_HIGHUSER_MOVABLE	(__GFP_WAIT | __GFP_IO | __GFP_FS | \
 				 __GFP_HARDWALL | __GFP_HIGHMEM | \
 				 __GFP_MOVABLE)
+#define GFP_NOFS_PAGECACHE	(__GFP_WAIT | __GFP_IO | __GFP_MOVABLE)
+#define GFP_USER_PAGECACHE	(__GFP_WAIT | __GFP_IO | __GFP_FS | \
+				 __GFP_HARDWALL | __GFP_MOVABLE)
+#define GFP_HIGHUSER_PAGECACHE	(__GFP_WAIT | __GFP_IO | __GFP_FS | \
+				 __GFP_HARDWALL | __GFP_HIGHMEM | \
+				 __GFP_MOVABLE)
 
 #ifdef CONFIG_NUMA
 #define GFP_THISNODE	(__GFP_THISNODE | __GFP_NOWARN | __GFP_NORETRY)
-
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