fs/buffer.c: support buffer cache allocations with gfp modifiers

A buffer cache is allocated from movable area because it is referred
for a while and released soon.  But some filesystems are taking buffer
cache for a long time and it can disturb page migration.

New APIs are introduced to allocate buffer cache with user specific
flag.  *_gfp APIs are for user want to set page allocation flag for
page cache allocation.  And *_unmovable APIs are for the user wants to
allocate page cache from non-movable area.

Signed-off-by: Gioh Kim <gioh.kim@lge.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Gioh Kim 2014-09-04 22:04:42 -04:00 committed by Theodore Ts'o
parent d26e2c4d72
commit 3b5e6454aa
2 changed files with 68 additions and 24 deletions

View file

@ -175,12 +175,13 @@ void __wait_on_buffer(struct buffer_head *);
wait_queue_head_t *bh_waitq_head(struct buffer_head *bh);
struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block,
unsigned size);
struct buffer_head *__getblk(struct block_device *bdev, sector_t block,
unsigned size);
struct buffer_head *__getblk_gfp(struct block_device *bdev, sector_t block,
unsigned size, gfp_t gfp);
void __brelse(struct buffer_head *);
void __bforget(struct buffer_head *);
void __breadahead(struct block_device *, sector_t block, unsigned int size);
struct buffer_head *__bread(struct block_device *, sector_t block, unsigned size);
struct buffer_head *__bread_gfp(struct block_device *,
sector_t block, unsigned size, gfp_t gfp);
void invalidate_bh_lrus(void);
struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
void free_buffer_head(struct buffer_head * bh);
@ -295,7 +296,13 @@ static inline void bforget(struct buffer_head *bh)
static inline struct buffer_head *
sb_bread(struct super_block *sb, sector_t block)
{
return __bread(sb->s_bdev, block, sb->s_blocksize);
return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
}
static inline struct buffer_head *
sb_bread_unmovable(struct super_block *sb, sector_t block)
{
return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, 0);
}
static inline void
@ -307,7 +314,7 @@ sb_breadahead(struct super_block *sb, sector_t block)
static inline struct buffer_head *
sb_getblk(struct super_block *sb, sector_t block)
{
return __getblk(sb->s_bdev, block, sb->s_blocksize);
return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
}
static inline struct buffer_head *
@ -344,6 +351,36 @@ static inline void lock_buffer(struct buffer_head *bh)
__lock_buffer(bh);
}
static inline struct buffer_head *getblk_unmovable(struct block_device *bdev,
sector_t block,
unsigned size)
{
return __getblk_gfp(bdev, block, size, 0);
}
static inline struct buffer_head *__getblk(struct block_device *bdev,
sector_t block,
unsigned size)
{
return __getblk_gfp(bdev, block, size, __GFP_MOVABLE);
}
/**
* __bread() - reads a specified block and returns the bh
* @bdev: the block_device to read from
* @block: number of block
* @size: size (in bytes) to read
*
* Reads a specified block, and returns buffer head that contains it.
* The page cache is allocated from movable area so that it can be migrated.
* It returns NULL if the block was unreadable.
*/
static inline struct buffer_head *
__bread(struct block_device *bdev, sector_t block, unsigned size)
{
return __bread_gfp(bdev, block, size, __GFP_MOVABLE);
}
extern int __set_page_dirty_buffers(struct page *page);
#else /* CONFIG_BLOCK */