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>
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 324329c..73b4522 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -175,12 +175,13 @@
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 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 @@
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 @@
__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 */