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btrfs: switch extent_state state to unsigned

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Currently there's a 4B hole in the structure between refs and state and there
are only 16 bits used so we can make it unsigned. This will get a better
packing and may save some stack space for local variables.

The size of extent_state gets reduced by 8B and there are usually a lot
of slab objects.

struct extent_state {
	u64                        start;                /*     0     8 */
	u64                        end;                  /*     8     8 */
	struct rb_node             rb_node;              /*    16    24 */
	wait_queue_head_t          wq;                   /*    40    24 */
	/* --- cacheline 1 boundary (64 bytes) --- */
	atomic_t                   refs;                 /*    64     4 */

	/* XXX 4 bytes hole, try to pack */

	long unsigned int          state;                /*    72     8 */
	u64                        private;              /*    80     8 */

	/* size: 88, cachelines: 2, members: 7 */
	/* sum members: 84, holes: 1, sum holes: 4 */
	/* last cacheline: 24 bytes */
};

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
David Sterba
2015-01-14 19:52:13 +01:00
committed by Chris Mason
parent 5efa0490cc
commit 9ee49a047d
4 changed files with 55 additions and 55 deletions
Download Patch File Download Diff File Expand all files Collapse all files

58
fs/btrfs/extent_io.h
View File

@@ -4,22 +4,22 @@
#include <linux/rbtree.h>
/* bits for the extent state */
#define EXTENT_DIRTY 1
#define EXTENT_WRITEBACK (1 << 1)
#define EXTENT_UPTODATE (1 << 2)
#define EXTENT_LOCKED (1 << 3)
#define EXTENT_NEW (1 << 4)
#define EXTENT_DELALLOC (1 << 5)
#define EXTENT_DEFRAG (1 << 6)
#define EXTENT_BOUNDARY (1 << 9)
#define EXTENT_NODATASUM (1 << 10)
#define EXTENT_DO_ACCOUNTING (1 << 11)
#define EXTENT_FIRST_DELALLOC (1 << 12)
#define EXTENT_NEED_WAIT (1 << 13)
#define EXTENT_DAMAGED (1 << 14)
#define EXTENT_NORESERVE (1 << 15)
#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
#define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC)
#define EXTENT_DIRTY (1U << 0)
#define EXTENT_WRITEBACK (1U << 1)
#define EXTENT_UPTODATE (1U << 2)
#define EXTENT_LOCKED (1U << 3)
#define EXTENT_NEW (1U << 4)
#define EXTENT_DELALLOC (1U << 5)
#define EXTENT_DEFRAG (1U << 6)
#define EXTENT_BOUNDARY (1U << 9)
#define EXTENT_NODATASUM (1U << 10)
#define EXTENT_DO_ACCOUNTING (1U << 11)
#define EXTENT_FIRST_DELALLOC (1U << 12)
#define EXTENT_NEED_WAIT (1U << 13)
#define EXTENT_DAMAGED (1U << 14)
#define EXTENT_NORESERVE (1U << 15)
#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
#define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC)
/*
* flags for bio submission. The high bits indicate the compression
@@ -81,9 +81,9 @@ struct extent_io_ops {
int (*writepage_end_io_hook)(struct page *page, u64 start, u64 end,
struct extent_state *state, int uptodate);
void (*set_bit_hook)(struct inode *inode, struct extent_state *state,
unsigned long *bits);
unsigned *bits);
void (*clear_bit_hook)(struct inode *inode, struct extent_state *state,
unsigned long *bits);
unsigned *bits);
void (*merge_extent_hook)(struct inode *inode,
struct extent_state *new,
struct extent_state *other);
@@ -108,7 +108,7 @@ struct extent_state {
/* ADD NEW ELEMENTS AFTER THIS */
wait_queue_head_t wq;
atomic_t refs;
unsigned long state;
unsigned state;
/* for use by the FS */
u64 private;
@@ -188,7 +188,7 @@ int try_release_extent_mapping(struct extent_map_tree *map,
int try_release_extent_buffer(struct page *page);
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end);
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, struct extent_state **cached);
unsigned bits, struct extent_state **cached);
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end);
int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached, gfp_t mask);
@@ -202,21 +202,21 @@ void extent_io_exit(void);
u64 count_range_bits(struct extent_io_tree *tree,
u64 *start, u64 search_end,
u64 max_bytes, unsigned long bits, int contig);
u64 max_bytes, unsigned bits, int contig);
void free_extent_state(struct extent_state *state);
int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, int filled,
unsigned bits, int filled,
struct extent_state *cached_state);
int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, gfp_t mask);
unsigned bits, gfp_t mask);
int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, int wake, int delete,
unsigned bits, int wake, int delete,
struct extent_state **cached, gfp_t mask);
int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, gfp_t mask);
unsigned bits, gfp_t mask);
int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, u64 *failed_start,
unsigned bits, u64 *failed_start,
struct extent_state **cached_state, gfp_t mask);
int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached_state, gfp_t mask);
@@ -229,14 +229,14 @@ int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
gfp_t mask);
int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, unsigned long clear_bits,
unsigned bits, unsigned clear_bits,
struct extent_state **cached_state, gfp_t mask);
int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached_state, gfp_t mask);
int set_extent_defrag(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached_state, gfp_t mask);
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, unsigned long bits,
u64 *start_ret, u64 *end_ret, unsigned bits,
struct extent_state **cached_state);
int extent_invalidatepage(struct extent_io_tree *tree,
struct page *page, unsigned long offset);
@@ -323,7 +323,7 @@ int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
int extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end);
int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
struct page *locked_page,
unsigned long bits_to_clear,
unsigned bits_to_clear,
unsigned long page_ops);
struct bio *
btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,