btrfs-progs/extent_io.h
David Sterba 944974b485 btrfs-progs: reorder extent buffer members for better packing
Afther the fs_info was added, the size was over 128 bytes but we still
have 8 bytes of holes, so with minor reordering we get back to that size.

Before:

struct extent_buffer {
        struct cache_extent        cache_node;           /*     0    48 */
        u64                        start;                /*    48     8 */
        u64                        dev_bytenr;           /*    56     8 */
        /* --- cacheline 1 boundary (64 bytes) --- */
        u32                        len;                  /*    64     4 */

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

        struct extent_io_tree *    tree;                 /*    72     8 */
        struct list_head           lru;                  /*    80    16 */
        struct list_head           recow;                /*    96    16 */
        int                        refs;                 /*   112     4 */
        u32                        flags;                /*   116     4 */
        int                        fd;                   /*   120     4 */

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

        /* --- cacheline 2 boundary (128 bytes) --- */
        struct btrfs_fs_info *     fs_info;              /*   128     8 */
        char                       data[0];              /*   136     0 */

        /* size: 136, cachelines: 3, members: 12 */
        /* sum members: 128, holes: 2, sum holes: 8 */
        /* last cacheline: 8 bytes */
};

After:

struct extent_buffer {
        struct cache_extent        cache_node;           /*     0    48 */
        u64                        start;                /*    48     8 */
        u64                        dev_bytenr;           /*    56     8 */
        /* --- cacheline 1 boundary (64 bytes) --- */
        struct extent_io_tree *    tree;                 /*    64     8 */
        struct list_head           lru;                  /*    72    16 */
        struct list_head           recow;                /*    88    16 */
        u32                        len;                  /*   104     4 */
        int                        refs;                 /*   108     4 */
        u32                        flags;                /*   112     4 */
        int                        fd;                   /*   116     4 */
        struct btrfs_fs_info *     fs_info;              /*   120     8 */
        /* --- cacheline 2 boundary (128 bytes) --- */
        char                       data[0];              /*   128     0 */

        /* size: 128, cachelines: 2, members: 12 */
};

Signed-off-by: David Sterba <dsterba@suse.com>
2018-04-24 13:00:12 +02:00

179 lines
5.9 KiB
C

/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#ifndef __BTRFS_EXTENT_IO_H__
#define __BTRFS_EXTENT_IO_H__
#if BTRFS_FLAT_INCLUDES
#include "kerncompat.h"
#include "extent-cache.h"
#include "list.h"
#else
#include <btrfs/kerncompat.h>
#include <btrfs/extent-cache.h>
#include <btrfs/list.h>
#endif /* BTRFS_FLAT_INCLUDES */
#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_DEFRAG_DONE (1U << 7)
#define EXTENT_BUFFER_FILLED (1U << 8)
#define EXTENT_CSUM (1U << 9)
#define EXTENT_BAD_TRANSID (1U << 10)
#define EXTENT_BUFFER_DUMMY (1U << 11)
#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
#define BLOCK_GROUP_DATA (1U << 1)
#define BLOCK_GROUP_METADATA (1U << 2)
#define BLOCK_GROUP_SYSTEM (1U << 4)
#define BLOCK_GROUP_DIRTY (1U)
/*
* The extent buffer bitmap operations are done with byte granularity instead of
* word granularity for two reasons:
* 1. The bitmaps must be little-endian on disk.
* 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
* single word in a bitmap may straddle two pages in the extent buffer.
*/
#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
#define BYTE_MASK ((1 << BITS_PER_BYTE) - 1)
#define BITMAP_FIRST_BYTE_MASK(start) \
((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
#define BITMAP_LAST_BYTE_MASK(nbits) \
(BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))
static inline int le_test_bit(int nr, const u8 *addr)
{
return 1U & (addr[BIT_BYTE(nr)] >> (nr & (BITS_PER_BYTE-1)));
}
struct btrfs_fs_info;
struct extent_io_tree {
struct cache_tree state;
struct cache_tree cache;
struct list_head lru;
u64 cache_size;
u64 max_cache_size;
};
struct extent_state {
struct cache_extent cache_node;
u64 start;
u64 end;
int refs;
unsigned long state;
u64 xprivate;
};
struct extent_buffer {
struct cache_extent cache_node;
u64 start;
u64 dev_bytenr;
struct extent_io_tree *tree;
struct list_head lru;
struct list_head recow;
u32 len;
int refs;
u32 flags;
int fd;
struct btrfs_fs_info *fs_info;
char data[] __attribute__((aligned(8)));
};
static inline void extent_buffer_get(struct extent_buffer *eb)
{
eb->refs++;
}
void extent_io_tree_init(struct extent_io_tree *tree);
void extent_io_tree_init_cache_max(struct extent_io_tree *tree,
u64 max_cache_size);
void extent_io_tree_cleanup(struct extent_io_tree *tree);
int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, int bits);
int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, int bits);
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, int bits);
int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
int bits, int filled);
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);
static inline int set_extent_buffer_uptodate(struct extent_buffer *eb)
{
eb->flags |= EXTENT_UPTODATE;
return 0;
}
static inline int clear_extent_buffer_uptodate(struct extent_buffer *eb)
{
eb->flags &= ~EXTENT_UPTODATE;
return 0;
}
static inline int extent_buffer_uptodate(struct extent_buffer *eb)
{
if (!eb || IS_ERR(eb))
return 0;
if (eb->flags & EXTENT_UPTODATE)
return 1;
return 0;
}
int set_state_private(struct extent_io_tree *tree, u64 start, u64 xprivate);
int get_state_private(struct extent_io_tree *tree, u64 start, u64 *xprivate);
struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
u64 bytenr, u32 blocksize);
struct extent_buffer *find_first_extent_buffer(struct extent_io_tree *tree,
u64 start);
struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
u64 bytenr, u32 blocksize);
struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src);
void free_extent_buffer(struct extent_buffer *eb);
void free_extent_buffer_nocache(struct extent_buffer *eb);
int read_extent_from_disk(struct extent_buffer *eb,
unsigned long offset, unsigned long len);
int write_extent_to_disk(struct extent_buffer *eb);
int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
unsigned long start, unsigned long len);
void read_extent_buffer(struct extent_buffer *eb, void *dst,
unsigned long start, unsigned long len);
void write_extent_buffer(struct extent_buffer *eb, const void *src,
unsigned long start, unsigned long len);
void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
unsigned long dst_offset, unsigned long src_offset,
unsigned long len);
void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
unsigned long src_offset, unsigned long len);
void memset_extent_buffer(struct extent_buffer *eb, char c,
unsigned long start, unsigned long len);
int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
unsigned long nr);
int set_extent_buffer_dirty(struct extent_buffer *eb);
int clear_extent_buffer_dirty(struct extent_buffer *eb);
int read_data_from_disk(struct btrfs_fs_info *info, void *buf, u64 offset,
u64 bytes, int mirror);
int write_data_to_disk(struct btrfs_fs_info *info, void *buf, u64 offset,
u64 bytes, int mirror);
#endif