linux/fs/btrfs/compression.h
Qu Wenruo 9150724048 btrfs: determine stripe boundary at bio allocation time in btrfs_submit_compressed_write
Currently btrfs_submit_compressed_write() will check
btrfs_bio_fits_in_stripe() each time a new page is going to be added.
Even if compressed extent is small, we don't really need to do that for
every page.

Align the behavior to extent_io.c, by determining the stripe boundary
when allocating a bio.

Unlike extent_io.c, in compressed.c we don't need to bother things like
different bio flags, thus no need to re-use bio_ctrl.

Here we just manually introduce new local variable, next_stripe_start,
and use that value returned from alloc_compressed_bio() to calculate
the stripe boundary.

Then each time we add some page range into the bio, we check if we
reached the boundary.  And if reached, submit it.

Also, since we have @cur_disk_bytenr to determine whether we're the last
bio, we don't need a explicit last_bio: tag for error handling any more.

And since we use @cur_disk_bytenr to wait, there is no need for
pending_bios, also remove it to save some memory of compressed_bio.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-10-26 19:08:04 +02:00

182 lines
6.0 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2008 Oracle. All rights reserved.
*/
#ifndef BTRFS_COMPRESSION_H
#define BTRFS_COMPRESSION_H
#include <linux/sizes.h>
struct btrfs_inode;
/*
* We want to make sure that amount of RAM required to uncompress an extent is
* reasonable, so we limit the total size in ram of a compressed extent to
* 128k. This is a crucial number because it also controls how easily we can
* spread reads across cpus for decompression.
*
* We also want to make sure the amount of IO required to do a random read is
* reasonably small, so we limit the size of a compressed extent to 128k.
*/
/* Maximum length of compressed data stored on disk */
#define BTRFS_MAX_COMPRESSED (SZ_128K)
/* Maximum size of data before compression */
#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
#define BTRFS_ZLIB_DEFAULT_LEVEL 3
struct compressed_bio {
/* Number of sectors with unfinished IO (unsubmitted or unfinished) */
refcount_t pending_sectors;
/* Number of compressed pages in the array */
unsigned int nr_pages;
/* the pages with the compressed data on them */
struct page **compressed_pages;
/* inode that owns this data */
struct inode *inode;
/* starting offset in the inode for our pages */
u64 start;
/* Number of bytes in the inode we're working on */
unsigned int len;
/* Number of bytes on disk */
unsigned int compressed_len;
/* The compression algorithm for this bio */
u8 compress_type;
/* IO errors */
u8 errors;
int mirror_num;
/* for reads, this is the bio we are copying the data into */
struct bio *orig_bio;
/*
* the start of a variable length array of checksums only
* used by reads
*/
u8 sums[];
};
static inline unsigned int btrfs_compress_type(unsigned int type_level)
{
return (type_level & 0xF);
}
static inline unsigned int btrfs_compress_level(unsigned int type_level)
{
return ((type_level & 0xF0) >> 4);
}
void __init btrfs_init_compress(void);
void __cold btrfs_exit_compress(void);
int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
u64 start, struct page **pages,
unsigned long *out_pages,
unsigned long *total_in,
unsigned long *total_out);
int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
unsigned long start_byte, size_t srclen, size_t destlen);
int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
struct compressed_bio *cb, u32 decompressed);
blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
unsigned int len, u64 disk_start,
unsigned int compressed_len,
struct page **compressed_pages,
unsigned int nr_pages,
unsigned int write_flags,
struct cgroup_subsys_state *blkcg_css);
blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
int mirror_num, unsigned long bio_flags);
unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
enum btrfs_compression_type {
BTRFS_COMPRESS_NONE = 0,
BTRFS_COMPRESS_ZLIB = 1,
BTRFS_COMPRESS_LZO = 2,
BTRFS_COMPRESS_ZSTD = 3,
BTRFS_NR_COMPRESS_TYPES = 4,
};
struct workspace_manager {
struct list_head idle_ws;
spinlock_t ws_lock;
/* Number of free workspaces */
int free_ws;
/* Total number of allocated workspaces */
atomic_t total_ws;
/* Waiters for a free workspace */
wait_queue_head_t ws_wait;
};
struct list_head *btrfs_get_workspace(int type, unsigned int level);
void btrfs_put_workspace(int type, struct list_head *ws);
struct btrfs_compress_op {
struct workspace_manager *workspace_manager;
/* Maximum level supported by the compression algorithm */
unsigned int max_level;
unsigned int default_level;
};
/* The heuristic workspaces are managed via the 0th workspace manager */
#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
extern const struct btrfs_compress_op btrfs_heuristic_compress;
extern const struct btrfs_compress_op btrfs_zlib_compress;
extern const struct btrfs_compress_op btrfs_lzo_compress;
extern const struct btrfs_compress_op btrfs_zstd_compress;
const char* btrfs_compress_type2str(enum btrfs_compression_type type);
bool btrfs_compress_is_valid_type(const char *str, size_t len);
int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
u64 start, struct page **pages, unsigned long *out_pages,
unsigned long *total_in, unsigned long *total_out);
int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
int zlib_decompress(struct list_head *ws, unsigned char *data_in,
struct page *dest_page, unsigned long start_byte, size_t srclen,
size_t destlen);
struct list_head *zlib_alloc_workspace(unsigned int level);
void zlib_free_workspace(struct list_head *ws);
struct list_head *zlib_get_workspace(unsigned int level);
int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
u64 start, struct page **pages, unsigned long *out_pages,
unsigned long *total_in, unsigned long *total_out);
int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
int lzo_decompress(struct list_head *ws, unsigned char *data_in,
struct page *dest_page, unsigned long start_byte, size_t srclen,
size_t destlen);
struct list_head *lzo_alloc_workspace(unsigned int level);
void lzo_free_workspace(struct list_head *ws);
int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
u64 start, struct page **pages, unsigned long *out_pages,
unsigned long *total_in, unsigned long *total_out);
int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
int zstd_decompress(struct list_head *ws, unsigned char *data_in,
struct page *dest_page, unsigned long start_byte, size_t srclen,
size_t destlen);
void zstd_init_workspace_manager(void);
void zstd_cleanup_workspace_manager(void);
struct list_head *zstd_alloc_workspace(unsigned int level);
void zstd_free_workspace(struct list_head *ws);
struct list_head *zstd_get_workspace(unsigned int level);
void zstd_put_workspace(struct list_head *ws);
#endif