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| author | Gao Xiang <hsiangkao@linux.alibaba.com> | 2021-10-11 00:31:45 +0300 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2021-10-19 18:44:30 +0300 |
| commit | 622ceaddb7649ca328832f50ba1400af778d75fa (patch) | |
| tree | 6e6a3db1cff711620944b9e283c2bd5f4dbd6171 /fs/erofs/compress.h | |
| parent | 966edfb0a3dc2adf5aab461c298fa0feb02f49d6 (diff) | |
| download | linux-622ceaddb7649ca328832f50ba1400af778d75fa.tar.xz | |
erofs: lzma compression support
Add MicroLZMA support in order to maximize compression ratios for
specific scenarios. For example, it's useful for low-end embedded
boards and as a secondary algorithm in a file for specific access
patterns.
MicroLZMA is a new container format for raw LZMA1, which was created
by Lasse Collin aiming to minimize old LZMA headers and get rid of
unnecessary EOPM (end of payload marker) as well as to enable
fixed-sized output compression, especially for 4KiB pclusters.
Similar to LZ4, inplace I/O approach is used to minimize runtime
memory footprint when dealing with I/O. Overlapped decompression is
handled with 1) bounced buffer for data under processing or 2) extra
short-lived pages from the on-stack pagepool which will be shared in
the same read request (128KiB for example).
Link: https://lore.kernel.org/r/20211010213145.17462-8-xiang@kernel.org
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs/compress.h')
| -rw-r--r-- | fs/erofs/compress.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h index ad62d1b4d371..8ea6a9b14962 100644 --- a/fs/erofs/compress.h +++ b/fs/erofs/compress.h @@ -20,6 +20,12 @@ struct z_erofs_decompress_req { bool inplace_io, partial_decoding; }; +struct z_erofs_decompressor { + int (*decompress)(struct z_erofs_decompress_req *rq, + struct list_head *pagepool); + char *name; +}; + /* some special page->private (unsigned long, see below) */ #define Z_EROFS_SHORTLIVED_PAGE (-1UL << 2) #define Z_EROFS_PREALLOCATED_PAGE (-2UL << 2) @@ -75,7 +81,17 @@ static inline bool z_erofs_put_shortlivedpage(struct list_head *pagepool, return true; } +#define MNGD_MAPPING(sbi) ((sbi)->managed_cache->i_mapping) +static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi, + struct page *page) +{ + return page->mapping == MNGD_MAPPING(sbi); +} + int z_erofs_decompress(struct z_erofs_decompress_req *rq, struct list_head *pagepool); +/* prototypes for specific algorithms */ +int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, + struct list_head *pagepool); #endif |