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| author | Huang Jianan <huangjianan@oppo.com> | 2021-03-29 04:23:06 +0300 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@redhat.com> | 2021-03-29 05:24:58 +0300 |
| commit | 5d50538fc567c6f3692dec1825fb38c5a0884d93 (patch) | |
| tree | 93389d04bec73677d08776d3306b8288949d192e /fs/erofs/internal.h | |
| parent | de06a6a375414be03ce5b1054f2d836591923a1d (diff) | |
| download | linux-5d50538fc567c6f3692dec1825fb38c5a0884d93.tar.xz | |
erofs: support adjust lz4 history window size
lz4 uses LZ4_DISTANCE_MAX to record history preservation. When
using rolling decompression, a block with a higher compression
ratio will cause a larger memory allocation (up to 64k). It may
cause a large resource burden in extreme cases on devices with
small memory and a large number of concurrent IOs. So appropriately
reducing this value can improve performance.
Decreasing this value will reduce the compression ratio (except
when input_size <LZ4_DISTANCE_MAX). But considering that erofs
currently only supports 4k output, reducing this value will not
significantly reduce the compression benefits.
The maximum value of LZ4_DISTANCE_MAX defined by lz4 is 64k, and
we can only reduce this value. For the old kernel, it just can't
reduce the memory allocation during rolling decompression without
affecting the decompression result.
Link: https://lore.kernel.org/r/20210329012308.28743-3-hsiangkao@aol.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Guo Weichao <guoweichao@oppo.com>
[ Gao Xiang: introduce struct erofs_sb_lz4_info for configurations. ]
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Diffstat (limited to 'fs/erofs/internal.h')
| -rw-r--r-- | fs/erofs/internal.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index a148a039cf67..875b2ebf2af9 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -59,6 +59,12 @@ struct erofs_fs_context { unsigned int mount_opt; }; +/* all filesystem-wide lz4 configurations */ +struct erofs_sb_lz4_info { + /* # of pages needed for EROFS lz4 rolling decompression */ + u16 max_distance_pages; +}; + struct erofs_sb_info { #ifdef CONFIG_EROFS_FS_ZIP /* list for all registered superblocks, mainly for shrinker */ @@ -72,6 +78,8 @@ struct erofs_sb_info { /* pseudo inode to manage cached pages */ struct inode *managed_cache; + + struct erofs_sb_lz4_info lz4; #endif /* CONFIG_EROFS_FS_ZIP */ u32 blocks; u32 meta_blkaddr; @@ -430,6 +438,8 @@ int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi, struct erofs_workgroup *egrp); int erofs_try_to_free_cached_page(struct address_space *mapping, struct page *page); +int z_erofs_load_lz4_config(struct super_block *sb, + struct erofs_super_block *dsb); #else static inline void erofs_shrinker_register(struct super_block *sb) {} static inline void erofs_shrinker_unregister(struct super_block *sb) {} @@ -437,6 +447,15 @@ static inline int erofs_init_shrinker(void) { return 0; } static inline void erofs_exit_shrinker(void) {} static inline int z_erofs_init_zip_subsystem(void) { return 0; } static inline void z_erofs_exit_zip_subsystem(void) {} +static inline int z_erofs_load_lz4_config(struct super_block *sb, + struct erofs_super_block *dsb) +{ + if (dsb->lz4_max_distance) { + erofs_err(sb, "lz4 algorithm isn't enabled"); + return -EINVAL; + } + return 0; +} #endif /* !CONFIG_EROFS_FS_ZIP */ #define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */ |