The patch titled
Subject: zram: add dictionary support to lz4hc
has been added to the -mm mm-unstable branch. Its filename is
zram-add-dictionary-support-to-lz4hc.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-add-dictionary-support-to-lz4hc.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: zram: add dictionary support to lz4hc
Date: Wed, 15 May 2024 16:12:57 +0900
Support pre-trained dictionary param. Just like lz4, lz4hc doesn't
mandate specific format of the dictionary and zstd --train can be used to
train a dictionary for lz4, according to [1].
TEST
====
- default lz4hc
/sys/block/zram0/mm_stat
1750315008 609010918 621006848 0 621006848 2 0 34288 34288
- lz4hc dict=/etc/dictionary
/sys/block/zram0/mm_stat
1750319104 499629401 509485056 0 509485056 1 0 34288 34288
[1] https://github.com/lz4/lz4/issues/557
Link: https://lkml.kernel.org/r/20240515071645.1788128-21-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nick Terrell <terrelln@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/backend_lz4hc.c | 54 ++++++++++++++++++++++++---
1 file changed, 48 insertions(+), 6 deletions(-)
--- a/drivers/block/zram/backend_lz4hc.c~zram-add-dictionary-support-to-lz4hc
+++ a/drivers/block/zram/backend_lz4hc.c
@@ -8,6 +8,12 @@
struct lz4hc_ctx {
void *mem;
s32 level;
+ LZ4_streamDecode_t *dstrm;
+ LZ4_streamHC_t *cstrm;
+
+ /* Shared between C/D streams */
+ void *dict;
+ size_t dict_sz;
};
static int lz4hc_init_config(struct zcomp_config *config)
@@ -26,6 +32,8 @@ static void lz4hc_destroy(void *ctx)
{
struct lz4hc_ctx *zctx = ctx;
+ kfree(zctx->dstrm);
+ kfree(zctx->cstrm);
vfree(zctx->mem);
kfree(zctx);
}
@@ -39,9 +47,22 @@ static void *lz4hc_create(struct zcomp_c
return NULL;
ctx->level = config->level;
- ctx->mem = vmalloc(LZ4HC_MEM_COMPRESS);
- if (!ctx->mem)
- goto error;
+ if (!config->dict) {
+ ctx->mem = vmalloc(LZ4HC_MEM_COMPRESS);
+ if (!ctx->mem)
+ goto error;
+ } else {
+ ctx->dstrm = kzalloc(sizeof(*ctx->dstrm), GFP_KERNEL);
+ if (!ctx->dstrm)
+ goto error;
+
+ ctx->cstrm = kzalloc(sizeof(*ctx->cstrm), GFP_KERNEL);
+ if (!ctx->cstrm)
+ goto error;
+
+ ctx->dict = config->dict;
+ ctx->dict_sz = config->dict_sz;
+ }
return ctx;
error:
@@ -55,8 +76,18 @@ static int lz4hc_compress(void *ctx, con
struct lz4hc_ctx *zctx = ctx;
int ret;
- ret = LZ4_compress_HC(src, dst, PAGE_SIZE, *dst_len,
- zctx->level, zctx->mem);
+ if (!zctx->cstrm) {
+ ret = LZ4_compress_HC(src, dst, PAGE_SIZE, *dst_len,
+ zctx->level, zctx->mem);
+ } else {
+ /* Cstrm needs to be reset */
+ LZ4_resetStreamHC(zctx->cstrm, zctx->level);
+ ret = LZ4_loadDictHC(zctx->cstrm, zctx->dict, zctx->dict_sz);
+ if (ret != zctx->dict_sz)
+ return -EINVAL;
+ ret = LZ4_compress_HC_continue(zctx->cstrm, src, dst,
+ PAGE_SIZE, *dst_len);
+ }
if (!ret)
return -EINVAL;
*dst_len = ret;
@@ -66,10 +97,21 @@ static int lz4hc_compress(void *ctx, con
static int lz4hc_decompress(void *ctx, const unsigned char *src,
size_t src_len, unsigned char *dst)
{
+ struct lz4hc_ctx *zctx = ctx;
int dst_len = PAGE_SIZE;
int ret;
- ret = LZ4_decompress_safe(src, dst, src_len, dst_len);
+ if (!zctx->dstrm) {
+ ret = LZ4_decompress_safe(src, dst, src_len, dst_len);
+ } else {
+ /* Dstrm needs to be reset */
+ ret = LZ4_setStreamDecode(zctx->dstrm, zctx->dict,
+ zctx->dict_sz);
+ if (!ret)
+ return -EINVAL;
+ ret = LZ4_decompress_safe_continue(zctx->dstrm, src, dst,
+ src_len, dst_len);
+ }
if (ret < 0)
return -EINVAL;
return 0;
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
zram-move-from-crypto-api-to-custom-comp-backends-api.patch
zram-add-lzo-and-lzorle-compression-backends-support.patch
zram-add-lz4-compression-backend-support.patch
zram-add-lz4hc-compression-backend-support.patch
zram-add-zstd-compression-backend-support.patch
zram-pass-estimated-src-size-hint-to-zstd.patch
zram-add-zlib-compression-backend-support.patch
zram-add-842-compression-backend-support.patch
zram-check-that-backends-array-has-at-least-one-backend.patch
zram-introduce-zcomp_config-structure.patch
zram-extend-comp_algorithm-attr-write-handling.patch
zram-support-compression-level-comp-config.patch
zram-add-support-for-dict-comp-config.patch
lib-zstd-export-api-needed-for-dictionary-support.patch
zram-add-dictionary-support-to-zstd-backend.patch
zram-add-config-init-release-backend-callbacks.patch
zram-share-dictionaries-between-per-cpu-contexts.patch
zram-add-dictionary-support-to-lz4.patch
lib-lz4hc-export-lz4_resetstreamhc-symbol.patch
zram-add-dictionary-support-to-lz4hc.patch
documentation-zram-add-documentation-for-algorithm-parameters.patch
