The patch titled
Subject: zram: add dictionary support to lz4
has been added to the -mm mm-unstable branch. Its filename is
zram-add-dictionary-support-to-lz4.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-lz4.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 lz4
Date: Mon, 2 Sep 2024 19:56:08 +0900
Support pre-trained dictionary param. lz4 doesn't mandate specific format
of the dictionary and even zstd --train can be used to train a dictionary
for lz4, according to [1].
TEST
====
*** lz4
/sys/block/zram0/mm_stat
1750654976 664188565 676864000 0 676864000 1 0 34288 34288
*** lz4 dict=/etc/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750638592 619891141 632053760 0 632053760 1 0 34278 34278
*** lz4 level=5 dict=/etc/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750638592 727174243 740810752 0 740810752 1 0 34437 34437
[1] https://github.com/lz4/lz4/issues/557
Link: https://lkml.kernel.org/r/20240902105656.1383858-21-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_lz4.c | 74 ++++++++++++++++++++++++++---
1 file changed, 67 insertions(+), 7 deletions(-)
--- a/drivers/block/zram/backend_lz4.c~zram-add-dictionary-support-to-lz4
+++ a/drivers/block/zram/backend_lz4.c
@@ -5,6 +5,13 @@
#include "backend_lz4.h"
+struct lz4_ctx {
+ void *mem;
+
+ LZ4_streamDecode_t *dstrm;
+ LZ4_stream_t *cstrm;
+};
+
static void lz4_release_params(struct zcomp_params *params)
{
}
@@ -19,25 +26,66 @@ static int lz4_setup_params(struct zcomp
static void lz4_destroy(struct zcomp_ctx *ctx)
{
- vfree(ctx->context);
+ struct lz4_ctx *zctx = ctx->context;
+
+ if (!zctx)
+ return;
+
+ vfree(zctx->mem);
+ kfree(zctx->dstrm);
+ kfree(zctx->cstrm);
+ kfree(zctx);
}
static int lz4_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
{
- ctx->context = vmalloc(LZ4_MEM_COMPRESS);
- if (!ctx->context)
+ struct lz4_ctx *zctx;
+
+ zctx = kzalloc(sizeof(*zctx), GFP_KERNEL);
+ if (!zctx)
return -ENOMEM;
+ ctx->context = zctx;
+ if (params->dict_sz == 0) {
+ zctx->mem = vmalloc(LZ4_MEM_COMPRESS);
+ if (!zctx->mem)
+ goto error;
+ } else {
+ zctx->dstrm = kzalloc(sizeof(*zctx->dstrm), GFP_KERNEL);
+ if (!zctx->dstrm)
+ goto error;
+
+ zctx->cstrm = kzalloc(sizeof(*zctx->cstrm), GFP_KERNEL);
+ if (!zctx->cstrm)
+ goto error;
+ }
+
return 0;
+
+error:
+ lz4_destroy(ctx);
+ return -ENOMEM;
}
static int lz4_compress(struct zcomp_params *params, struct zcomp_ctx *ctx,
struct zcomp_req *req)
{
+ struct lz4_ctx *zctx = ctx->context;
int ret;
- ret = LZ4_compress_fast(req->src, req->dst, req->src_len,
- req->dst_len, params->level, ctx->context);
+ if (!zctx->cstrm) {
+ ret = LZ4_compress_fast(req->src, req->dst, req->src_len,
+ req->dst_len, params->level,
+ zctx->mem);
+ } else {
+ /* Cstrm needs to be reset */
+ ret = LZ4_loadDict(zctx->cstrm, params->dict, params->dict_sz);
+ if (ret != params->dict_sz)
+ return -EINVAL;
+ ret = LZ4_compress_fast_continue(zctx->cstrm, req->src,
+ req->dst, req->src_len,
+ req->dst_len, params->level);
+ }
if (!ret)
return -EINVAL;
req->dst_len = ret;
@@ -47,10 +95,22 @@ static int lz4_compress(struct zcomp_par
static int lz4_decompress(struct zcomp_params *params, struct zcomp_ctx *ctx,
struct zcomp_req *req)
{
+ struct lz4_ctx *zctx = ctx->context;
int ret;
- ret = LZ4_decompress_safe(req->src, req->dst, req->src_len,
- req->dst_len);
+ if (!zctx->dstrm) {
+ ret = LZ4_decompress_safe(req->src, req->dst, req->src_len,
+ req->dst_len);
+ } else {
+ /* Dstrm needs to be reset */
+ ret = LZ4_setStreamDecode(zctx->dstrm, params->dict,
+ params->dict_sz);
+ if (!ret)
+ return -EINVAL;
+ ret = LZ4_decompress_safe_continue(zctx->dstrm, req->src,
+ req->dst, req->src_len,
+ req->dst_len);
+ }
if (ret < 0)
return -EINVAL;
return 0;
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
lib-zstd-export-api-needed-for-dictionary-support.patch
lib-lz4hc-export-lz4_resetstreamhc-symbol.patch
lib-zstd-fix-null-deref-in-zstd_createcdict_advanced2.patch
zram-introduce-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_params-structure.patch
zram-recalculate-zstd-compression-params-once.patch
zram-introduce-algorithm_params-device-attribute.patch
zram-add-support-for-dict-comp-config.patch
zram-introduce-zcomp_req-structure.patch
zram-introduce-zcomp_ctx-structure.patch
zram-move-immutable-comp-params-away-from-per-cpu-context.patch
zram-add-dictionary-support-to-lz4.patch
zram-add-dictionary-support-to-lz4hc.patch
zram-add-dictionary-support-to-zstd-backend.patch
documentation-zram-add-documentation-for-algorithm-parameters.patch
zram-support-priority-parameter-in-recompression.patch
