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Message-ID: <20240506075834.302472-17-senozhatsky@chromium.org>
Date: Mon, 6 May 2024 16:58:29 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Andrew Morton <akpm@...ux-foundation.org>,
Minchan Kim <minchan@...nel.org>
Cc: linux-kernel@...r.kernel.org,
linux-block@...r.kernel.org,
Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCHv2 16/17] zram: share dictionaries between per-CPU contexts
zstd's CDict and DDict are accessed read-only during compression
and decompression, so instead of allocation per-context dictionaries
we can create just one CDict and DDict in init_config() and make
per-CPU contexts use them. This saves quite a lot of memory: on my
system CDict requires 408128 bytes and DDict requires 27352 bytes.
Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
drivers/block/zram/backend_zstd.c | 106 ++++++++++++++++++++----------
1 file changed, 70 insertions(+), 36 deletions(-)
diff --git a/drivers/block/zram/backend_zstd.c b/drivers/block/zram/backend_zstd.c
index df59584b0337..99115b21c264 100644
--- a/drivers/block/zram/backend_zstd.c
+++ b/drivers/block/zram/backend_zstd.c
@@ -7,14 +7,18 @@
#include "backend_zstd.h"
+struct zstd_ctx_data {
+ ZSTD_customMem ctx_mem;
+ ZSTD_CDict *cdict;
+ ZSTD_DDict *ddict;
+};
+
struct zstd_ctx {
zstd_cctx *cctx;
zstd_dctx *dctx;
void *cctx_mem;
void *dctx_mem;
- ZSTD_customMem ctx_mem;
- ZSTD_CDict *cdict;
- ZSTD_DDict *ddict;
+ struct zstd_ctx_data *ctx_data;
s32 level;
};
@@ -38,32 +42,81 @@ static void zstd_ctx_free(void *opaque, void *address)
static int zstd_init_config(struct zcomp_config *config)
{
+ struct zstd_ctx_data *ctx_data = config->private;
+ ZSTD_compressionParameters params;
+
+ /* Already initialized */
+ if (ctx_data)
+ return 0;
+
if (config->level == ZCOMP_CONFIG_NO_LEVEL)
config->level = ZSTD_defaultCLevel();
+ if (config->dict_sz == 0)
+ return 0;
+
+ ctx_data = kzalloc(sizeof(*ctx_data), GFP_KERNEL);
+ if (!ctx_data)
+ return -ENOMEM;
+
+ ctx_data->ctx_mem.customAlloc = zstd_ctx_alloc;
+ ctx_data->ctx_mem.customFree = zstd_ctx_free;
+
+ params = ZSTD_getCParams(config->level, PAGE_SIZE, config->dict_sz);
+
+ ctx_data->cdict = ZSTD_createCDict_advanced(config->dict,
+ config->dict_sz,
+ ZSTD_dlm_byRef,
+ ZSTD_dct_auto,
+ params,
+ ctx_data->ctx_mem);
+ if (!ctx_data->cdict)
+ goto error;
+
+ ctx_data->ddict = ZSTD_createDDict_advanced(config->dict,
+ config->dict_sz,
+ ZSTD_dlm_byRef,
+ ZSTD_dct_auto,
+ ctx_data->ctx_mem);
+ if (!ctx_data->ddict)
+ goto error;
+
+ config->private = ctx_data;
return 0;
+
+error:
+ ZSTD_freeCDict(ctx_data->cdict);
+ ZSTD_freeDDict(ctx_data->ddict);
+ kfree(ctx_data);
+ return -EINVAL;
}
static void zstd_release_config(struct zcomp_config *config)
{
+ struct zstd_ctx_data *ctx_data = config->private;
+
+ if (!ctx_data)
+ return;
+
+ config->private = NULL;
+ ZSTD_freeCDict(ctx_data->cdict);
+ ZSTD_freeDDict(ctx_data->ddict);
+ kfree(ctx_data);
}
static void zstd_destroy(void *ctx)
{
struct zstd_ctx *zctx = ctx;
+ /* Don't free zctx->ctx_data, it's done in release_config() */
if (zctx->cctx_mem)
vfree(zctx->cctx_mem);
else
ZSTD_freeCCtx(zctx->cctx);
-
if (zctx->dctx_mem)
vfree(zctx->dctx_mem);
else
ZSTD_freeDCtx(zctx->dctx);
-
- ZSTD_freeCDict(zctx->cdict);
- ZSTD_freeDDict(zctx->ddict);
kfree(zctx);
}
@@ -75,9 +128,8 @@ static void *zstd_create(struct zcomp_config *config)
if (!ctx)
return NULL;
+ ctx->ctx_data = config->private;
ctx->level = config->level;
- ctx->ctx_mem.customAlloc = zstd_ctx_alloc;
- ctx->ctx_mem.customFree = zstd_ctx_free;
if (config->dict_sz == 0) {
zstd_parameters params;
@@ -102,35 +154,15 @@ static void *zstd_create(struct zcomp_config *config)
if (!ctx->dctx)
goto error;
} else {
- ZSTD_compressionParameters params;
+ struct zstd_ctx_data *ctx_data = ctx->ctx_data;
- ctx->cctx = ZSTD_createCCtx_advanced(ctx->ctx_mem);
+ ctx->cctx = ZSTD_createCCtx_advanced(ctx_data->ctx_mem);
if (!ctx->cctx)
goto error;
- ctx->dctx = ZSTD_createDCtx_advanced(ctx->ctx_mem);
+ ctx->dctx = ZSTD_createDCtx_advanced(ctx_data->ctx_mem);
if (!ctx->dctx)
goto error;
-
- params = ZSTD_getCParams(ctx->level, PAGE_SIZE,
- config->dict_sz);
-
- ctx->cdict = ZSTD_createCDict_advanced(config->dict,
- config->dict_sz,
- ZSTD_dlm_byRef,
- ZSTD_dct_auto,
- params,
- ctx->ctx_mem);
- if (!ctx->cdict)
- goto error;
-
- ctx->ddict = ZSTD_createDDict_advanced(config->dict,
- config->dict_sz,
- ZSTD_dlm_byRef,
- ZSTD_dct_auto,
- ctx->ctx_mem);
- if (!ctx->ddict)
- goto error;
}
return ctx;
@@ -144,15 +176,16 @@ static int zstd_compress(void *ctx, const unsigned char *src,
unsigned char *dst, size_t *dst_len)
{
struct zstd_ctx *zctx = ctx;
+ struct zstd_ctx_data *ctx_data = zctx->ctx_data;
const zstd_parameters params = zstd_get_params(zctx->level, PAGE_SIZE);
size_t ret;
- if (!zctx->cdict)
+ if (!ctx_data)
ret = zstd_compress_cctx(zctx->cctx, dst, *dst_len,
src, PAGE_SIZE, ¶ms);
else
ret = ZSTD_compress_usingCDict(zctx->cctx, dst, *dst_len,
- src, PAGE_SIZE, zctx->cdict);
+ src, PAGE_SIZE, ctx_data->cdict);
if (zstd_is_error(ret))
return -EINVAL;
*dst_len = ret;
@@ -163,14 +196,15 @@ static int zstd_decompress(void *ctx, const unsigned char *src, size_t src_len,
unsigned char *dst)
{
struct zstd_ctx *zctx = ctx;
+ struct zstd_ctx_data *ctx_data = zctx->ctx_data;
size_t ret;
- if (!zctx->ddict)
+ if (!ctx_data)
ret = zstd_decompress_dctx(zctx->dctx, dst, PAGE_SIZE,
src, src_len);
else
ret = ZSTD_decompress_usingDDict(zctx->dctx, dst, PAGE_SIZE,
- src, src_len, zctx->ddict);
+ src, src_len, ctx_data->ddict);
if (zstd_is_error(ret))
return -EINVAL;
return 0;
--
2.45.0.rc1.225.g2a3ae87e7f-goog
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