The patch titled
Subject: zram: pass estimated src size hint to zstd
has been added to the -mm mm-unstable branch. Its filename is
zram-pass-estimated-src-size-hint-to-zstd.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-pass-estimated-src-size-hint-to-zstd.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: pass estimated src size hint to zstd
Date: Fri, 12 Jul 2024 14:18:20 +0900
zram works with PAGE_SIZE buffers, so we always know exact
size of the source buffer and hence can pass estimated_src_size
to zstd_get_params().
This hint on x86_64, for example, reduces the size of the work
memory buffer from 1303520 bytes down to 90080 bytes. Given that
compression streams are per-CPU that's quite some memory saving.
Link: https://lkml.kernel.org/r/20240712051850.484318-10-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Nick Terrell <terrelln@xxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/backend_zstd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/block/zram/backend_zstd.c~zram-pass-estimated-src-size-hint-to-zstd
+++ a/drivers/block/zram/backend_zstd.c
@@ -35,7 +35,7 @@ static void *zstd_create(void)
return NULL;
ctx->level = zstd_default_clevel();
- params = zstd_get_params(ctx->level, 0);
+ params = zstd_get_params(ctx->level, PAGE_SIZE);
sz = zstd_cctx_workspace_bound(¶ms.cParams);
ctx->cctx_mem = vzalloc(sz);
if (!ctx->cctx_mem)
@@ -65,7 +65,7 @@ static int zstd_compress(void *ctx, cons
unsigned char *dst, size_t *dst_len)
{
struct zstd_ctx *zctx = ctx;
- const zstd_parameters params = zstd_get_params(zctx->level, 0);
+ const zstd_parameters params = zstd_get_params(zctx->level, PAGE_SIZE);
size_t ret;
ret = zstd_compress_cctx(zctx->cctx, dst, *dst_len,
_
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-extend-comp_algorithm-attr-write-handling.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
