The quilt patch titled Subject: zram: pass estimated src size hint to zstd has been removed from the -mm tree. Its filename was zram-pass-estimated-src-size-hint-to-zstd.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> Subject: zram: pass estimated src size hint to zstd Date: Mon, 2 Sep 2024 19:55:57 +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/20240902105656.1383858-10-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_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 zsmalloc-use-unique-zsmalloc-caches-names.patch