Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793976882; b=HKiDgMcZdc9gnlVInZAcZf3iJKwR66F79xEh6agphmCaIv7X/YyQnsWcJpOGioznGFMK 6UYGmyTBvuNshOZraNRWhhSi2x8O6+ONn1olJbamVCDgXb3sF8Iby/a2Ks/Cpg5N/QWsS +afXg2hI0huY2aVXKUEEkzW+SHBLnglAHT9eibUW7PqvSEiyLuyccP7XDyNZb4tDKWYd8 P1vNt8r5XXouy7+VCnKieKt0IH6lJcjbPrEnPANIZCzpAL72hh63YXeg2bLG/u1BDFg8B SvnlJYTBMZOna9R8Q1TBnfDLmk5y8GD6zlyj6VS61jQi4pI8v2mZnzg3BCJ/eKgXl7g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793976882; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=ZMdjumYXDl5RgqVJl4+LfUpD2v9DOkyCDQnFVlrFRtU=; b=LaGnrw+Uq2TU8o1DTRlg9VlfoJcl+vI2RsARF8SFGpt5TmWgPh3tjy0RnFUSIsp0jB+m SGC1yl59lkRjowzzD00pMLdsd1giw4k47niYnBHnCRuN1M6XQqQ1LNt5PCy/bpcgYqP+p asxvGXaqoYw10lo/vZWAeCVib1c5q7kPBZ2aZh12wCd/X0mEb1qegWI/Zuol18LiAzQ97 TzoI+uvJ4WtwobM3OiYl8dQ/0lEc5FUT5OEWbAUgOKGQoANqBIgP3aHFEyLS3xcoJmgfh QChDVNvWD+RYCRRVVVW1gado7+I6xO2xBXlTpUWV2S55nT0MbrXv1cTmTL+LqhauuXg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XoOB0nfN; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8D828606A326 for ; Fri, 6 Nov 2026 14:54:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XoOB0nfN Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1EB371F008A1; Fri, 6 Nov 2026 14:54:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793976882; bh=ZMdjumYXDl5RgqVJl4+LfUpD2v9DOkyCDQnFVlrFRtU=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=XoOB0nfNbj0Oom8ASVItsRveL83TxqFGgZmJX8cXyXoSyWePnr6QBQ+RfKnvOlauT CuuoP7Eal9EQYhngQkYwHYjBXkox0xTzSytJ1CReQUEp/CGlybMp3U1yzZHMD6WsnT Zh8maLOVuE/pQLU5fkqplPpHFlGdBkP8Spiw5HT5HVqllXFkAwozM0k17NGrjMuDjK bcHBZaAxvSthI0KQRczV0Vlxm6ASVk4fqnEM/pZ3cyKb0avwsfC1Hdj3eILFQGHKgm 2YGq0ikBJAMLj5L5Ady/lNBaJwFrl7IYNwPRkOAAWOM/Y9Ysrt/HNErtgynwa+/5WH +nfvx/3cKf17w== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 11/15] lib/lz4: switch the HC compressor to the vendored sources Reply-To: sashiko-reviews@lists.linux.dev To: "Michal Wilczynski" Cc: linux-s390@vger.kernel.org, "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" In-Reply-To: <20261106-lz4-vendor-upstream-v2-11-ee04c3f0d7dc@samsung.com> References: <20261106-lz4-vendor-upstream-v2-0-ee04c3f0d7dc@samsung.com> <20261106-lz4-vendor-upstream-v2-11-ee04c3f0d7dc@samsung.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 06 Nov 2026 14:54:41 +0000 X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > Replace the forked LZ4HC with thin entry points over the vendored > lz4hc.c. >=20 > Upstream routes levels 10 and up to its optimal parser, whose ~64K > workspace the kernel cannot provide. Clamp those levels to 9 rather than > reject them, so existing f2fs and zram settings keep working, and add > LZ4HC_CLAMP_CLEVEL to . Document the clamp in f2fs.rst. >=20 > Levels 1 and 2 now use upstream's lz4mid: on kernel source they are > 50-84% faster for 4-9% larger output. Levels 3 to 9 compress the same, > but at 4K are up to 15% slower on poorly compressible data, including at > level 9, zram's lz4hc default. >=20 > LZ4_compress_HC() and LZ4_resetStreamHC() check the state's alignment > like the compressor's entry points. >=20 > LZ4_streamHC_t becomes incomplete and the macros that laid out the forked > structure go. LZ4HC_MEM_COMPRESS grows from 262192 to upstream's 262200, > static_asserted against LZ4_STREAMHC_MINSIZE. lz4hc.c pulls in lz4.c's > decoder tables, unused here when the fast decode loop is off, so silence > -Wunused-const-variable for this object. >=20 > This retires commit b08918fb3f27 ("lz4: do not export static symbol"): > the glue exports only the five LZ4HC entry points. >=20 > Signed-off-by: Michal Wilczynski Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261106-lz4-vendor= -upstream-v2-0-ee04c3f0d7dc@samsung.com?part=3D11