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![Nick Terrell](/assets/img/avatar_default.png)
Upgrade to the latest upstream zstd version 1.4.10. This patch is 100% generated from upstream zstd commit 20821a46f412 [0]. This patch is very large because it is transitioning from the custom kernel zstd to using upstream directly. The new zstd follows upstreams file structure which is different. Future update patches will be much smaller because they will only contain the changes from one upstream zstd release. As an aid for review I've created a commit [1] that shows the diff between upstream zstd as-is (which doesn't compile), and the zstd code imported in this patch. The verion of zstd in this patch is generated from upstream with changes applied by automation to replace upstreams libc dependencies, remove unnecessary portability macros, replace `/**` comments with `/*` comments, and use the kernel's xxhash instead of bundling it. The benefits of this patch are as follows: 1. Using upstream directly with automated script to generate kernel code. This allows us to update the kernel every upstream release, so the kernel gets the latest bug fixes and performance improvements, and doesn't get 3 years out of date again. The automation and the translated code are tested every upstream commit to ensure it continues to work. 2. Upgrades from a custom zstd based on 1.3.1 to 1.4.10, getting 3 years of performance improvements and bug fixes. On x86_64 I've measured 15% faster BtrFS and SquashFS decompression+read speeds, 35% faster kernel decompression, and 30% faster ZRAM decompression+read speeds. 3. Zstd-1.4.10 supports negative compression levels, which allow zstd to match or subsume lzo's performance. 4. Maintains the same kernel-specific wrapper API, so no callers have to be modified with zstd version updates. One concern that was brought up was stack usage. Upstream zstd had already removed most of its heavy stack usage functions, but I just removed the last functions that allocate arrays on the stack. I've measured the high water mark for both compression and decompression before and after this patch. Decompression is approximately neutral, using about 1.2KB of stack space. Compression levels up to 3 regressed from 1.4KB -> 1.6KB, and higher compression levels regressed from 1.5KB -> 2KB. We've added unit tests upstream to prevent further regression. I believe that this is a reasonable increase, and if it does end up causing problems, this commit can be cleanly reverted, because it only touches zstd. I chose the bulk update instead of replaying upstream commits because there have been ~3500 upstream commits since the 1.3.1 release, zstd wasn't ready to be used in the kernel as-is before a month ago, and not all upstream zstd commits build. The bulk update preserves bisectablity because bugs can be bisected to the zstd version update. At that point the update can be reverted, and we can work with upstream to find and fix the bug. Note that upstream zstd release 1.4.10 doesn't exist yet. I have cut a staging branch at 20821a46f412 [0] and will apply any changes requested to the staging branch. Once we're ready to merge this update I will cut a zstd release at the commit we merge, so we have a known zstd release in the kernel. The implementation of the kernel API is contained in zstd_compress_module.c and zstd_decompress_module.c. [0]20821a46f4
[1]e0fa481d0e
Signed-off-by: Nick Terrell <terrelln@fb.com> Tested By: Paul Jones <paul@pauljones.id.au> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 on x86-64 Tested-by: Jean-Denis Girard <jd.girard@sysnux.pf>
105 lines
2.7 KiB
C
105 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
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/*
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* Copyright (c) Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/zstd.h>
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#include "common/zstd_deps.h"
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/* Common symbols. zstd_compress must depend on zstd_decompress. */
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unsigned int zstd_is_error(size_t code)
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{
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return ZSTD_isError(code);
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}
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EXPORT_SYMBOL(zstd_is_error);
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zstd_error_code zstd_get_error_code(size_t code)
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{
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return ZSTD_getErrorCode(code);
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}
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EXPORT_SYMBOL(zstd_get_error_code);
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const char *zstd_get_error_name(size_t code)
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{
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return ZSTD_getErrorName(code);
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}
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EXPORT_SYMBOL(zstd_get_error_name);
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/* Decompression symbols. */
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size_t zstd_dctx_workspace_bound(void)
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{
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return ZSTD_estimateDCtxSize();
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}
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EXPORT_SYMBOL(zstd_dctx_workspace_bound);
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zstd_dctx *zstd_init_dctx(void *workspace, size_t workspace_size)
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{
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if (workspace == NULL)
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return NULL;
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return ZSTD_initStaticDCtx(workspace, workspace_size);
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}
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EXPORT_SYMBOL(zstd_init_dctx);
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size_t zstd_decompress_dctx(zstd_dctx *dctx, void *dst, size_t dst_capacity,
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const void *src, size_t src_size)
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{
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return ZSTD_decompressDCtx(dctx, dst, dst_capacity, src, src_size);
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}
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EXPORT_SYMBOL(zstd_decompress_dctx);
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size_t zstd_dstream_workspace_bound(size_t max_window_size)
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{
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return ZSTD_estimateDStreamSize(max_window_size);
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}
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EXPORT_SYMBOL(zstd_dstream_workspace_bound);
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zstd_dstream *zstd_init_dstream(size_t max_window_size, void *workspace,
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size_t workspace_size)
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{
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if (workspace == NULL)
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return NULL;
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(void)max_window_size;
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return ZSTD_initStaticDStream(workspace, workspace_size);
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}
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EXPORT_SYMBOL(zstd_init_dstream);
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size_t zstd_reset_dstream(zstd_dstream *dstream)
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{
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return ZSTD_resetDStream(dstream);
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}
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EXPORT_SYMBOL(zstd_reset_dstream);
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size_t zstd_decompress_stream(zstd_dstream *dstream, zstd_out_buffer *output,
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zstd_in_buffer *input)
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{
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return ZSTD_decompressStream(dstream, output, input);
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}
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EXPORT_SYMBOL(zstd_decompress_stream);
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size_t zstd_find_frame_compressed_size(const void *src, size_t src_size)
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{
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return ZSTD_findFrameCompressedSize(src, src_size);
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}
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EXPORT_SYMBOL(zstd_find_frame_compressed_size);
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size_t zstd_get_frame_header(zstd_frame_header *header, const void *src,
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size_t src_size)
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{
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return ZSTD_getFrameHeader(header, src, src_size);
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}
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EXPORT_SYMBOL(zstd_get_frame_header);
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MODULE_LICENSE("Dual BSD/GPL");
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MODULE_DESCRIPTION("Zstd Decompressor");
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