en Copyright 2015 Java http://172.16.0.5:8080/history/linux-6.15/lib/zstd/common/allocations.h#65d1f550 zstd: Import upstream v1.5.7In addition to keeping the kernel's copy of zstd up to date, this updatewas requested by Intel to expose upstream's APIs that allow QAT to acceleratethe LZ match finding stage of Zstd.This patch is imported from the upstream tag v1.5.7-kernel [0], which is signedwith upstream's signing key EF8FE99528B52FFD [1]. It was imported from upstreamusing this command: export ZSTD=/path/to/repo/zstd/ export LINUX=/path/to/repo/linux/ cd "$ZSTD/contrib/linux-kernel" git checkout v1.5.7-kernel make import LINUX="$LINUX"This patch has been tested on x86-64, and has been boot tested witha zstd compressed kernel & initramfs on i386 and aarch64. I benchmarkedthe patch on x86-64 with gcc-14.2.1 on an Intel i9-9900K by measruing theperformance of compressed filesystem reads and writes.Component, Level, Size delta, C. time delta, D. time deltaBtrfs , 1, +0.00%, -6.1%, +1.4%Btrfs , 3, +0.00%, -9.8%, +3.0%Btrfs , 5, +0.00%, +1.7%, +1.4%Btrfs , 7, +0.00%, -1.9%, +2.7%Btrfs , 9, +0.00%, -3.4%, +3.7%Btrfs , 15, +0.00%, -0.3%, +3.6%SquashFS , 1, +0.00%, N/A, +1.9%The major changes that impact the kernel use cases for each version are:v1.5.7: https://github.com/facebook/zstd/releases/tag/v1.5.7* Add zstd_compress_sequences_and_literals() for use by Intel's QAT driver to implement Zstd compression acceleration in the kernel.* Fix an underflow bug in 32-bit builds that can cause data corruption when processing more than 4GB of data with a single `ZSTD_CCtx` object, when an input crosses the 4GB boundry. I don't believe this impacts any current kernel use cases, because the `ZSTD_CCtx` is typically reconstructed between compressions.* Levels 1-4 see 5-10% compression speed improvements for inputs smaller than 128KB.v1.5.6: https://github.com/facebook/zstd/releases/tag/v1.5.6* Improved compression ratio for the highest compression levels. I don't expect these see much use however, due to their slow speeds.v1.5.5: https://github.com/facebook/zstd/releases/tag/v1.5.5* Fix a rare corruption bug that can trigger on levels 13 and above.* Improve compression speed of levels 5-11 on incompressible data.v1.5.4: https://github.com/facebook/zstd/releases/tag/v1.5.4* Improve copmression speed of levels 5-11 on ARM.* Improve dictionary compression speed.Signed-off-by: Nick Terrell <terrelln@fb.com> List of files: /linux-6.15/lib/zstd/common/allocations.h Sat, 08 Mar 2025 20:09:33 +0000 Nick Terrell <terrelln@meta.com>