Linux 6.15 keeps getting more exciting… The big Zstd update has landed! The in-kernel Zstandard compression code is finally re-based against the newer upstream state that brings better performance as well as new APIs for allowing Intel QAT acceleration by Intel hardware offering QuickAssist Technology. This Zstd code is relied upon by Btrfs transparent file-system compression and other in-kernel users for compression/decompression.
The in-kernel Zstd code has struggled to stay up-to-date against the upstream Zstd codebase. This re-base to Zstd 1.5.7 incorporates tons of changes amounting to around 8.7k lines of new code and 4.3k lines removed. The kernel patch updating it was posted earlier this month. Moving forward the Zstd code will be more punctually updated with now having a Zstd co-maintainer to help in the kernel upstreaming process.
Meta’s Nick Terrell commented in the Zstd pull request:
“This pull request updates Zstandard to the latest upstream release v1.5.7. The two major motivations for updating Zstandard are to keep the code up to date, and to expose API’s needed by Intel for the QAT compression accelerator.
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This pull request has been baking in linux-next since March 18th. This is on the short side because the commit was only completed on the 13th. If this is acceptable, I would still like to merge the zstd update, so we don’t have to wait for another cycle. The updated Zstandard has been tested in btrfs and squashfs on x86-64, and tested in kernel & initramfs decompression on x86-64, i386, and aarch64.”
Overnight Linus Torvalds merged the code and thus Zstd 1.5.7 is now in Linux 6.15 for providing a nice performance speed-up for those making use of in-kernel Zstandard compression/decompression and also being helpful to Intel engineers in their QAT accelerator work.
