News

Linux 5.10 Released: Bigger Kernel Release Than Expected

• By John K. Waters
• October 27, 2020

Linus Torvalds this week announced the first release candidate of version 5.10 of the Linux kernel (Linux 5.10-rcl), a release that also marks the end of the feature merge window for this EOY 2020 kernel. Version 5.10 should debut as stable by mid-December. This kernel will then be maintained under the Linux long-term support (LTS) program.

"This looks to be a bigger release than I expected," Torvalds said on the Linux kernel mailing list, "and while the merge window is smaller than the one for 5.8 was, it's not a lot smaller.
And 5.8 was our biggest release ever."

The merging window is a key part of the new kernel release process. Up to 1,000 patches are submitted by the developer community and merged every day into the mainline repository managed by Torvalds. A review process ensures that each patch implements a desirable change.

Linux 5.9 to 5.10-rc1 added about 704k lines of new code and approximately 419k lines were deleted. By comparison, Linux 5.8 to 5.9-rc1 had 727k lines added and 270k deletions, and 5.7 to 5.8-rc1 had 973k lines added and 429k deletions (that was largest ever).

For his part, Torvalds, who created and open sourced the Linux OS in 1991, found the most interesting change in this release to be the removal of the setf_fs() addressing tool.

"It's not a _huge_ change, but it's interesting because the whole model of set_fs() to specify whether a userspace copy actually goes to user space or kernel space goes back to pretty much the original release of Linux," he wrote, "and while the name is entirely historic (it hasn't used the %fs segment register in a long time), the concept has remained. Until now."

"We still do have 'set_fs()' around," he added, "and not every architecture has been converted to the new world order, but x86, powerpc, s390 and RISC-V have had the address space overrides removed, and all the core work is done. Other architectures will hopefully get converted away from that very historic model too, but it might take a while to get rid of it all."