Linux kernel head Linus Torvalds seems delighted with the first release candidate (rc1) of the Linux kernel version 5.8, which contains 800,000 new lines of code and over 14,000 changed files, representing about a 20% overhaul of the kernel’s files.
“So I didn’t really expect this, but 5.8 looks to be one of our biggest releases of all time,” writes Torvalds on the Linux kernel mailing list.
Earlier this month Torvalds’ fired off a stern email rejecting a security patch developed by Amazon Web Services engineers for Linux 5.8, which could have caused a performance hit on some applications.
With that patch out of the way, he’s now pleased with the pace of development in the Linux kernel, which focuses on core components, driver updates, and improvements to the kernel’s design.
Linux kernel version 5.8 is about the same size as Linux 4.9 from 2016, which Torvalds at the time crowned the “the biggest we’ve ever had” and spanned over 22 million lines of code.
However, he says Linux 4.9 was “artificially big”, partly because of the Greybus driver subsystem to support Google’s now-abandoned modular smartphone, Project Ara.
“In 5.8, we have no sign of those kinds of issues making the release bigger – there’s just simply a lot of development in there,” wrote Torvalds.
The other comparably large release was version 4.12 from June 2017, which brought support for AMD’s new Radeon RX Vega graphics card.
That version contained more new lines than version 5.8 and remained the “undisputed size champion”. However, that was “simply because it had a _huge_ number of new lines due to lots of register descriptions for the AMD GPU drivers,” he says.
Torvalds points out that other kernels have been of a comparable size because of particular subsystems. For example, v4.2 had another AMD GPU driver line count bump, while 2.6.29 had big staging driver additions.
“But again, 5.8 is up there with the best, despite not really having any single thing that stands out. Yes, there’s a couple of big driver changes (habanalabs and atomisp) that are certainly part of it, but it’s not nearly as one-sided as some of the other historical big releases have been,” writes Torvalds.
“The development is really all over the place: there’s tons of fairly fundamental core work and cleanups, but there is also lots of filesystem work and obviously all the usual driver updates too. Plus documentation and architecture work.”
But by the number of commits and new lines, Torvalds says 5.8 is the “outstanding champion”.
“So in the 5.8 merge window we have modified about 20% of all the files in the kernel source repository. That’s really a fairly big percentage, and while some of it _is_ scripted, on the whole it’s really just the same pattern: 5.8 has simply seen a lot of development,” Torvalds says.
“5.8 looks big. Really big,” he adds.
Linux 5.8 brings updates for Microsoft’s Hyper-V virtualization platform, Arm chips, the Direct Rendering Manager (DRM) subsystem, networking, drivers, IBM Power PC, Microsoft’s recently open-sourced exFAT file system, and much more.
Despite the size, Torvalds doesn’t expect the Linux 5.8 to be a troublesome release.