Linus Torvalds has loosed the first release candidate for version 5.15 of the Linux kernel, with but isn’t sure if it’s a big ‘un or nothing to get excited about.
“So 5.15 isn’t shaping up to be a particularly large release, at least in number of commits. At only just over 10k non-merge commits, this is in fact the smallest rc1 we have had in the 5.x series,” he wrote in his weekly missive on the state of kernel development. But he also wondered if measuring kernels by commits is valid and suggested measuring new kernel versions by the number of lines changed.
On the latter measure, thanks to substantial new subsystems like NTFSv3 and KSMBD, Torvalds stated “5.15-rc1 ends up looking much more middle-of-the-road. It still doesn’t look like a particularly _big_ merge window, but also not remotely the smallest one.”null
Whatever the size of the new kernel, Torvalds rated it “one of the messier merge windows”.
“Part of it was self-inflicted damage from me trying to enable -Werror much more aggressively, but I also ended up having to push back a lot more on some of the patch series and had a number o[f] full requests where I went ‘ok, I’ve pulled this, but XYZ is wrong’.”
Developers pushed back against -Werror as it labelled all warnings about code in the kernel as errors. A compromise was reached whereby it will only be applied to test builds.
Torvalds also revealed he has “a pull request or two that I just didn’t feel like going through fully, and I might still pull the upcoming week”.
His reticence wasn’t just caused by being busy: Torvalds admitted “I got a bit fed up with how I ended up seeing new pull requests – and not for fixes – coming in fairly late in the merge window.
“Yes, the merge window is two weeks, but part of that is very literally to give _me_ time to actually look things through, not for people to send me new requests up until the very end of the merge window,” he wrote.
“Anyway, I’m hoping that things calm down, and I’ll take a look at a few things still in my inbox,” Torvalds added, “but on the whole you should expect that ‘that’s it’ and send me fixes only.”
Among the big additions to this cut of the kernel are the addition of the KSMBD, a CIFS/SMB3 server in kernel space that allows sharing files and IPC services over a network, and drivers for AMD’s PassThru DMA engine that speeds data sharing from memory in AMD-powered systems.
Intel’s forthcoming standalone GPUs also get a little love, as does its Alder Lake diverse-multi-core architecture.