Linux 5.9-rc2 Released With EXT4 Updates, More POWER10 Bits

It's been one week already since feature work ended on Linux 5.9 and that means it's time for the 5.9-rc2 kernel. Like clockwork, Linux Torvalds has shipped Linux 5.9-rc2 with the initial batch of bug/regression fixes as well as some late changes for the cycle.

Linus noted in the release announcement for Linux 5.9-rc2 that "Nothing in particular stands out, there's a random collection of fixes and updates in here. It is perhaps a bit filesystem-heavy, because the ext4 updates came in late, so a bit unusually we have 20+% of the patch being under fs/, and that's the biggest chunk in here after the usual driver updates (sound, gpu, networking, scsi, vfio). Other than that, it's mostly arch fixes and some tooling fixes, with a smattering elsewhere."

As outlined earlier this weekend, the EXT4 file-system updates that came in a week late include block allocator performance improvements, a new prefetch_block_bitmaps mount option, and other changes for this mature and widely-used Linux file-system.

Another pull request worth mentioning for Linux 5.9-rc2 were some IBM POWER changes merged earlier today. Continuing the POWER10 trend of Linux 5.8 and 5.9, some more POWER10 bits landed. This includes perf support for emitting extended registers on POWER10, a raw CPU table entry for POWER10 that is needed for their PMU setup to work correctly in guests, and other POWER architecture changes/fixes in general.

See our Linux 5.9 feature overview to learn about all of the changes at large for this next major kernel release. Linux 5.9 is currently tracking for releasing in early to mid October depending upon how the release candidates play out over the weeks ahead.