Tomorrow I'll have published our extensive feature overview of Linux 5.15 changes, but some of the highlights include Paragon NTFS3 as the new NTFS file-system driver, KSMBD as an in-kernel SMB3 file server, opt-in L1d cache flushing on context switching, continued Apple M1 bring-up work, many AMD improvements , and initial Intel DG2/Alchemist and XeHP discrete graphics bring-up work, among a lot of other new hardware enablement.
Linus Torvalds wrote of Linux 5.15-rc1 in the announcement , " 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. We're usually hovering in the 12-14k commit range. That said, counting commits isn't necessarily the best measure, and that might be particularly true this time around. We have a few new subsystems, with NTFSv3 and ksmbd standing out. And as a result, when you look at the stats on a "lines changed" basis, 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. "
Stay tuned for the complete Linux 5.15 feature overview and our Linux 5.15 kernel benchmarks. Linux 5.15 stable should be out in November.