Linus Torvalds has announced the release of the Linux 3.0-rc4 kernel.
Besides the usual bug-fixes to the drivers, file-systems, and other areas of the kernel for being mid-way in this kernel's development cycle, there's also a couple performance regression fixes noted by Torvalds.
These performance regressions relate to RCU not needing threads and the conversion from spin-locks to mutexes in a particular area had caused scalability issues.
Besides that, there's various fixes in the DRM area for the open-source graphics drivers, Btrfs file-system fixes, and much more.
Read more in the Linux 3.0 release candidate 4 announcement on the Linux kernel mailing list