The VM code almost ended up being reverted, but in the end the issue was tracked down and corrected. Many other bugs have also been squashed in 2.6.34-rc4 and a new network driver has been added. The new Linux network driver is cxgb4 and is for Chelsio's new 1G and 10G T4 adapters. There's also a fairly sizable kernel DRM (Direct Rendering Manager) pull in this release that brings a few Radeon KMS fixes and a healthy set of Nouveau DRM changes.
The Linux 2.6.34-rc4 release announcement with the short change-log can be found at LKML.org. We continue to monitor the performance of the very latest Linux kernel code on a daily basis at kernel-tracker.phoromatic.com.