Linux founder, Linus Torvalds has released
the third new Linux kernel of 2011, which adds support for more devices and features improvements on performance and virtualization.
This release also brings new features, new drivers, and does not inlcude the Big Kernel Lock, which was almost removed in the 2.6.37 kernel but some of the code was still there.
From a virtualization perspective, the KVM hypervisor now handles asynchronous page fault processing. Some of the virtualization improvements have already been backported by Red Hat into their new Red Hat Enterprise Linux 6.1 release.
The new kernel also supports new hardware, including support for lots of laptop special keys (Dell's All-in-One series or Samsung notebooks, for example), a number of hardware controllers from Texas Instruments and ST-Ericsson, as well as drivers for Realtek RTL8192CU and RTL8188CU Wi-Fi chips.
This release also provides support for some USB 3.0 hubs, meaning that Linux users will be able to enjoy USB 3.0 devices soon.
The kernel also includes a number of improvements to existing drivers and features. Many users will apreciate the support for Intel's GMA500 graphics device found in many netbooks. Improvements have been also seen in Nouveau for Nvidia chipsets, and support for AMD's Cayman video cards and chipsets.
The 2.6.39 kernel also marks the introduction of user namespaces, which provide more fine-grained control over privileges that a process can have. Namespaces provide "containers" for processes that keeps them walled off from the rest of the system. User namespaces allow unprivileged users to create a namespace, rather than having the namespace created by the system administrator.
This release also adds support for IP sets to the Linux kernel. IP set allows creation of iptables rules that deal with a set of ports or IP addresses without having to have a rule for each address or port. Just using iptables, for example, you'd create a rule to block or reject packets from a single address or network - but using ipsets you could generate a rule that looks at an ipset table and deals with all the ports or addresses appropriately.
Another interesting feature in 2.6.39 is the pstore filesystem, which creates a filesystem for platform-specific storage. This might be used to store a small amount of data when a system crashes, for examination later.
Unforunately, the new Kernel is still not fuly supporting Intel's Sandy Bridge processors.
The next kernel (2.6.40) may be also coming in July or August. It is expected to will mainly clean up the ARM-related code in the Linux kernel and also it may add support for Nvidia Optimus technology.