Android and Linux are officially back together.
Linus Torvalds released the Linux 3.3 kernel on Sunday, formally ending a two year dispute between mainline Linux kernel developers and Google Android developers.
The Linux 2.6.38 kernel that was released in February of 2010 removed Android code after Linux kernel developers alleged that it wasn’t being maintained properly. Friction between Linux and Android developers boiled over in the summer of 2010, as each side blamed the other for not being in the Linux kernel. Since then, tempers have cooled and an understanding has been reached and with Linux 3.3, Android is back.
“Turns out I was wrong, we want these in the tree,” Linux kernel developer Greg Kroah-Hartman wrote in his code commit adding Android drivers back into the Linux mainline.
Looking beyond Android, Linux 3.3 is also a noteworthy release for its filesystem improvements. The Btrfs next generation Linux filesystem is getting improved integrity checks for data. New balancing capabilities are included in Linux 3.3 to help Btrfs work with RAID storage. Ext4 which is currently the default filesystem used by many Linux distributions also gets a boost. There is now an online resizing interface for Ext4 that is intended to help speed up resizing activities.
“This patch adds new online resize interface, whose input argument is a 64-bit integer indicating how many blocks there are in the resized fs,” Kernel developer, Yongqiang Yang wrote in his code commit.
The Linux 3.3 kernel is also notable for a new virtual networking feature. The Open vSwitch virtual network switch is already being used in the OpenStack open source cloud computing framework.
“In addition to supporting a variety of features expected in a traditional hardware switch, it enables fine-grained programmatic extension and flow-based control of the network,” Kernel developer Jess Gross wrote in his kernel commit. “This control is useful in a wide variety of applications but is particularly important in multi-server virtualization deployments, which are often characterized by highly dynamic endpoints and the need to maintain logical abstractions for multiple tenants.”
Networking in Linux 3.3 also gets a boost by way of an Ethernet bonding technology called, ‘team’ contributed by Red Hat. Bonding enables multiple Ethernet devices to virtually be combined together. According to Red Hat kernel developer Jiri Pirki, ‘team’ is intended to be a very fast simple, userspace driven alternative to the existing bonding driver.
The Linux 3.3 kernel is the second kernel released so far in 2012, following the Linux 3.2 kernel that came out in January. With the release, developers now turn their focus to Linux 3.4.
“And obviously, the 3.3 release means that the merge window for 3.4 is now open, although I may keep of pulling stuff for a day or so to encourage people to test the actual release,” Linus Torvalds wrote.