Kernel Log: Linux 3.3 goes into testing
by Thorsten Leemhuis
Linux 3.3 can change the size of ext4 filesystems faster and supports ACPI 5.0, LPAE for ARM processors, Ethernet teaming and hot replace for software RAID. Meanwhile, Linux 3.1 has reached the end of the line, and the Linux Ate My RAM web site explains why Linux often appears to use all of the RAM.
Two weeks after Linux 3.2 was released, Linus Torvalds has announced the first Linux 3.3 release candidate. As usual, this step signals the end of the merge window at the beginning of the development cycle; during the merge window, Torvalds integrates the major changes for a new Linux version before the focus is moved to stabilising the version over the following two months. In his message announcing the new version, Torvalds writes that it "really was a pretty busy merge window" and that he is "taking off early for a weekend of beer, skiing and poker" while remembering the motto "don't drink and ski". At close to 9,000 commits, however, the number of changes is actually within the normal range.
One of the changes in 3.3 is a new mechanism to adjust the size of ext4 filesystems that is supposed to work much faster than the previous method. Functions were added to the software RAID code to move data currently in use from one data volume to another so that the first can then be removed ("hot replace"). Support was also added for Texas Instruments' C6X architecture, ACPI 5.0 and the LPAE (Large Physical Address Extension) technology for ARM, with which some 32-bit ARM v7 processors can use more than 4 GB of memory.
The developers also say they have improved HDMI audio support in the DRM/KMS drivers for AMD and NVIDIA graphic chips. Open vSwitch and an Ethernet teaming driver, which combines multiple network ports into one virtual one, were added to the network subsystem. As expected, some Android-specific drivers were merged to the staging area, the area for code that needs to be improved. The GMA500 graphics driver for Intel's US15W and some Hyper V drivers have matured in the staging area and were moved to the subsystems responsible for these kind of drivers.
With these and other changes, the tar archive for the first Linux 3.3 release candidate grew to 38,173 files with a total of 15,207,578 lines. The kernel has therefore now far surpassed the recently crossed 15-million-line mark. The Kernel Log will provide more detailed information about the changes in Linux 3.3 over the next few weeks, before it is released in early or mid-March.
Kernel version status
Greg Kroah-Hartman has recently released the long-term kernels 126.96.36.199 and 3.0.17, as well as the stable kernels Linux 3.1.9 and Linux 3.2.1. A few days after that, he also released Linux 3.1.10, saying that he is now done maintaining the 3.1 series and that users should switch to Linux 3.2.
After Kroah-Hartman announced that he would no longer maintain the 2.6.32 kernel, Tim Gardner of Canonical reported that Ubuntu would maintain it until April 2015. In the course of the discussion, Kroah-Hartman mentioned that he has most likely already found someone else who will continue maintenance.
- Philipp Reisner has released DRBD 8.4.1, which includes support for read load balancing and is intended to work with Linux 3.2.
Christoph Hellwig has sent the "XFS status update for December 2011" to the LKML.
- In a G+ post, Greg Kroah-Hartman called attention to the Linux Ate My RAM web site. It explains that Linux uses unused RAM as a cache rather than leaving it unused; applications therefore do still have memory available, even if programmes like
freesay that the RAM is completely used up.