Kernel Log: Videos from LinuxCon and end to maintenance of 2.4 and 2.6.27 nears
by Thorsten Leemhuis
Videos and presentations from LinuxCon and the Embedded Linux Conference provide information about the development status of Btrfs and about problems between kernel hackers and the makers of Android. With the latest stable kernels, Linux 2.6.34 has reached the end of its life; furthermore, there are signs that maintenance of 2.4 and 2.6.27 will soon be discontinued or reduced.
The Linux Foundation recently made video recordings of some of the presentations held at LinuxCon 2010 (August 10-12, Boston) available online. A number of the videos available for free after registration or as downloadable OGG files as well as some of the presentation slides available under the details on the conference program provide information about the latest developments concerning the Linux kernel.
This year there was, once again, a kernel panel discussion where the audience could ask questions. The panel included SCSI subsystem maintainer James Bottomley, Fedora kernel and Cpufreq maintainer Dave Jones, Btrfs developer Chris Mason, and long term kernel contributer and Ext file system developer Ted Tso. LWN.net editor and kernel developer Jon Corbet moderated the discussion, which can be viewed as a video. If you do so, you will see Theodore 'tytso' Tso once again bring up the topic of "responsibility in troubleshooting and quality assurance", which was also discussed in a recent Kernel Log; the discussion seemed to have died down on the Linux Kernel Mailing List (LKML) but picked up again last week.
A member of the audience asked whether and when there might once again be an unstable series like 2.3 and 2.5 for the development of a "next-generation" kernel with a version number like 2.8 or 3.0; the kernel hackers responded by listing a number of problems in unstable series and discussing the numerous advantages of the current development model. Clearly, they are satisfied with the current strategy and believe that launching a new unstable series would be a bad idea.
The kernel panel spent more time on the problems concerning interaction with the developers of the Android kernels covered in past Kernel Logs. The presentation entitled "Android/Linux Kernel: Lessons Learned" (slides), which is available as a video, held by kernel hacker and power management expert Matthew Garrett sheds light on the issues; for example, he explains the history of wakelocks, which have also become notorious as "suspend blockers", and explains why Android does not have much in common with Linux distributions for PCs aside from the kernel. Like Tso, who currently works at Google, Garrett also praised a number of the efforts made by Android kernel developers, who he says have spent a lot of time including their improvements in the official kernel.
In his presentation entitled "Btrfs File System: Status and Future", also available as a video, Chris Mason (slides) lists a number of recent improvements and explains that he and other Btrfs developers are currently working hard on a program to review and repair Btrfs file system structures. He answers a number of questions from the audience and uses three demonstrations to show how Btrfs can be used to quickly find changed files, how files can be cloned, and how an old file system snapshot can be booted if something goes wrong when the distribution is updated. He jokes that, while he originally thought the main Btrfs development phase would be finished six months ago, he now believes that it could be completed in the next 6 to 12 months. He adds that the file system is already usable; he has never lost data, though others have not been so lucky.
The "Kernel Report" video is also worth watching, where Jon Corbet provides a far-ranging but nonetheless detailed and informative overview of current and future developments in the Linux kernel. Those interested in storage topics – such as disks with 4 KB blocks or discard for SSD – should also have a look at the video of Martin K. Peterson's presentation entitled "Linux and Advanced Storage Technologies." The list of videos and the conference program includes a number of other videos on kernel topics.