Linux kernel 2.6.36 has been released by Linus Torvalds and includes a number of performance and security enhancements, including integration of the AppArmor access control system.
Some Linux distributions, including Ubuntu and OpenSUSE, already ship AppArmor but with its inclusion into the mainline kernel less integration work is now required by distributors.
For improved desktop responsiveness, 2.6.36 includes code to fix problems where a desktop system could be unresponsive while performing tasks like writing to a slow USB storage device.
Also new is concurrency-managed workqueues, which re-designs workqueues to add a true thread pool manager.
Dedicated threads are replaced with a pool of kernel threads that grows dynamically as needed.
In announcing the release on the Linux kernel mailing list, Torvalds said 2.6.36 comes a week later than expected and hopes the first release candidate of the 2.6.37 will arrive before the 2010 Kernel Summit begins on November 1.
“The delay means that the merge window that opens now would cover the upcoming kernel summit,” Torvalds wrote. “However, I really hope that everybody sends me their patches and pull requests before [it] even starts.”
Kernel 2.6.36 includes a preliminary merge of a new file notification interface, fanotify, which bases notification on giving user space both an event type (open, close, read, write) and an open read-only file descriptor to the object in question.
Fanotify should fix scalability problems with the older inotify and dnotify systems and allows blocking or access controlled notification.
Torvalds said the developers ended up disabling the new fanotify system calls “because people were still unsure about the interfaces”.
“Better let the interface discussion cook a bit longer than release with a bad interface that we need to redo,” he said.
The kernel-based virtual machine (KVM) virtualization hypervisor gets more live migration support and along with the usual plethora of architecture and device driver improvement, 2.6.36 adds support for the Tilera Corporation’s Tile processor a new CPU designed to scale to hundreds of cores on a single chip.
See the Kernelnewbies 2.6.36 page for a detailed list of changes.