New Linux Kernel Arrives
- By Joab Jackson
- April 18, 2008
Version 2.6.25 of the Linux
has been released, Linux coordinator Linus Torvalds announced yesterday
on the kernel's development mailing
"It's been long promised, but there it is now," he wrote. In addition
to updating many drivers, the new kernel has additional support for real-time
computing and multiprocessor clustered computing. It also improves memory management
and comes with some new security enhancements.
The updates to 2.6.24 can be downloaded in one compressed patch of 12M. The
log of changes is 7.5M, or about 3,674 pages.
Changes include the addition
- A Memory Resource Controller, a framework for virtual containers to share
memory and other resources.
- Real-time group scheduling, or the ability to offer multiple groups a fixed
portion of CPU time.
- Read Copy Update (RCU) pre-emption support, the ability to pre-empt RCU
locking for real-time workloads.
- A new spinlock for x86 processors. Multiple programs running at once juggle
CPU time through the use of spinlocks, which lets one program execute while
keeping the others in a holding loop. This new spinlock cuts the potential
amount of time that a program may be stuck in a wait state. The spinlock can
work up to 65,536 processors at once.
- Improved measurement of memory use, to more accurately gauge how much memory
each program uses.
- Simplified Mandatory Access Control is a Mandatory Access Control (MAC)
implementation, like the National Security Agency's Security Enhanced Linux
(SELinux), but easier to set up and use than SELinux. Unlike SELinux, it does
not offer role-based access control.
- LatencyTop, a tool for pinpointing where delays occur in the execution
of a program.
- Completion of address space randomization, a security feature that places
programs in different spaces in working memory, so they can't be found easily
- Controller area network protocol support, allowing microcontrollers on
a circuit to communicate with one another without a centralized computer facilitating
- Updated EXT4 file system, to better support large files and extended attributes.
The last version of Linux, 2.6.24, was released in January. This release took
longer than expected, according to Torvalds, because of the time it took to
track down and correct a hard-to-find bug that reappeared in the recent release
candidates of the kernel.