Linux kernel maintainer Andrew Morton last week revealed some of his plans for the next kernel version, a few days after the final release of Linux 2.6.20.

Developers are currently revving up the development phase of the 2.6.21 kernel, with major additions planned for the next week or two, before beginning to lock down and stabilise the software.

In a message to the kernel developers mailing list, Morton gave an indication of some of the major new components that will go into 2.6.21. One change will be improvements to the KVM virtualisation system, which made its debut in 2.6.20 along with an implementation of paravirtualisation.

Another addition is an upgrade to the high-resolution kernel timers subsystem, which is designed to handle high-resolution and high-precision timer features that are beyond the standard timer subsystem. This is designed to allow for features that can, for instance, reduce power consumption by temporarily switching off the timer interrupt.

Morton said he would put other additions on hold for the time being, such as the reiser4 filesystem and readahead, a technique designed to improve file reading performance.

Among the several hundred patches Linus Torvalds has already integrated for the new kernel are those upgrading the ACPI subsystem, improving PlayStation 3 support and updating network and IDE drivers. ACPI is a standard for hardware recognition, motherboard and device configuration and power management.

Morton expressed some annoyance at the sluggishness with which patches were being handled by subsystem maintainers. "I'm getting fed up of holding onto hundreds of patches against subsystem trees, sending them over and over again and seeing nothing happen," he wrote.