Welcome to the Linux Weather Forecast.

This page is an attempt to track ongoing developments in the Linux development community that have a good chance of appearing in a mainline kernel and/or major distributions sometime in the near future. Your "chief meteorologist" is Jonathan Corbet, Executive Editor at LWN.net. If you have suggestions on improving the forecast (and particularly if you have a project or patchset that you think should be tracked), please add your comments to the Discussion page. There's a blog that reports on the main changes to the forecast. You can view it directly or use a feed reader to subscribe to the blog feed. You can also subscribe directly to the changes feed for this page to see feed all forecast edits.

Forecast summaries

Current conditions:  the 2.6.30 kernel was released on June 9.  The 2.6.30 development cycle saw the addition of almost 12,000 individual changes from over 1100 developers representing some 200 different companies.  2.6.30 has  624,000 more lines of code than 2.6.29.

Some of the more interesting changes in 2.6.30 include:

• After a long series of discussions, the kernel developers decided to make a modified version of the "relatime" mount option the default.  This change will reduce disk traffic and improve battery life, at the cost of changing longstanding Unix-like behavior.

• The ext3 filesystem has seen a number of performance improvements, and now operates in the data=writeback mode by default (though distributors may well change that default).  See this article for a description of these changes and how they came about.

• Support for integrity management in the kernel has been merged.  This code makes use of the trusted platform module (TPM) built into many systems to ensure that the system's files (including its executable software) have not been corrupted, maliciously or otherwise.

• The TOMOYO Linux security module has been merged, providing a new type of pathname-based mandatory access control.

• The reliable datagram sockets protocol is now supported in the networking layer.

• Low-level support for object storage devices has been merged, along with the "exofs" filesystem which operates on top of such devices.

• The Nilfs log-structured filesystem has been merged.

• FS-Cache, a local caching layer for network filesystems, is now part of the mainline kernel (after some four years of development).

• The kernel has gained support for AMD/ATI R6xx and R7xx graphics chipsets.  Currently only two-dimensional graphics are supported; 3D support will come later.

See this article for more statistics on this kernel cycle.

Short-term forecast: the 2.6.31 merge window closed on June 24 with the release of the 2.6.31-rc1 prepatch.  Some of the more interesting 2.6.31 features will be:

• Performance counter support for the x86 and PowerPC architectures.  Performance counters have long been an out-of-tree feature; 2.6.31 will finally make this important hardware capability available in the mainline kernel.

• Support for char devices in user space.  The immediate application of this feature may be to provide support for the legacy Open Sound System driver architecture.

• Kmemleak, a development tool capable of finding memory leaks in kernel code.  Support for profiling the kernel with gcov has also been added.

• fsnotify, a new infrastructure for handling notification of filesystem events.  In 2.6.31, fsnotify will provide a unified implementation underlying the inotify and dnotify APIs.  In the future, it is intended to support the addition of an API so support malware scanning applications under Linux.

• New support for ATI Radeon graphics chipsets, using kernel mode setting and the (also merged) TTM memory manager.  These components should bring much better support for Radeon hardware, but this code remains a work in progress for 2.6.31.

• Storage topology support, which will help Linux provide high-performance support for future storage devices, has been merged.

The 2.6.31 kernel is now in the stabilization phase.  The final release of this kernel is likely to happen sometime around the end of August or the beginning of September.

Specific Areas of Interest

The forecast has been divided into a number of specific subject areas.

• Core Kernel Developments: schedulers, real-time support, event management, and memory management.
• Virtualization and containers: Xen, KVM, control groups, etc.
• Filesystems: ext4, btrfs, and other ways of storing data.
• Security: technologies and enhancements for keeping Linux systems secure.
• Networking: Network channels and other technologies for connecting systems together.
• Hardware Support: Topics of interest in hardware support.
• Miscellaneous: Topics which do not fit under any other heading.
• User Space: user-space code which forms an important part of the low-level platform.

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