Coming to you from Cambridge, Massachusetts, for Wednesday May 27th 2009, I'm Jon Masters with a summary of today's LKML traffic.

In today's issue: Kernel based checkpoint and restart, per-BDI writeback
flusher threads, Microblaze MMU support, ARM devicetree support, and Xen.

Kernel based checkpoint and restart. Oren Laadan posted version 16 of his
patch series intended to add kernel based checkpointing and restart to the
official Linux kernel. With the patch series applied, the kernel can save
state information for running applications so that they can be later resumed
from the time that they were checkpointed, or on another machine entirely.

Per-BDI writeback flusher threads. Jens Axboe posted version 8 of his patch
series implementing per-BDI writeback flusher threads. This patch series was
covered by the "In Brief" section of this week's Linux Weekly News Kernel
Page. In the latest version, various cleanup and hang fixes have been
incorporated. On a tangentially related note, Artem Bityutskiy posted a second
attempt at periodic writeback timer optimization. In this patch series, the
'pdflush' kernel threads are modified such that they won't wakeup every 5
seconds as they do now, but rather will intelligently do so when data
needs to be flushed out to disk or other secondary storage.

Microblaze MMU support. Michal Simek posted version two of the patchset adding
support for the Microblaze MMU. For those just tuning in, Microblaze (for
which support is being added in 2.6.30) is a soft synthesized core from
Xilinx. John Williams, and a team of merry men, have been diligently working
on support for the Microblaze for many years now. Your author can't wait to
finally be able to use an upstream kernel on his Xilinx ML403 boards.

ARM device tree support. On another embedded note, support for device tree on
ARM was finally posted to LKML. Janboe Ye posted a patch based on Grant Likely
and Josh Boyer's original work for powerpc. This allows ARM platforms to read a
flattened OpenFirmware-esque device tree blob passed in by the bootloader that
describes the platform. Your author was one of those suggesting this idea back
in 2005 at the Linux Symposium. Since then, many others have actually made it
happen, including Grant Likely of Secret Lab, the general ringleader.

Xen. Jeremy Fitzhardinge reposted several of his recent Xen patch series for
inclusion in the 2.6.31 merge window. No changes were made and apparently the
patch series posted have "no outstanding issues". This is, however, unlikely
to guarantee that fully Xen Dom0 support will make it into 2.6.31.

In today's announcements: Jon Masters announced release 3.9 of
module-init-tools. The latest version includes a large amount of ELF cleanup
work from Andreas Robinson. Karel Zak announced release 2.15.1-rc1 of
util-linux-ng. This release candidate includes a number of fixes. The
Linux Weekly News kernel page for May 28th is now available. It
includes the new "In Brief" summary section.

The latest kernel release remains at 2.6.30-rc7. An rc8 release is expected to
follow very soon, since several fixes are deemed urgent for 2.6.30 final.

Stephen Rothwell posted a linux-next tree for May 27th. Since Tuesday, a new
microblaze tree was added to the compose, the linux-next tree still fails to
build for powerpc allyesconfig, the vfs tree gained a conflict against the
gfs2 tree, the kbuild tree lot its build failure, the v4l-dvb tree lost its
build failure, the mtd tree gained a build failure to the previous day's
version was used, and the rr tree gained a conflict against Linus' tree. The
addition of microblaze brings the total subtree count to an impressive 141.

This final note today. Paul McKenney finally got added to the kernel
MAINTAINERS file. Paul has long-since been the go to guy for RCU releated
issues but wasn't listed as an official kernel maintainer until now.

That's a summary of today's LKML traffic. For further information visit kernel.org. I'm Jon Masters.