For Tuesday, May 12th 2009, I'm Jon Masters with a summary of today's LKML traffic.

In today's issue: vmscan, irqfd, OOM, and Xen.

vmscan. Ongoing work is taking place to improve the page evict code in
situations such as a typical desktop environment, and in particular to protect
referenced PROT_EXEC pages from being displaced by large single-use file IO or
other similar activities. Wu Fengguang posted a patch that aims to make mapped
executable pages a first class citizen by keeping them on the active list as
long as they are referenced during each full scan of the active list. The
patch interacts with another recent one from Rik van Riel that aimed to
explicitly evict use-once pages (for example, those due to an updatedb
operation) by preference.

irqfd. Gregory Haskins posted version 6 (and later in the day, versions 7,
7.1, and version 7.2) of a patch aimed at adding irqfd support to the Kernel
Virtual Machine (KVM) hypervisor. This patch adds a mechanism for injecting a
specific emulated interrupt into a running guest. Any valid signal on the irqfd
will translate into an interrupt seen by the running virtual machine when the
next availabe interrupt window is reached.

OOM. Christoph Lameter took issue at ongoing use of the term "Out of memory"
to describe the process whereby the kernel fails to perform a memory reclaim
and must kill something to free up memory for future and ongoing allocations.
When "out of memory" occurs, the system may not actually be out of memory at
all, but the kernel was certainly unable to make use of whatever was
available at the time of the OOM. Christoph says that he's seen scores of
people add memory to systems or lower ulimit values for users after receiving
warnings from the OOM killer, expensive actions and not necessarily helpful.

Xen. Jeremy Fitzhardinge reposted some Dom0 core changes and requested
inclusion against a specific topic branch to be created within Ingo's x86
tree on approval. The changes are varied and include some basic functionality
required of the hypervisor (such as basic IO permissions), and some cleanups.
Jeremy also posted updated Xen Dom0 PCI access patches, swiotlb updates, Xen
APIC hooks, a Xen /proc/mtrr implemenation, and likely more. Jeremy has been
aggressively pursuing the upstreaming of Xen Dom0 support recently, to
complement the existing support for DomU guests built into the kernel.

In today's announcements: Thomas Gleixner posted version rt12 of the RT
patches against stable kernel 2.6.29.3. This is a simple rebase featuring
loadavg calculation optimization and some futex fixes from Thomas and Peter
Zjilstra. Andrew Morton release an "mm of the moment": 2009-05-12-16-51.
It contains a large number of patches against 2.6.30-rc5. Kay Sievers
announced udev version 142 had been released. The release furthers the
ongoing effort at consolidation and cleanup, and also includes an updated
libudev for which no major changes of interface are planned. Version 2.6
of the alternative Gujin bootloader was released.

The latest kernel release remains 2.6.30-rc5, which was released by Linus on
Friday afternoon, just over a week after the release before that. A number of
additional patches are now sitting in Linus' tree, leading to a likely release
of a 2.6.30-rc6 kernel at the end of this week.

Stephen Rothwell posted a linux-next tree for May 12th. Since Monday's tree,
the driver-core tree gained a build failure for which Stephen reverted the
offending commit, and the staging tree lost a conflict. There remain 136 trees
comprising the linux-next tree at this time.

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