LKML Summary Podcast

Audio: http://media.libsyn.com/media/jcm/linux_kernel_podcast_20090716.mp3

For Thursday, July 16th, 2009, I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: Git, Moorestown, scheduler, and Xinterface.

Git. Yesterday’s announcement of a new git release (1.6.4.rc1) triggered some discussion (from Jeff Garzik) concerning the correct ways to create new git repositories, especially “bare” repositories as are often hosted on kernel.org, and the correct gitconfig entires involved in so doing. On a related note, this author is hopeful that someone will document the best practices for git tree management on kernel.org, including whether the use of “shared” repositories on git.kernel.org is actually to be recommended.

Moorestown. Jacob Jun Pan posted (obviously from Intel) with a series of ten patches implementing x86 support for the new Intel Moorestown MID platform. Moorsetown is not a standard x86 system, does not include non-MMAPed IO, doesn’t feature ACPI, and so forth. It does include Lincroft (a north complex with CPU, memory controller, and graphics unit), and Langwell (IO hub, system controller unit, etc.). The posted patchset includes a number of features.

Scheduler. Frederic Weisbecker posted a series of patches, including an update to one scheduler patch that drops a looping call to need_resched() in cond_resched(), since the check has already been performed elsewhere. This improves overall performance and was mentioned previously. Separately, Peter Zijlstra posted a series of other scheduler fixes.

Xinterface. Gregory Haskins posted a series of patches implementing “xinterface”, this is the successor to the original vbus code, which was tightly integrated with KVM and which Avi Kivity had suggested be split out. That lead in part to what is now irqfd/ioeventfd, but one of the remaining pieces (pointer-translation) had been outstanding. Greg’s latest patches aim to implement a generic means for tracking of guest memory slots and notifying upon changes to them, in a generic fashion that can be used by things like virtio-net, and other modules, at some point. This allows kernel modules that are external to KVM to interface with a running guest, as Greg explains.

In today’s miscellaneous items: some powerpc fixes (Ben Herrenschmidt), version 4 of the Zero Page patches (Kamezawa Hitoyuki), a suggestion from Catalin Marinas that it would be worthwhile creating a tree containing fixes to leaks found by the kmemleak detector (presumably intended for linux-next inclusion), an RFC patch from Luming Yu stating that the current hotplug memory code is making inappropriate assumptions about the meaning of the Hot Pluggable bit of the Memory Affinity Structure (the SRAT table in the ACPI spec), some timer fixes (again) from Thomas Gleixner, some perfcounter fixes (Anton Blanchard), version two of the VGA arbitration patches (Tiago Vignatti), a libata patch (Matthew Garrett) exposing information about port hotplug capabilities to userspace, some Blackfix fixes (Mike Frysinger), and a request for clarification from Ted T’so (of Alan Cox) as to whether there is still an outstanding PTY bug in 2.6.31 or whether that has been fixed by now (he had been experiencing a weird PTY failure after a number of hours).

The latest kernel release was 2.6.31-rc3, which was released by Linus over the weekend. Caleb Cushing posted to say that he has seen a 20-50% drop in packets since switching from 2.6.30 to 2.6.30.1, which if true, needs investigation.

Andrew Morton posted another mm-of-the-moment for 2009-07-16-14-32.

Stephen Rothwell posted a linux-next tree for July 16th. Since Wednesday, the tree still fails to build in an allyesconfig build configuration on powerpc, and several trees lost their build failures. The total number of sub-trees remains steady at 132 sub-trees in the latest compose.

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