LKML Summary Podcast

Audio: COMING SOON

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

In today’s issue: Devtmpfs, kernel.h, mm, and power management.

Devtmpfs. Al Viro came forth with a couple of remarks concerning devtmpfs. He feels that there is a race waiting to happen with the code using a kstrdup (that might sleep) while holding an rwlock. This situation could arise in the case that a call is made to device_add, for example. Separately, Al posted part one of his VFS updates for the 2.6.33 kernel.

Kernel.h. Joe Perches posted a number of cleanups against the kernel.h header file, which he described as a “chaotic jumble collected over time”. Since, apparently, nobody specifically owns this, he sent the patches to Linus.

MM. Hiroyuki Kamezawa posted an updated eleven part patch series based upon Christoph Lameter’s mm_accessor patch that had been posted on November 5th. These patches replace all accesses to mm->mmap_sem with accessor functions that can be used to optimize such accesses in the future, for example by not taking mmap_sem in certain situations. Hiroyuki believes that the patch size is very large and so for eventual merging, it will be necessary to implement it in stages, with architectures later.

Power Management. Ingo Molnar sent his usual round of updates for the 2.6.33 merge window, including some updated Power Management patches. These contain, amongst other things, a patch from Arjan van de Ven that can be used to chart suspend and resume times for devices (especially when doing async suspend and resume, but also otherwise). Arjan continues to facilitate charting of boot and other latencies in getting devices up and running under Linux. On the subject of asynchronous suspend and resume, Linus Torvalds weighed in with some comments on the relative difficulty of asynchronous suspend and resume as applied to Cardbus bridges with many attached devices.

In today’s announcements: LTTng 0.182. Mathieu Desnoyers announced the release of LTTng 0.182 for the 2.6.32 series kernel. The latest release fixes builds on ppc440, and adds full support for ARM omap3 to the trace clock code (power management support, DVFS). Separately, Mathieu announced LTTV 0.12.25, the corresponding view tool that includes support for reading traces taken from an ARM omap3-based board.

The latest kernel release was 2.6.32.

Stephen Rothwell posted a linux-next tree for December 16th. Since Tuesday, the origin tree lost its build failure, the avr32 tree lost its conflict, the microblaze tree lost its conflict, the mips tree lost 4 of its conflicts, the acpi tree still had a build failure so the version from Friday was used (it also gianed a conflict against Linus’ tree), the hwpoison tree gained a conflict against Linus’ tree and also a build failure for which Stephen applied a merge fixup patch. The total subtree count remained steady at 155 trees and Stephen repeated his usual “call for calm” in not merging patches intended for 2.6.34 until after 2.6.33-rc1 has been released.

That’s a summary of today’s Linux Kernel Mailing List traffic, for further information visit www.kernel.org. I’m Jon Masters.