LKML Summary Podcast

Audio: http://media.libsyn.com/media/jcm/linux_kernel_podcast_20090913.mp3

I’m at the Linux Plumbers Conference, uploading a few updates between tracks. We’ll get there – sorry I’m behind again, but this isn’t an easy task!

For the weekend of September 13th, 2009, I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: Cpuidle, Dynamic Logical Partitioning, Localmodconfig, RO/NX protection for loadable kernel modules, and Timechart.

Cpuidle. Arjan van de Ven posted a patch implementing a new variant of menu cpuidle governor to boost IO performance, “[balancing] power savings, energy efficiency and performance impact.” The raison d’etre for this patch series stems from poor performance of the existing cpuidle governor code on recent Intel Nehalem server systems. Arjan includes some benchmarks, showing as much as 1.8 times performance improvement over the existing code, with only a very minimal overhead as compared with running a system without dynamically changing power cstates.

Dynamic Logical Partitioning (DLPAR). Nathan Fontenot posted a five part patch series implementing “Dynamic Logical Partitioning” (DLPAR) support for IBM pseries PowerPC 64-bit systems supporting dynamic hardware provisioning (addition, removal, and reconfiguration of processor and memory resources via the underlying hypervisor). The patches implement a number of probe/release sysfs files on such systems that can be used to signal the addition or removal of CPU and memory resources as required.

Localmodconfig. As covered previously, Steven Rostedt has implemented a Kbuild extension providing a Kconfig build target of “localmodconfig”. This will build a kernel that includes modular support for all locally present hardware, and is useful for kernel testing (without requiring a full build with support for non-present hardware). Steven posted an official merge request for 2.6.32.

RO/NX protection for loadable kernel modules. Siarhei Liak posted version 6 of a patch series implementing RO/NX page level protections for loadable kernel modules. This patch is a logical extension of the existing in-kernel page level protections for kernel executable code, but now adds such protections to loadable kernel modules by way of modifying the kernel module loading code.

Timechart. Arjan ven de Ven, known for his previous work using utilities such as bootchart (a tool to visualize the system boot process) announced the release of a new “timechart” utility that can be used to visualize exactly what is happening on a running system. It builds upon various timestamp counters added to the existing performance counters code, and a few other changes that Arjan has proposed to be added to the performance counters “perf” userspace utility.

In today’s pull requests: some updates to infiniband for 2.6.32 from Roland Dreier, some updates to ummunotify, which is a new character device that allows a userspace library to register for MMU notifications, also from Roland Dreier, some updates to libata-dev from Jeff Garzik (mostly trivial and driver updates), some powerpc updates for 2.6.32 from Ben Herrenschmidt (which Ben points out include a dependency upon various IOMMU and swiotlb bits currently in Ingo’s tree – so he is happy for Linus to delay pulling until after pulling from Ingo’s tree), some kmemleak patches from Catalin Marinas, some s390 patches for 2.6.31+ from Martin Schwidefsky (including “call home support”), the merge plan for linux-2.6-block bits in 2.6.32 from Jens Axboe (including updates to CFQ, cleanup of BIO IO flags, and various others), some tracing updates from Steven Rostedt, an official request to pull the per-bdi writeback flusher threads patches from Jens Axboe (including various benchmarks), some sound updates for 2.6.32 from Takashi Iwai, an official merge request for the HWPOISON patch series from Andi Kleen (these extend existing MCE handler coverage to catch transient bit errors in memory pages and take pre-emptive action by killing or otherwise signalling tasks experiencing memory corruption, in certain cases), some NFS client changes for 2.6.32 from Trond Myklebust, some OCFS2 updates for 2.6.32 from Joel Becker, some networking and SPARC updates (including initial LEON processor support from Konrad Eisele, basic software performance counters support from Jens Axboe, and very simple hardware counter support for UltraSPARC IIIi and Niagara-2) from David Miller, some KVM updates (including support for MCE injection, irqfd/ioeventfd mechanisms for communicating with guests, “unrestricted guests” on Intel systems – improving real-mode support – nested SVM improvements, syscall and sysenter emulation support, support for 1GB pages on AMD systems, and x2apic support for improved SMP performance all around) from Avi Kivity, some documentation updates from Jonathan Corbet, an initial round of SCSI updates for 2.6.32 from James Bottomley, some suspend updates from Rafael J. Wysocki, and several ftrace updates from Steven Rostedt (including a new mechanism to automate discovery of the output format being used by ftrace).

In today’s pull requests from (the village of) Ingo Molnar: core, debug, futuxes, Oprofile updates for 2.6.32, some threaded IRQ updates for 2.6.32, performance counters updates for 2.6.32, scheduling updates, tracing updates for 2.6.32, x86 updates for 2.6.32, and probably a lot more.

In today’s miscellaneous items: a patch splitting out separated read and write statistics for in flight block IO (bio) requests from Nikanth Karthikesan, a fix to fanotify support in the networking tree adding defines for the fanotify socket number declarations from Eric Paris, a fix to the io controller group code “root only” group optimization from Gui Jianfeng, some /dev/mem cleanups from Fengguang Wu, version 20 of the per-bdi writeback flusher threads patch series from Jens Axboe (mostly a rebase to 2.6.31 – Jens also posted a series of patches separately that should be applied post-merge of the per-bdi writeback flusher threads patch series), a patch removing automated scaling of readahead size on md if the RAID chunk size is greater than or equal to 4MB from Fengguang Wu, some tracing cleanups from Jiri Olsa, some documentation updates from Randy Dunlap, a kernel-level configfs enabled generic target engine for Linux (allowing for persistent registrations and multipath configurations within the ISCSI stack) from Nicholas A. Bellinger (he includes links to online wiki resources providing documentation), an RFC patch series implementing a trace module extension for crash (allowing for flight-recorder style usage) from Lai Jiangshan, support for timestamps on fork events in performance counters from Arjan van de Ven (as a required dependency of his timechart tool), an update to fix a situation in which creds->security could be NULL if SELinux is disabled from Eric Paris, some tree RCU fixes from Paul E. McKenney, some trivial warning cleanups from Filipe Contreras, some RFC PCI/ACPI run-time PM patches from Rafael J. Wysocki, and some ongoing discussion of the BFS.

In today’s announcements: Linux 2.4.37.6. Willy Tarreau announced version 2.4.37.6 of the Linux kernel. This release focuses mostly on fixing the various vulnerabilities causing information leakage to userspace, and so it is obviously a good idea to upgrade if you are running a 2.4 series kernel.

Git 1.6.4.3. Junio C Hamno announced the release of version 1.6.4.3 of the GIT SCM utility used in Linux kernel development (and other projects). The latest release includes a fix for an unnecessary error message during the git clone operation of an empty directory, and a number of other fixes.

The latest kernel release was 2.6.31.

Gene Heskett reported a potential regression on 2.6.31, which occurs when enabling the latency tester, and manifests in the form of zeroed CPU usage statistics reported in the gkrellm utility. Tetsuo Handa noticed a potential memory leak in load_module that was being reported by kmemleak. Parag Warudkar noted that the boot time trace testing recently increased from 3 seconds to 41 seconds and seems to be performing some tests three times.

Stephen Rothwell posted a linux-next tree for September 11th. Since Thursday, the rr and block trees have build failures, which the scsi-post-merge tree lost its build failure. Stephen reminds everyone that they should not begin pushing patches intended for 2.6.33 into linux-next until at least 2.6.32-rc1 has been released. The total sub-tree count remains steady today at 140 trees in the latest linux-next compose.

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