LKML Summary Podcast

Audio: http://media.libsyn.com/media/jcm/linux_kernel_podcast_20091213.mp3

Wondering if the latest Linus kernel tree builds? Why not follow @kernelbuild on twitter. I’ll be refining the format and adding additional tracking to it over time, and I welcome feedback. It builds every 3 hours at the moment.

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

In today’s issue: ATA, BFS, dm and md, FBAC-LSM, idle disks, nouveau, and the vger outage is now complete.

ATA. Apparently the long-awaited general support in hardware for 4K sector sizes is now becoming a reality. Mathew wilcox, James Andrewartha, and Peter Anvin all had things to say about this, especially James, who posted a number of links to manufacturer specific documents on the matter.

BFS. Con Kolivas announced that version 0.311 of his “Brain Fuck Scheduler” (BFS) is now available for kernel release 2.6.32. He included a summary of a number of changes, including code to measure cache locality and determine the best task to wakup (complete with a preference list).

dm and md. Alasdair Kergon and Neil Brown both announced updates for dm and md respectively. Both featured barrier updates (Alasdair announcing that dm now supports barriers on all devices, while Neil Brown noted that barriers are supported on all RAID levels – including RAID5 now). It is now possible to convert a 2-disk RAID5 md to RAID1 and vice versa (as possible before).

FBAC-LSM. Z. Cliffe Schreuders posted an initial version of a new LSM (Linux Security Module) intended to limit applications based on the specific features that each provides. He cites a number of items of documentation produced as part of his PhD research, including a comparison to SELinux. More will be available in his LCA (LinuxConf AU) presentation on the topic.

Idle disks. Mathew Garrett posted an RFC patch intended to add an event on block device idle change occurance. The idea is that userspace can monitor when disks are becoming idle (and when not) in order to adjust the power management policy on the fly in accordance with usage.

Nouveau. Following various ongoing debate (especially stired by Linus in response to earlier DRM tree updates, as also reported on LWN), Dave Airlie posted a tree entitled “drm-nouveau-pony” in an email thread entitled “drm pony for Xmas”. In the posting, Dave indirectly references the reasoning behind the driver not being available in mainline sooner (that it requires firmware or other code extract from the device, which isn’t included), notes that the driver alone is 36K lines of code (”bigger than most subsystems we carry, so hopefully ppl realise the monumental scale of writing a driver for these things”), and adds that he’ll be pushing the VMWare virtual GPU KMS driver “early next week” for good measure. There are some other legal topics being discussed surrounding this whole issue: refer to LWN for detail.

Vger. Remember that the mailing list server vger.kernel.org was moved over the weekend, and so consequently list traffic was significantly reduced. On a related note, David Miller noted in the thread discussing kernel names that he “should just remove” the hard-coded block list of words that cannot be said on LKML since the list does “dynamic spam filtering these days”.

In today’s announcements: Git version 1.6.5.6. Junio C Hamano announde version 1.6.5.6 of the GIT SCM as used by the kernel development community has been released. This version includes a number of minor fixes, as well as the removal of the “post-upload-hook” script run in response to “git fetch” due to some security concerns.

The latest kernel release is 2.6.32.

Stephen Rothwell posted a linux-next tree for December 11th. Since Thursday, the origin tree lost its build failure, the microblaze tree lost its conflict, the ext4 tree lost its build failure, the rr tree lost its conflict but gained a build failure for which Stephen applied a patch, the trivial tree lost its conflicts, and the usb tree still has its build failure for which he reverted a commit. The total number of sub-trees remained steady at 155, and Stephen repeated his usual “call for calm” in not pushing updates intended for 2.6.34 until after 2.6.33-rc1.

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

Audio: http://media.libsyn.com/media/jcm/linux_kernel_podcast_20091210.mp3

For my 28th birthday (December 10th 2009), I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: BKL, email clients, RCU, and VM.

BKL. Arnd Bergmann posted some compat_ioctl cleanups that also included BKL ellimination. He noted though, that some of these might want to wait for 2.6.34 if Linus felt that they should go through a linux-next cycle.

Email clients. Alan Jenkins posted some helpful updates to the Documentation/email-clients.txt file intended to clarify the situation for those who are using the “Thunderbird” mail client, I assume in light of the recent changes in behavior that have been reported, for which a fix may be forthcoming (and for which Jim Owens noted he had already taken measures to ensure that his modified config would continue to work after any “fix”).

RCU. Thomas Gleixner posted a 9 part patch series entitled “Fix various __task_cred related invalid RCU assumptions” in which he pointed out a number of incorrect assumptions (that happened to be true, but were not generally correct nor guaranteed to hold true forever) in RCU usage along with fixes.

VM. Hiroyuki Kamezawa posted a number of patches for the VM, including several intended to reduce a lock contention problem in vmscan that Larry Woodman had noticed, and several more that introduced an explicit entry for the number of swap entries in use by a given process within its /proc/self/status file.

In today’s announcements: Git version 1.6.6.rc2. Junio C Hamano announced the latest release of the GIT SCM as used by the kernel development community. This update had a large number of minor fixes. On a related note, do take a look at the excellent GIT Manual, available in PDF format. I love it.

Userspace RCU 0.3.2. Mathieu Desnoyers announced release 0.3.2 of his userspace RCU library, “which includes a complete rework of s390/s390x uatomic_* operations”. It is available from http://www.lttng.org/urcu.

The latest kernel release is 2.6.32.

Andrew Morton posted an mm-of-the-moment (mmotm) for 2009-12-10-17-19.

Greg Kroah-Hartman posted a series of review patches for the forthcoming 2.6.31.8 and 2.6.32.1 stable kernels, including a large number of ext4 fixes, and an obscurely unlikely stack corruption on 2.6.32.

Ingo Molnar reported a regression in the SLOB allocator code on an IA32 system for which he posted a complete kernel config. The system hung without any usable logs available.

Jens Axboe dissected an issue with Nehalem-EX failing to boot due to a faulty commit entitled “x86: Move find_smp_config() earlier and avoid bootmem usage”.

Xose Vazquez Perez pointed out some recent benchmarks from Phoronix in which, allegedly, “Solaris is 2.4X times faster than Linux” (in some configuration) when measuring OpenSSL performance. As was noted indirectly by Andi Kleen and others, these benchmarks were performed using vendor kernels (Fedora and Ubuntu – although apparently the tests were also done on a vanilla 2.6.32) and vendor compiled OpenSSL binaries that likely have issues. Andi said the best thing was to report any regressions (especially with OpenSSL) to Fedora directly as they were unlikely to be a kernel problem.

Stephen Rothwell posted a linux-next tree for December 10th. Since Wednesday, the origin tree gained a build failure for which Stephen applied a patch, the powerpc tree lost its conflict, the ext4 tree gained a build failure for which Stephen reverted a commit, the cpufreq tree lost its conflict, the trivial tree gained a conflict against the net-current tree, the tip tree lost its conflicts, and the usb tree still has its build failure for which Stephen reverted a commit. The total sub-tree count remained steady at 155 trees in the latest compose, and Stephen repeated his usual “call for calm” the folks not push patches intended for 2.6.34 until after 2.6.33-rc1.

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

Audio: http://media.libsyn.com/media/jcm/linux_kernel_podcast_20091209.mp3

For Wednesday, December 9th 2009, I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: Audio, hardware breakpoints, kbuild, and tracing.

Audio. Mark Brown, Linus Torvalds, Alan Stern, and others had a conversation concerning audio chipsets requiring reference voltages in which the hardware isn’t wired with a convenient reference to use and so various ramping up and down is required at suspend and resume time. Apparently, a delay is necessary in order to avoid a loud noise coming from the sound device on such hardware.

Hardware Breakpoints. Frederic Weisbecker noted a design flaw with the existing hardware breakpoint code. It turns out that the current design, which allows one to modify an existing breakpoint entry, does so by first unregistering and then re-registering the modified form thereof. This is racy with respect to another task creating a similar breakpoint. Frederic’s fix is to instead mark a breakpoint disabled during modification, then re-enable it.

Kbuild. Nir Tzachar pointed out some issues with the new ncurses based menu system that is being worked on. Specifically that lxdialog/check-lxdialog.sh always includes the “wide” (ncursesw) version of the library even if only the “narrow” version is needed, as in the case with the kernel. This can result (on systems with both versions installed) in non-color menus. Nir’s fix is essentially to ignore the “wide” version since it is not being used.

Tracing. Tim Bird posted a variant of the ftrace function tracer (build upon it) that can be used to filter on function duration, especially useful for embedded devices that wish to measure function duration during boot.

In today’s announcements: util-linux-ng version 2.17-rc2. Karel Zak announced the second RC of the forthcoming 2.17 release of util-linux-ng. As Karel previously mentioned, this version introduces a number of overhauls.

The latest kernel release is 2.6.32.

Americo Wang noted a regression in the current git tree, in the VM. He can’t reproduce it at the moment but it triggers in swap_free. Hugh Dickens said it looked like something had corrupted the start of a page table.

Stephen Rothwell posted a linux-next tree for December 9th. Since Tuesday, the omap tree lost its conflict, the samsung tree no longer needed a fixup and lost all its conflicts, the powerpc tree gained a conflict against Linus’ tree, the ext3 tree lost its conflict, the kbuild tree inherited a merge fixup from the net tree, the kvm tree lost its conflicts, the net tree lost its merge fixups, the kgdb tree lost its conflict, the slab tree lost its build failure, the omap_dss2 tree gained a conflict against the omap tree, the tip tree gained a conflict against Linus’ tree, the percpu tree lost 2 conflicts and its merge fixup (due to changes in the kgdb and tip trees), the hwpoison tree lost its build failure, the sysctl tree lost its conflicts, the tty tree gained a conflict against the trivial tree, the usb tree gained a build failure for which Stephen revered a commit, and the staging tree gained a conflict against Linus’ tree. The total sub-tree count remained steady at 155 trees in the latest compose and Stephen repeated his usual “call for calm” that people not merge items intended for 2.6.34 until after 2.6.33-rc1.

Finally today, Johannes Stezen asked Linus why the kernel name was no longer being updated post-2.6.32. Linus eventually replied (a day later, but since this update is late anyway, I’ll add it now) saying that he updates the name totally randomly, usually after he reads something that strikes him as funny.

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