LKML Summary Podcast

Audio: http://media.libsyn.com/media/jcm/linux_kernel_podcast_20091208.mp3

For Tuesday, December 8th, 2009, I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: Async resume, HWPOISON, perl and vger.kernel.org is moving.

Async resume. Rafael J. Wysocki posted a patch intended to implement asynchronous *resume*, as a counterpart to the asynchronous suspend patch, which he also posted an update for (along with rollback support to undo a suspend if part of it fails to complete). The main issue, as Rafael mentions, is in locking and knowing which devices should wait for which other devices, in what order, and handling this in reverse during wakeup. The patches were only “lightly tested”, according to the posting by Rafael.

HWPOISON. Andi Kleen posted some updates to HWPOISON, including a nifty feature entitled “soft offlining” in which pages are selectively offlined without killing a process (when they have too many corrected errors), implemented through userspace policy on kernel reporting.

Perl. Rob Landley posted a series of three patches intended to remove perl from the kernel build system and consequently do away with the dependency upon it. Not to play favorites here, but this author is extremely happy to see any use of perl go away, especially within the kernel community. There are of course a few ancillary functions that will need cleanup after Rob’s work.

Vger. The mail server that hosts the LKML will be taking an outage over the weekend while the server is relocated from one co-location facility to another. Consequently there will at least be downtime on the 12th and 13th, giving everyone an opportunity to take a rest from the LKML In noting the move, David Miller added that the IP address of the server will change.

In today’s announcements: Michal Marek posted a patch formally taking over kbuild maintainership from Sam Ravnborg, who no longer has time for it. Almost immediately, Michal posted his first round of updates, for kernel 2.6.33.

The latest kernel release is 2.6.32. Patches continue to accumulate in Linus’ tree. The latest pull includes DRBD as well as other gems. There was some good news also on the latest IO Controller (V4) patches, which Vivek asked to be repeated now that the patches have hit the blk tree and are in 2.6.33. Alan D. Brunelle (HP) stated that he would repeat his runs with the update.

Andrew Morton posted an mm-of-the-moment (mmotm) for 2009-12-08-17-45.

Greg Kroah-Hartman announced the latest stable kernels: 2.6.27.41 and 2.6.31.7. These contain a number of fixes. Note that there was a 2.6.27.40 kernel for a few hours, which missed a single fix for a driver that many users likely do not have installed.

Stephen Rothwell posted a linux-next tree for December 8th. Since Monday, the samsung tree needed a fixup for left over merge conflict artifacts, the nfs tree lost its built failure, the kbuild tree lost its conflict, the input tree lost its build failure, the block tree lost its build failure, the pcmcia tree lost its conflicts, the slab tree lost its build failure but gained another so the version from Friday was used, the percpu tree gained a build failure due to an interaction with the tip tree for which a patch was applied, and the hwpoison tree gained a build failure so the previous days’ version was used. The total sub-tree count remains steady at 155, and Stephen repeats his usual call for folks not to push items 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_20091207.mp3

For Monday, December 7th, 2009, I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: Ceph, errors, perf and VM.

Ceph. Sage Weil requested that Linus pull his “Ceph” distributed file system client, which has “made a half dozen rounds on linux-fsdevel, and has been in linux-next for the last month or so. Although review has been sparse, Andrew said the code looks reasonable for 2.6.33.”. Ceph apparently is intended for both high availability (HA) and reliability by having no single points of failure and strong data consistency between clients using replicated data stored across N storage nodes. For more, visit: http://ceph.newdream.net.

Errors. Roel Kluin posted a number of patches changing various use of PTR_ERR to use the correct pointer in a number of places within the kernel.

Perf. Mitake Hitoshi is working on a new round of updates for “perf lock”, the ability to profile the performance of spinlocks. He asked Steven Rostedt and Tom Zanussi whether raw_field_ptr() supports __data_loc (which is used to determine that a spinlock has been acquired in the “perf lock” code). He posted a temporary hack patch, and also noted that the meta-data surrounding held locks currently doesn’t include a numeric identifier, making it hard to tell the difference in “perf lock” between an rq lock on CPU0 and CPU1. Finally, Mitake pointed out a lack of information being provided by the trace events component even though it’s available (e.g. lock held time data). On a related note, Frederic Weisbecker sent posted some “urgent” hw-breakpoint fixes and asked that they be pulled.

VM. Al Viro sent one of his classical round of updates, this time for the VM implementation of “do_mremap”. Mostly, his code split out existing stuff into helper functions and added some cleanups. It was light on the usual sorts of “discriptive” language, however Not even one “turd” in there!

Finally today, Thomas Gleixner noted that a one line change to a header file (including a reference to an unused “extern int bla(void)” on an x86_64 system running the GCC 4.x compiler suite seemingly generated a bunch of “random” code changes in the assembler output. He (and Peter Zijlstra) provided other examples and Thomas wondered aloud if there were ways to turn off this “random number generator” or otherwise figure out what the heck is going on with GCC. Jakub Jelinek (of the GCC tools team) noted that the source had changed, which can result in various indexed hash tables changing (with the addition of the new variable reference), and could well explain this. He offered to look further if Thomas repeated his experiments with GCC 4.4 or 4.5.

The latest kernel release is 2.6.32.

Andrew Morton posted an mm-of-the-moment (mmotm) for 2009-12-07-17-01.

Someone identifying themself as merely “walt” (and who doesn’t bother to use a full name in other postings either, according to Google) noted that a recent commit from Frederic Weisbecker affecting hardware breakpoints seems to have also broken gdb.

Stephen Rothwell posted a linux-next tree for December 7th. Since Friday, the microblaze tree lost a conflict, the nfs tree lost a build failure but gained another for which a patch was applied, the pci tree gained 2 conflicts against Linus’ tree, the net tree lost its conflict and a merge fixup but gained a build failure due to an interaction with the kbuild tree for which Stephen applied a patch, the input tree gained a build failure for which Stephen reverted a commit, the block tree lost its build failure but gained another for which Stephen applied a patch, the pcmcia tree lost its conflicts, the slab tree gained a build failure so the version from Friday was used, the trivial tree gained a trivial conflict against the v4l-dvb tree, the i7core_edac tree lost its merge fixup and the tip tree lost 5 conflicts. The total subtree count remained steady at 155 trees, and Stephen repeated his usual call for calm in not pulling items intended for 2.6.34 until 2.6.33-rc1 has been released. The reason for so many conflicts at the moment in large part stems from Linus beginning to pull things into his treef for .33.

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