LKML Summary Podcast

Audio: COMING SOON

For Monday, September 21st, 2009, I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: Optimization, performance events, and trace events.

Optimization. Johannes Buchner posted some comparisons between kernel builds with varying optimization levels, pre-emption settings, and IO scheduling policy as pertained to overall system boot time. Overall, his figures indicated that optimization level and pre-emption setting had “no significant influence on speed”, while “CFQ let [his] system boot several seconds faster”. He posted some graphs on his blog. Of course, these figures are only from a single system, but they may be of interest to some others. Arjan van de Ven was interested that the IO scheduler mattered, given that (s)readahead is supposed to help with this, to which Johannes replied that he wasn’t using readahead for his measurements (CFQ apparently wasn’t improved using readahead, whereas the other scheduling algorithms might have been).

Performance Events. Ingo Molnar posted a merge request intending to rename the “performance counters” to “performance events” in light of the ever-expanding all-encompassing nature of the subsystem formerly known as “performance counters”. The tools remain unchanged (as does the ABI that they rely upon), and the rename is largely symbolic in terms of correcting a “missnomer”, largely done using a script that Ingo also included in his posting.

Trace events. Arjan van de Ven posted to bring up a suggestion that Ingo Molnar had made previously, involving the creation of a TRACE_EVENT_ABI, which would be equivalent to TRACE_EVENT except that it would signal a stable interface. But he was running in to some issues where TRACE_EVENT was being defined differently “all over the place”, leading to “really nasty hack[s]” just to make an alias. He wondered if Steven Rostedt had any clever ideas for making an alias “without fouling up the whole tracing system”.

In today’s pull requests: some DRM fixes from Dave Airlie (containing “the main chunk of the drm changes for 2.6.32″ – Ed Tomlinson wondered what was needed to actually use the R300 3D features), some UBIFS and UBI patches for 2.6.32 from Artem Bityutski, some writeback fixes from Jens Axboe, some x86 fixes from Ingo Molnar, some tracing fixes from Ingo Molnar, some scheduler fixes from Ingo Molnar, some performance counters fixes and updates from Ingo Molnar, some core kernel fixes from Ingo Molnar (including a bunch of RCU updates that came from Paul E. McKenney), some “performance events” patches from Ingo Molnar, some HID fixes from Jiri Kosina, sine trivial fixes from Jiri Kosina, some kbuild fixes from Sam Ravnborg (including kconfig refactoring), some firewire updates from Stefan Richter, some xen updates from Jeremy Fitzhardinge (including a fix for stack protector NX support on 64-bit processors that either don’t have the feature or have it disabled in the BIOS on those PC-BIOS systems), and some ioat/async_tx fixes for 2.6.32 from Dan Williams (the Intel one).

In today’s miscellaneous items: ongoing discussion of the best mechanism for implementing a callback when a swap slot is freed, a fix for a hardware erratum issue affecting AMD 813x rev. B1/B2/etc. parts that won’t generate interrupts when using legacy boot quirks from Stefan Assmann (who continues the fight against legacy “boot interrupts” – thanks!), a fix for a rare case when stable_tree_insert() finds a match when the prior stable_tree_search() did not occasionally causing a page leak from Hugh Dickins, helper functions for data filling of seq_file buffers without directly exposing the internal implementation from Miklos Szeredi (apparently suggested by Al Viro), some concerns about the mmapstress03 test in LTP having some “weirdness” from Geert Uytterhoeven, some wonderings whether wake_up_new_task really needs to play with task priorities from Peter Zijlstra (in reply to comments originally raised by a curious Peter Williams), an “alternative implementation” to handle d-cache aliases in performance counters without having to change how x86 does regular allocations (allowing such architectures to avoid unnecessary vmalloc, but necessitating a difference from e.g. sparc, which does) from Peter Zijlstra, a suggestion that a warning be printed whenever attempting to use kernel headers that have not been installed from Arnd Bergmann, version 2 of an RFC patch intended to allow use of SLQB on architectures that allow memoryless nodes to be installed from Mel Gorman, a patch adding a tracepoint for block request mapping from Jun’ichi Nomura, a patch increasing MAX_STACK_TRACE_ENTRIES from John Kacur (to Ingo Molnar – intended to avoid problems with lockdep running out of entries and falling over), and a discussion of when to perform access checks in fchdir from Trond Myklebust and Jamie Lokier.

The latest kernel release was 2.6.31.

Ingo Molnar pointed out that an earlier regression in tty_open last reported in 2.6.31-rc9 was still occasionally rearing its ugly head in -tip testing. Heiko Carstens reported that the latest git tree occasionally saw the “events” kernel thread running on the wrong CPU(!) on s390 with a default kconfig, but it turned out that this was already in a patch heading “Linuswards” later on in the day (Separately, Heiko posted a patch always showing cpus_allowed in /proc/ /status).

Stephen Rothwell announced that there would be no linux-next tree for the 21st, and possibly the 22nd also as he was “a bit under the weather”.

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

Audio: COMING SOON

For the weekend of September 20th 2009, I’m Jon Masters with a summary of the weekend’s LKML traffic.

In this weekend’s issue: devtmpfs, external module building, NOHZ, and PAUSE.

Devtmpfs. Various discussion continued concerning the allegedy “broken by design and implementation” devtmpfs support in recent kernels. Eric W. Biederman’s initial (highly critical and overtly negative) comments gave way to a general discussion as to whether waiting for certain hardware to stabilize could be pushed back out into userspace by means of modifying utilities such as modprobe. I am reviewing that particular thread at the moment since I missed out on it the first time around while at Plumbers. Separately, Kay provided some driver core patches providing devtmpfs with non-default permissions for device nodes.

External module building. Discussion continues about building modules (and other code) outside of the kernel. The original discussion had pertained to kernels built without certain optimization preferences, but had proceeded toward a general argument against certain practices common amongst those building out of tree pieces, such as expecting certain symlinks (e.g. /lib/modules/${krel}/build/arch/${arch}/include) to be present. Arnd Bergmann stated that he was considering adding a warning when -D__KERNEL__ is not set and one attempts to make use of the kernel header files. He would like to know if this would break any legitimate users (other than “make headers_install”, which he already made an allowance for).

NOHZ. Martin Schwidefsky reposted an RFC patch series adding “arch_needs_cpu” and implementing essentially the notion that one need not make the kernel enter into its “tickless” mode if the CPU did some work during the last tick period. In the case that the CPU does go truly idle, this does cause an unnecessary additional tick, but it has been shown to improve performance in Martin’s testing, especially in the s390 case that he is working on in general. He requests feedback.

PAUSE. Mark Langsdorf posted a patch enabling support for the “Pause Filter” in modern (”family 0×10 models 8+”) AMD CPUs. This feature provides a new field in the VMCB called “Pause Filter Count” and will keep a record of the number of times a PAUSE instruction occurs, which can optionally trigger a PAUSE intercept that the kernel can use to keep track of heavily contended spinlocks. In testing, Mark finds that most spinlocks are held for only around 1000 PAUSE cycles, so he defaults the threshold for reporting to 3000 cycles in order to detect contended spinlocks. This looks like a nice feature, which Mark is using with virtualized guests in order to force the yielding of an obviously busy VCPU that is just waiting on a contended spinlock variable.

In the weekend’s pull requests: some sh updates for 2.6.32-rc1 from Paul Mundt, some md updates for 2.6.32 from Neil Brown (mostly RAID6 offload), version 5 of the S+Core architecture support tree from Liqin Chen, some watchdog updates from Wim Van Sebroeck, some 2.6.32 ext4 updates from Ted T’so, some x86 platform support for 2.6.32 updates from Thomas Gleixner (laying the groundwork for upcoming Intel Moorsetown support – as Thomas has previously commented upon in variously varied ways), some i2c updates for 2.6.32 from Jean Delvare, some ISDN patches for 2.6.32 from Tilman Schmidt, some tracing/syscalls patches from Frederic Weisbecker, some ACPI and SFI patches for 2.6.32 from Len Brown, some timechart patches from Arjan van de Ven (who later added a new “perf timechart record” patch, ’similar to “perf sched record”‘), some tracing cleanups for 2.6.32 from Steven Rostedt, some performance counters patches for 2.6.32 from Ingo Molnar (who notes that two of the commits had “mingo” as the owner due to a broken git configuration), some driver core and TTY patches from Greg Kroah-Hartman, some i2c patches from Ben Dooks, and some includecheck fixes from Jaswinder Singh Rajput.

In the weekend’s miscellaneous items: an iocontroller patch fixing a system hang from Gui Jianfeng, a couple of tracing (profiling) updates from Frederic Weisbecker (sent a couple of times for good measure), some ftrace updates from Li Zefan, a new –input option for the performance counter tools allowing one to pass input files from Mike Galbraith, some feedback from Ryo Tsuruta to Vivek Goyal concerning some benchmarks he had previously done of Ryo’s work on the ioband competing patches to [Vivek's] io controller patch series, a crash report from Ingo Molnar in -tip testing (dev_attr_show), a series of MCE ring buffer fixes from Huang Ying, the removal of markers from Ingo’s tree by way of him applying Christoph’s “kill markers” patch, a typically very helpful reply from Alan Jenkins (to Vprabu Vprabu) on the nature of loadable modules and how they work in recent kernels (as well as how they fit in with hot/coldplugging – Kay Sievers added some additional comments too), an EDAC build error fix from Ted T’so, a patch preventing vgacon_deint from touching hardware in the case of inactive consoles from Fancisco Jerez, version 2 of the Dynamic Logical Partitioning support patches from Nathan
Fontenot, a patch for m68knommu to allow kernel command line parameters to be passed through from the uboot firmware bootloader from Lennart Sorensen, an RFC “hatchet job” for SLQB on memoryless node configurations (as pertains to PPC and s390 systems) from Mel Gorman (this is not a full implementation yet though, since it only boots on “at least one machine” Mel has available), a patch preventing the scheduler from immediately rescheduling a yielding process if another process is available from Mark Langsdorf, some more linker script cleanup patches (facilitating ksplice integration) from Tim Abbott, a criticism of “global” events in fanotify from Andreas Gruenbacher (since “virtual machines” in separate namespaces with confuse matters), another round of ISCSI TCM/ConfigFS patches from Nicholas A. Bellinger, some patches removing a perl dependency (always a good idea) introduced in 2.6.25 (making it possible to build at least a “bootable” kernel without perl) from Rob Landley, some interesting patches proporting to migrate x86 Intel systems with fewer than 8 logical CPUs over to the “flat mode” APIC routing (which I didn’t think was necessary until you had more than 8 logical CPUs – but maybe it’s not worth having the two different modes any more?) from Suresh Siddha, a new per-cpu notifier that is called whenever the kernel is about to return to userspace from Avi Kivity (sounds very useful), a note from Avi Kivity that the KVM folks reached a similar conclusion to the VMWare guys that many of the paravirtualization hooks are no longer necessary for performance reasons over native EPT/NPT support (causing Alok Kataria to send along the patches actually removing the VMWare VMI code, for general review – and causing Ingo Molnar to remind everyone that this needs to be handled “carefully” over a few kernel cycles with a proper sunset period), fscache support for plan9 filesystems from Abhishek Kulkarni, a patch exporting a couple of tracing symbols otherwise leading to build errors from Peter Zijlstra, some comments on the modules.builtin implementation from Sam Ravnborg, a patch adding coretemp support for the Core i5 (Lynnfield model 0×1E) CPU from Robert Hancock, and a question as to what the pgpgin/s and pgpgout/s columns in “sar” should actually be measuring from Ted T’so.

The in weekend’s quote of the day: Greg Kroah-Hartman responded to some rather hostile comments from Eric W. Biederman (refering to devtmpfs coolaid) with the line “Oh, we have official team drinks now? Great, sign me up, can I pick a t-shirt logo as well? ”.

In today’s announcements: fopsbench. Tobias Oetiker announced the release of a new benchmarking tool for measuring the response time of various filesystem operations, which he calls “fopsbench”. He includes various example output, though I admit to being unclear whether bonnie++ already provides these.

2.6.31-rt11. Thomas Gleixner announced version 2.6.31-rt11 of the preempt-rt patchset, which (amongst other things) includes a latencytop fix and some IRQ fixes. There are still some scheduler issues that Peter Zijlstra is continuing to work on.

The latest kernel release was 2.6.31.

David Miller reported a regression on sparc64 that he suggested might be attributed to recent percpu changes from Tejun Heo, which he verified by reverting the offending commit in his local tree. Robert Hancock reported a problem with recent git trees failure to boot with a DMAR error on his Intel Lynnfield CPU-based Asus laptop.

Stephen Rothwell posted a linux-next tree for September 18th. Since Thursday, the input-current and rr trees had issues, while the blackfin, ext4, nfsd, xfs, and i2c trees lost their issues. The tree continued to have problems bouncing from one sub-tree to another as Linus continued merging for .32. The total tree count in the latest compose remained at 140 trees, and Stephen repeated calls to avoid adding features intended for 2.6.33 until after the RC1 of 2.6.32 was out.

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

I just recorded 7 podcasts and have a few more going through production at the moment. I am doing my best to get up to date today…here’s hoping. Of course, feel free to volunteer to help

Jon.

Audio: http://media.libsyn.com/media/jcm/linux_kernel_podcast_20090917.mp3

For Thursday, September 17th, 2009, I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: devtmpfs, performance counters, ummunotify, VFS, and VMI.

Devtmpfs. Eric W. Biederman posted a patch entitled “Remove broken by design and by implementation devtmpfs maintenance disaster”, which was bound to get some attention in the process. Devtmpfs is a recent effort from Kay Sievers (and several others) to implement some of the better minimal features of an in-kernel udev-style device tmpfs for pre-udev or non-udev environments. It isn’t intended to be a replacement for a userspace device filesystem (udev came about following previous attempts at in-kernel filesystems such as Richard Gouch’s devfs), but can help with initial device node population. Eric wasn’t buying it though, and criticized devtmpfs for breaking tmpfs, not handling errors, being in the wrong kernel tree location, having an incorrect Kconfig, and fundamentally having a “bogus” justification for existing. He (Eric) believes that it doesn’t solve any hotplug problems (which can be addressed – in his opinion – with a static dev), and that doing it in userspace is not slower but is more flexible. He also takes issue with the way devtmpfs was developed and the fashion in which it was merged, especially suggesting that review issues were “dismissed, ignored, or met with lies”.

Kay answered each of Eric’s points calmly and with a carefully reasoned response, which included pointing out devtmpfs isn’t strictly a filesystem (it just populates a tmpfs superblock, which is why it doesn’t live in fs/), isn’t intended to exist for speed purposes (he asks Eric to re-read the archive), and includes another explanation of how static /dev filesystems are unreliable and unpredictable and why this is useful, given that it is being proposed by precisely the same people who develop the userspace tools and generally prefer to have as much hotplug functionality in userspace as they can. Overall, Kay’s response is very much worth reading for anyone else who is confused about the raison d’etre for devtmpfs. Greg’s reply was much shorter (and very much not liked by Eric, who said he wasn’t “relevant to this discussion”). Greg wondered aloud why Eric didn’t see fit to CC both him and Kay on the original message, saying “if I was a paranoid person, I would think that you were somehow trying to skirt around us for some unknown reason”. He defered to Kay’s response (which Eric thought showed how Kay “wasn’t paying attention”) for the remaining technical justifications.

Alan Cox agreed with Eric’s assertion that someone in the filesystem camp should sign off on devtmpfs. He prefers that someone to be Al Viro (as Eric had suggested), and is less concerned about arguments of “devfs2″ than whether any implementation of an in-kernel device filesystem is technically correct and “doesn’t screw stuff up”.

Performance Counters. Ingo Molnar announced a new utility forming part of the ever-growing family of “perf” tools. “perf sched” is a utility to “capture, measure and analyze scheduler latencies and behavior”. It is intended to provide hard data to meet the “ambitious goal” of using performance events to objectively characterize arbitrary workloads from a scheduling and latency point of view. Using “perf sched”, one can record and visualize various aspects of scheduling workloads such as latencies and context-switches. Ingo includes several full examples, documentation, and a new branch on his “tip” tree that he requests Linus consider merging into the tree immediately. Ingo would clearly prefer this utility for more “apples to apples” type of comparisons between future competing scheduler implementations.

ummunotify. Peter Zijlstra followed up to the recent request that ummunotify be pulled in reviving a previous comment (apparently from Aton Blanchard) that this stuff “might be integrated with perf-counters” (since performance counters already features mmap() tracking and provides events through an mmap buffer). It’s a stretch, but one can see where Peter is coming from without going too far down the “let’s put everything in perf. counters” road. Still, Roland Dreier didn’t think it was a good fit to be integrating these. As he puts it, he’s trying to solve the problem of allowing an app to request notification when a (small) subset of its address ranges are backed by mappings that then become invalidated, whereas performance counters doesn’t provide a mechanism to track individual ranges (only all mmap() traffic). Peter thinks this could still be added to performance counters though.

VFS. Jan Kara posted version 3 of a 7 part RFC patch series entitled “Improve VFS to handle better mmaps when blocksize < pagesize”. This is intended to solve problems that arise with mmap()’d writes when the blocksize is less than the pagesize. Jan explains that we would like to use page_mkwrite() to allocate such blocks (the filesystem can return a page fault in certain error situations), but cites a situation where only one block is allocated for a page that – on later write – suddenly needs additional blocks allocated, that we ideally should have allocated ahead of time). So far, apparently ext2 and ext4 have “survived some beating”, so Jan is seeking further comments.

VMI. Alok Kataria posted to let everyone know that the folks at VMWare have been performing experiments to compare the performance of VMware’s paravirtualixation technique (VMI) with modern hardware MMU technologies in recent Intel and AMD processors, on VMware’s hypervisor. They found that in most of the benchmarks, the hardware EPT/NPT technologies are at par or provide better performance than using the older VMI approach. For this and other reasons explained in the email, VMWare have decided to discontinue support for VMI and they request comments on how best to go about “retiring” the VMI code from mainline Linux in due course. Various others were appreciative of the heads up and supportive of removing code that won’t be supported in future.

In today’s pull requests: a series of tracing fixes for 2.6.32 from Steven Rostedt, some MFD updates for 2.6.32 from Samuel Ortiz (requested twice, the second time without one of the drivers being incorrect), some FUSE updates from Miklos Szeredi, some Blackfin patches from Mike Frysinger, a request to pull the async_tx tree in order to receive dmaengine, async_tx, and RAID6 updates from Dan Williams (the Intel one), some networking and SPARC updates from David Miller (including John Linville’s latest wireless updates), some sound fixes from Takashi Iwai, some further tracing updates from Steven Rostedt, some timechart patches from Arjan van de Ven, some libata updates from Jeff Garzik, some further tracing updates from Ingo Molnar, some scheduler updates from Ingo Molnar (which include the remainder of the rework on the load balancer rewrite, but which are very new and potentially have some risk), some additional x86 fixes from Peter Anvin, and some x86/mce fixes from Peter Anvin.

In today’s miscellaneous items: a Makefile patch from Caveh Jalali fixing build problems for external modules on certain architectures, ongoing discussion of mm-of-the-moment (mmotm) merge plans for 2.6.32, a series of USB console fixes for 2.6.32 from Jason Wessel, version 2 (and then 3, and then 4) of an RFC patch checking for negative f_pos handling from Kamezawa Hiroyuki (the 4th version introduces a new flag S_VERYBIG for which negative offsets will be allowed – covering certain special system files), version 3 of a patch series moving use_mm/unuse_mm from “aio” into the core “mm” directory from Michael S. Tsirkin, a defense of DRBD from Lars Marowsky-Bree (in response to a – typically blunt – commentary from Christoph Hellwig), a suggestion from Mel Gorman that having an in-kernel user of the altered hugetlbfs interface might need to be a pre-requsite to mergeing of the recent hugetlb patches, a fix for softirq_to_name from Li Zefan, a question from Jan Kara as to whether the nobh_ versions of various functions in fs/buffer.c are still useful (was it because buffer heads consume memory? if so, why are only ext2/3/4 using them?, and in only a limited capacity), a patch killing off kernel markers (”now that the last users of markers have migrated to the event tracer code”) from Christoph Hellwig, a patch supporting the recent addition to qemu of a VIRTIO_BLK_F_FLUSH flag marking a virtual disk has having a volatile write cache, a large number of mmotm merge plan comments from Oleg Nesterov, a report of a 2.6.31-rt10 crash from John Kacur (a stack corruption bug during a “make modules_install install”), a patch adding support for dumping the stack and VM state on OOM kill from David Rientjes, and version 3 of the “compcache” compressed swap patches from Nitin Gupta.

Finally today, Linus rants about how everything could be implemented as a system call (including, in some ideal world, even representing page faults as pseudo-system calls for tracing purposes), and criticizes “idiotic packet interface[s]” (he was replying to a thread discussing fanotify) that are “just a fancy way to do ioctl’s, and everybody knows that ioctl’s are bad and evil. Why are fancy packet interfaces suddenly much better?”. Why indeed Arjan van de Ven decided that adding page faults to his timechart utility was probably a good idea, based on Linus’ tracing comment.

The latest kernel release was 2.6.31.

Ingo Molnar notes that a previous round of PCI updates from Jesse Barnes have been causing “nasty bo tup crashes” in the PCI code for -tip. He cites an example of such a failure.

Andrew Morton posted an mm-of-the-moment for 2009-09-17-18-00.

Stephen Rothwell posted a linux-next tree for September 17th. Since Wednesday, the blackfin tree changed location and owner, the ia64 tree returned after the author came back from vacation, and the reiserfs-blk (part of the ongoing effort to kill off the Big Kernel Lock or BKL) was temporarily removed. Stephen reports that conflicts are still bouncing from one tree to another as Linus merges trees: the tty.current, input-current, blackfin, ia64, ext4, rr, and nfsd trees had issues, while the thumb-2, microblaze, sh, pci, and driver-core trees lost their previous issues. The total sub-tree count remained steady at 140 trees in the latest compose.

Eric Paris reports that linux-next trees after September 14th are unbootable on his KVM guests. He posts a bisect that comes down to a series of scheduler fixes, along with the panic message from his Fedora system.

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_20090916.mp3

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

In today’s issue: Blackfin, Fanotify, KVM, and tracing.

Blackfin. Daniel Walker ranted about Mike Frysinger’s posting of Blackfin patches to the LKML. Mike responded that he hadn’t seen any complaints from others about large patch series being posted, and that those with “sane” mail clients wouldn’t have to deal with much more than skipping an entire thread anyway. Andrew Morton then steered the conversion towards why Blackfin wasn’t being pulled into linux-next, to which Mike replied with a request for further information about the process for getting his patches into Stephen’s tree.

Fanotify. In response to comments from Linus on the previous afternoon (in which Linus questioned “what’s so wonderful about fanotify that we would actually want yet-another-filesystem-notification-interface”), Eric Paris posted a rather detailed overview of the kinds of features offered by his interface. Chiefly, Eric cites the fact that fanotify passes an open fd with each event rather than “some arbitrary ‘watch descriptor’, along with an extensible data format, and a commitment from several anti-malware companies to use the new interface once it is available in the mainline kernel. Jamie Lokier sent a rather terse (however quite lengthy) response that criticised various features not currently available with fanotify (such as subtree notification) and suggested that his main concern was avoiding mistakes made with the previous inotify and dnotify mechanisms, while encouraging Eric to consider other use cases not covered by anti-malware consumers.

KVM. Today being a KVM Wednesday, there were a number of patches posted. First off were some rather cool looking patches from Avi Kivity implementing “just in time” MSR switching. These aim to reduce the need to perform expensive MSR update operations on guest pre-emption. KVM already optimizes to avoid such writes on every guest entry/exit, but it will now defer to the very last possible moment before performing such an update. Not to be outdone, Joerg Roedel posted some nested SVM “fixes and cleanups” aswell.

Tracing. Steven Rostedt inquired as to collective viewpoints on a dedicated tracing list, to be held on vger.kernel.org. The idea would be to have a separate place for discussions related to users of tracers and the “perf” performance counters utility. This “will not be a place for kernel development”, according to Steven, who wishes to address the issue of LKML being intimidating for those having questions, without causing development fragmentation by taking important discussions elsewhere.

In today’s pull requests: an XFS update from Alex Elder (including a large number of the fixes previously discussed from Christoph Hellwig), some networking and SPARC fixes from David Miller (containing quite a few important looking fixes in both cases), an official request to merge the latest version of Andi Kleen’s hwposion patches into 2.6.32, part two of some AMD64 EDAC updates from Borislav Petkov, some ext3 fixes from Jan Kara, an email from Roland Dreier (in which he also reminds us that he’s been showering and brushing his teeth, so shouldn’t be entirely ignored) asking Linus where his ummunotify request stands, some DLM updates for 2.6.32 from David Teigland, some tracing updates from Steven Rostedt, and the latest round of wireless patches from John Linville (who describes them as being “nothing too controversial”).

In today’s miscellaneous items: some further kmem and hwpoison bits from Fengguang Wu, a rant from Daniel Walker about Mike Frysinger’s posting of Blackfin arcihtectural patches to the LKML (which nobody else endorsed), a patch marking the SLQB allocator as “broken” on PowerPC and s390 from Pekka Enberg, a fix to use the correct export symbol to walk a system ram range in infiniband from Kamezawa Hiroyuki, a question about explicitly putting a PCI device into an ACPI D0 state from Michal Witkowski, a patch to disable preemption within stop_machine from Xiao Guangrong, a suggestion from Balbir Singh that the memcg patches in Andrew’s mm tree be merged for 2.6.32, version 3 of a patch series from Jiri Olsa implementing multiple pids within the tracing set_pid_ftrace file, a patch changing the name of the kernel thread managing an md raid device according to the type of RAID level in use (rather than the default of merely always using “5″) from Zen Chen Jin, an RFC patch series from Sheng Yang entitled “Xen Hybrid extension support” intending to allow guests to run in other than ring0 context (thus avoiding the TLB flush overhead in context switching between guest and hypervisor), some comments from Vivek Goyal concerning the fairness (or lack thereof) of the ioband patches when running on rotational media (as compared with his own IO scheduler based IO controller patches), a regression in kallsyms reported by Paul Mundt (who says that both Sam Ravnborg and Lai Jiangshan have yet to respond), version 2 of a patch adding support for walltime to ftrace from Zhao Lei, an RFC patch to handle a negative f_pos when manipulating /dev/kmem from Kamezawa Hiroyuki, some updates to the page-types utility from Fengguang Wu, version 4 of the post merge per-bdi writeback patches from Jens Axboe, the latest version of the “Memory Protection Units” (MPU – a simpler MMU alternative implementation) from Mike Frysinger and originally authored by Bernd Schmidt, a patch finally updating the MAINTAINERS file with the new location of the ARM linux mailing lists on infradead from Joe Perches, some linker script cleanups from Tim Abbott (enabling ksplice pre-requisites), a patch warning when selecting symbols with unmet direct dependencies in kbuild from Catalin Marinas, a fix for degraded performance when all inodes are under writeback from Jan Kara, a reiserfs patch also from Jan Kara, a defense of the vnet bus patches from Gregory Haskins (in which he lays out the case for kernel-to-kernel virtualizable communication), a fix for an oprofile related ring buffer regression from Christian Borntraeger, and some futex comments from Darren Hart.

Finally today, various responses came in related to the “Tricks to speed up kernel builds”. Thomas Fjellstrom says he prefers using icecream with make -jX, while David Lang provides further build analysis.

In today’s announcements: Greg Kroah-Hartman posted review patches for the stable 2.6.27.35 and 2.6.30.8 kernels, and Jakub Narebski announced that the Git User’s Survey 2009 had ended (for which results will be available soon). On that note, Junio C Hamano announced the release of git version 1.6.4.4 (which includes an important fix for users of github occasionally experiencing an HTTP 500 error response).

The latest kernel release was 2.6.31.

Andreas Mohr reported a regression in which USB autosuspend no longer functions after performing a suspend-to-RAM and resume cycle.

Stephen Rothwell posted a linux-next tree for September 16th. Since Tuesday, conflicts continue to bounce between various trees as Linus continues to perform various merges. Linus’ tree had a build failure (for which a patch was applied), the rr tree also had a build failure, while the drbd and staging trees lost their conflicts. The total sub-tree count remains steady at 140 trees in the latest compose. Stephen reminds everyone not to post patches destined for 2.6.33 until at least 2.6.32-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.