LKML Summary Podcast

Audio: COMING SOON

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

In today’s issue: KFIFO, PCI asynchronous power management concerns, and Transcendent memory.

kfifo. One of the several revived patchsets posted today was an updated version .08 of the “new kqueue API”, posted by Stefani Seibold. The patches provide generic macros providing for kernel FIFO management, in order to have only one full FIFO implementation in the kernel tree. The latest version retains the existing API but also implements in-place FIFOs where the data space is part of the FIFO structure itself.

PCI asynchronous power management concerns. Rafael J. Wysocki posted an RFD inquiring as to general consensus on his ongoing effort to provide asynchronous power management for PCI devices (by suspending and resuming unused devices dynamically when they are not in use) and whether this was really as “dangerous”, in general, as Linus had implied. He specifically wanted to know what provides could exist and what could be done about those problems in order to implement full support for this concept.

Transcendent memory. Dan Magenheimer posted an updated version of his July 2009 “Transcendent memory” patchset, rebased to 2.6.32. This patchset provides support for resizeable memory regions that are opportunistically provided by the kernel to support certain applications and virtual machines, but which may be recalled at any time if memory pressure becomes tight. The basic idea is to provide for cacheing needs of database apps, virtual machines, and the like, while not committing large chunks of memory that cannot be reused. In the latest version, Dan includes fixes, support for btrfs and ext4, and has added some performance measurements that were presented at OLS this year. On another VM note, Hiroyuki Kamezawa posted some speculative pagefault patches that were based upon the previous “mm accessor updates” patches.

In today’s announcements: Linux 2.6.33-rc1. Linus Torvalds, in announcing that the merge window for 2.6.33 is now closed, posted the first 2.6.33 (rc1) kernel on Thursday evening at 18:05 Best Coast Time (PST). Linus grumbled that developers left their pull requests pretty late this time around, saying, ‘The two-week merge window is _not_ supposed to be “one day merge window after thirteen days of silence”. He says he may try shortening the merge window next time just to catch these people off guard and “unceremoniously” bump their bits to 2.6.35 instead. There were a few last minute pull requests for s390x, wireless, and so forth.

LTTng 0.183/0.183o. Mathieu Desnoyers posted an updated version of the LTTng patches, addressing a minor issue with the OMAP timer code.

The latest kernel release is 2.6.33-rc1.

Greg Kroah-Hartman announced the release of stable kernels 2.6.27.42, 2.6.31.9, and 2.6.32.2.

Torsten Kaiser noted that he again experienced issues with the new support for MSI (Message Signalled Interrupts) in certain SATA drivers (sata_sil24 is new in 2.6.33, but sata_nv was not working either with 2.6.33).

Stephen Rothwell posted a linux-next tree for December 18th. Since Thursday, the m68knommu tree lost its conflict, the ocfs2 tree gained a conflict against Linus’ tree, the build tree lost its merge fix, the fsnotify tree still had a build failure for which Stephen applied a merge fixup patch, and the tip tree lost its conflict. The total subtree count remained steady at 155 trees, and Stephen let us know that he’s taking a break over the holidays, “most likely, Dec 29″ will be the next linux-next release. No sooner had he sent that than he noticed Linus’ 2.6.33-rc1 posting and did one more rebase for December 19, “so it will be based in -rc1″, albeit with slightly less testing time.

Finally today, Joe Perches posted an updated patch to checkpatch, increasing the warn limit on long lines of program source code to 105 from 80. It seems the VT100 is finally dead to even the last die-hard enthusiasts amongst us.

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