3.3 merge window part 2

As of this writing, almost 8,800 non-merge changesets have been pulled into the mainline kernel for the 3.3 development cycle - 2,900 since last week's summary. The pace of the merge window clearly slowed in its second week, but there were still a number of interesting changes merged.

User-visible changes merged since last week include:

• The kernel has gained the ability to verify RSA digital signatures. The extended verification module (EVM) makes use of this capability.

• The slab allocator supports a new slab_max_order= boot parameter controlling the maximum size of a slab. Setting it to a larger number may increase memory efficiency at the cost of increasing the probability of allocation failures.

• The ALSA core has gained support for compressed audio on devices that are able to handle it.

• There have been some significant changes made to the memory compaction code to avoid the lengthy stalls experienced by some users when writing data to slow devices (USB keys, for example). This problem was described in this article, but the solution has evolved considerably. By making a number of changes to how compaction works, the memory management hackers (and Mel Gorman in particular) were able to avoid disabling synchronous compaction, which had the unfortunate effect of reducing huge page usage. See this commit for a lot of information on how this problem was addressed.

• There is a new "charger manager" subsystem intended for use with batteries that must be monitored occasionally, even when the system is suspended. The charger manager can partially resume the system as needed to poll the battery, then immediately re-suspend afterward. See Documentation/power/charger-manager.txt for more information.

• The Btrfs balancing/restriping code has been reworked to allow a lot more flexibility in how a volume is rearranged. Restriping operations can now be paused, canceled, or resumed after a crash.

• The audit subsystem is now supported on the ARM architecture.

• New device drivers include:
  • Systems and processors: Renesas R8A7740 CPUs, R-Car H1 (R8A77790) processors, NetLogic DB1300 boards, Ubiquiti Networks XM (rev 1.0) boards, Atheros AP121 reference boards, and Netlogic XLP SoC and systems.

  • Audio: Realtek ALC5632 codecs and Cirrus Logic CS42L73 codecs.

  • Block: Micron PCIe SSD cards and solid-state drives supporting the NVM Express standard.

  • Miscellaneous: TI TWL4030 battery chargers, Dialog DA9052 battery chargers, Maxim MAX8997 MUIC devices, Samsung Electronics S5M multifunction devices, and CSR SiRFprimaII DMA engines.

  • Video4Linux: Samsung S5P and EXYNOS4 G2D 2d graphics accelerators, remote controls using the Sanyo protocol, Austria Microsystems AS3645A and LM3555 flash controllers, Microtune MT2063 silicon IF tuners, Jellin JL2005B, JL2005C, or JL2005D-based cameras, HDIC HD29L2 demodulators, and Samsung S5P/Exynos4 JPEG codecs.

Changes visible to kernel developers include:

• The memory control group naturalization patches have been merged. These patches eliminate the double-tracking of memory and, thus, substantially reduce the overhead associated with the memory controller.

• The framebuffer device subsystem has a new FOURCC-based configuration API; see Documentation/fb/api.txt for details.

• The Btrfs filesystem has gained an integrity checking tool that monitors traffic to the storage device and looks for operations that could leave the filesystem corrupted if the system fails at the wrong time. See the comments at the top of fs/btrfs/check-integrity.c for more information.

The 3.3-rc1 release can be expected at almost any point; after that, the stabilization process begins for the 3.3 development cycle. If the usual timing holds (and it almost always does anymore), the final 3.3 kernel release can be expected in the second half of March.

Index entries for this article
Kernel	Releases/3.3

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