3.6 merge window part 2

As of this writing, just over 8,200 non-merge changesets have been pulled into Linus's repository; that's nearly 4,000 since last week's summary. It seems that any hopes that 3.6 might be a relatively low-volume cycle are not meant to be fulfilled. That said, things seem to be going relatively smoothly, with only a small number of problems being reported so far.

User-visible changes merged since last week include:

• The btrfs send/receive feature has been merged. Send/receive can calculate the differences between two btrfs subvolumes or snapshots and serialize the result; it can be used for, among other things, easy mirroring of volumes and incremental backups.

• Btrfs has also gained the ability to apply disk quotas to subvolumes. According to btrfs maintainer Chris Mason, "This enables full tracking of how many blocks are allocated to each subvolume (and all snapshots) and you can set limits on a per-subvolume basis. You can also create quota groups and toss multiple subvolumes into a big group. It's everything you need to be a web hosting company and give each user their own subvolume."

• The kernel has gained better EFI booting support. This should allow the removal of a lot of EFI setup code from various bootloaders, which now need only load the kernel and jump into it.

• The new "coupled cpuidle" code enables better CPU power management on systems where CPUs cannot be powered down individually. See this commit for more information on how this feature works.

• The LED code supports a new "oneshot" mode where applications can request a single LED blink via sysfs. See Documentation/leds/ledtrig-oneshot.txt for details.

• A number of random number generator changes have been merged, hopefully leading to more secure random numbers, especially on embedded devices.

• The VFIO subsystem, intended to be a safe mechanism for the creation of user-space device drivers, has been merged; see Documentation/vfio.txt for more information.

• The swap-over-NFS patch set has been merged, making the placement of swap files on NFS-mounted filesystems a not entirely insane thing to do.

• New hardware support includes:
  • Processors and systems: Loongson 1B CPUs.

  • Audio: Wolfson Micro "Arizona" audio controllers (WM5102 and WM5110 in particular).

  • Input: NXP LPC32XX key scanners, MELFAS MMS114 touchscreen controllers, and EDT ft5x06 based polytouch devices.

  • Miscellaneous: National Semiconductor/TI LM3533 ambient light sensors, Analog Devices AD9523 clock generators, Analog Devices ADF4350/ADF4351 wideband synthesizers, Analog Devices AD7265/AD7266 analog to digital converters, Analog Devices AD-FMCOMMS1-EBZ SPI-I2C-bridges, Microchip MCP4725 digital-to-analog converters, Maxim DS28E04-100 1-Wire EEPROMs, Vishay VCNL4000 ambient light/proximity sensors, Texas Instruments OMAP4+ temperature sensors, EXYNOS HW random number generators, Atmel AES, SHA1/SHA256, and AES crypto accelerators, Blackfin CRC accelerators, AMD 8111 GPIO controllers, TI LM3556 and LP8788 LED controllers, BlinkM I2C RGB LED controllers, Calxeda Highbank memory controllers, Maxim Semiconductor MAX77686 PMICs, Marvell 88PM800 and 88PM805 PMICs, Lantiq Falcon SPI controllers, and Broadcom BCM63xx random number generators.

  • Networking: Cambridge Silicon Radio wireless controllers.

  • USB: Freescale i.MX ci13xxx USB controllers, Marvell PXA2128 USB 3.0 controllers, and Maxim MAX77693 MUIC USB port accessory detectors.

  • Video4Linux: Realtek RTL2832 DVB-T demodulators, Analog Devices ADV7393 encoders, Griffin radioSHARK and radioSHARK2 USB radio receivers, and IguanaWorks USB IR transceivers.

  • Staging graduations: IIO digital-to-analog converter drivers.

Changes visible to kernel developers include:

• The pstore persistent storage mechanism has improved handling of console log messages. The Android RAM buffer console mechanism has been removed, since pstore is now able to provide all of the same functionality. Pstore has also gained function tracer support, allowing the recording of function calls prior to a panic.

• The new PWM framework eases the writing of drivers for pulse-width modulation devices, including LEDs, fans, and more. See Documentation/pwm.txt for details.

• There is a new utility function:

       size_t memweight(const void *ptr, size_t bytes);
  

  It returns the number of bits set in the given memory region.

• The fault injection subsystem has a new module which can inject errors into notifier call chains.

• There is a new "flexible proportions" library allowing the calculation of proportions over a variable period. See <linux/flex_proportions.h> for the interface.

• The new __GFP_MEMALLOC flag allows memory allocations to dip into the emergency reserves.

• The IRQF_SAMPLE_RANDOM interrupt flag no longer does anything; it has been removed from the kernel.

Andrew Morton's big pile of patches was merged on August 1; that is usually a sign that the merge window is nearing its end. Expect a brief update after the 3.6 merge window closes, but, at this point, the feature set for this release can be expected to be nearly complete.

Index entries for this article
Kernel	Releases/3.6

---

to post comments