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2.6.35 merge window part 1

By Jonathan Corbet
May 19, 2010
It's that time again: a new kernel development cycle has started and the merge window is currently open for new code. As of this writing, some 1100 non-merge changes have been incorporated into the mainline kernel. The most significant user-visible changes include:

  • The performance monitoring subsystem supports the Intel "precise event based sampling" (PEBS) mode, in which the hardware directly records event information into a dedicated memory region. The perf subsystem also can now obtain performance information from old Pentium4 CPUs.

  • The "perf kvm" tool, which allows the monitoring of virtualized guests from the host, has been merged.

  • The dynamic probe code has better support for a number of basic integer types.

  • The "fair sleepers," "sync wakeups," and "affine wakeup" scheduler feature flags have been removed. It seems that, at this point, the scheduler developers don't believe that things will work properly without those features, so they are always enabled.

  • The SuperH architecture now has hotplug CPU support.

  • New drivers:

    • Processors and boards: HP iPAQ rx1950 devices, Acer N35 systems, Samsung S3C2416-based systems, Marvell GuruPlug reference boards, Voipac PXA270 single-board computers, Aeronix Zipit Z2 systems, Cavium Networks CNS3xxx processors, Cavium Networks CNS3420 MPCore boards, taskit PortuxG20 and Stamp9G20 boards, ARM SPEAr3XX- and SPEAr6XX-based systems, Versatile Express CA9x4 processors, and ARM Ltd Versatile Express boards.

    • Miscellaneous: DaVinci DM365-based realtime clock devices.

Changes visible to kernel developers include:

  • The "cpu_stop" (formerly cpuhog) mechanism has been merged. A cpu_stop allows kernel code to monopolize one or more processors for brief periods.

  • Augmented rbtrees are now in the mainline kernel.

  • The INIT_RCU_HEAD() macro is going away; it was never really needed for RCU functionality, and RCU debugging is moving to the object debugging infrastructure.

As can be seen above, the 2.6.35 merge window has gotten off to a bit of a slow start. By the old schedule, the window would remain open through the end of the month; there has been speculation that Linus will close it rather sooner than that this time around, though, to inconvenience maintainers who wait too long to get their pull requests in. One way or another, there should certainly be more changes to report on next week.

Index entries for this article
KernelReleases/2.6.35


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