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
- 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
- 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
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.
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