[patch V2 00/12] cpu/hotplug: SMT control

[Thomas Gleixner <tglx@linutronix.de>]

The following series is a reworked version of the initial proof of concept
patch. The main changes are:

  - The primary sibling evaluation has been changed to use APIC ID, so the
    hacky stuff is gone.

  - The control has now 3 states: on, off, forceoff

    forceoff is a irreversible operation and if given on the command line
    via 'nosmt=force' it makes the processor/APIC enumeration code discard
    the non primary siblings. That affects also the number of possible CPUs
    and is more or less equivalent to disabling SMT in the BIOS.

    If 'forceoff' is written to the sysfs file, then the non primamry
    siblings are offlined as with 'off', but the operation cannot be
    undone. That has obviously no effect on num_possible_cpus as that has
    been evaluated in the early boot process.

  - Command line and sysfs interface are documented

Survived testing on various Intel and AMD machines and in VMs of different
flavours and topology configurations.

Applies on top of Linus tree.

Thanks,

	tglx

---
 Documentation/ABI/testing/sysfs-devices-system-cpu |   16 ++
 Documentation/admin-guide/kernel-parameters.txt    |    4 
 arch/Kconfig                                       |    3 
 arch/x86/include/asm/apic.h                        |    8 +
 arch/x86/include/asm/topology.h                    |    4 
 arch/x86/kernel/acpi/boot.c                        |    3 
 arch/x86/kernel/apic/apic.c                        |   34 ++++
 arch/x86/kernel/cpu/amd.c                          |   18 +-
 arch/x86/kernel/cpu/common.c                       |   36 ++--
 arch/x86/kernel/cpu/cpu.h                          |    2 
 arch/x86/kernel/cpu/intel.c                        |    7 
 arch/x86/kernel/cpu/topology.c                     |   41 +++--
 arch/x86/kernel/smpboot.c                          |    9 +
 b/arch/x86/Kconfig                                 |    1 
 include/linux/cpu.h                                |   12 +
 kernel/cpu.c                                       |  152 +++++++++++++++++++--
 kernel/sched/core.c                                |   32 +---
 kernel/sched/fair.c                                |    1 
 18 files changed, 308 insertions(+), 75 deletions(-)