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Subject[PATCH v2 0/2] cpu: pseries: Offline state framework.
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Hi,

This is the version 2 of the patch series to provide a cpu-offline framework
that enables the administrators choose the state the offline CPU must be put
into when multiple such states are exposed by the underlying architecture.

Version 1 of the Patch can be found here:
http://lkml.org/lkml/2009/8/6/236

The patch-series exposes the following sysfs tunables to
allow the system-adminstrator to choose the state of a CPU:

To query the available hotplug states, one needs to read the sysfs tunable:
/sys/devices/system/cpu/cpu<number>/available_hotplug_states
To query or set the current state, on needs to read/write the sysfs tunable:
/sys/devices/system/cpu/cpu<number>/current_states

The patchset ensures that the writes to the "current_state" sysfs file are
serialized against the writes to the "online" file.

This patchset also contains the offline state driver implemented for
pSeries. For pSeries, we define three available_hotplug_states. They are:

online: The processor is online.

deallocate: This is the the default behaviour when the cpu is offlined
even in the absense of this driver. The CPU would call make an
rtas_stop_self() call and hand over the CPU back to the resource pool,
thereby effectively deallocating that vCPU from the LPAR.
NOTE: This would result in a configuration change to the LPAR
which is visible to the outside world.

deactivate: This cedes the vCPU to the hypervisor which
in turn can put the vCPU time to the best use.
NOTE: This option DOES NOT result in a configuration change
and the vCPU would be still entitled to the LPAR to which it earlier
belong to.

Awaiting your feedback.
---
Gautham R Shenoy (2):
cpu: Implement cpu-offline-state driver for pSeries.
cpu: Offline state Framework.


arch/powerpc/platforms/pseries/Makefile | 2
arch/powerpc/platforms/pseries/hotplug-cpu.c | 76 +++++++++-
arch/powerpc/platforms/pseries/offline_driver.c | 161 +++++++++++++++++++++
arch/powerpc/platforms/pseries/offline_driver.h | 20 +++
arch/powerpc/platforms/pseries/smp.c | 17 ++
drivers/base/cpu.c | 176 ++++++++++++++++++++++-
include/linux/cpu.h | 30 ++++
7 files changed, 465 insertions(+), 17 deletions(-)
create mode 100644 arch/powerpc/platforms/pseries/offline_driver.c
create mode 100644 arch/powerpc/platforms/pseries/offline_driver.h
--
Thanks and Regards
gautham.


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