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. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
