Re: [PATCH v3 0/3] cpu: pseries: Cpu offline states framework

From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Gautham R Shenoy <ego@in.ibm.com>
Cc: Joel Schopp <jschopp@austin.ibm.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Balbir Singh <balbir@in.ibm.com>,
	Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>,
	Dipankar Sarma <dipankar@in.ibm.com>,
	Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
	Arun R Bharadwaj <arun@linux.vnet.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	"Darrick J. Wong" <djwong@us.ibm.com>
Subject: Re: [PATCH v3 0/3] cpu: pseries: Cpu offline states framework
Date: Tue, 15 Sep 2009 14:11:41 +0200	[thread overview]
Message-ID: <1253016701.5506.73.camel@laptop> (raw)
In-Reply-To: <20090915120629.20523.79019.stgit@sofia.in.ibm.com>

On Tue, 2009-09-15 at 17:36 +0530, Gautham R Shenoy wrote:
> This patchset contains the offline state driver implemented for
> pSeries. For pSeries, we define three available_hotplug_states. They are:
> 
>         online: The processor is online.
> 
>         offline: 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.
> 
>         inactive: This cedes the vCPU to the hypervisor with a cede latency
>         specifier value 2.
>         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.
> 
> Any feedback on the patchset will be immensely valuable.

I still think its a layering violation... its the hypervisor manager
that should be bothered in what state an off-lined cpu is in. 