From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryan Harper Subject: Re: [PATCH][RESUBMIT] don't schedule unplugged vcpus Date: Wed, 8 Jun 2005 17:18:51 -0500 Message-ID: <20050608221851.GI13586@us.ibm.com> References: <0e458b5371820d127c90ac838f760c9c@cl.cam.ac.uk> <20050608220004.GG13586@us.ibm.com> <816f5179e028e5f8b970d0476a3479ac@cl.cam.ac.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <816f5179e028e5f8b970d0476a3479ac@cl.cam.ac.uk> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: Ian Pratt , Ryan Harper , xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org * Keir Fraser [2005-06-08 17:07]: > > On 8 Jun 2005, at 23:00, Ryan Harper wrote: > > >So, when I trigger a vcpu to go down via dom0 xm operation, I have to > >trust that it worked? I have no way of knowing at some point later > >which vcpus are up or down? I don't see any cost to this other than > >during the getdominfo hcall. > > The ones you can retrieve info about are up. The ones you can't, are > down. :-) Indeed. =) > Let me put it this way: I reserve the right in future to change my mind > and free the vcpu info structures for vcpus that are down (and > re-allocate when they come back up). If I do that then you will not get > info about them via hypercalls. There's no good reason to return info > about them -- you can infer they are 'down'/non-existent from their > absence -- so why bother? It seemed nicer/easier/cheaper (to me) to mark up/down in the dominfo hypercall rather than issue MAX_VIRT_CPUS vcpucontext hypercalls. -- Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx (512) 838-9253 T/L: 678-9253 ryanh@us.ibm.com