From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: Re: [PATCH] [RFC] Credit2 scheduler prototype Date: Tue, 08 Dec 2009 18:20:53 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: George Dunlap Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 08/12/2009 14:48, "George Dunlap" wrote: > My main concern is that sharing the runqueue between cores requires > some changes to the core context switch code. The kinks aren't 100% > worked out yet, so there's a risk that there will be an impact on the > correctness of the credit1 scheduler. Ah, if that's the problem with selecting a vcpu which happens to still be 'is_running' then I had some ideas how you could deal with that within the credit2 scheduler. If you see such a vcpu when searching the runqueue, ignore it, but set VPF_migrating. You'll then get a 'pick_cpu' callback when descheduling of the vcpu is completed. That should play nice with the lazy context switch logic while keeping things work conserving. -- Keir