From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephan Diestelhorst Subject: Re: scheduler independent forced vcpu selection Date: Thu, 19 May 2005 14:25:09 +0100 Message-ID: <428C93B5.6060001@cl.cam.ac.uk> References: <20050517204832.GH7305@us.ibm.com> <428B30BC.8070602@cl.cam.ac.uk> <20050518223744.GL7305@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20050518223744.GL7305@us.ibm.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ryan Harper Cc: Stephan Diestelhorst , xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Ryan Harper schrieb: > * Stephan Diestelhorst [2005-05-18 09:04]: > >>>I'm working on a new hypercall, do_confer, which allows the directed >>>yielding of a vcpu to another vcpu. It is mainly used when a vcpu fails >>>to acquire a spinlock, yielding to the lock holder instead of spinning. I >>>ported the ppc64 spinlock implementation for the i386 linux portion. In >>>implementing the hypercall, I've been trying to figure out how to get >>>the scheduler (I've only played with bvt) to run the vcpu passed in the >>>hypercall (after some validation) but I've run into various bad state >>>situations (do_softirq pending != 0 assert, '!active_ac_timer(timer)' >>>failed , and __task_on_runqueue(prev) failed) which tells me I >>>don't fully understand all of the book-keeping that is needed. Has >>>anyone thought about how to do this with either BVT or the new EDF >>>scheduler? > > > After some thought, domain_wake(), followed by > raise_softirq(SCHEDULE_SOFTIRQ) does what I want and removes the huge > mess I was making in __enter_scheduler(). Are you waking up the domain that holds the lock? Then you would rely on the scheduler to give the woken domain a high "priority" (whatever this means for the current scheduler) and should start that domain immediatelly, right? Best, Stephan