From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH] Add need_resched check before go to kvm_resched Date: Wed, 25 Apr 2007 19:35:03 -0500 Message-ID: <462FF3B7.6010707@codemonkey.ws> References: <10EA09EFD8728347A513008B6B0DA77A01599FA7@pdsmsx411.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel To: "Dong, Eddie" Return-path: In-Reply-To: <10EA09EFD8728347A513008B6B0DA77A01599FA7-wq7ZOvIWXbNpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Dong, Eddie wrote: > In this case, IOCTL return to Qemu will trigger scheduling at least. > I think a scheduling change won't happen until the next timer tick. AFAICT, there's nothing explicit in the ioctl return path that will result in rescheduling. I'm not entirely confident in how the timer interrupt gets handled when it arrives in the guest. My understanding is that while the timer interrupt is delivered in the host, since preempt is disabled, the rescheduling opportunity is lost even though the current task is marked as needing rescheduling. I think the next time that bit will get checked is the next timer interrupt but I may be wrong. Regards, Anthony Liguori > Maybe I miss something. > > thx,eddie > > ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/