From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:48994) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UXZz6-0008OY-Uj for qemu-devel@nongnu.org; Wed, 01 May 2013 12:34:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UXZz5-0008OF-OV for qemu-devel@nongnu.org; Wed, 01 May 2013 12:34:24 -0400 Received: from g1t0029.austin.hp.com ([15.216.28.36]:31487) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UXZz5-0008Na-JK for qemu-devel@nongnu.org; Wed, 01 May 2013 12:34:23 -0400 Message-ID: <5181440D.7060006@hp.com> Date: Wed, 01 May 2013 09:34:21 -0700 From: Chegu Vinod MIME-Version: 1.0 References: <1367410972-22972-1-git-send-email-chegu_vinod@hp.com> <51810CC0.2080407@redhat.com> <51810F9D.3000605@hp.com> <1062403018.4755871.1367422845697.JavaMail.root@redhat.com> In-Reply-To: <1062403018.4755871.1367422845697.JavaMail.root@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3] Throttle-down guest when live migration does not converge. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: owasserm@redhat.com, qemu-devel@nongnu.org, anthony@codemonkey.ws, quintela@redhat.com On 5/1/2013 8:40 AM, Paolo Bonzini wrote: >> I shall make the suggested changes. >> Appreciate your review feedback on this part of the change. Hi Paolo., Thanks for taking a look (BTW, I accidentally left out the "RFC" in the patch subject line...my bad!). > Hi Vinod, > > I think unfortunately it is not acceptable to make this patch work only > for KVM. (It cannot work for Xen, but that's not a problem since Xen > uses a different migration mechanism; but it should work for TCG). Ok. I hadn't yet looked at TCG aspects etc. Will follow up offline... > > Unfortunately, as you noted the run_on_cpu callbacks currently run > under the big QEMU lock. We need to fix that first. We have time > for that during 1.6. Ok. Was under the impression that anytime a vcpu thread enters to do anything in qemu the BQL had to be held. So choose to go with run_on_cpu() . Will follow up offline on alternatives "Holding" the vcpus in the host context (i.e. kvm module) itself is perhaps another way. Would need some handshakes (i.e. new ioctls ) with the kernel. Would that be acceptable way to proceed? Thanks Vinod > > Paolo > . >