From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] KVM breaks CPU hotplug Date: Mon, 26 Mar 2007 12:58:17 +0200 Message-ID: <4607A749.30603@qumranet.com> References: <1174898893.14063.7.camel@sli10-conroe.sh.intel.com> <46078E2C.9010100@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , Andrew Morton To: Shaohua Li Return-path: In-Reply-To: <46078E2C.9010100-atKUWr5tajBWk0Htik3J/w@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 Avi Kivity wrote: > Shaohua Li wrote: >> When testing CPU hotplug, I found cpu can't be onlined with kvm enabled >> sometimes. The reason is smp_call_function_single is a nop if the thread >> is running on the target cpu. I think CPU_ONLINE case doesn't require >> the fix as the online CPU isn't plugged into sheduler yet. >> >> > > I think this is not enough, because: > > - this path is preemptible code, so the test (this_cpu == cpu) can run > one on cpu and execute later code on another >> + this_cpu = get_cpu(); ... >> + put_cpu(); Sorry, I see you handled that. But the other argument (scheduling vcpus later on same cpu) still holds, I think. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV