From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40706) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ag4Aj-0002Eh-QI for qemu-devel@nongnu.org; Wed, 16 Mar 2016 01:39:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ag4Ae-0004sV-QZ for qemu-devel@nongnu.org; Wed, 16 Mar 2016 01:39:05 -0400 Received: from e23smtp09.au.ibm.com ([202.81.31.142]:46619) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ag4Ae-0004sP-7W for qemu-devel@nongnu.org; Wed, 16 Mar 2016 01:39:00 -0400 Received: from localhost by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 16 Mar 2016 15:38:56 +1000 Date: Wed, 16 Mar 2016 11:07:44 +0530 From: Bharata B Rao Message-ID: <20160316053744.GF13176@in.ibm.com> References: <1457672078-17307-1-git-send-email-bharata@linux.vnet.ibm.com> <1457672078-17307-10-git-send-email-bharata@linux.vnet.ibm.com> <20160316052704.GF9032@voom> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160316052704.GF9032@voom> Subject: Re: [Qemu-devel] [RFC PATCH v2 9/9] spapr: CPU hot unplug support Reply-To: bharata@linux.vnet.ibm.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson Cc: mjrosato@linux.vnet.ibm.com, agraf@suse.de, thuth@redhat.com, pkrempa@redhat.com, ehabkost@redhat.com, aik@ozlabs.ru, qemu-devel@nongnu.org, armbru@redhat.com, borntraeger@de.ibm.com, qemu-ppc@nongnu.org, pbonzini@redhat.com, imammedo@redhat.com, afaerber@suse.de, mdroth@linux.vnet.ibm.com On Wed, Mar 16, 2016 at 04:27:04PM +1100, David Gibson wrote: > On Fri, Mar 11, 2016 at 10:24:38AM +0530, Bharata B Rao wrote: > > Remove the CPU core device by removing the underlying CPU thread devices. > > Hot removal of CPU for sPAPR guests is achieved by sending the hot unplug > > notification to the guest. Release the vCPU object after CPU hot unplug so > > that vCPU fd can be parked and reused. > > > > Signed-off-by: Bharata B Rao > > --- > > hw/ppc/spapr.c | 21 ++++++++++ > > hw/ppc/spapr_cpu_core.c | 86 +++++++++++++++++++++++++++++++++++++++++ > > include/hw/ppc/spapr.h | 1 + > > include/hw/ppc/spapr_cpu_core.h | 12 ++++++ > > 4 files changed, 120 insertions(+) > > > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > > index 822c87d..b1e9ba2 100644 > > --- a/hw/ppc/spapr.c > > +++ b/hw/ppc/spapr.c > > @@ -2345,7 +2345,12 @@ static void spapr_machine_device_plug(HotplugHandler *hotplug_dev, > > > > spapr_memory_plug(hotplug_dev, dev, node, errp); > > } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) { > > + /* > > + * TODO: Move this check to pre_plug handler at which point > > + * spapr_core_release() won't be necessary. > > + */ > > if (!smc->dr_cpu_enabled && dev->hotplugged) { > > + spapr_core_release(dev); > > error_setg(errp, "CPU hotplug not supported for this machine"); > > return; > > } > > This hunk doesn't look like its related to unplug. Did it belong in > another patch? Yes, it actually belongs to hot-plug but the whole infrastructure to release the core and associated threads get introduced in this patch, hence put this hunk here. However, if pre_plug is the way to go forward, we woudn't need this altogether as roll-back is much easier from there than from here. Regards, Bharata.