From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42541) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cyPPd-0007aS-C5 for qemu-devel@nongnu.org; Wed, 12 Apr 2017 17:02:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cyPPc-0003xU-B9 for qemu-devel@nongnu.org; Wed, 12 Apr 2017 17:02:49 -0400 Date: Wed, 12 Apr 2017 18:02:39 -0300 From: Eduardo Habkost Message-ID: <20170412210239.GC27126@thinpad.lan.raisama.net> References: <1490189568-167621-1-git-send-email-imammedo@redhat.com> <1490189568-167621-8-git-send-email-imammedo@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1490189568-167621-8-git-send-email-imammedo@redhat.com> Subject: Re: [Qemu-devel] [PATCH for-2.10 07/23] pc: add node-id property to CPU List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: qemu-devel@nongnu.org, Peter Maydell , Andrew Jones , qemu-arm@nongnu.org, qemu-ppc@nongnu.org, Shannon Zhao , Paolo Bonzini , David Gibson On Wed, Mar 22, 2017 at 02:32:32PM +0100, Igor Mammedov wrote: > it will allow switching from cpu_index to property based > numa mapping in follow up patches. I am not sure I understand all the consequences of this, so I will give it a try: "node-id" is an existing field in CpuInstanceProperties. CpuInstanceProperties is used on both query-hotpluggable-cpus output and in MachineState::possible_cpus. We will start using MachineState::possible_cpus to keep track of NUMA CPU affinity, and that means query-hotpluggable-cpus will start reporting a "node-id" property when a NUMA mapping is configured. To allow query-hotpluggable-cpus to report "node-id", the CPU objects must have a "node-id" property that can be set. This patch adds the "node-id" property to X86CPU. Is this description accurate? Is the presence of "node-id" in query-hotpluggable-cpus the only reason we really need this patch, or is there something else that requires the "node-id" property? Why exactly do we need to change the output of query-hotpluggable-cpus for all machines to include "node-id", to make "-numa cpu" work? Did you consider saving node_id inside CPUArchId and outside CpuInstanceProperties, so query-hotplugabble-cpus output won't be affected by "-numa cpu"? I'm asking this because I believe we will eventually need a mechanism that lets management check what are the valid arguments for "-numa cpu" for a given machine, and it looks like query-hotpluggable-cpus is already the right mechanism for that. But we can't make query-hotpluggable-cpus output depend on "-numa cpu" input, if the "-numa cpu" input will also depend on query-hotpluggable-cpus output. > > Signed-off-by: Igor Mammedov > --- > hw/i386/pc.c | 17 +++++++++++++++++ > target/i386/cpu.c | 1 + > 2 files changed, 18 insertions(+) > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index 7031100..873bbfa 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -1895,6 +1895,7 @@ static void pc_cpu_pre_plug(HotplugHandler *hotplug_dev, > DeviceState *dev, Error **errp) > { > int idx; > + int node_id; > CPUState *cs; > CPUArchId *cpu_slot; > X86CPUTopoInfo topo; > @@ -1984,6 +1985,22 @@ static void pc_cpu_pre_plug(HotplugHandler *hotplug_dev, > > cs = CPU(cpu); > cs->cpu_index = idx; > + > + node_id = numa_get_node_for_cpu(cs->cpu_index); > + if (node_id == nb_numa_nodes) { > + /* by default CPUState::numa_node was 0 if it's not set via CLI > + * keep it this way for now but in future we probably should > + * refuse to start up with incomplete numa mapping */ > + node_id = 0; > + } > + if (cs->numa_node == CPU_UNSET_NUMA_NODE_ID) { > + cs->numa_node = node_id; > + } else if (cs->numa_node != node_id) { > + error_setg(errp, "node-id %d must match numa node specified" > + "with -numa option for cpu-index %d", > + cs->numa_node, cs->cpu_index); > + return; > + } > } > > static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev, > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 7aa7622..d690244 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -3974,6 +3974,7 @@ static Property x86_cpu_properties[] = { > DEFINE_PROP_INT32("core-id", X86CPU, core_id, -1), > DEFINE_PROP_INT32("socket-id", X86CPU, socket_id, -1), > #endif > + DEFINE_PROP_INT32("node-id", CPUState, numa_node, CPU_UNSET_NUMA_NODE_ID), > DEFINE_PROP_BOOL("pmu", X86CPU, enable_pmu, false), > { .name = "hv-spinlocks", .info = &qdev_prop_spinlocks }, > DEFINE_PROP_BOOL("hv-relaxed", X86CPU, hyperv_relaxed_timing, false), > -- > 2.7.4 > > -- Eduardo