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Re: [Qemu-ppc] [PATCH v2 03/24] hw/arm/virt: use machine->possible_cpus
From: |
Andrew Jones |
Subject: |
Re: [Qemu-ppc] [PATCH v2 03/24] hw/arm/virt: use machine->possible_cpus for storing possible topology info |
Date: |
Thu, 4 May 2017 11:38:22 +0200 |
User-agent: |
Mutt/1.6.0.1 (2016-04-01) |
On Wed, May 03, 2017 at 02:56:57PM +0200, Igor Mammedov wrote:
> for now precalculate and store mp_afinity in possible_cpus
> as ARM cpus don't have socket/core/thread-id properties yet.
> In follow patches possible_cpus will be used for storing
> and setting NUMA node mapping and replace legacy bitmap
> based numa_info[node_id].node_cpu/numa_get_node_for_cpu()
>
> For the lack of better idea, this patch cannibalizes
> possible_cpus.cpus[x].props.thread_id so that
> *_cpu_index_to_props() callback could return addressable
> by props CPU which will be used by machine_set_cpu_numa_node()
> in follow up patches to assign a CPU to node. But
> cannibalizing is fine for now as that thread_id isn't exposed
> to users (no hotpluggable_cpus callback support for ARM yet)
> and it will be used only internally until 'device_add cpu'
> is supported where we can decide on which properties to use.
>
> Signed-off-by: Igor Mammedov <address@hidden>
> ---
> v2:
> (Drew)
> - discarding result of possible_cpu_arch_ids() makes
> call not obvious and is confusing. Instead assign
> possible_cpu_arch_ids() result to local var and use
> it instead of direct access to machine->possible_cpus
> field, as it's done in pc.c
> ---
> hw/arm/virt.c | 40 +++++++++++++++++++++++++++++++++++++---
> 1 file changed, 37 insertions(+), 3 deletions(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 61ae437..e2c5626 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -1221,6 +1221,8 @@ static void machvirt_init(MachineState *machine)
> {
> VirtMachineState *vms = VIRT_MACHINE(machine);
> VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(machine);
> + MachineClass *mc = MACHINE_GET_CLASS(machine);
> + const CPUArchIdList *possible_cpus;
> qemu_irq pic[NUM_IRQS];
> MemoryRegion *sysmem = get_system_memory();
> MemoryRegion *secure_sysmem = NULL;
> @@ -1344,10 +1346,16 @@ static void machvirt_init(MachineState *machine)
> exit(1);
> }
>
> - for (n = 0; n < smp_cpus; n++) {
> - Object *cpuobj = object_new(typename);
> + possible_cpus = mc->possible_cpu_arch_ids(machine);
> + for (n = 0; n < possible_cpus->len; n++) {
> + Object *cpuobj;
>
> - object_property_set_int(cpuobj, virt_cpu_mp_affinity(vms, n),
> + if (n >= smp_cpus) {
> + break;
> + }
Why the break instead of just looping 'n < smp_cpus' like x86 does? Is
there some future work where looping up to possible_cpus->len (aka
max_cpus) is what we'll eventually want? If so, then we need a TODO
comment here. If not, then we should clean this up by removing the break.
Thanks,
drew
> +
> + cpuobj = object_new(typename);
> + object_property_set_int(cpuobj, possible_cpus->cpus[n].arch_id,
> "mp-affinity", NULL);
>
> if (!vms->secure) {
> @@ -1527,6 +1535,31 @@ static void virt_set_gic_version(Object *obj, const
> char *value, Error **errp)
> }
> }
>
> +static const CPUArchIdList *virt_possible_cpu_arch_ids(MachineState *ms)
> +{
> + int n;
> + VirtMachineState *vms = VIRT_MACHINE(ms);
> +
> + if (ms->possible_cpus) {
> + assert(ms->possible_cpus->len == max_cpus);
> + return ms->possible_cpus;
> + }
> +
> + ms->possible_cpus = g_malloc0(sizeof(CPUArchIdList) +
> + sizeof(CPUArchId) * max_cpus);
> + ms->possible_cpus->len = max_cpus;
> + for (n = 0; n < ms->possible_cpus->len; n++) {
> + ms->possible_cpus->cpus[n].arch_id =
> + virt_cpu_mp_affinity(vms, n);
> + ms->possible_cpus->cpus[n].props.has_thread_id = true;
> + ms->possible_cpus->cpus[n].props.thread_id = n;
> +
> + /* TODO: add 'has_node/node' here to describe
> + to which node core belongs */
> + }
> + return ms->possible_cpus;
> +}
> +
> static void virt_machine_class_init(ObjectClass *oc, void *data)
> {
> MachineClass *mc = MACHINE_CLASS(oc);
> @@ -1543,6 +1576,7 @@ static void virt_machine_class_init(ObjectClass *oc,
> void *data)
> mc->pci_allow_0_address = true;
> /* We know we will never create a pre-ARMv7 CPU which needs 1K pages */
> mc->minimum_page_bits = 12;
> + mc->possible_cpu_arch_ids = virt_possible_cpu_arch_ids;
> }
>
> static const TypeInfo virt_machine_info = {
> --
> 2.7.4
>
[Qemu-ppc] [PATCH v2 04/24] hw/arm/virt: explicitly allocate cpu_index for cpus, Igor Mammedov, 2017/05/03
[Qemu-ppc] [PATCH v2 05/24] numa: move source of default CPUs to NUMA node mapping into boards, Igor Mammedov, 2017/05/03
Re: [Qemu-ppc] [PATCH v2 05/24] numa: move source of default CPUs to NUMA node mapping into boards, Eduardo Habkost, 2017/05/03