On Wed, Oct 16, 2019 at 02:24:50PM +0100, Beata Michalska wrote:
> On Tue, 15 Oct 2019 at 12:56, Beata Michalska
> <beata.michal...@linaro.org> wrote:
> >
> > On Tue, 15 Oct 2019 at 11:56, Andrew Jones <drjo...@redhat.com> wrote:
> > >
> > > On Tue, Oct 15, 2019 at 10:59:16AM +0100, Beata Michalska wrote:
> > > > On Tue, 1 Oct 2019 at 14:04, Andrew Jones <drjo...@redhat.com> wrote:
> > > > > +
> > > > > + obj = object_new(object_class_get_name(oc));
> > > > > +
> > > > > + if (qdict_in) {
> > > > > + Visitor *visitor;
> > > > > + Error *err = NULL;
> > > > > +
> > > > > + visitor = qobject_input_visitor_new(model->props);
> > > > > + visit_start_struct(visitor, NULL, NULL, 0, &err);
> > > > > + if (err) {
> > > > > + object_unref(obj);
> > > >
> > > > Shouldn't we free the 'visitor' here as well ?
> > >
> > > Yes. Good catch. So we also need to fix
> > > target/s390x/cpu_models.c:cpu_model_from_info(), which has the same
> > > construction (the construction from which I derived this)
> > >
> > > >
> > > > > + error_propagate(errp, err);
> > > > > + return NULL;
> > > > > + }
> > > > > +
> > >
> > > What about the rest of the patch? With that fixed for v6 can I
> > > add your r-b?
> > >
> >
> > I still got this feeling that we could optimize that a bit - which I'm
> > currently on, so hopefully I'll be able to add more comments soon if
> > that proves to be the case.
> >
> > BR
> > Beata
>
> I think there are few options that might be considered though the gain
> is not huge .. but it's always smth:
>
> > +CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType
> > type,
> > + CpuModelInfo *model,
> > + Error **errp)
> > +{
> > + CpuModelExpansionInfo *expansion_info;
> > + const QDict *qdict_in = NULL;
> > + QDict *qdict_out;
> > + ObjectClass *oc;
> > + Object *obj;
> > + const char *name;
> > + int i;
> > +
> > + if (type != CPU_MODEL_EXPANSION_TYPE_FULL) {
> > + error_setg(errp, "The requested expansion type is not supported");
> > + return NULL;
> > + }
> > +
> > + if (!kvm_enabled() && !strcmp(model->name, "host")) {
> > + error_setg(errp, "The CPU type '%s' requires KVM", model->name);
> > + return NULL;
> > + }
> > +
> > + oc = cpu_class_by_name(TYPE_ARM_CPU, model->name);
> > + if (!oc) {
> > + error_setg(errp, "The CPU type '%s' is not a recognized ARM CPU
> > type",
> > + model->name);
> > + return NULL;
> > + }
> > +
> > + if (kvm_enabled()) {
> > + const char *cpu_type = current_machine->cpu_type;
> > + int len = strlen(cpu_type) - strlen(ARM_CPU_TYPE_SUFFIX);
> > + bool supported = false;
> > +
> > + if (!strcmp(model->name, "host") || !strcmp(model->name, "max")) {
> > + /* These are kvmarm's recommended cpu types */
> > + supported = true;
> > + } else if (strlen(model->name) == len &&
> > + !strncmp(model->name, cpu_type, len)) {
> > + /* KVM is enabled and we're using this type, so it works. */
> > + supported = true;
> > + }
> > + if (!supported) {
> > + error_setg(errp, "We cannot guarantee the CPU type '%s' works "
> > + "with KVM on this host", model->name);
> > + return NULL;
> > + }
> > + }
> > +
>
> The above section can be slightly reduced and rearranged - preferably
> moved to a separate function
> -> get_cpu_model (...) ?
>
> * You can check the 'host' model first and then validate the accelerator ->
> if ( !strcmp(model->name, "host")
> if (!kvm_enabled())
> log_error & leave
> else
> goto cpu_class_by_name /*cpu_class_by_name moved after the
> final model check @see below */
>
> * the kvm_enabled section can be than slightly improved (dropping the
> second compare against 'host')
>
> if (kvm_enabled() && strcmp(model->name, "max") {
> /*Validate the current_machine->cpu_type against the
> model->name and report error case mismatch
> /* otherwise just fall through */
> }
> * cpu_class_by_name moved here ...
> > + if (model->props) {
> MInor: the CPUModelInfo seems to have dedicated field for that
> verification -> has_props
>
> > + qdict_in = qobject_to(QDict, model->props);
> > + if (!qdict_in) {
> > + error_setg(errp, QERR_INVALID_PARAMETER_TYPE, "props", "dict");
> > + return NULL;
> > + }
> > + }
> > +
> > + obj = object_new(object_class_get_name(oc));
> > +
> > + if (qdict_in) {
> > + Visitor *visitor;
> > + Error *err = NULL;
> > +
> > + visitor = qobject_input_visitor_new(model->props);
> > + visit_start_struct(visitor, NULL, NULL, 0, &err);
> > + if (err) {
> > + object_unref(obj);
> > + error_propagate(errp, err);
> > + return NULL;
> > + }
> > +
> > + i = 0;
> > + while ((name = cpu_model_advertised_features[i++]) != NULL) {
> > + if (qdict_get(qdict_in, name)) {
> > + object_property_set(obj, visitor, name, &err);
> > + if (err) {
> > + break;
> > + }
> > + }
> > + }
> > +
> > + if (!err) {
> > + visit_check_struct(visitor, &err);
> > + }
> > + visit_end_struct(visitor, NULL);
> > + visit_free(visitor);
> > + if (err) {
> > + object_unref(obj);
> > + error_propagate(errp, err);
> > + return NULL;
> > + }
> > + }
>
> The both >> if (err) << blocks could be extracted and moved at the end
> of the function
> to mark a 'cleanup section' and both here and few lines before
> (with the visit_start_struct failure) could use goto.
> Easier to maintain and to make sure we make the proper cleanup in any case.
>
> > +
> > + expansion_info = g_new0(CpuModelExpansionInfo, 1);
> > + expansion_info->model = g_malloc0(sizeof(*expansion_info->model));
> > + expansion_info->model->name = g_strdup(model->name);
> > +
> > + qdict_out = qdict_new();
> > +
> > + i = 0;
> > + while ((name = cpu_model_advertised_features[i++]) != NULL) {
> > + ObjectProperty *prop = object_property_find(obj, name, NULL);
> > + if (prop) {
> > + Error *err = NULL;
> > + QObject *value;
> > +
> > + assert(prop->get);
> > + value = object_property_get_qobject(obj, name, &err);
> > + assert(!err);
> > +
> > + qdict_put_obj(qdict_out, name, value);
> > + }
> > + }
> > +
>
> This could be merged with the first iteration over the features,
> smth like:
>
> while () {
> if ((value = qdict_get(qdict_in, name))) {
> object_property_set ...
> if (!err)
> qobject_ref(value) /* we have the weak reference */
> else
> break;
> } else {
> value = object_property_get_qobject()
> }
> if (value) qdict_put_object(qdict_out, name, value)
> }
>
> This way you iterate over the table once and you do not query
> for the same property twice by getting the value from the qdict_in.
> If the value is not acceptable we will fail either way so should be all good.
>
>
> > + if (!qdict_size(qdict_out)) {
> > + qobject_unref(qdict_out);
> > + } else {
> > + expansion_info->model->props = QOBJECT(qdict_out);
> > + expansion_info->model->has_props = true;
> > + }
> > +
> > + object_unref(obj);
> > +
> > + return expansion_info;
>
> Mentioned earlier cleanup section:
> cleanup:
> object_unref(obj);
> qobject_unref(qdict_out) ; /* if single loop is used */
> error_propagate(errp,err);
> return NULL;
>
> > +}
> > --
> > 2.20.1
> >
>
> Hope I haven't missed anything.
> What do you think ?
>
I think you need to post an entire function that incorporates all the
proposed changes, or at least a diff that I can apply in order to get
the entirely changed function. I also think that it's fine the way
it is, so it would take a justification stronger than a potential
micro optimization to get me to change it.
Thanks,
drew
