Re: [PATCH v4 1/2] x86/resctrl: Pass domain to target CPU

Hi Tony,

On 3/5/2024 8:37 AM, Luck, Tony wrote:

quoted

If I understand correctly that would always look for a valid "cpu"
even when none is needed. Not quite what I proposed but should
work. Just some wasted cycles in a non critical path. 

Reinette,

Sorry for misunderstanding. You are right. Assignment to msr_param.dom
can also be deferred to the same point. Like this:

        list_for_each_entry(d, &r->domains, list) {
                hw_dom = resctrl_to_arch_dom(d);
                msr_param.res = NULL;
                for (t = 0; t < CDP_NUM_TYPES; t++) {
                        cfg = &hw_dom->d_resctrl.staged_config[t];
                        if (!cfg->have_new_ctrl)
                                continue;

                        idx = get_config_index(closid, t);
                        if (cfg->new_ctrl == hw_dom->ctrl_val[idx])
                                continue;
                        hw_dom->ctrl_val[idx] = cfg->new_ctrl;

                        if (!msr_param.res) {
                                msr_param.low = idx;
                                msr_param.high = msr_param.low + 1;
                                msr_param.res = r;
                                msr_param.dom = d;
                                cpu = cpumask_any(&d->cpu_mask);
                        } else {
                                msr_param.low = min(msr_param.low, idx);
                                msr_param.high = max(msr_param.high, idx + 1);
                        }
                }
                if (msr_param.res)
                        smp_call_function_single(cpu, rdt_ctrl_update, &msr_param, 1);
        }

This looks good to me. 

Thank you very much.

Reinette