On 8 September 2016 at 04:57, Fenghua Yu <fenghua...@intel.com> wrote:
> diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
> index 9f30492..4537658 100644
> --- a/arch/x86/kernel/cpu/intel_rdt.c
> +++ b/arch/x86/kernel/cpu/intel_rdt.c
> @@ -141,6 +145,80 @@ static inline bool rdt_cpumask_update(int cpu)
> return false;
> }
>
> +/*
> + * cbm_update_msrs() - Updates all the existing IA32_L3_MASK_n MSRs
> + * which are one per CLOSid on the current package.
> + */
> +static void cbm_update_msrs(void *dummy)
> +{
> + int maxid = boot_cpu_data.x86_cache_max_closid;
> + struct rdt_remote_data info;
> + unsigned int i;
> +
> + for (i = 0; i < maxid; i++) {
> + if (cctable[i].clos_refcnt) {
> + info.msr = CBM_FROM_INDEX(i);
> + info.val = cctable[i].cbm;
> + msr_cpu_update(&info);
> + }
> + }
> +}
> +
> +static int intel_rdt_online_cpu(unsigned int cpu)
> +{
> + struct intel_pqr_state *state = &per_cpu(pqr_state, cpu);
> +
> + state->closid = 0;
> + mutex_lock(&rdtgroup_mutex);
> + /* The cpu is set in root rdtgroup after online. */
> + cpumask_set_cpu(cpu, &root_rdtgrp->cpu_mask);
> + per_cpu(cpu_rdtgroup, cpu) = root_rdtgrp;
> + /*
> + * If the cpu is first time found and set in its siblings that
> + * share the same cache, update the CBM MSRs for the cache.
> + */
I am finding it slightly hard to parse the comment above. Does the
following sound better: If the cpu is the first one found and set
amongst its siblings that ...
> + if (rdt_cpumask_update(cpu))
> + smp_call_function_single(cpu, cbm_update_msrs, NULL, 1);
> + mutex_unlock(&rdtgroup_mutex);
> +}
> +
> +static int clear_rdtgroup_cpumask(unsigned int cpu)
> +{
> + struct list_head *l;
> + struct rdtgroup *r;
> +
> + list_for_each(l, &rdtgroup_lists) {
> + r = list_entry(l, struct rdtgroup, rdtgroup_list);
> + if (cpumask_test_cpu(cpu, &r->cpu_mask)) {
> + cpumask_clear_cpu(cpu, &r->cpu_mask);
> + return 0;
> + }
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int intel_rdt_offline_cpu(unsigned int cpu)
> +{
> + int i;
> +
> + mutex_lock(&rdtgroup_mutex);
> + if (!cpumask_test_and_clear_cpu(cpu, &rdt_cpumask)) {
> + mutex_unlock(&rdtgroup_mutex);
> + return;
> + }
> +
> + cpumask_and(&tmp_cpumask, topology_core_cpumask(cpu),
> cpu_online_mask);
> + cpumask_clear_cpu(cpu, &tmp_cpumask);
> + i = cpumask_any(&tmp_cpumask);
> +
> + if (i < nr_cpu_ids)
> + cpumask_set_cpu(i, &rdt_cpumask);
> +
> + clear_rdtgroup_cpumask(cpu);
> + mutex_unlock(&rdtgroup_mutex);
> +}
> +
Just for my info, why do we need not update MSRs when a cpu goes offline?
Thanks
Nilay
