Hi Tony,
On 5/21/25 3:50 PM, Tony Luck wrote:
> The L3 resource has several requirements for domains. There are structures
> that hold the 64-bit values of counters, and elements to keep track of
> the overflow and limbo threads.
>
> None of these are needed for the PERF_PKG resource. The hardware counters
> are wide enough that they do not wrap around for decades.
>
> Define a new rdt_perf_pkg_mon_domain structure which just consists of
> the standard rdt_domain_hdr to keep track of domain id and CPU mask.
>
> Change domain_add_cpu_mon(), domain_remove_cpu_mon(),
> resctrl_offline_mon_domain(), and resctrl_online_mon_domain() to check
> resource type and perform only the operations needed for domains in the
> PERF_PKG resource.
>
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---
> arch/x86/kernel/cpu/resctrl/core.c | 41 ++++++++++++++++++++++++++++++
> fs/resctrl/rdtgroup.c | 4 +++
> 2 files changed, 45 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 64ce561e77a0..18d84c497ee4 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -540,6 +540,38 @@ static void l3_mon_domain_setup(int cpu, int id, struct rdt_resource *r, struct
> }
> }
>
> +/**
> + * struct rdt_perf_pkg_mon_domain - CPUs sharing an Intel-PMT-scoped resctrl monitor resource
> + * @hdr: common header for different domain types
> + */
> +struct rdt_perf_pkg_mon_domain {
> + struct rdt_domain_hdr hdr;
> +};
> +
> +static void setup_intel_aet_mon_domain(int cpu, int id, struct rdt_resource *r,
> + struct list_head *add_pos)
> +{
> + struct rdt_perf_pkg_mon_domain *d;
> + int err;
> +
> + d = kzalloc_node(sizeof(*d), GFP_KERNEL, cpu_to_node(cpu));
> + if (!d)
> + return;
> +
> + d->hdr.id = id;
> + d->hdr.type = RESCTRL_MON_DOMAIN;
> + d->hdr.rid = r->rid;
> + cpumask_set_cpu(cpu, &d->hdr.cpu_mask);
> + list_add_tail_rcu(&d->hdr.list, add_pos);
> +
> + err = resctrl_online_mon_domain(r, &d->hdr);
> + if (err) {
> + list_del_rcu(&d->hdr.list);
> + synchronize_rcu();
> + kfree(d);
> + }
> +}
> +
> static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
> {
> int id = get_domain_id_from_scope(cpu, r->mon_scope);
> @@ -567,6 +599,9 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
> case RDT_RESOURCE_L3:
> l3_mon_domain_setup(cpu, id, r, add_pos);
> break;
> + case RDT_RESOURCE_PERF_PKG:
> + setup_intel_aet_mon_domain(cpu, id, r, add_pos);
> + break;
> default:
> WARN_ON_ONCE(1);
> }
> @@ -666,6 +701,12 @@ static void domain_remove_cpu_mon(int cpu, struct rdt_resource *r)
> default:
> pr_warn_once("Unknown resource rid=%d\n", r->rid);
> break;
Please keep "default" last.
> + case RDT_RESOURCE_PERF_PKG:
> + resctrl_offline_mon_domain(r, hdr);
> + list_del_rcu(&hdr->list);
> + synchronize_rcu();
> + kfree(container_of(hdr, struct rdt_perf_pkg_mon_domain, hdr));
> + break;
> }
> }
>
> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
> index 1e1cc8001cbc..6078cdd5cad0 100644
> --- a/fs/resctrl/rdtgroup.c
> +++ b/fs/resctrl/rdtgroup.c
> @@ -4170,6 +4170,8 @@ int resctrl_online_mon_domain(struct rdt_resource *r, struct rdt_domain_hdr *hdr
> if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, r->rid))
> goto out_unlock;
>
> + if (r->rid == RDT_RESOURCE_PERF_PKG)
> + goto do_mkdir;
Please move this "r->rid == RDT_RESOURCE_PERF_PKG" to be right after getting the mutex, there is
no reason to check the domain header for this resource. This enables the domain_header_is_valid()
check to use hardcoded RDT_RESOURCE_L3 as parameter to match the required L3 resource domain used
in container_of() below.
> d = container_of(hdr, struct rdt_l3_mon_domain, hdr);
> err = domain_setup_l3_mon_state(r, d);
> if (err)
> @@ -4184,6 +4186,8 @@ int resctrl_online_mon_domain(struct rdt_resource *r, struct rdt_domain_hdr *hdr
> if (resctrl_is_mon_event_enabled(QOS_L3_OCCUP_EVENT_ID))
> INIT_DELAYED_WORK(&d->cqm_limbo, cqm_handle_limbo);
>
> +do_mkdir:
"do_mkdir" -> "mkdir"
> + err = 0;
> /*
> * If the filesystem is not mounted then only the default resource group
> * exists. Creation of its directories is deferred until mount time
Reinette