[PATCH v8 1/3] perf: cavium: Support memory controller PMU counters

Jonathan Cameron
2017-07-25T15:56:34Z

On Tue, 25 Jul 2017 17:04:20 +0200
Jan Glauber <jglauber@cavium.com> wrote:

> Add support for the PMU counters on Cavium SOC memory controllers.
>
> This patch also adds generic functions to allow supporting more
> devices with PMU counters.
>
> Properties of the LMC PMU counters:
> - not stoppable
> - fixed purpose
> - read-only
> - one PCI device per memory controller
>
> Signed-off-by: Jan Glauber <jglauber@cavium.com>
One trivial point inline which, whilst it obviously makes to actual
difference, makes review a tiny bit easier.

Otherwise looks good to me, but I'm somewhat new to this area
so who knows what I've missed ;)

> ---
> drivers/perf/Kconfig | 8 +
> drivers/perf/Makefile | 1 +
> drivers/perf/cavium_pmu.c | 424 +++++++++++++++++++++++++++++++++++++++++++++
> include/linux/cpuhotplug.h | 1 +
> 4 files changed, 434 insertions(+)
> create mode 100644 drivers/perf/cavium_pmu.c
<snip>
> +static int cvm_pmu_lmc_probe(struct pci_dev *pdev)
> +{
> + struct cvm_pmu_dev *next, *lmc;
> + int nr = 0, ret = -ENOMEM;
> +
> + lmc = kzalloc(sizeof(*lmc), GFP_KERNEL);
> + if (!lmc)
> + return -ENOMEM;
> +
> + lmc->map = ioremap(pci_resource_start(pdev, 0),
> + pci_resource_len(pdev, 0));
> + if (!lmc->map)
> + goto fail_ioremap;
> +
> + list_for_each_entry(next, &cvm_pmu_lmcs, entry)
> + nr++;
> + lmc->pmu_name = kasprintf(GFP_KERNEL, "lmc%d", nr);
> + if (!lmc->pmu_name)
> + goto fail_kasprintf;
> +
> + lmc->pdev = pdev;
> + lmc->num_counters = ARRAY_SIZE(lmc_events);
> + lmc->pmu = (struct pmu) {
> + .task_ctx_nr = perf_invalid_context,
> + .event_init = cvm_pmu_event_init,
> + .add = cvm_pmu_lmc_add,
> + .del = cvm_pmu_del,
> + .start = cvm_pmu_start,
> + .stop = cvm_pmu_stop,
> + .read = cvm_pmu_read,
> + .attr_groups = cvm_pmu_lmc_attr_groups,
> + };
> +
> + cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_CVM_ONLINE,
> + &lmc->cpuhp_node);
> +
> + /*
> + * perf PMU is CPU dependent so pick a random CPU and migrate away
> + * if it goes offline.
> + */
> + cpumask_set_cpu(smp_processor_id(), &lmc->active_mask);
> +
> + list_add(&lmc->entry, &cvm_pmu_lmcs);
> + lmc->event_valid = cvm_pmu_lmc_event_valid;
> +
> + ret = perf_pmu_register(&lmc->pmu, lmc->pmu_name, -1);
> + if (ret)
> + goto fail_pmu;
> +
> + dev_info(&pdev->dev, "Enabled %s PMU with %d counters\n",
> + lmc->pmu_name, lmc->num_counters);
> + return 0;
> +
> +fail_pmu:
> + kfree(lmc->pmu_name);
> + cpuhp_state_remove_instance(CPUHP_AP_PERF_ARM_CVM_ONLINE,
> + &lmc->cpuhp_node);
Expected order to unwind the above would be the reverse of this.

> +fail_kasprintf:
> + iounmap(lmc->map);
> +fail_ioremap:
> + kfree(lmc);
> + return ret;
> +}
> +
> +static int __init cvm_pmu_init(void)
> +{
> + unsigned long implementor = read_cpuid_implementor();
> + unsigned int vendor_id = PCI_VENDOR_ID_CAVIUM;
> + struct pci_dev *pdev = NULL;
> + int rc;
> +
> + if (implementor != ARM_CPU_IMP_CAVIUM)
> + return -ENODEV;
> +
> + INIT_LIST_HEAD(&cvm_pmu_lmcs);
> +
> + rc = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_CVM_ONLINE,
> + "perf/arm/cvm:online", NULL,
> + cvm_pmu_offline_cpu);
> +
> + /* detect LMC devices */
> + while ((pdev = pci_get_device(vendor_id, 0xa022, pdev))) {
> + if (!pdev)
> + break;
> + rc = cvm_pmu_lmc_probe(pdev);
> + if (rc)
> + return rc;
> + }
> + return 0;
> +}
> +late_initcall(cvm_pmu_init); /* should come after PCI init */
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index b56573b..78ac3d2 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -141,6 +141,7 @@ enum cpuhp_state {
> CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE,
> CPUHP_AP_WORKQUEUE_ONLINE,
> CPUHP_AP_RCUTREE_ONLINE,
> + CPUHP_AP_PERF_ARM_CVM_ONLINE,
> CPUHP_AP_ONLINE_DYN,
> CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 30,
> CPUHP_AP_X86_HPET_ONLINE,