Re: [PATCH 1/5] powercap/drivers/dtpm: Encapsulate even more the code

Daniel Lezcano
2021-03-08T19:31:57Z

On 01/03/2021 22:21, Daniel Lezcano wrote:
> In order to increase the self-encapsulation of the dtpm generic code,
> the following changes are adding a power update ops to the dtpm
> ops. That allows the generic code to call directly the dtpm backend
> function to update the power values.
>
> The power update function does compute the power characteristics when
> the function is invoked. In the case of the CPUs, the power
> consumption depends on the number of online CPUs. The online CPUs mask
> is not up to date at CPUHP_AP_ONLINE_DYN state in the tear down
> callback. That is the reason why the online / offline are at separate
> state. As there is already an existing state for DTPM, this one is
> only moved to the DEAD state, so there is no addition of new state
> with these changes.
>
> That simplifies the code for the next changes and results in a more
> self-encapsulated code.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Is there any comment on this series ?

> ---
> drivers/powercap/dtpm.c | 54 ++++++++--------
> drivers/powercap/dtpm_cpu.c | 124 +++++++++++++-----------------------
> include/linux/cpuhotplug.h | 2 +-
> include/linux/dtpm.h | 3 +-
> 4 files changed, 76 insertions(+), 107 deletions(-)
>
> diff --git a/drivers/powercap/dtpm.c b/drivers/powercap/dtpm.c
> index c2185ec5f887..1085dccf9c58 100644
> --- a/drivers/powercap/dtpm.c
> +++ b/drivers/powercap/dtpm.c
> @@ -116,8 +116,6 @@ static void __dtpm_sub_power(struct dtpm *dtpm)
> parent->power_limit -= dtpm->power_limit;
> parent = parent->parent;
> }
> -
> - __dtpm_rebalance_weight(root);
> }
>
> static void __dtpm_add_power(struct dtpm *dtpm)
> @@ -130,45 +128,45 @@ static void __dtpm_add_power(struct dtpm *dtpm)
> parent->power_limit += dtpm->power_limit;
> parent = parent->parent;
> }
> +}
> +
> +static int __dtpm_update_power(struct dtpm *dtpm)
> +{
> + int ret;
> +
> + __dtpm_sub_power(dtpm);
>
> - __dtpm_rebalance_weight(root);
> + ret = dtpm->ops->upt_power_uw(dtpm);
> + if (ret)
> + pr_err("Failed to update power for '%s': %d\n",
> + dtpm->zone.name, ret);
> +
> + if (!test_bit(DTPM_POWER_LIMIT_FLAG, &dtpm->flags))
> + dtpm->power_limit = dtpm->power_max;
> +
> + __dtpm_add_power(dtpm);
> +
> + if (root)
> + __dtpm_rebalance_weight(root);
> +
> + return ret;
> }
>
> /**
> * dtpm_update_power - Update the power on the dtpm
> * @dtpm: a pointer to a dtpm structure to update
> - * @power_min: a u64 representing the new power_min value
> - * @power_max: a u64 representing the new power_max value
> *
> * Function to update the power values of the dtpm node specified in
> * parameter. These new values will be propagated to the tree.
> *
> * Return: zero on success, -EINVAL if the values are inconsistent
> */
> -int dtpm_update_power(struct dtpm *dtpm, u64 power_min, u64 power_max)
> +int dtpm_update_power(struct dtpm *dtpm)
> {
> - int ret = 0;
> + int ret;
>
> mutex_lock(&dtpm_lock);
> -
> - if (power_min == dtpm->power_min && power_max == dtpm->power_max)
> - goto unlock;
> -
> - if (power_max < power_min) {
> - ret = -EINVAL;
> - goto unlock;
> - }
> -
> - __dtpm_sub_power(dtpm);
> -
> - dtpm->power_min = power_min;
> - dtpm->power_max = power_max;
> - if (!test_bit(DTPM_POWER_LIMIT_FLAG, &dtpm->flags))
> - dtpm->power_limit = power_max;
> -
> - __dtpm_add_power(dtpm);
> -
> -unlock:
> + ret = __dtpm_update_power(dtpm);
> mutex_unlock(&dtpm_lock);
>
> return ret;
> @@ -436,6 +434,7 @@ int dtpm_register(const char *name, struct dtpm *dtpm, struct dtpm *parent)
>
> if (dtpm->ops && !(dtpm->ops->set_power_uw &&
> dtpm->ops->get_power_uw &&
> + dtpm->ops->upt_power_uw &&
> dtpm->ops->release))
> return -EINVAL;
>
> @@ -455,7 +454,8 @@ int dtpm_register(const char *name, struct dtpm *dtpm, struct dtpm *parent)
> root = dtpm;
> }
>
> - __dtpm_add_power(dtpm);
> + if (dtpm->ops && !dtpm->ops->upt_power_uw(dtpm))
> + __dtpm_add_power(dtpm);
>
> pr_info("Registered dtpm node '%s' / %llu-%llu uW, \n",
> dtpm->zone.name, dtpm->power_min, dtpm->power_max);
> diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
> index 51c366938acd..aff79c649345 100644
> --- a/drivers/powercap/dtpm_cpu.c
> +++ b/drivers/powercap/dtpm_cpu.c
> @@ -14,6 +14,8 @@
> * The CPU hotplug is supported and the power numbers will be updated
> * if a CPU is hot plugged / unplugged.
> */
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> #include <linux/cpumask.h>
> #include <linux/cpufreq.h>
> #include <linux/cpuhotplug.h>
> @@ -23,8 +25,6 @@
> #include <linux/slab.h>
> #include <linux/units.h>
>
> -static struct dtpm *__parent;
> -
> static DEFINE_PER_CPU(struct dtpm *, dtpm_per_cpu);
>
> struct dtpm_cpu {
> @@ -32,57 +32,16 @@ struct dtpm_cpu {
> int cpu;
> };
>
> -/*
> - * When a new CPU is inserted at hotplug or boot time, add the power
> - * contribution and update the dtpm tree.
> - */
> -static int power_add(struct dtpm *dtpm, struct em_perf_domain *em)
> -{
> - u64 power_min, power_max;
> -
> - power_min = em->table[0].power;
> - power_min *= MICROWATT_PER_MILLIWATT;
> - power_min += dtpm->power_min;
> -
> - power_max = em->table[em->nr_perf_states - 1].power;
> - power_max *= MICROWATT_PER_MILLIWATT;
> - power_max += dtpm->power_max;
> -
> - return dtpm_update_power(dtpm, power_min, power_max);
> -}
> -
> -/*
> - * When a CPU is unplugged, remove its power contribution from the
> - * dtpm tree.
> - */
> -static int power_sub(struct dtpm *dtpm, struct em_perf_domain *em)
> -{
> - u64 power_min, power_max;
> -
> - power_min = em->table[0].power;
> - power_min *= MICROWATT_PER_MILLIWATT;
> - power_min = dtpm->power_min - power_min;
> -
> - power_max = em->table[em->nr_perf_states - 1].power;
> - power_max *= MICROWATT_PER_MILLIWATT;
> - power_max = dtpm->power_max - power_max;
> -
> - return dtpm_update_power(dtpm, power_min, power_max);
> -}
> -
> static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
> {
> struct dtpm_cpu *dtpm_cpu = dtpm->private;
> - struct em_perf_domain *pd;
> + struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu);
> struct cpumask cpus;
> unsigned long freq;
> u64 power;
> int i, nr_cpus;
>
> - pd = em_cpu_get(dtpm_cpu->cpu);
> -
> cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
> -
> nr_cpus = cpumask_weight(&cpus);
>
> for (i = 0; i < pd->nr_perf_states; i++) {
> @@ -113,6 +72,7 @@ static u64 get_pd_power_uw(struct dtpm *dtpm)
>
> pd = em_cpu_get(dtpm_cpu->cpu);
> freq = cpufreq_quick_get(dtpm_cpu->cpu);
> +
> cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
> nr_cpus = cpumask_weight(&cpus);
>
> @@ -128,6 +88,27 @@ static u64 get_pd_power_uw(struct dtpm *dtpm)
> return 0;
> }
>
> +static int upt_pd_power_uw(struct dtpm *dtpm)
> +{
> + struct dtpm_cpu *dtpm_cpu = dtpm->private;
> + struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu);
> + struct cpumask cpus;
> + int nr_cpus;
> +
> + cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus));
> + nr_cpus = cpumask_weight(&cpus);
> +
> + dtpm->power_min = em->table[0].power;
> + dtpm->power_min *= MICROWATT_PER_MILLIWATT;
> + dtpm->power_min *= nr_cpus;
> +
> + dtpm->power_max = em->table[em->nr_perf_states - 1].power;
> + dtpm->power_max *= MICROWATT_PER_MILLIWATT;
> + dtpm->power_max *= nr_cpus;
> +
> + return 0;
> +}
> +
> static void pd_release(struct dtpm *dtpm)
> {
> struct dtpm_cpu *dtpm_cpu = dtpm->private;
> @@ -141,37 +122,25 @@ static void pd_release(struct dtpm *dtpm)
> static struct dtpm_ops dtpm_ops = {
> .set_power_uw = set_pd_power_limit,
> .get_power_uw = get_pd_power_uw,
> + .upt_power_uw = upt_pd_power_uw,
> .release = pd_release,
> };
>
> static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
> {
> - struct cpufreq_policy *policy;
> + struct cpumask cpus;
> struct em_perf_domain *pd;
> struct dtpm *dtpm;
>
> - policy = cpufreq_cpu_get(cpu);
> -
> - if (!policy)
> - return 0;
> -
> pd = em_cpu_get(cpu);
> if (!pd)
> return -EINVAL;
>
> - dtpm = per_cpu(dtpm_per_cpu, cpu);
> -
> - power_sub(dtpm, pd);
> -
> - if (cpumask_weight(policy->cpus) != 1)
> - return 0;
> -
> - for_each_cpu(cpu, policy->related_cpus)
> - per_cpu(dtpm_per_cpu, cpu) = NULL;
> + cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
>
> - dtpm_unregister(dtpm);
> + dtpm = per_cpu(dtpm_per_cpu, cpu);
>
> - return 0;
> + return dtpm_update_power(dtpm);
> }
>
> static int cpuhp_dtpm_cpu_online(unsigned int cpu)
> @@ -184,7 +153,6 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
> int ret = -ENOMEM;
>
> policy = cpufreq_cpu_get(cpu);
> -
> if (!policy)
> return 0;
>
> @@ -194,7 +162,7 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
>
> dtpm = per_cpu(dtpm_per_cpu, cpu);
> if (dtpm)
> - return power_add(dtpm, pd);
> + return dtpm_update_power(dtpm);
>
> dtpm = dtpm_alloc(&dtpm_ops);
> if (!dtpm)
> @@ -210,27 +178,20 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
> for_each_cpu(cpu, policy->related_cpus)
> per_cpu(dtpm_per_cpu, cpu) = dtpm;
>
> - sprintf(name, "cpu%d", dtpm_cpu->cpu);
> + sprintf(name, "cpu%d-cpufreq", dtpm_cpu->cpu);
>
> - ret = dtpm_register(name, dtpm, __parent);
> + ret = dtpm_register(name, dtpm, NULL);
> if (ret)
> goto out_kfree_dtpm_cpu;
>
> - ret = power_add(dtpm, pd);
> - if (ret)
> - goto out_dtpm_unregister;
> -
> ret = freq_qos_add_request(&policy->constraints,
> &dtpm_cpu->qos_req, FREQ_QOS_MAX,
> pd->table[pd->nr_perf_states - 1].frequency);
> if (ret)
> - goto out_power_sub;
> + goto out_dtpm_unregister;
>
> return 0;
>
> -out_power_sub:
> - power_sub(dtpm, pd);
> -
> out_dtpm_unregister:
> dtpm_unregister(dtpm);
> dtpm_cpu = NULL;
> @@ -248,10 +209,17 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
>
> int dtpm_register_cpu(struct dtpm *parent)
> {
> - __parent = parent;
> + int ret;
>
> - return cpuhp_setup_state(CPUHP_AP_DTPM_CPU_ONLINE,
> - "dtpm_cpu:online",
> - cpuhp_dtpm_cpu_online,
> - cpuhp_dtpm_cpu_offline);
> + ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline",
> + NULL, cpuhp_dtpm_cpu_offline);
> + if (ret < 0)
> + return ret;
> +
> + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online",
> + cpuhp_dtpm_cpu_online, NULL);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> }
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index ee09a39627d6..fcb2967fb5ba 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -61,6 +61,7 @@ enum cpuhp_state {
> CPUHP_LUSTRE_CFS_DEAD,
> CPUHP_AP_ARM_CACHE_B15_RAC_DEAD,
> CPUHP_PADATA_DEAD,
> + CPUHP_AP_DTPM_CPU_DEAD,
> CPUHP_WORKQUEUE_PREP,
> CPUHP_POWER_NUMA_PREPARE,
> CPUHP_HRTIMERS_PREPARE,
> @@ -193,7 +194,6 @@ enum cpuhp_state {
> CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 30,
> CPUHP_AP_X86_HPET_ONLINE,
> CPUHP_AP_X86_KVM_CLK_ONLINE,
> - CPUHP_AP_DTPM_CPU_ONLINE,
> CPUHP_AP_ACTIVE,
> CPUHP_ONLINE,
> };
> diff --git a/include/linux/dtpm.h b/include/linux/dtpm.h
> index e80a332e3d8a..d29be6a0e513 100644
> --- a/include/linux/dtpm.h
> +++ b/include/linux/dtpm.h
> @@ -29,6 +29,7 @@ struct dtpm {
> struct dtpm_ops {
> u64 (*set_power_uw)(struct dtpm *, u64);
> u64 (*get_power_uw)(struct dtpm *);
> + int (*upt_power_uw)(struct dtpm *);
> void (*release)(struct dtpm *);
> };
>
> @@ -62,7 +63,7 @@ static inline struct dtpm *to_dtpm(struct powercap_zone *zone)
> return container_of(zone, struct dtpm, zone);
> }
>
> -int dtpm_update_power(struct dtpm *dtpm, u64 power_min, u64 power_max);
> +int dtpm_update_power(struct dtpm *dtpm);
>
> int dtpm_release_zone(struct powercap_zone *pcz);
>
>

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