Add support for other devices than CPUs. The registration function does not require a valid cpumask pointer and is ready to handle new devices. Some of the internal structures has been reorganized in order to keep consistent view (like removing per_cpu pd pointers).
Signed-off-by: Lukasz Luba lukasz.luba@arm.com --- Hi all,
This is just a small change compared to v8 addressing Rafael's comments an Dan's static analyzes. Here are the changes: - added comment about mutex usage in the unregister function - changed 'dev' into @dev in the kerneldoc comments - removed 'else' statement from em_create_pd() to calm down static analizers
Regards, Lukasz
include/linux/device.h | 5 + include/linux/energy_model.h | 29 ++++- kernel/power/energy_model.c | 244 ++++++++++++++++++++++++----------- 3 files changed, 194 insertions(+), 84 deletions(-)
diff --git a/include/linux/device.h b/include/linux/device.h index ac8e37cd716a..7023d3ea189b 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -13,6 +13,7 @@ #define _DEVICE_H_
#include <linux/dev_printk.h> +#include <linux/energy_model.h> #include <linux/ioport.h> #include <linux/kobject.h> #include <linux/klist.h> @@ -559,6 +560,10 @@ struct device { struct dev_pm_info power; struct dev_pm_domain *pm_domain;
+#ifdef CONFIG_ENERGY_MODEL + struct em_perf_domain *em_pd; +#endif + #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN struct irq_domain *msi_domain; #endif diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index 7076cb22b247..2d4689964029 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -12,8 +12,10 @@
/** * em_perf_state - Performance state of a performance domain - * @frequency: The CPU frequency in KHz, for consistency with CPUFreq - * @power: The power consumed by 1 CPU at this level, in milli-watts + * @frequency: The frequency in KHz, for consistency with CPUFreq + * @power: The power consumed at this level, in milli-watts (by 1 CPU or + by a registered device). It can be a total power: static and + dynamic. * @cost: The cost coefficient associated with this level, used during * energy calculation. Equal to: power * max_frequency / frequency */ @@ -27,12 +29,16 @@ struct em_perf_state { * em_perf_domain - Performance domain * @table: List of performance states, in ascending order * @nr_perf_states: Number of performance states - * @cpus: Cpumask covering the CPUs of the domain + * @cpus: Cpumask covering the CPUs of the domain. It's here + * for performance reasons to avoid potential cache + * misses during energy calculations in the scheduler + * and simplifies allocating/freeing that memory region. * - * A "performance domain" represents a group of CPUs whose performance is - * scaled together. All CPUs of a performance domain must have the same - * micro-architecture. Performance domains often have a 1-to-1 mapping with - * CPUFreq policies. + * In case of CPU device, a "performance domain" represents a group of CPUs + * whose performance is scaled together. All CPUs of a performance domain + * must have the same micro-architecture. Performance domains often have + * a 1-to-1 mapping with CPUFreq policies. In case of other devices the @cpus + * field is unused. */ struct em_perf_domain { struct em_perf_state *table; @@ -71,10 +77,12 @@ struct em_data_callback { #define EM_DATA_CB(_active_power_cb) { .active_power = &_active_power_cb }
struct em_perf_domain *em_cpu_get(int cpu); +struct em_perf_domain *em_pd_get(struct device *dev); int em_register_perf_domain(cpumask_t *span, unsigned int nr_states, struct em_data_callback *cb); int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, struct em_data_callback *cb, cpumask_t *span); +void em_dev_unregister_perf_domain(struct device *dev);
/** * em_pd_energy() - Estimates the energy consumed by the CPUs of a perf. domain @@ -184,10 +192,17 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, { return -EINVAL; } +static inline void em_dev_unregister_perf_domain(struct device *dev) +{ +} static inline struct em_perf_domain *em_cpu_get(int cpu) { return NULL; } +static inline struct em_perf_domain *em_pd_get(struct device *dev) +{ + return NULL; +} static inline unsigned long em_pd_energy(struct em_perf_domain *pd, unsigned long max_util, unsigned long sum_util) { diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index 5b8a1566526a..32d76e78f992 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -1,9 +1,10 @@ // SPDX-License-Identifier: GPL-2.0 /* - * Energy Model of CPUs + * Energy Model of devices * - * Copyright (c) 2018, Arm ltd. + * Copyright (c) 2018-2020, Arm ltd. * Written by: Quentin Perret, Arm ltd. + * Improvements provided by: Lukasz Luba, Arm ltd. */
#define pr_fmt(fmt) "energy_model: " fmt @@ -15,15 +16,17 @@ #include <linux/sched/topology.h> #include <linux/slab.h>
-/* Mapping of each CPU to the performance domain to which it belongs. */ -static DEFINE_PER_CPU(struct em_perf_domain *, em_data); - /* * Mutex serializing the registrations of performance domains and letting * callbacks defined by drivers sleep. */ static DEFINE_MUTEX(em_pd_mutex);
+static bool _is_cpu_device(struct device *dev) +{ + return (dev->bus == &cpu_subsys); +} + #ifdef CONFIG_DEBUG_FS static struct dentry *rootdir;
@@ -49,22 +52,30 @@ static int em_debug_cpus_show(struct seq_file *s, void *unused) } DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);
-static void em_debug_create_pd(struct em_perf_domain *pd, int cpu) +static void em_debug_create_pd(struct device *dev) { struct dentry *d; - char name[8]; int i;
- snprintf(name, sizeof(name), "pd%d", cpu); - /* Create the directory of the performance domain */ - d = debugfs_create_dir(name, rootdir); + d = debugfs_create_dir(dev_name(dev), rootdir);
- debugfs_create_file("cpus", 0444, d, pd->cpus, &em_debug_cpus_fops); + if (_is_cpu_device(dev)) + debugfs_create_file("cpus", 0444, d, dev->em_pd->cpus, + &em_debug_cpus_fops);
/* Create a sub-directory for each performance state */ - for (i = 0; i < pd->nr_perf_states; i++) - em_debug_create_ps(&pd->table[i], d); + for (i = 0; i < dev->em_pd->nr_perf_states; i++) + em_debug_create_ps(&dev->em_pd->table[i], d); + +} + +static void em_debug_remove_pd(struct device *dev) +{ + struct dentry *debug_dir; + + debug_dir = debugfs_lookup(dev_name(dev), rootdir); + debugfs_remove_recursive(debug_dir); }
static int __init em_debug_init(void) @@ -76,40 +87,34 @@ static int __init em_debug_init(void) } core_initcall(em_debug_init); #else /* CONFIG_DEBUG_FS */ -static void em_debug_create_pd(struct em_perf_domain *pd, int cpu) {} +static void em_debug_create_pd(struct device *dev) {} +static void em_debug_remove_pd(struct device *dev) {} #endif -static struct em_perf_domain * -em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb, - cpumask_t *span) + +static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd, + int nr_states, struct em_data_callback *cb) { unsigned long opp_eff, prev_opp_eff = ULONG_MAX; unsigned long power, freq, prev_freq = 0; - int i, ret, cpu = cpumask_first(span); struct em_perf_state *table; - struct em_perf_domain *pd; + int i, ret; u64 fmax;
- if (!cb->active_power) - return NULL; - - pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL); - if (!pd) - return NULL; - table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL); if (!table) - goto free_pd; + return -ENOMEM;
/* Build the list of performance states for this performance domain */ for (i = 0, freq = 0; i < nr_states; i++, freq++) { /* * active_power() is a driver callback which ceils 'freq' to - * lowest performance state of 'cpu' above 'freq' and updates + * lowest performance state of 'dev' above 'freq' and updates * 'power' and 'freq' accordingly. */ ret = cb->active_power(&power, &freq, dev); if (ret) { - pr_err("pd%d: invalid perf. state: %d\n", cpu, ret); + dev_err(dev, "EM: invalid perf. state: %d\n", + ret); goto free_ps_table; }
@@ -118,7 +123,8 @@ em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb, * higher performance states. */ if (freq <= prev_freq) { - pr_err("pd%d: non-increasing freq: %lu\n", cpu, freq); + dev_err(dev, "EM: non-increasing freq: %lu\n", + freq); goto free_ps_table; }
@@ -127,7 +133,8 @@ em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb, * positive, in milli-watts and to fit into 16 bits. */ if (!power || power > EM_MAX_POWER) { - pr_err("pd%d: invalid power: %lu\n", cpu, power); + dev_err(dev, "EM: invalid power: %lu\n", + power); goto free_ps_table; }
@@ -142,8 +149,8 @@ em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb, */ opp_eff = freq / power; if (opp_eff >= prev_opp_eff) - pr_warn("pd%d: hertz/watts ratio non-monotonically decreasing: em_perf_state %d >= em_perf_state%d\n", - cpu, i, i - 1); + dev_dbg(dev, "EM: hertz/watts ratio non-monotonically decreasing: em_perf_state %d >= em_perf_state%d\n", + i, i - 1); prev_opp_eff = opp_eff; }
@@ -156,30 +163,82 @@ em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb,
pd->table = table; pd->nr_perf_states = nr_states; - cpumask_copy(to_cpumask(pd->cpus), span);
- em_debug_create_pd(pd, cpu); - - return pd; + return 0;
free_ps_table: kfree(table); -free_pd: - kfree(pd); + return -EINVAL; +} + +static int em_create_pd(struct device *dev, int nr_states, + struct em_data_callback *cb, cpumask_t *cpus) +{ + struct em_perf_domain *pd; + struct device *cpu_dev; + int cpu, ret; + + if (_is_cpu_device(dev)) { + pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL); + if (!pd) + return -ENOMEM; + + cpumask_copy(em_span_cpus(pd), cpus); + } else { + pd = kzalloc(sizeof(*pd), GFP_KERNEL); + if (!pd) + return -ENOMEM; + } + + ret = em_create_perf_table(dev, pd, nr_states, cb); + if (ret) { + kfree(pd); + return ret; + } + + if (_is_cpu_device(dev)) + for_each_cpu(cpu, cpus) { + cpu_dev = get_cpu_device(cpu); + cpu_dev->em_pd = pd; + } + + dev->em_pd = pd; + + return 0; +} + +/** + * em_pd_get() - Return the performance domain for a device + * @dev : Device to find the performance domain for + * + * Returns the performance domain to which @dev belongs, or NULL if it doesn't + * exist. + */ +struct em_perf_domain *em_pd_get(struct device *dev) +{ + if (IS_ERR_OR_NULL(dev)) + return NULL;
- return NULL; + return dev->em_pd; } +EXPORT_SYMBOL_GPL(em_pd_get);
/** * em_cpu_get() - Return the performance domain for a CPU * @cpu : CPU to find the performance domain for * - * Return: the performance domain to which 'cpu' belongs, or NULL if it doesn't + * Returns the performance domain to which @cpu belongs, or NULL if it doesn't * exist. */ struct em_perf_domain *em_cpu_get(int cpu) { - return READ_ONCE(per_cpu(em_data, cpu)); + struct device *cpu_dev; + + cpu_dev = get_cpu_device(cpu); + if (!cpu_dev) + return NULL; + + return em_pd_get(cpu_dev); } EXPORT_SYMBOL_GPL(em_cpu_get);
@@ -188,7 +247,7 @@ EXPORT_SYMBOL_GPL(em_cpu_get); * @dev : Device for which the EM is to register * @nr_states : Number of performance states to register * @cb : Callback functions providing the data of the Energy Model - * @span : Pointer to cpumask_t, which in case of a CPU device is + * @cpus : Pointer to cpumask_t, which in case of a CPU device is * obligatory. It can be taken from i.e. 'policy->cpus'. For other * type of devices this should be set to NULL. * @@ -201,13 +260,12 @@ EXPORT_SYMBOL_GPL(em_cpu_get); * Return 0 on success */ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, - struct em_data_callback *cb, cpumask_t *span) + struct em_data_callback *cb, cpumask_t *cpus) { unsigned long cap, prev_cap = 0; - struct em_perf_domain *pd; - int cpu, ret = 0; + int cpu, ret;
- if (!dev || !span || !nr_states || !cb) + if (!dev || !nr_states || !cb) return -EINVAL;
/* @@ -216,47 +274,50 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, */ mutex_lock(&em_pd_mutex);
- for_each_cpu(cpu, span) { - /* Make sure we don't register again an existing domain. */ - if (READ_ONCE(per_cpu(em_data, cpu))) { - ret = -EEXIST; - goto unlock; - } + if (dev->em_pd) { + ret = -EEXIST; + goto unlock; + }
- /* - * All CPUs of a domain must have the same micro-architecture - * since they all share the same table. - */ - cap = arch_scale_cpu_capacity(cpu); - if (prev_cap && prev_cap != cap) { - pr_err("CPUs of %*pbl must have the same capacity\n", - cpumask_pr_args(span)); + if (_is_cpu_device(dev)) { + if (!cpus) { + dev_err(dev, "EM: invalid CPU mask\n"); ret = -EINVAL; goto unlock; } - prev_cap = cap; + + for_each_cpu(cpu, cpus) { + if (em_cpu_get(cpu)) { + dev_err(dev, "EM: exists for CPU%d\n", cpu); + ret = -EEXIST; + goto unlock; + } + /* + * All CPUs of a domain must have the same + * micro-architecture since they all share the same + * table. + */ + cap = arch_scale_cpu_capacity(cpu); + if (prev_cap && prev_cap != cap) { + dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n", + cpumask_pr_args(cpus)); + + ret = -EINVAL; + goto unlock; + } + prev_cap = cap; + } }
- /* Create the performance domain and add it to the Energy Model. */ - pd = em_create_pd(dev, nr_states, cb, span); - if (!pd) { - ret = -EINVAL; + ret = em_create_pd(dev, nr_states, cb, cpus); + if (ret) goto unlock; - }
- for_each_cpu(cpu, span) { - /* - * The per-cpu array can be read concurrently from em_cpu_get(). - * The barrier enforces the ordering needed to make sure readers - * can only access well formed em_perf_domain structs. - */ - smp_store_release(per_cpu_ptr(&em_data, cpu), pd); - } + em_debug_create_pd(dev); + dev_info(dev, "EM: created perf domain\n");
- pr_debug("Created perf domain %*pbl\n", cpumask_pr_args(span)); unlock: mutex_unlock(&em_pd_mutex); - return ret; } EXPORT_SYMBOL_GPL(em_dev_register_perf_domain); @@ -285,3 +346,32 @@ int em_register_perf_domain(cpumask_t *span, unsigned int nr_states, return em_dev_register_perf_domain(cpu_dev, nr_states, cb, span); } EXPORT_SYMBOL_GPL(em_register_perf_domain); + +/** + * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device + * @dev : Device for which the EM is registered + * + * Unregister the EM for the specified @dev (but not a CPU device). + */ +void em_dev_unregister_perf_domain(struct device *dev) +{ + if (IS_ERR_OR_NULL(dev) || !dev->em_pd) + return; + + if (_is_cpu_device(dev)) + return; + + /* + * The mutex separates all register/unregister requests and protects + * from potential clean-up/setup issues in the debugfs directories. + * The debugfs directory name is the same as device's name. + */ + mutex_lock(&em_pd_mutex); + em_debug_remove_pd(dev); + + kfree(dev->em_pd->table); + kfree(dev->em_pd); + dev->em_pd = NULL; + mutex_unlock(&em_pd_mutex); +} +EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);