diff options
author | Ionela Voinescu <ionela.voinescu@arm.com> | 2020-12-14 12:38:23 +0000 |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2020-12-15 19:19:32 +0100 |
commit | a28b2bfc099c6b9caa6ef697660408e076a32019 (patch) | |
tree | e456767ea3f1de1125199964810f7c2bb8572f05 /drivers/cpufreq/cppc_cpufreq.c | |
parent | cfdc589f4b5f94bf1a975b4a67d8163d533f6e9b (diff) | |
download | lwn-a28b2bfc099c6b9caa6ef697660408e076a32019.tar.gz lwn-a28b2bfc099c6b9caa6ef697660408e076a32019.zip |
cppc_cpufreq: replace per-cpu data array with a list
The cppc_cpudata per-cpu storage was inefficient (1) additional to causing
functional issues (2) when CPUs are hotplugged out, due to per-cpu data
being improperly initialised.
(1) The amount of information needed for CPPC performance control in its
cpufreq driver depends on the domain (PSD) coordination type:
ANY: One set of CPPC control and capability data (e.g desired
performance, highest/lowest performance, etc) applies to all
CPUs in the domain.
ALL: Same as ANY. To be noted that this type is not currently
supported. When supported, information about which CPUs
belong to a domain is needed in order for frequency change
requests to be sent to each of them.
HW: It's necessary to store CPPC control and capability
information for all the CPUs. HW will then coordinate the
performance state based on their limitations and requests.
NONE: Same as HW. No HW coordination is expected.
Despite this, the previous initialisation code would indiscriminately
allocate memory for all CPUs (all_cpu_data) and unnecessarily
duplicate performance capabilities and the domain sharing mask and type
for each possible CPU.
(2) With the current per-cpu structure, when having ANY coordination,
the cppc_cpudata cpu information is not initialised (will remain 0)
for all CPUs in a policy, other than policy->cpu. When policy->cpu is
hotplugged out, the driver will incorrectly use the uninitialised (0)
value of the other CPUs when making frequency changes. Additionally,
the previous values stored in the perf_ctrls.desired_perf will be
lost when policy->cpu changes.
Therefore replace the array of per cpu data with a list. The memory for
each structure is allocated at policy init, where a single structure
can be allocated per policy, not per cpu. In order to accommodate the
struct list_head node in the cppc_cpudata structure, the now unused cpu
and cur_policy variables are removed.
For example, on a arm64 Juno platform with 6 CPUs: (0, 1, 2, 3) in PSD1,
(4, 5) in PSD2 - ANY coordination, the memory allocation comparison shows:
Before patch:
- ANY coordination:
total slack req alloc/free caller
0 0 0 0/1 _kernel_size_le_hi32+0x0xffff800008ff7810
0 0 0 0/6 _kernel_size_le_hi32+0x0xffff800008ff7808
128 80 48 1/0 _kernel_size_le_hi32+0x0xffff800008ffc070
768 0 768 6/0 _kernel_size_le_hi32+0x0xffff800008ffc0e4
After patch:
- ANY coordination:
total slack req alloc/free caller
256 0 256 2/0 _kernel_size_le_hi32+0x0xffff800008fed410
0 0 0 0/2 _kernel_size_le_hi32+0x0xffff800008fed274
Additional notes:
- A pointer to the policy's cppc_cpudata is stored in policy->driver_data
- Driver registration is skipped if _CPC entries are not present.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/cppc_cpufreq.c')
-rw-r--r-- | drivers/cpufreq/cppc_cpufreq.c | 174 |
1 files changed, 91 insertions, 83 deletions
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index 40b58d2dbbc6..8a482c434ea6 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -30,13 +30,13 @@ #define DMI_PROCESSOR_MAX_SPEED 0x14 /* - * These structs contain information parsed from per CPU - * ACPI _CPC structures. - * e.g. For each CPU the highest, lowest supported - * performance capabilities, desired performance level - * requested etc. + * This list contains information parsed from per CPU ACPI _CPC and _PSD + * structures: e.g. the highest and lowest supported performance, capabilities, + * desired performance, level requested etc. Depending on the share_type, not + * all CPUs will have an entry in the list. */ -static struct cppc_cpudata **all_cpu_data; +static LIST_HEAD(cpu_data_list); + static bool boost_supported; struct cppc_workaround_oem_info { @@ -148,8 +148,9 @@ static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu_data, static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) + { - struct cppc_cpudata *cpu_data = all_cpu_data[policy->cpu]; + struct cppc_cpudata *cpu_data = policy->driver_data; unsigned int cpu = policy->cpu; struct cpufreq_freqs freqs; u32 desired_perf; @@ -183,7 +184,7 @@ static int cppc_verify_policy(struct cpufreq_policy_data *policy) static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy) { - struct cppc_cpudata *cpu_data = all_cpu_data[policy->cpu]; + struct cppc_cpudata *cpu_data = policy->driver_data; struct cppc_perf_caps *caps = &cpu_data->perf_caps; unsigned int cpu = policy->cpu; int ret; @@ -194,6 +195,12 @@ static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy) if (ret) pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n", caps->lowest_perf, cpu, ret); + + /* Remove CPU node from list and free driver data for policy */ + free_cpumask_var(cpu_data->shared_cpu_map); + list_del(&cpu_data->node); + kfree(policy->driver_data); + policy->driver_data = NULL; } /* @@ -239,25 +246,61 @@ static unsigned int cppc_cpufreq_get_transition_delay_us(unsigned int cpu) } #endif -static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) + +static struct cppc_cpudata *cppc_cpufreq_get_cpu_data(unsigned int cpu) { - struct cppc_cpudata *cpu_data = all_cpu_data[policy->cpu]; - struct cppc_perf_caps *caps = &cpu_data->perf_caps; - unsigned int cpu = policy->cpu; - int i, ret = 0; + struct cppc_cpudata *cpu_data; + int ret; + + cpu_data = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL); + if (!cpu_data) + goto out; - cpu_data->cpu = cpu; - ret = cppc_get_perf_caps(cpu, caps); + if (!zalloc_cpumask_var(&cpu_data->shared_cpu_map, GFP_KERNEL)) + goto free_cpu; + ret = acpi_get_psd_map(cpu, cpu_data); if (ret) { - pr_debug("Err reading CPU%d perf capabilities. ret:%d\n", - cpu, ret); - return ret; + pr_debug("Err parsing CPU%d PSD data: ret:%d\n", cpu, ret); + goto free_mask; + } + + ret = cppc_get_perf_caps(cpu, &cpu_data->perf_caps); + if (ret) { + pr_debug("Err reading CPU%d perf caps: ret:%d\n", cpu, ret); + goto free_mask; } /* Convert the lowest and nominal freq from MHz to KHz */ - caps->lowest_freq *= 1000; - caps->nominal_freq *= 1000; + cpu_data->perf_caps.lowest_freq *= 1000; + cpu_data->perf_caps.nominal_freq *= 1000; + + list_add(&cpu_data->node, &cpu_data_list); + + return cpu_data; + +free_mask: + free_cpumask_var(cpu_data->shared_cpu_map); +free_cpu: + kfree(cpu_data); +out: + return NULL; +} + +static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) +{ + unsigned int cpu = policy->cpu; + struct cppc_cpudata *cpu_data; + struct cppc_perf_caps *caps; + int ret; + + cpu_data = cppc_cpufreq_get_cpu_data(cpu); + if (!cpu_data) { + pr_err("Error in acquiring _CPC/_PSD data for CPU%d.\n", cpu); + return -ENODEV; + } + caps = &cpu_data->perf_caps; + policy->driver_data = cpu_data; /* * Set min to lowest nonlinear perf to avoid any efficiency penalty (see @@ -287,16 +330,12 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) /* Nothing to be done - we'll have a policy for each CPU */ break; case CPUFREQ_SHARED_TYPE_ANY: - /* All CPUs in the domain will share a policy */ + /* + * All CPUs in the domain will share a policy and all cpufreq + * operations will use a single cppc_cpudata structure stored + * in policy->driver_data. + */ cpumask_copy(policy->cpus, cpu_data->shared_cpu_map); - - for_each_cpu(i, policy->cpus) { - if (unlikely(i == cpu)) - continue; - - memcpy(&all_cpu_data[i]->perf_caps, caps, - sizeof(cpu_data->perf_caps)); - } break; default: pr_debug("Unsupported CPU co-ord type: %d\n", @@ -304,8 +343,6 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) return -EFAULT; } - cpu_data->cur_policy = policy; - /* * If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost * is supported. @@ -360,9 +397,12 @@ static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu_data, static unsigned int cppc_cpufreq_get_rate(unsigned int cpu) { struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0}; - struct cppc_cpudata *cpu_data = all_cpu_data[cpu]; + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + struct cppc_cpudata *cpu_data = policy->driver_data; int ret; + cpufreq_cpu_put(policy); + ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t0); if (ret) return ret; @@ -378,7 +418,7 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu) static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state) { - struct cppc_cpudata *cpu_data = all_cpu_data[policy->cpu]; + struct cppc_cpudata *cpu_data = policy->driver_data; struct cppc_perf_caps *caps = &cpu_data->perf_caps; int ret; @@ -404,9 +444,9 @@ static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state) static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf) { - unsigned int cpu = policy->cpu; + struct cppc_cpudata *cpu_data = policy->driver_data; - return cpufreq_show_cpus(all_cpu_data[cpu]->shared_cpu_map, buf); + return cpufreq_show_cpus(cpu_data->shared_cpu_map, buf); } cpufreq_freq_attr_ro(freqdomain_cpus); @@ -435,10 +475,13 @@ static struct cpufreq_driver cppc_cpufreq_driver = { */ static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpu) { - struct cppc_cpudata *cpu_data = all_cpu_data[cpu]; + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + struct cppc_cpudata *cpu_data = policy->driver_data; u64 desired_perf; int ret; + cpufreq_cpu_put(policy); + ret = cppc_get_desired_perf(cpu, &desired_perf); if (ret < 0) return -EIO; @@ -471,68 +514,33 @@ static void cppc_check_hisi_workaround(void) static int __init cppc_cpufreq_init(void) { - struct cppc_cpudata *cpu_data; - int i, ret = 0; - - if (acpi_disabled) + if ((acpi_disabled) || !acpi_cpc_valid()) return -ENODEV; - all_cpu_data = kcalloc(num_possible_cpus(), sizeof(void *), - GFP_KERNEL); - if (!all_cpu_data) - return -ENOMEM; - - for_each_possible_cpu(i) { - all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL); - if (!all_cpu_data[i]) - goto out; - - cpu_data = all_cpu_data[i]; - if (!zalloc_cpumask_var(&cpu_data->shared_cpu_map, GFP_KERNEL)) - goto out; - } - - ret = acpi_get_psd_map(all_cpu_data); - if (ret) { - pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n"); - goto out; - } + INIT_LIST_HEAD(&cpu_data_list); cppc_check_hisi_workaround(); - ret = cpufreq_register_driver(&cppc_cpufreq_driver); - if (ret) - goto out; + return cpufreq_register_driver(&cppc_cpufreq_driver); +} - return ret; +static inline void free_cpu_data(void) +{ + struct cppc_cpudata *iter, *tmp; -out: - for_each_possible_cpu(i) { - cpu_data = all_cpu_data[i]; - if (!cpu_data) - break; - free_cpumask_var(cpu_data->shared_cpu_map); - kfree(cpu_data); + list_for_each_entry_safe(iter, tmp, &cpu_data_list, node) { + free_cpumask_var(iter->shared_cpu_map); + list_del(&iter->node); + kfree(iter); } - kfree(all_cpu_data); - return -ENODEV; } static void __exit cppc_cpufreq_exit(void) { - struct cppc_cpudata *cpu_data; - int i; - cpufreq_unregister_driver(&cppc_cpufreq_driver); - for_each_possible_cpu(i) { - cpu_data = all_cpu_data[i]; - free_cpumask_var(cpu_data->shared_cpu_map); - kfree(cpu_data); - } - - kfree(all_cpu_data); + free_cpu_data(); } module_exit(cppc_cpufreq_exit); |