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author | Ionela Voinescu <ionela.voinescu@arm.com> | 2020-12-14 12:38:23 +0000 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2020-12-15 19:19:32 +0100 |
commit | a28b2bfc099c6b9caa6ef697660408e076a32019 (patch) | |
tree | e456767ea3f1de1125199964810f7c2bb8572f05 /drivers/acpi | |
parent | cfdc589f4b5f94bf1a975b4a67d8163d533f6e9b (diff) | |
download | linux-a28b2bfc099c6b9caa6ef697660408e076a32019.tar.gz linux-a28b2bfc099c6b9caa6ef697660408e076a32019.tar.bz2 linux-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/acpi')
-rw-r--r-- | drivers/acpi/cppc_acpi.c | 141 |
1 files changed, 60 insertions, 81 deletions
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 9e335f0d2595..8c1d62e88c46 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -413,109 +413,88 @@ end: return result; } +bool acpi_cpc_valid(void) +{ + struct cpc_desc *cpc_ptr; + int cpu; + + for_each_possible_cpu(cpu) { + cpc_ptr = per_cpu(cpc_desc_ptr, cpu); + if (!cpc_ptr) + return false; + } + + return true; +} +EXPORT_SYMBOL_GPL(acpi_cpc_valid); + /** - * acpi_get_psd_map - Map the CPUs in a common freq domain. - * @all_cpu_data: Ptrs to CPU specific CPPC data including PSD info. + * acpi_get_psd_map - Map the CPUs in the freq domain of a given cpu + * @cpu: Find all CPUs that share a domain with cpu. + * @cpu_data: Pointer to CPU specific CPPC data including PSD info. * * Return: 0 for success or negative value for err. */ -int acpi_get_psd_map(struct cppc_cpudata **all_cpu_data) +int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data) { - int count_target; - int retval = 0; - unsigned int i, j; - cpumask_var_t covered_cpus; - struct cppc_cpudata *pr, *match_pr; - struct acpi_psd_package *pdomain; - struct acpi_psd_package *match_pdomain; struct cpc_desc *cpc_ptr, *match_cpc_ptr; - - if (!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL)) - return -ENOMEM; + struct acpi_psd_package *match_pdomain; + struct acpi_psd_package *pdomain; + int count_target, i; /* * Now that we have _PSD data from all CPUs, let's setup P-state * domain info. */ - for_each_possible_cpu(i) { - if (cpumask_test_cpu(i, covered_cpus)) - continue; - - pr = all_cpu_data[i]; - cpc_ptr = per_cpu(cpc_desc_ptr, i); - if (!cpc_ptr) { - retval = -EFAULT; - goto err_ret; - } + cpc_ptr = per_cpu(cpc_desc_ptr, cpu); + if (!cpc_ptr) + return -EFAULT; - pdomain = &(cpc_ptr->domain_info); - cpumask_set_cpu(i, pr->shared_cpu_map); - cpumask_set_cpu(i, covered_cpus); - if (pdomain->num_processors <= 1) - continue; + pdomain = &(cpc_ptr->domain_info); + cpumask_set_cpu(cpu, cpu_data->shared_cpu_map); + if (pdomain->num_processors <= 1) + return 0; - /* Validate the Domain info */ - count_target = pdomain->num_processors; - if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL) - pr->shared_type = CPUFREQ_SHARED_TYPE_ALL; - else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL) - pr->shared_type = CPUFREQ_SHARED_TYPE_HW; - else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY) - pr->shared_type = CPUFREQ_SHARED_TYPE_ANY; - - for_each_possible_cpu(j) { - if (i == j) - continue; - - match_cpc_ptr = per_cpu(cpc_desc_ptr, j); - if (!match_cpc_ptr) { - retval = -EFAULT; - goto err_ret; - } + /* Validate the Domain info */ + count_target = pdomain->num_processors; + if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL) + cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ALL; + else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL) + cpu_data->shared_type = CPUFREQ_SHARED_TYPE_HW; + else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY) + cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ANY; - match_pdomain = &(match_cpc_ptr->domain_info); - if (match_pdomain->domain != pdomain->domain) - continue; + for_each_possible_cpu(i) { + if (i == cpu) + continue; - /* Here i and j are in the same domain */ - if (match_pdomain->num_processors != count_target) { - retval = -EFAULT; - goto err_ret; - } + match_cpc_ptr = per_cpu(cpc_desc_ptr, i); + if (!match_cpc_ptr) + goto err_fault; - if (pdomain->coord_type != match_pdomain->coord_type) { - retval = -EFAULT; - goto err_ret; - } + match_pdomain = &(match_cpc_ptr->domain_info); + if (match_pdomain->domain != pdomain->domain) + continue; - cpumask_set_cpu(j, covered_cpus); - cpumask_set_cpu(j, pr->shared_cpu_map); - } + /* Here i and cpu are in the same domain */ + if (match_pdomain->num_processors != count_target) + goto err_fault; - for_each_cpu(j, pr->shared_cpu_map) { - if (i == j) - continue; + if (pdomain->coord_type != match_pdomain->coord_type) + goto err_fault; - match_pr = all_cpu_data[j]; - match_pr->shared_type = pr->shared_type; - cpumask_copy(match_pr->shared_cpu_map, - pr->shared_cpu_map); - } + cpumask_set_cpu(i, cpu_data->shared_cpu_map); } - goto out; -err_ret: - for_each_possible_cpu(i) { - pr = all_cpu_data[i]; + return 0; - /* Assume no coordination on any error parsing domain info */ - cpumask_clear(pr->shared_cpu_map); - cpumask_set_cpu(i, pr->shared_cpu_map); - pr->shared_type = CPUFREQ_SHARED_TYPE_NONE; - } -out: - free_cpumask_var(covered_cpus); - return retval; +err_fault: + /* Assume no coordination on any error parsing domain info */ + cpumask_clear(cpu_data->shared_cpu_map); + cpumask_set_cpu(cpu, cpu_data->shared_cpu_map); + cpu_data->shared_type = CPUFREQ_SHARED_TYPE_NONE; + + return -EFAULT; } EXPORT_SYMBOL_GPL(acpi_get_psd_map); |