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authorIonela Voinescu <ionela.voinescu@arm.com>2020-12-14 15:38:23 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-12-15 21:19:32 +0300
commita28b2bfc099c6b9caa6ef697660408e076a32019 (patch)
treee456767ea3f1de1125199964810f7c2bb8572f05 /drivers/acpi
parentcfdc589f4b5f94bf1a975b4a67d8163d533f6e9b (diff)
downloadlinux-a28b2bfc099c6b9caa6ef697660408e076a32019.tar.xz
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.c141
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);