From a28b2bfc099c6b9caa6ef697660408e076a32019 Mon Sep 17 00:00:00 2001 From: Ionela Voinescu Date: Mon, 14 Dec 2020 12:38:23 +0000 Subject: 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 Tested-by: Mian Yousaf Kaukab Signed-off-by: Rafael J. Wysocki --- include/acpi/cppc_acpi.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/acpi/cppc_acpi.h') diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h index a6a9373ab863..232838d28f50 100644 --- a/include/acpi/cppc_acpi.h +++ b/include/acpi/cppc_acpi.h @@ -124,11 +124,10 @@ struct cppc_perf_fb_ctrs { /* Per CPU container for runtime CPPC management. */ struct cppc_cpudata { - int cpu; + struct list_head node; struct cppc_perf_caps perf_caps; struct cppc_perf_ctrls perf_ctrls; struct cppc_perf_fb_ctrs perf_fb_ctrs; - struct cpufreq_policy *cur_policy; unsigned int shared_type; cpumask_var_t shared_cpu_map; }; @@ -137,7 +136,8 @@ extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf); extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs); extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls); extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps); -extern int acpi_get_psd_map(struct cppc_cpudata **); +extern bool acpi_cpc_valid(void); +extern int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data); extern unsigned int cppc_get_transition_latency(int cpu); extern bool cpc_ffh_supported(void); extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val); -- cgit