diff options
| -rw-r--r-- | arch/arm/Kconfig | 4 | ||||
| -rw-r--r-- | arch/arm/kernel/topology.c | 69 |
2 files changed, 72 insertions, 1 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 99d41f9633b..bc19fa61b90 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1528,13 +1528,15 @@ config HMP_FAST_CPU_MASK string "HMP scheduler fast CPU mask" depends on SCHED_HMP help - Specify the cpuids of the fast CPUs in the system as a list string, + Leave empty to use device tree information. + Specify the cpuids of the fast CPUs in the system as a list string, e.g. cpuid 0+1 should be specified as 0-1. config HMP_SLOW_CPU_MASK string "HMP scheduler slow CPU mask" depends on SCHED_HMP help + Leave empty to use device tree information. Specify the cpuids of the slow CPUs in the system as a list string, e.g. cpuid 0+1 should be specified as 0-1. diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index c5a59546a25..e6e430a567c 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -289,6 +289,75 @@ void store_cpu_topology(unsigned int cpuid) cpu_topology[cpuid].socket_id, mpidr); } + +#ifdef CONFIG_SCHED_HMP + +static const char * const little_cores[] = { + "arm,cortex-a7", + NULL, +}; + +static bool is_little_cpu(struct device_node *cn) +{ + const char * const *lc; + for (lc = little_cores; *lc; lc++) + if (of_device_is_compatible(cn, *lc)) + return true; + return false; +} + +void __init arch_get_fast_and_slow_cpus(struct cpumask *fast, + struct cpumask *slow) +{ + struct device_node *cn = NULL; + int cpu = 0; + + cpumask_clear(fast); + cpumask_clear(slow); + + /* + * Use the config options if they are given. This helps testing + * HMP scheduling on systems without a big.LITTLE architecture. + */ + if (strlen(CONFIG_HMP_FAST_CPU_MASK) && strlen(CONFIG_HMP_SLOW_CPU_MASK)) { + if (cpulist_parse(CONFIG_HMP_FAST_CPU_MASK, fast)) + WARN(1, "Failed to parse HMP fast cpu mask!\n"); + if (cpulist_parse(CONFIG_HMP_SLOW_CPU_MASK, slow)) + WARN(1, "Failed to parse HMP slow cpu mask!\n"); + return; + } + + /* + * Else, parse device tree for little cores. + */ + while ((cn = of_find_node_by_type(cn, "cpu"))) { + + if (cpu >= num_possible_cpus()) + break; + + if (is_little_cpu(cn)) + cpumask_set_cpu(cpu, slow); + else + cpumask_set_cpu(cpu, fast); + + cpu++; + } + + if (!cpumask_empty(fast) && !cpumask_empty(slow)) + return; + + /* + * We didn't find both big and little cores so let's call all cores + * fast as this will keep the system running, with all cores being + * treated equal. + */ + cpumask_setall(fast); + cpumask_clear(slow); +} + +#endif /* CONFIG_SCHED_HMP */ + + /* * init_cpu_topology is called at boot when only one cpu is running * which prevent simultaneous write access to cpu_topology array |