Messages in this thread Patch in this message | | | From | Qing Wang <> | Subject | [PATCH V2 1/2] arch_topology: support for parsing cache topology from DT | Date | Fri, 22 Apr 2022 04:51:25 -0700 |
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From: Wang Qing <wangqing@vivo.com>
When ACPI is not enabled, we can get cache topolopy from DT like: * cpu0: cpu@000 { * next-level-cache = <&L2_1>; * L2_1: l2-cache { * compatible = "cache"; * next-level-cache = <&L3_1>; * }; * L3_1: l3-cache { * compatible = "cache"; * }; * }; * * cpu1: cpu@001 { * next-level-cache = <&L2_1>; * }; * ... * }; cache_topology[] hold the pointer describing by "next-level-cache", which can describe the cache topology of every level.
MAX_CACHE_LEVEL is strictly corresponding to the cache level from L2.
V2: make function name more sense
Signed-off-by: Wang Qing <wangqing@vivo.com> --- drivers/base/arch_topology.c | 47 ++++++++++++++++++++++++++++++++++- include/linux/arch_topology.h | 3 +++ 2 files changed, 49 insertions(+), 1 deletion(-)
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 1d6636ebaac5..46e84ce2ec0c 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -480,8 +480,10 @@ static int __init get_cpu_for_node(struct device_node *node) return -1; cpu = of_cpu_node_to_id(cpu_node); - if (cpu >= 0) + if (cpu >= 0) { topology_parse_cpu_capacity(cpu_node, cpu); + topology_parse_cpu_caches(cpu_node, cpu); + } else pr_info("CPU node for %pOF exist but the possible cpu range is :%*pbl\n", cpu_node, cpumask_pr_args(cpu_possible_mask)); @@ -647,6 +649,49 @@ static int __init parse_dt_topology(void) } #endif +/* + * cpu cache topology table + */ +#define MAX_CACHE_LEVEL 7 +static struct device_node *cache_topology[NR_CPUS][MAX_CACHE_LEVEL]; + +void topology_parse_cpu_caches(struct device_node *cpu_node, int cpu) +{ + struct device_node *node_cache = cpu_node; + int level = 0; + + while (level < MAX_CACHE_LEVEL) { + node_cache = of_parse_phandle(node_cache, "next-level-cache", 0); + if (!node_cache) + break; + + cache_topology[cpu][level++] = node_cache; + } +} + +/* + * find the largest subset of the shared cache in the range of cpu_mask + */ +void find_subset_of_share_cache(const struct cpumask *cpu_mask, int cpu, + struct cpumask *sc_mask) +{ + int cache_level, cpu_id; + + for (cache_level = MAX_CACHE_LEVEL - 1; cache_level >= 0; cache_level--) { + if (!cache_topology[cpu][cache_level]) + continue; + + cpumask_clear(sc_mask); + for (cpu_id = 0; cpu_id < NR_CPUS; cpu_id++) { + if (cache_topology[cpu][cache_level] == cache_topology[cpu_id][cache_level]) + cpumask_set_cpu(cpu_id, sc_mask); + } + + if (cpumask_subset(sc_mask, cpu_mask)) + break; + } +} + /* * cpu topology table */ diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h index 58cbe18d825c..c6ed727e453c 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -93,6 +93,9 @@ void update_siblings_masks(unsigned int cpu); void remove_cpu_topology(unsigned int cpuid); void reset_cpu_topology(void); int parse_acpi_topology(void); +void topology_parse_cpu_caches(struct device_node *cpu_node, int cpu); +void find_subset_of_share_cache(const struct cpumask *cpu_mask, int cpu, + struct cpumask *sc_mask); #endif #endif /* _LINUX_ARCH_TOPOLOGY_H_ */ -- 2.7.4
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