From 36bbc5b4ffab33ccac0f4db27f619a6ba7a4fd32 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Mon, 4 Jul 2022 11:15:50 +0100 Subject: [PATCH] cacheinfo: Allow early detection and population of cache attributes Some architecture/platforms may need to setup cache properties very early in the boot along with other cpu topologies so that all these information can be used to build sched_domains which is used by the scheduler. Allow detect_cache_attributes to be called quite early during the boot. Link: https://lore.kernel.org/r/20220704101605.1318280-7-sudeep.holla@arm.com Tested-by: Ionela Voinescu Tested-by: Conor Dooley Reviewed-by: Gavin Shan Signed-off-by: Sudeep Holla --- drivers/base/cacheinfo.c | 55 ++++++++++++++++++++++++++------------- include/linux/cacheinfo.h | 1 + 2 files changed, 38 insertions(+), 18 deletions(-) diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index fdc1baa342f1..4d21a1022fa9 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -193,14 +193,8 @@ static int cache_setup_of_node(unsigned int cpu) { struct device_node *np; struct cacheinfo *this_leaf; - struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu); unsigned int index = 0; - /* skip if fw_token is already populated */ - if (this_cpu_ci->info_list->fw_token) { - return 0; - } - np = of_cpu_device_node_get(cpu); if (!np) { pr_err("Failed to find cpu%d device node\n", cpu); @@ -236,6 +230,18 @@ int __weak cache_setup_acpi(unsigned int cpu) unsigned int coherency_max_size; +static int cache_setup_properties(unsigned int cpu) +{ + int ret = 0; + + if (of_have_populated_dt()) + ret = cache_setup_of_node(cpu); + else if (!acpi_disabled) + ret = cache_setup_acpi(cpu); + + return ret; +} + static int cache_shared_cpu_map_setup(unsigned int cpu) { struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu); @@ -246,21 +252,21 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) if (this_cpu_ci->cpu_map_populated) return 0; - if (of_have_populated_dt()) - ret = cache_setup_of_node(cpu); - else if (!acpi_disabled) - ret = cache_setup_acpi(cpu); - - if (ret) - return ret; + /* + * skip setting up cache properties if LLC is valid, just need + * to update the shared cpu_map if the cache attributes were + * populated early before all the cpus are brought online + */ + if (!last_level_cache_is_valid(cpu)) { + ret = cache_setup_properties(cpu); + if (ret) + return ret; + } for (index = 0; index < cache_leaves(cpu); index++) { unsigned int i; this_leaf = per_cpu_cacheinfo_idx(cpu, index); - /* skip if shared_cpu_map is already populated */ - if (!cpumask_empty(&this_leaf->shared_cpu_map)) - continue; cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map); for_each_online_cpu(i) { @@ -330,17 +336,28 @@ int __weak populate_cache_leaves(unsigned int cpu) return -ENOENT; } -static int detect_cache_attributes(unsigned int cpu) +int detect_cache_attributes(unsigned int cpu) { int ret; + /* Since early detection of the cacheinfo is allowed via this + * function and this also gets called as CPU hotplug callbacks via + * cacheinfo_cpu_online, the initialisation can be skipped and only + * CPU maps can be updated as the CPU online status would be update + * if called via cacheinfo_cpu_online path. + */ + if (per_cpu_cacheinfo(cpu)) + goto update_cpu_map; + if (init_cache_level(cpu) || !cache_leaves(cpu)) return -ENOENT; per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu), sizeof(struct cacheinfo), GFP_KERNEL); - if (per_cpu_cacheinfo(cpu) == NULL) + if (per_cpu_cacheinfo(cpu) == NULL) { + cache_leaves(cpu) = 0; return -ENOMEM; + } /* * populate_cache_leaves() may completely setup the cache leaves and @@ -349,6 +366,8 @@ static int detect_cache_attributes(unsigned int cpu) ret = populate_cache_leaves(cpu); if (ret) goto free_ci; + +update_cpu_map: /* * For systems using DT for cache hierarchy, fw_token * and shared_cpu_map will be set up here only if they are diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h index 7e429bc5c1a4..00b7a6ae8617 100644 --- a/include/linux/cacheinfo.h +++ b/include/linux/cacheinfo.h @@ -84,6 +84,7 @@ int populate_cache_leaves(unsigned int cpu); int cache_setup_acpi(unsigned int cpu); bool last_level_cache_is_valid(unsigned int cpu); bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y); +int detect_cache_attributes(unsigned int cpu); #ifndef CONFIG_ACPI_PPTT /* * acpi_find_last_cache_level is only called on ACPI enabled