From cc1cfc47ea47187a21ec1f079b3c53264157fe15 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Mon, 4 Jul 2022 11:15:49 +0100 Subject: cacheinfo: Add support to check if last level cache(LLC) is valid or shared It is useful to have helper to check if the given two CPUs share last level cache. We can do that check by comparing fw_token or by comparing the cache ID. Currently we check just for fw_token as the cache ID is optional. This helper can be used to build the llc_sibling during arch specific topology parsing and feeding information to the sched_domains. This also helps to get rid of llc_id in the CPU topology as it is sort of duplicate information. Also add helper to check if the llc information in cacheinfo is valid or not. Link: https://lore.kernel.org/r/20220704101605.1318280-6-sudeep.holla@arm.com Tested-by: Ionela Voinescu Tested-by: Conor Dooley Reviewed-by: Gavin Shan Signed-off-by: Sudeep Holla --- include/linux/cacheinfo.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/cacheinfo.h') diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h index 4ff37cb763ae..7e429bc5c1a4 100644 --- a/include/linux/cacheinfo.h +++ b/include/linux/cacheinfo.h @@ -82,6 +82,8 @@ struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu); int init_cache_level(unsigned int cpu); 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); #ifndef CONFIG_ACPI_PPTT /* * acpi_find_last_cache_level is only called on ACPI enabled -- cgit v1.3-8-gc7d7 From 36bbc5b4ffab33ccac0f4db27f619a6ba7a4fd32 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Mon, 4 Jul 2022 11:15:50 +0100 Subject: 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(-) (limited to 'include/linux/cacheinfo.h') 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 -- cgit v1.3-8-gc7d7