diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index cbae8be1fe520..585c66fce9d95 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -898,6 +898,48 @@ static int cache_add_dev(unsigned int cpu) return rc; } +/* + * Calculate the size of the per-CPU data cache slice. This can be + * used to estimate the size of the data cache slice that can be used + * by one CPU under ideal circumstances. UNIFIED caches are counted + * in addition to DATA caches. So, please consider code cache usage + * when use the result. + * + * Because the cache inclusive/non-inclusive information isn't + * available, we just use the size of the per-CPU slice of LLC to make + * the result more predictable across architectures. + */ +static void update_per_cpu_data_slice_size_cpu(unsigned int cpu) +{ + struct cpu_cacheinfo *ci; + struct cacheinfo *llc; + unsigned int nr_shared; + + if (!last_level_cache_is_valid(cpu)) + return; + + ci = ci_cacheinfo(cpu); + llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1); + + if (llc->type != CACHE_TYPE_DATA && llc->type != CACHE_TYPE_UNIFIED) + return; + + nr_shared = cpumask_weight(&llc->shared_cpu_map); + if (nr_shared) + ci->per_cpu_data_slice_size = llc->size / nr_shared; +} + +static void update_per_cpu_data_slice_size(bool cpu_online, unsigned int cpu) +{ + unsigned int icpu; + + for_each_online_cpu(icpu) { + if (!cpu_online && icpu == cpu) + continue; + update_per_cpu_data_slice_size_cpu(icpu); + } +} + static int cacheinfo_cpu_online(unsigned int cpu) { int rc = detect_cache_attributes(cpu); @@ -906,7 +948,11 @@ static int cacheinfo_cpu_online(unsigned int cpu) return rc; rc = cache_add_dev(cpu); if (rc) - free_cache_attributes(cpu); + goto err; + update_per_cpu_data_slice_size(true, cpu); + return 0; +err: + free_cache_attributes(cpu); return rc; } @@ -916,6 +962,7 @@ static int cacheinfo_cpu_pre_down(unsigned int cpu) cpu_cache_sysfs_exit(cpu); free_cache_attributes(cpu); + update_per_cpu_data_slice_size(false, cpu); return 0; } diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h index a5cfd44fab45b..d504eb4b49abe 100644 --- a/include/linux/cacheinfo.h +++ b/include/linux/cacheinfo.h @@ -73,6 +73,7 @@ struct cacheinfo { struct cpu_cacheinfo { struct cacheinfo *info_list; + unsigned int per_cpu_data_slice_size; unsigned int num_levels; unsigned int num_leaves; bool cpu_map_populated;