From 93197a36a9c16a85fb24cf5a8639f7bf9af838a3 Mon Sep 17 00:00:00 2001 From: Nathan Lynch Date: Tue, 23 Dec 2008 18:55:54 +0000 Subject: powerpc: Rewrite sysfs processor cache info code The current code for providing processor cache information in sysfs has the following deficiencies: - several complex functions that are hard to understand - implicit recursion (cache_desc_release -> kobject_put -> cache_desc_release) - explicit recursion (create_cache_index_info) - use of two per-cpu arrays when one would suffice - duplication of work on systems where CPUs share cache Also, when I looked at implementing support for a shared_cpu_map attribute, it was pretty much impossible to handle hotplug without checking every single online CPU's cache_desc list and fixing things up... not that this is a hot path, but it would have introduced O(n^2)-ish behavior during boot. Addressing this involved rethinking the core data structures used, which didn't lend itself to an incremental approach. This implementation maintains a "forest" (potentially more than one tree) of cache objects which reflects the system's cache topology. Cache objects are instantiated as needed as CPUs come online. A per-cpu array is used mainly for sysfs-related bookkeeping; the objects in the array just point to the appropriate points in the forest. This maintains compatibility with the existing code and includes some enhancements: - Implement the shared_cpu_map attribute, which is essential for enabling userspace to discover the system's overall cache topology. - Use cache-block-size properties if cache-line-size is not available. I chose to place this implementation in a new file since it would have roughly doubled the size of sysfs.c, which is already kind of messy. Signed-off-by: Nathan Lynch Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/sysfs.c | 300 +------------------------------------------- 1 file changed, 4 insertions(+), 296 deletions(-) (limited to 'arch/powerpc/kernel/sysfs.c') diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index 0c64f10087b..4a2ee08af6a 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -18,6 +18,8 @@ #include #include +#include "cacheinfo.h" + #ifdef CONFIG_PPC64 #include #include @@ -25,8 +27,6 @@ static DEFINE_PER_CPU(struct cpu, cpu_devices); -static DEFINE_PER_CPU(struct kobject *, cache_toplevel); - /* * SMT snooze delay stuff, 64-bit only for now */ @@ -343,283 +343,6 @@ static struct sysdev_attribute pa6t_attrs[] = { #endif /* HAS_PPC_PMC_PA6T */ #endif /* HAS_PPC_PMC_CLASSIC */ -struct cache_desc { - struct kobject kobj; - struct cache_desc *next; - const char *type; /* Instruction, Data, or Unified */ - u32 size; /* total cache size in KB */ - u32 line_size; /* in bytes */ - u32 nr_sets; /* number of sets */ - u32 level; /* e.g. 1, 2, 3... */ - u32 associativity; /* e.g. 8-way... 0 is fully associative */ -}; - -DEFINE_PER_CPU(struct cache_desc *, cache_desc); - -static struct cache_desc *kobj_to_cache_desc(struct kobject *k) -{ - return container_of(k, struct cache_desc, kobj); -} - -static void cache_desc_release(struct kobject *k) -{ - struct cache_desc *desc = kobj_to_cache_desc(k); - - pr_debug("%s: releasing %s\n", __func__, kobject_name(k)); - - if (desc->next) - kobject_put(&desc->next->kobj); - - kfree(kobj_to_cache_desc(k)); -} - -static ssize_t cache_desc_show(struct kobject *k, struct attribute *attr, char *buf) -{ - struct kobj_attribute *kobj_attr; - - kobj_attr = container_of(attr, struct kobj_attribute, attr); - - return kobj_attr->show(k, kobj_attr, buf); -} - -static struct sysfs_ops cache_desc_sysfs_ops = { - .show = cache_desc_show, -}; - -static struct kobj_type cache_desc_type = { - .release = cache_desc_release, - .sysfs_ops = &cache_desc_sysfs_ops, -}; - -static ssize_t cache_size_show(struct kobject *k, struct kobj_attribute *attr, char *buf) -{ - struct cache_desc *cache = kobj_to_cache_desc(k); - - return sprintf(buf, "%uK\n", cache->size); -} - -static struct kobj_attribute cache_size_attr = - __ATTR(size, 0444, cache_size_show, NULL); - -static ssize_t cache_line_size_show(struct kobject *k, struct kobj_attribute *attr, char *buf) -{ - struct cache_desc *cache = kobj_to_cache_desc(k); - - return sprintf(buf, "%u\n", cache->line_size); -} - -static struct kobj_attribute cache_line_size_attr = - __ATTR(coherency_line_size, 0444, cache_line_size_show, NULL); - -static ssize_t cache_nr_sets_show(struct kobject *k, struct kobj_attribute *attr, char *buf) -{ - struct cache_desc *cache = kobj_to_cache_desc(k); - - return sprintf(buf, "%u\n", cache->nr_sets); -} - -static struct kobj_attribute cache_nr_sets_attr = - __ATTR(number_of_sets, 0444, cache_nr_sets_show, NULL); - -static ssize_t cache_type_show(struct kobject *k, struct kobj_attribute *attr, char *buf) -{ - struct cache_desc *cache = kobj_to_cache_desc(k); - - return sprintf(buf, "%s\n", cache->type); -} - -static struct kobj_attribute cache_type_attr = - __ATTR(type, 0444, cache_type_show, NULL); - -static ssize_t cache_level_show(struct kobject *k, struct kobj_attribute *attr, char *buf) -{ - struct cache_desc *cache = kobj_to_cache_desc(k); - - return sprintf(buf, "%u\n", cache->level); -} - -static struct kobj_attribute cache_level_attr = - __ATTR(level, 0444, cache_level_show, NULL); - -static ssize_t cache_assoc_show(struct kobject *k, struct kobj_attribute *attr, char *buf) -{ - struct cache_desc *cache = kobj_to_cache_desc(k); - - return sprintf(buf, "%u\n", cache->associativity); -} - -static struct kobj_attribute cache_assoc_attr = - __ATTR(ways_of_associativity, 0444, cache_assoc_show, NULL); - -struct cache_desc_info { - const char *type; - const char *size_prop; - const char *line_size_prop; - const char *nr_sets_prop; -}; - -/* PowerPC Processor binding says the [di]-cache-* must be equal on - * unified caches, so just use d-cache properties. */ -static struct cache_desc_info ucache_info = { - .type = "Unified", - .size_prop = "d-cache-size", - .line_size_prop = "d-cache-line-size", - .nr_sets_prop = "d-cache-sets", -}; - -static struct cache_desc_info dcache_info = { - .type = "Data", - .size_prop = "d-cache-size", - .line_size_prop = "d-cache-line-size", - .nr_sets_prop = "d-cache-sets", -}; - -static struct cache_desc_info icache_info = { - .type = "Instruction", - .size_prop = "i-cache-size", - .line_size_prop = "i-cache-line-size", - .nr_sets_prop = "i-cache-sets", -}; - -static struct cache_desc * __cpuinit create_cache_desc(struct device_node *np, struct kobject *parent, int index, int level, struct cache_desc_info *info) -{ - const u32 *cache_line_size; - struct cache_desc *new; - const u32 *cache_size; - const u32 *nr_sets; - int rc; - - new = kzalloc(sizeof(*new), GFP_KERNEL); - if (!new) - return NULL; - - rc = kobject_init_and_add(&new->kobj, &cache_desc_type, parent, - "index%d", index); - if (rc) - goto err; - - /* type */ - new->type = info->type; - rc = sysfs_create_file(&new->kobj, &cache_type_attr.attr); - WARN_ON(rc); - - /* level */ - new->level = level; - rc = sysfs_create_file(&new->kobj, &cache_level_attr.attr); - WARN_ON(rc); - - /* size */ - cache_size = of_get_property(np, info->size_prop, NULL); - if (cache_size) { - new->size = *cache_size / 1024; - rc = sysfs_create_file(&new->kobj, - &cache_size_attr.attr); - WARN_ON(rc); - } - - /* coherency_line_size */ - cache_line_size = of_get_property(np, info->line_size_prop, NULL); - if (cache_line_size) { - new->line_size = *cache_line_size; - rc = sysfs_create_file(&new->kobj, - &cache_line_size_attr.attr); - WARN_ON(rc); - } - - /* number_of_sets */ - nr_sets = of_get_property(np, info->nr_sets_prop, NULL); - if (nr_sets) { - new->nr_sets = *nr_sets; - rc = sysfs_create_file(&new->kobj, - &cache_nr_sets_attr.attr); - WARN_ON(rc); - } - - /* ways_of_associativity */ - if (new->nr_sets == 1) { - /* fully associative */ - new->associativity = 0; - goto create_assoc; - } - - if (new->nr_sets && new->size && new->line_size) { - /* If we have values for all of these we can derive - * the associativity. */ - new->associativity = - ((new->size * 1024) / new->nr_sets) / new->line_size; -create_assoc: - rc = sysfs_create_file(&new->kobj, - &cache_assoc_attr.attr); - WARN_ON(rc); - } - - return new; -err: - kfree(new); - return NULL; -} - -static bool cache_is_unified(struct device_node *np) -{ - return of_get_property(np, "cache-unified", NULL); -} - -static struct cache_desc * __cpuinit create_cache_index_info(struct device_node *np, struct kobject *parent, int index, int level) -{ - struct device_node *next_cache; - struct cache_desc *new, **end; - - pr_debug("%s(node = %s, index = %d)\n", __func__, np->full_name, index); - - if (cache_is_unified(np)) { - new = create_cache_desc(np, parent, index, level, - &ucache_info); - } else { - new = create_cache_desc(np, parent, index, level, - &dcache_info); - if (new) { - index++; - new->next = create_cache_desc(np, parent, index, level, - &icache_info); - } - } - if (!new) - return NULL; - - end = &new->next; - while (*end) - end = &(*end)->next; - - next_cache = of_find_next_cache_node(np); - if (!next_cache) - goto out; - - *end = create_cache_index_info(next_cache, parent, ++index, ++level); - - of_node_put(next_cache); -out: - return new; -} - -static void __cpuinit create_cache_info(struct sys_device *sysdev) -{ - struct kobject *cache_toplevel; - struct device_node *np = NULL; - int cpu = sysdev->id; - - cache_toplevel = kobject_create_and_add("cache", &sysdev->kobj); - if (!cache_toplevel) - return; - per_cpu(cache_toplevel, cpu) = cache_toplevel; - np = of_get_cpu_node(cpu, NULL); - if (np != NULL) { - per_cpu(cache_desc, cpu) = - create_cache_index_info(np, cache_toplevel, 0, 1); - of_node_put(np); - } - return; -} - static void __cpuinit register_cpu_online(unsigned int cpu) { struct cpu *c = &per_cpu(cpu_devices, cpu); @@ -684,25 +407,10 @@ static void __cpuinit register_cpu_online(unsigned int cpu) sysdev_create_file(s, &attr_dscr); #endif /* CONFIG_PPC64 */ - create_cache_info(s); + cacheinfo_cpu_online(cpu); } #ifdef CONFIG_HOTPLUG_CPU -static void remove_cache_info(struct sys_device *sysdev) -{ - struct kobject *cache_toplevel; - struct cache_desc *cache_desc; - int cpu = sysdev->id; - - cache_desc = per_cpu(cache_desc, cpu); - if (cache_desc != NULL) - kobject_put(&cache_desc->kobj); - - cache_toplevel = per_cpu(cache_toplevel, cpu); - if (cache_toplevel != NULL) - kobject_put(cache_toplevel); -} - static void unregister_cpu_online(unsigned int cpu) { struct cpu *c = &per_cpu(cpu_devices, cpu); @@ -769,7 +477,7 @@ static void unregister_cpu_online(unsigned int cpu) sysdev_remove_file(s, &attr_dscr); #endif /* CONFIG_PPC64 */ - remove_cache_info(s); + cacheinfo_cpu_offline(cpu); } #endif /* CONFIG_HOTPLUG_CPU */ -- cgit v1.2.3