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authorNathan Lynch <ntl@pobox.com>2008-12-23 18:55:54 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-01-08 16:25:10 +1100
commit93197a36a9c16a85fb24cf5a8639f7bf9af838a3 (patch)
treec8f70ac532dd9fa2d1de142994383c108603499a /arch/powerpc/kernel/sysfs.c
parent5c9a2606bcad101e169012d9f79ab3aed60926aa (diff)
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 <ntl@pobox.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/sysfs.c')
-rw-r--r--arch/powerpc/kernel/sysfs.c300
1 files changed, 4 insertions, 296 deletions
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 <asm/machdep.h>
#include <asm/smp.h>
+#include "cacheinfo.h"
+
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#include <asm/lppaca.h>
@@ -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 */