linux/drivers/base/cacheinfo.c
Huang Ying 362d37a106 mm, pcp: reduce lock contention for draining high-order pages
In commit f26b3fa046 ("mm/page_alloc: limit number of high-order pages
on PCP during bulk free"), the PCP (Per-CPU Pageset) will be drained when
PCP is mostly used for high-order pages freeing to improve the cache-hot
pages reusing between page allocating and freeing CPUs.

On system with small per-CPU data cache slice, pages shouldn't be cached
before draining to guarantee cache-hot.  But on a system with large
per-CPU data cache slice, some pages can be cached before draining to
reduce zone lock contention.

So, in this patch, instead of draining without any caching, "pcp->batch"
pages will be cached in PCP before draining if the size of the per-CPU
data cache slice is more than "3 * batch".

In theory, if the size of per-CPU data cache slice is more than "2 *
batch", we can reuse cache-hot pages between CPUs.  But considering the
other usage of cache (code, other data accessing, etc.), "3 * batch" is
used.

Note: "3 * batch" is chosen to make sure the optimization works on recent
x86_64 server CPUs.  If you want to increase it, please check whether it
breaks the optimization.

On a 2-socket Intel server with 128 logical CPU, with the patch, the
network bandwidth of the UNIX (AF_UNIX) test case of lmbench test suite
with 16-pair processes increase 70.5%.  The cycles% of the spinlock
contention (mostly for zone lock) decreases from 46.1% to 21.3%.  The
number of PCP draining for high order pages freeing (free_high) decreases
89.9%.  The cache miss rate keeps 0.2%.

Link: https://lkml.kernel.org/r/20231016053002.756205-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-25 16:47:10 -07:00

978 lines
24 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* cacheinfo support - processor cache information via sysfs
*
* Based on arch/x86/kernel/cpu/intel_cacheinfo.c
* Author: Sudeep Holla <sudeep.holla@arm.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/acpi.h>
#include <linux/bitops.h>
#include <linux/cacheinfo.h>
#include <linux/compiler.h>
#include <linux/cpu.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/sysfs.h>
/* pointer to per cpu cacheinfo */
static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
#define ci_cacheinfo(cpu) (&per_cpu(ci_cpu_cacheinfo, cpu))
#define cache_leaves(cpu) (ci_cacheinfo(cpu)->num_leaves)
#define per_cpu_cacheinfo(cpu) (ci_cacheinfo(cpu)->info_list)
#define per_cpu_cacheinfo_idx(cpu, idx) \
(per_cpu_cacheinfo(cpu) + (idx))
/* Set if no cache information is found in DT/ACPI. */
static bool use_arch_info;
struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
{
return ci_cacheinfo(cpu);
}
static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
struct cacheinfo *sib_leaf)
{
/*
* For non DT/ACPI systems, assume unique level 1 caches,
* system-wide shared caches for all other levels.
*/
if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)) ||
use_arch_info)
return (this_leaf->level != 1) && (sib_leaf->level != 1);
if ((sib_leaf->attributes & CACHE_ID) &&
(this_leaf->attributes & CACHE_ID))
return sib_leaf->id == this_leaf->id;
return sib_leaf->fw_token == this_leaf->fw_token;
}
bool last_level_cache_is_valid(unsigned int cpu)
{
struct cacheinfo *llc;
if (!cache_leaves(cpu))
return false;
llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);
return (llc->attributes & CACHE_ID) || !!llc->fw_token;
}
bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y)
{
struct cacheinfo *llc_x, *llc_y;
if (!last_level_cache_is_valid(cpu_x) ||
!last_level_cache_is_valid(cpu_y))
return false;
llc_x = per_cpu_cacheinfo_idx(cpu_x, cache_leaves(cpu_x) - 1);
llc_y = per_cpu_cacheinfo_idx(cpu_y, cache_leaves(cpu_y) - 1);
return cache_leaves_are_shared(llc_x, llc_y);
}
#ifdef CONFIG_OF
static bool of_check_cache_nodes(struct device_node *np);
/* OF properties to query for a given cache type */
struct cache_type_info {
const char *size_prop;
const char *line_size_props[2];
const char *nr_sets_prop;
};
static const struct cache_type_info cache_type_info[] = {
{
.size_prop = "cache-size",
.line_size_props = { "cache-line-size",
"cache-block-size", },
.nr_sets_prop = "cache-sets",
}, {
.size_prop = "i-cache-size",
.line_size_props = { "i-cache-line-size",
"i-cache-block-size", },
.nr_sets_prop = "i-cache-sets",
}, {
.size_prop = "d-cache-size",
.line_size_props = { "d-cache-line-size",
"d-cache-block-size", },
.nr_sets_prop = "d-cache-sets",
},
};
static inline int get_cacheinfo_idx(enum cache_type type)
{
if (type == CACHE_TYPE_UNIFIED)
return 0;
return type;
}
static void cache_size(struct cacheinfo *this_leaf, struct device_node *np)
{
const char *propname;
int ct_idx;
ct_idx = get_cacheinfo_idx(this_leaf->type);
propname = cache_type_info[ct_idx].size_prop;
of_property_read_u32(np, propname, &this_leaf->size);
}
/* not cache_line_size() because that's a macro in include/linux/cache.h */
static void cache_get_line_size(struct cacheinfo *this_leaf,
struct device_node *np)
{
int i, lim, ct_idx;
ct_idx = get_cacheinfo_idx(this_leaf->type);
lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
for (i = 0; i < lim; i++) {
int ret;
u32 line_size;
const char *propname;
propname = cache_type_info[ct_idx].line_size_props[i];
ret = of_property_read_u32(np, propname, &line_size);
if (!ret) {
this_leaf->coherency_line_size = line_size;
break;
}
}
}
static void cache_nr_sets(struct cacheinfo *this_leaf, struct device_node *np)
{
const char *propname;
int ct_idx;
ct_idx = get_cacheinfo_idx(this_leaf->type);
propname = cache_type_info[ct_idx].nr_sets_prop;
of_property_read_u32(np, propname, &this_leaf->number_of_sets);
}
static void cache_associativity(struct cacheinfo *this_leaf)
{
unsigned int line_size = this_leaf->coherency_line_size;
unsigned int nr_sets = this_leaf->number_of_sets;
unsigned int size = this_leaf->size;
/*
* If the cache is fully associative, there is no need to
* check the other properties.
*/
if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
}
static bool cache_node_is_unified(struct cacheinfo *this_leaf,
struct device_node *np)
{
return of_property_read_bool(np, "cache-unified");
}
static void cache_of_set_props(struct cacheinfo *this_leaf,
struct device_node *np)
{
/*
* init_cache_level must setup the cache level correctly
* overriding the architecturally specified levels, so
* if type is NONE at this stage, it should be unified
*/
if (this_leaf->type == CACHE_TYPE_NOCACHE &&
cache_node_is_unified(this_leaf, np))
this_leaf->type = CACHE_TYPE_UNIFIED;
cache_size(this_leaf, np);
cache_get_line_size(this_leaf, np);
cache_nr_sets(this_leaf, np);
cache_associativity(this_leaf);
}
static int cache_setup_of_node(unsigned int cpu)
{
struct device_node *np, *prev;
struct cacheinfo *this_leaf;
unsigned int index = 0;
np = of_cpu_device_node_get(cpu);
if (!np) {
pr_err("Failed to find cpu%d device node\n", cpu);
return -ENOENT;
}
if (!of_check_cache_nodes(np)) {
of_node_put(np);
return -ENOENT;
}
prev = np;
while (index < cache_leaves(cpu)) {
this_leaf = per_cpu_cacheinfo_idx(cpu, index);
if (this_leaf->level != 1) {
np = of_find_next_cache_node(np);
of_node_put(prev);
prev = np;
if (!np)
break;
}
cache_of_set_props(this_leaf, np);
this_leaf->fw_token = np;
index++;
}
of_node_put(np);
if (index != cache_leaves(cpu)) /* not all OF nodes populated */
return -ENOENT;
return 0;
}
static bool of_check_cache_nodes(struct device_node *np)
{
struct device_node *next;
if (of_property_present(np, "cache-size") ||
of_property_present(np, "i-cache-size") ||
of_property_present(np, "d-cache-size") ||
of_property_present(np, "cache-unified"))
return true;
next = of_find_next_cache_node(np);
if (next) {
of_node_put(next);
return true;
}
return false;
}
static int of_count_cache_leaves(struct device_node *np)
{
unsigned int leaves = 0;
if (of_property_read_bool(np, "cache-size"))
++leaves;
if (of_property_read_bool(np, "i-cache-size"))
++leaves;
if (of_property_read_bool(np, "d-cache-size"))
++leaves;
if (!leaves) {
/* The '[i-|d-|]cache-size' property is required, but
* if absent, fallback on the 'cache-unified' property.
*/
if (of_property_read_bool(np, "cache-unified"))
return 1;
else
return 2;
}
return leaves;
}
int init_of_cache_level(unsigned int cpu)
{
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
struct device_node *np = of_cpu_device_node_get(cpu);
struct device_node *prev = NULL;
unsigned int levels = 0, leaves, level;
if (!of_check_cache_nodes(np)) {
of_node_put(np);
return -ENOENT;
}
leaves = of_count_cache_leaves(np);
if (leaves > 0)
levels = 1;
prev = np;
while ((np = of_find_next_cache_node(np))) {
of_node_put(prev);
prev = np;
if (!of_device_is_compatible(np, "cache"))
goto err_out;
if (of_property_read_u32(np, "cache-level", &level))
goto err_out;
if (level <= levels)
goto err_out;
leaves += of_count_cache_leaves(np);
levels = level;
}
of_node_put(np);
this_cpu_ci->num_levels = levels;
this_cpu_ci->num_leaves = leaves;
return 0;
err_out:
of_node_put(np);
return -EINVAL;
}
#else
static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
int init_of_cache_level(unsigned int cpu) { return 0; }
#endif
int __weak cache_setup_acpi(unsigned int cpu)
{
return -ENOTSUPP;
}
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);
// Assume there is no cache information available in DT/ACPI from now.
if (ret && use_arch_cache_info())
use_arch_info = true;
return ret;
}
static int cache_shared_cpu_map_setup(unsigned int cpu)
{
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
struct cacheinfo *this_leaf, *sib_leaf;
unsigned int index, sib_index;
int ret = 0;
if (this_cpu_ci->cpu_map_populated)
return 0;
/*
* 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) && !use_arch_info) {
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);
cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
for_each_online_cpu(i) {
struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
if (i == cpu || !sib_cpu_ci->info_list)
continue;/* skip if itself or no cacheinfo */
for (sib_index = 0; sib_index < cache_leaves(i); sib_index++) {
sib_leaf = per_cpu_cacheinfo_idx(i, sib_index);
/*
* Comparing cache IDs only makes sense if the leaves
* belong to the same cache level of same type. Skip
* the check if level and type do not match.
*/
if (sib_leaf->level != this_leaf->level ||
sib_leaf->type != this_leaf->type)
continue;
if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
break;
}
}
}
/* record the maximum cache line size */
if (this_leaf->coherency_line_size > coherency_max_size)
coherency_max_size = this_leaf->coherency_line_size;
}
/* shared_cpu_map is now populated for the cpu */
this_cpu_ci->cpu_map_populated = true;
return 0;
}
static void cache_shared_cpu_map_remove(unsigned int cpu)
{
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
struct cacheinfo *this_leaf, *sib_leaf;
unsigned int sibling, index, sib_index;
for (index = 0; index < cache_leaves(cpu); index++) {
this_leaf = per_cpu_cacheinfo_idx(cpu, index);
for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
struct cpu_cacheinfo *sib_cpu_ci =
get_cpu_cacheinfo(sibling);
if (sibling == cpu || !sib_cpu_ci->info_list)
continue;/* skip if itself or no cacheinfo */
for (sib_index = 0; sib_index < cache_leaves(sibling); sib_index++) {
sib_leaf = per_cpu_cacheinfo_idx(sibling, sib_index);
/*
* Comparing cache IDs only makes sense if the leaves
* belong to the same cache level of same type. Skip
* the check if level and type do not match.
*/
if (sib_leaf->level != this_leaf->level ||
sib_leaf->type != this_leaf->type)
continue;
if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
break;
}
}
}
}
/* cpu is no longer populated in the shared map */
this_cpu_ci->cpu_map_populated = false;
}
static void free_cache_attributes(unsigned int cpu)
{
if (!per_cpu_cacheinfo(cpu))
return;
cache_shared_cpu_map_remove(cpu);
}
int __weak early_cache_level(unsigned int cpu)
{
return -ENOENT;
}
int __weak init_cache_level(unsigned int cpu)
{
return -ENOENT;
}
int __weak populate_cache_leaves(unsigned int cpu)
{
return -ENOENT;
}
static inline
int allocate_cache_info(int cpu)
{
per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
sizeof(struct cacheinfo), GFP_ATOMIC);
if (!per_cpu_cacheinfo(cpu)) {
cache_leaves(cpu) = 0;
return -ENOMEM;
}
return 0;
}
int fetch_cache_info(unsigned int cpu)
{
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
unsigned int levels = 0, split_levels = 0;
int ret;
if (acpi_disabled) {
ret = init_of_cache_level(cpu);
} else {
ret = acpi_get_cache_info(cpu, &levels, &split_levels);
if (!ret) {
this_cpu_ci->num_levels = levels;
/*
* This assumes that:
* - there cannot be any split caches (data/instruction)
* above a unified cache
* - data/instruction caches come by pair
*/
this_cpu_ci->num_leaves = levels + split_levels;
}
}
if (ret || !cache_leaves(cpu)) {
ret = early_cache_level(cpu);
if (ret)
return ret;
if (!cache_leaves(cpu))
return -ENOENT;
this_cpu_ci->early_ci_levels = true;
}
return allocate_cache_info(cpu);
}
static inline int init_level_allocate_ci(unsigned int cpu)
{
unsigned int early_leaves = cache_leaves(cpu);
/* Since early initialization/allocation of the cacheinfo is allowed
* via fetch_cache_info() and this also gets called as CPU hotplug
* callbacks via cacheinfo_cpu_online, the init/alloc can be skipped
* as it will happen only once (the cacheinfo memory is never freed).
* Just populate the cacheinfo. However, if the cacheinfo has been
* allocated early through the arch-specific early_cache_level() call,
* there is a chance the info is wrong (this can happen on arm64). In
* that case, call init_cache_level() anyway to give the arch-specific
* code a chance to make things right.
*/
if (per_cpu_cacheinfo(cpu) && !ci_cacheinfo(cpu)->early_ci_levels)
return 0;
if (init_cache_level(cpu) || !cache_leaves(cpu))
return -ENOENT;
/*
* Now that we have properly initialized the cache level info, make
* sure we don't try to do that again the next time we are called
* (e.g. as CPU hotplug callbacks).
*/
ci_cacheinfo(cpu)->early_ci_levels = false;
if (cache_leaves(cpu) <= early_leaves)
return 0;
kfree(per_cpu_cacheinfo(cpu));
return allocate_cache_info(cpu);
}
int detect_cache_attributes(unsigned int cpu)
{
int ret;
ret = init_level_allocate_ci(cpu);
if (ret)
return ret;
/*
* If LLC is valid the cache leaves were already populated so just go to
* update the cpu map.
*/
if (!last_level_cache_is_valid(cpu)) {
/*
* populate_cache_leaves() may completely setup the cache leaves and
* shared_cpu_map or it may leave it partially setup.
*/
ret = populate_cache_leaves(cpu);
if (ret)
goto free_ci;
}
/*
* For systems using DT for cache hierarchy, fw_token
* and shared_cpu_map will be set up here only if they are
* not populated already
*/
ret = cache_shared_cpu_map_setup(cpu);
if (ret) {
pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
goto free_ci;
}
return 0;
free_ci:
free_cache_attributes(cpu);
return ret;
}
/* pointer to cpuX/cache device */
static DEFINE_PER_CPU(struct device *, ci_cache_dev);
#define per_cpu_cache_dev(cpu) (per_cpu(ci_cache_dev, cpu))
static cpumask_t cache_dev_map;
/* pointer to array of devices for cpuX/cache/indexY */
static DEFINE_PER_CPU(struct device **, ci_index_dev);
#define per_cpu_index_dev(cpu) (per_cpu(ci_index_dev, cpu))
#define per_cache_index_dev(cpu, idx) ((per_cpu_index_dev(cpu))[idx])
#define show_one(file_name, object) \
static ssize_t file_name##_show(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
struct cacheinfo *this_leaf = dev_get_drvdata(dev); \
return sysfs_emit(buf, "%u\n", this_leaf->object); \
}
show_one(id, id);
show_one(level, level);
show_one(coherency_line_size, coherency_line_size);
show_one(number_of_sets, number_of_sets);
show_one(physical_line_partition, physical_line_partition);
show_one(ways_of_associativity, ways_of_associativity);
static ssize_t size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cacheinfo *this_leaf = dev_get_drvdata(dev);
return sysfs_emit(buf, "%uK\n", this_leaf->size >> 10);
}
static ssize_t shared_cpu_map_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cacheinfo *this_leaf = dev_get_drvdata(dev);
const struct cpumask *mask = &this_leaf->shared_cpu_map;
return sysfs_emit(buf, "%*pb\n", nr_cpu_ids, mask);
}
static ssize_t shared_cpu_list_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cacheinfo *this_leaf = dev_get_drvdata(dev);
const struct cpumask *mask = &this_leaf->shared_cpu_map;
return sysfs_emit(buf, "%*pbl\n", nr_cpu_ids, mask);
}
static ssize_t type_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cacheinfo *this_leaf = dev_get_drvdata(dev);
const char *output;
switch (this_leaf->type) {
case CACHE_TYPE_DATA:
output = "Data";
break;
case CACHE_TYPE_INST:
output = "Instruction";
break;
case CACHE_TYPE_UNIFIED:
output = "Unified";
break;
default:
return -EINVAL;
}
return sysfs_emit(buf, "%s\n", output);
}
static ssize_t allocation_policy_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cacheinfo *this_leaf = dev_get_drvdata(dev);
unsigned int ci_attr = this_leaf->attributes;
const char *output;
if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
output = "ReadWriteAllocate";
else if (ci_attr & CACHE_READ_ALLOCATE)
output = "ReadAllocate";
else if (ci_attr & CACHE_WRITE_ALLOCATE)
output = "WriteAllocate";
else
return 0;
return sysfs_emit(buf, "%s\n", output);
}
static ssize_t write_policy_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cacheinfo *this_leaf = dev_get_drvdata(dev);
unsigned int ci_attr = this_leaf->attributes;
int n = 0;
if (ci_attr & CACHE_WRITE_THROUGH)
n = sysfs_emit(buf, "WriteThrough\n");
else if (ci_attr & CACHE_WRITE_BACK)
n = sysfs_emit(buf, "WriteBack\n");
return n;
}
static DEVICE_ATTR_RO(id);
static DEVICE_ATTR_RO(level);
static DEVICE_ATTR_RO(type);
static DEVICE_ATTR_RO(coherency_line_size);
static DEVICE_ATTR_RO(ways_of_associativity);
static DEVICE_ATTR_RO(number_of_sets);
static DEVICE_ATTR_RO(size);
static DEVICE_ATTR_RO(allocation_policy);
static DEVICE_ATTR_RO(write_policy);
static DEVICE_ATTR_RO(shared_cpu_map);
static DEVICE_ATTR_RO(shared_cpu_list);
static DEVICE_ATTR_RO(physical_line_partition);
static struct attribute *cache_default_attrs[] = {
&dev_attr_id.attr,
&dev_attr_type.attr,
&dev_attr_level.attr,
&dev_attr_shared_cpu_map.attr,
&dev_attr_shared_cpu_list.attr,
&dev_attr_coherency_line_size.attr,
&dev_attr_ways_of_associativity.attr,
&dev_attr_number_of_sets.attr,
&dev_attr_size.attr,
&dev_attr_allocation_policy.attr,
&dev_attr_write_policy.attr,
&dev_attr_physical_line_partition.attr,
NULL
};
static umode_t
cache_default_attrs_is_visible(struct kobject *kobj,
struct attribute *attr, int unused)
{
struct device *dev = kobj_to_dev(kobj);
struct cacheinfo *this_leaf = dev_get_drvdata(dev);
const struct cpumask *mask = &this_leaf->shared_cpu_map;
umode_t mode = attr->mode;
if ((attr == &dev_attr_id.attr) && (this_leaf->attributes & CACHE_ID))
return mode;
if ((attr == &dev_attr_type.attr) && this_leaf->type)
return mode;
if ((attr == &dev_attr_level.attr) && this_leaf->level)
return mode;
if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
return mode;
if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
return mode;
if ((attr == &dev_attr_coherency_line_size.attr) &&
this_leaf->coherency_line_size)
return mode;
if ((attr == &dev_attr_ways_of_associativity.attr) &&
this_leaf->size) /* allow 0 = full associativity */
return mode;
if ((attr == &dev_attr_number_of_sets.attr) &&
this_leaf->number_of_sets)
return mode;
if ((attr == &dev_attr_size.attr) && this_leaf->size)
return mode;
if ((attr == &dev_attr_write_policy.attr) &&
(this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
return mode;
if ((attr == &dev_attr_allocation_policy.attr) &&
(this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
return mode;
if ((attr == &dev_attr_physical_line_partition.attr) &&
this_leaf->physical_line_partition)
return mode;
return 0;
}
static const struct attribute_group cache_default_group = {
.attrs = cache_default_attrs,
.is_visible = cache_default_attrs_is_visible,
};
static const struct attribute_group *cache_default_groups[] = {
&cache_default_group,
NULL,
};
static const struct attribute_group *cache_private_groups[] = {
&cache_default_group,
NULL, /* Place holder for private group */
NULL,
};
const struct attribute_group *
__weak cache_get_priv_group(struct cacheinfo *this_leaf)
{
return NULL;
}
static const struct attribute_group **
cache_get_attribute_groups(struct cacheinfo *this_leaf)
{
const struct attribute_group *priv_group =
cache_get_priv_group(this_leaf);
if (!priv_group)
return cache_default_groups;
if (!cache_private_groups[1])
cache_private_groups[1] = priv_group;
return cache_private_groups;
}
/* Add/Remove cache interface for CPU device */
static void cpu_cache_sysfs_exit(unsigned int cpu)
{
int i;
struct device *ci_dev;
if (per_cpu_index_dev(cpu)) {
for (i = 0; i < cache_leaves(cpu); i++) {
ci_dev = per_cache_index_dev(cpu, i);
if (!ci_dev)
continue;
device_unregister(ci_dev);
}
kfree(per_cpu_index_dev(cpu));
per_cpu_index_dev(cpu) = NULL;
}
device_unregister(per_cpu_cache_dev(cpu));
per_cpu_cache_dev(cpu) = NULL;
}
static int cpu_cache_sysfs_init(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
if (per_cpu_cacheinfo(cpu) == NULL)
return -ENOENT;
per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
if (IS_ERR(per_cpu_cache_dev(cpu)))
return PTR_ERR(per_cpu_cache_dev(cpu));
/* Allocate all required memory */
per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
sizeof(struct device *), GFP_KERNEL);
if (unlikely(per_cpu_index_dev(cpu) == NULL))
goto err_out;
return 0;
err_out:
cpu_cache_sysfs_exit(cpu);
return -ENOMEM;
}
static int cache_add_dev(unsigned int cpu)
{
unsigned int i;
int rc;
struct device *ci_dev, *parent;
struct cacheinfo *this_leaf;
const struct attribute_group **cache_groups;
rc = cpu_cache_sysfs_init(cpu);
if (unlikely(rc < 0))
return rc;
parent = per_cpu_cache_dev(cpu);
for (i = 0; i < cache_leaves(cpu); i++) {
this_leaf = per_cpu_cacheinfo_idx(cpu, i);
if (this_leaf->disable_sysfs)
continue;
if (this_leaf->type == CACHE_TYPE_NOCACHE)
break;
cache_groups = cache_get_attribute_groups(this_leaf);
ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
"index%1u", i);
if (IS_ERR(ci_dev)) {
rc = PTR_ERR(ci_dev);
goto err;
}
per_cache_index_dev(cpu, i) = ci_dev;
}
cpumask_set_cpu(cpu, &cache_dev_map);
return 0;
err:
cpu_cache_sysfs_exit(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);
if (rc)
return rc;
rc = cache_add_dev(cpu);
if (rc)
goto err;
update_per_cpu_data_slice_size(true, cpu);
setup_pcp_cacheinfo();
return 0;
err:
free_cache_attributes(cpu);
return rc;
}
static int cacheinfo_cpu_pre_down(unsigned int cpu)
{
if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
cpu_cache_sysfs_exit(cpu);
free_cache_attributes(cpu);
update_per_cpu_data_slice_size(false, cpu);
setup_pcp_cacheinfo();
return 0;
}
static int __init cacheinfo_sysfs_init(void)
{
return cpuhp_setup_state(CPUHP_AP_BASE_CACHEINFO_ONLINE,
"base/cacheinfo:online",
cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
}
device_initcall(cacheinfo_sysfs_init);