From: Keith Busch keith.busch@intel.com
mainline inclusion from mainline-v5.2-rc1 commit acc02a109b0497e917c83f986a89c51e47d0022c category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I47H3V CVE: NA
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commit acc02a109b0497e917c83f986a89c51e47d0022c upstream.
System memory may have caches to help improve access speed to frequently requested address ranges. While the system provided cache is transparent to the software accessing these memory ranges, applications can optimize their own access based on cache attributes.
Provide a new API for the kernel to register these memory-side caches under the memory node that provides it.
The new sysfs representation is modeled from the existing cpu cacheinfo attributes, as seen from /sys/devices/system/cpu/<cpu>/cache/. Unlike CPU cacheinfo though, the node cache level is reported from the view of the memory. A higher level number is nearer to the CPU, while lower levels are closer to the last level memory.
The exported attributes are the cache size, the line size, associativity indexing, and write back policy, and add the attributes for the system memory caches to sysfs stable documentation.
Signed-off-by: Keith Busch keith.busch@intel.com Reviewed-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Reviewed-by: Brice Goglin Brice.Goglin@inria.fr Tested-by: Brice Goglin Brice.Goglin@inria.fr Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Fan Du fan.du@intel.com Signed-off-by: Jackie Liu liuyun01@kylinos.cn Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Hanjun Guo guohanjun@huawei.com Reviewed-by: Xie XiuQi xiexiuqi@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- Documentation/ABI/stable/sysfs-devices-node | 34 +++++ drivers/base/node.c | 151 ++++++++++++++++++++ include/linux/node.h | 39 +++++ 3 files changed, 224 insertions(+)
diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node index 735a40a3f9b2..f7ce68fbd4b9 100644 --- a/Documentation/ABI/stable/sysfs-devices-node +++ b/Documentation/ABI/stable/sysfs-devices-node @@ -142,3 +142,37 @@ Contact: Keith Busch keith.busch@intel.com Description: This node's write latency in nanoseconds when access from nodes found in this class's linked initiators. + +What: /sys/devices/system/node/nodeX/memory_side_cache/indexY/ +Date: December 2018 +Contact: Keith Busch keith.busch@intel.com +Description: + The directory containing attributes for the memory-side cache + level 'Y'. + +What: /sys/devices/system/node/nodeX/memory_side_cache/indexY/indexing +Date: December 2018 +Contact: Keith Busch keith.busch@intel.com +Description: + The caches associativity indexing: 0 for direct mapped, + non-zero if indexed. + +What: /sys/devices/system/node/nodeX/memory_side_cache/indexY/line_size +Date: December 2018 +Contact: Keith Busch keith.busch@intel.com +Description: + The number of bytes accessed from the next cache level on a + cache miss. + +What: /sys/devices/system/node/nodeX/memory_side_cache/indexY/size +Date: December 2018 +Contact: Keith Busch keith.busch@intel.com +Description: + The size of this memory side cache in bytes. + +What: /sys/devices/system/node/nodeX/memory_side_cache/indexY/write_policy +Date: December 2018 +Contact: Keith Busch keith.busch@intel.com +Description: + The cache write policy: 0 for write-back, 1 for write-through, + other or unknown. diff --git a/drivers/base/node.c b/drivers/base/node.c index e0d497f13f1e..07b9424ca9eb 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -205,6 +205,155 @@ void node_set_perf_attrs(unsigned int nid, struct node_hmem_attrs *hmem_attrs, } } } + +/** + * struct node_cache_info - Internal tracking for memory node caches + * @dev: Device represeting the cache level + * @node: List element for tracking in the node + * @cache_attrs:Attributes for this cache level + */ +struct node_cache_info { + struct device dev; + struct list_head node; + struct node_cache_attrs cache_attrs; +}; +#define to_cache_info(device) container_of(device, struct node_cache_info, dev) + +#define CACHE_ATTR(name, fmt) \ +static ssize_t name##_show(struct device *dev, \ + struct device_attribute *attr, \ + char *buf) \ +{ \ + return sprintf(buf, fmt "\n", to_cache_info(dev)->cache_attrs.name);\ +} \ +DEVICE_ATTR_RO(name); + +CACHE_ATTR(size, "%llu") +CACHE_ATTR(line_size, "%u") +CACHE_ATTR(indexing, "%u") +CACHE_ATTR(write_policy, "%u") + +static struct attribute *cache_attrs[] = { + &dev_attr_indexing.attr, + &dev_attr_size.attr, + &dev_attr_line_size.attr, + &dev_attr_write_policy.attr, + NULL, +}; +ATTRIBUTE_GROUPS(cache); + +static void node_cache_release(struct device *dev) +{ + kfree(dev); +} + +static void node_cacheinfo_release(struct device *dev) +{ + struct node_cache_info *info = to_cache_info(dev); + kfree(info); +} + +static void node_init_cache_dev(struct node *node) +{ + struct device *dev; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) + return; + + dev->parent = &node->dev; + dev->release = node_cache_release; + if (dev_set_name(dev, "memory_side_cache")) + goto free_dev; + + if (device_register(dev)) + goto free_name; + + pm_runtime_no_callbacks(dev); + node->cache_dev = dev; + return; +free_name: + kfree_const(dev->kobj.name); +free_dev: + kfree(dev); +} + +/** + * node_add_cache() - add cache attribute to a memory node + * @nid: Node identifier that has new cache attributes + * @cache_attrs: Attributes for the cache being added + */ +void node_add_cache(unsigned int nid, struct node_cache_attrs *cache_attrs) +{ + struct node_cache_info *info; + struct device *dev; + struct node *node; + + if (!node_online(nid) || !node_devices[nid]) + return; + + node = node_devices[nid]; + list_for_each_entry(info, &node->cache_attrs, node) { + if (info->cache_attrs.level == cache_attrs->level) { + dev_warn(&node->dev, + "attempt to add duplicate cache level:%d\n", + cache_attrs->level); + return; + } + } + + if (!node->cache_dev) + node_init_cache_dev(node); + if (!node->cache_dev) + return; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return; + + dev = &info->dev; + dev->parent = node->cache_dev; + dev->release = node_cacheinfo_release; + dev->groups = cache_groups; + if (dev_set_name(dev, "index%d", cache_attrs->level)) + goto free_cache; + + info->cache_attrs = *cache_attrs; + if (device_register(dev)) { + dev_warn(&node->dev, "failed to add cache level:%d\n", + cache_attrs->level); + goto free_name; + } + pm_runtime_no_callbacks(dev); + list_add_tail(&info->node, &node->cache_attrs); + return; +free_name: + kfree_const(dev->kobj.name); +free_cache: + kfree(info); +} + +static void node_remove_caches(struct node *node) +{ + struct node_cache_info *info, *next; + + if (!node->cache_dev) + return; + + list_for_each_entry_safe(info, next, &node->cache_attrs, node) { + list_del(&info->node); + device_unregister(&info->dev); + } + device_unregister(node->cache_dev); +} + +static void node_init_caches(unsigned int nid) +{ + INIT_LIST_HEAD(&node_devices[nid]->cache_attrs); +} +#else +static void node_init_caches(unsigned int nid) { } +static void node_remove_caches(struct node *node) { } #endif
#define K(x) ((x) << (PAGE_SHIFT - 10)) @@ -489,6 +638,7 @@ void unregister_node(struct node *node) { hugetlb_unregister_node(node); /* no-op, if memoryless node */ node_remove_accesses(node); + node_remove_caches(node); device_unregister(&node->dev); }
@@ -789,6 +939,7 @@ int __register_one_node(int nid) INIT_LIST_HEAD(&node_devices[nid]->access_list); /* initialize work queue for memory hot plug */ init_node_hugetlb_work(nid); + node_init_caches(nid);
return error; } diff --git a/include/linux/node.h b/include/linux/node.h index 526f1523c0f1..d5215b2319b9 100644 --- a/include/linux/node.h +++ b/include/linux/node.h @@ -35,10 +35,45 @@ struct node_hmem_attrs { unsigned int write_latency; };
+enum cache_indexing { + NODE_CACHE_DIRECT_MAP, + NODE_CACHE_INDEXED, + NODE_CACHE_OTHER, +}; + +enum cache_write_policy { + NODE_CACHE_WRITE_BACK, + NODE_CACHE_WRITE_THROUGH, + NODE_CACHE_WRITE_OTHER, +}; + +/** + * struct node_cache_attrs - system memory caching attributes + * + * @indexing: The ways memory blocks may be placed in cache + * @write_policy: Write back or write through policy + * @size: Total size of cache in bytes + * @line_size: Number of bytes fetched on a cache miss + * @level: The cache hierarchy level + */ +struct node_cache_attrs { + enum cache_indexing indexing; + enum cache_write_policy write_policy; + u64 size; + u16 line_size; + u8 level; +}; + #ifdef CONFIG_HMEM_REPORTING +void node_add_cache(unsigned int nid, struct node_cache_attrs *cache_attrs); void node_set_perf_attrs(unsigned int nid, struct node_hmem_attrs *hmem_attrs, unsigned access); #else +static inline void node_add_cache(unsigned int nid, + struct node_cache_attrs *cache_attrs) +{ +} + static inline void node_set_perf_attrs(unsigned int nid, struct node_hmem_attrs *hmem_attrs, unsigned access) @@ -53,6 +88,10 @@ struct node { #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS) struct work_struct node_work; #endif +#ifdef CONFIG_HMEM_REPORTING + struct list_head cache_attrs; + struct device *cache_dev; +#endif };
struct memory_block;