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![Keith Busch](/assets/img/avatar_default.png)
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>
193 lines
4.9 KiB
C
193 lines
4.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* include/linux/node.h - generic node definition
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*
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* This is mainly for topological representation. We define the
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* basic 'struct node' here, which can be embedded in per-arch
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* definitions of processors.
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*
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* Basic handling of the devices is done in drivers/base/node.c
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* and system devices are handled in drivers/base/sys.c.
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*
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* Nodes are exported via driverfs in the class/node/devices/
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* directory.
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*/
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#ifndef _LINUX_NODE_H_
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#define _LINUX_NODE_H_
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#include <linux/device.h>
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#include <linux/cpumask.h>
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#include <linux/list.h>
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#include <linux/workqueue.h>
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/**
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* struct node_hmem_attrs - heterogeneous memory performance attributes
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*
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* @read_bandwidth: Read bandwidth in MB/s
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* @write_bandwidth: Write bandwidth in MB/s
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* @read_latency: Read latency in nanoseconds
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* @write_latency: Write latency in nanoseconds
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*/
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struct node_hmem_attrs {
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unsigned int read_bandwidth;
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unsigned int write_bandwidth;
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unsigned int read_latency;
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unsigned int write_latency;
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};
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enum cache_indexing {
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NODE_CACHE_DIRECT_MAP,
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NODE_CACHE_INDEXED,
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NODE_CACHE_OTHER,
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};
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enum cache_write_policy {
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NODE_CACHE_WRITE_BACK,
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NODE_CACHE_WRITE_THROUGH,
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NODE_CACHE_WRITE_OTHER,
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};
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/**
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* struct node_cache_attrs - system memory caching attributes
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*
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* @indexing: The ways memory blocks may be placed in cache
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* @write_policy: Write back or write through policy
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* @size: Total size of cache in bytes
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* @line_size: Number of bytes fetched on a cache miss
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* @level: The cache hierarchy level
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*/
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struct node_cache_attrs {
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enum cache_indexing indexing;
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enum cache_write_policy write_policy;
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u64 size;
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u16 line_size;
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u8 level;
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};
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#ifdef CONFIG_HMEM_REPORTING
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void node_add_cache(unsigned int nid, struct node_cache_attrs *cache_attrs);
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void node_set_perf_attrs(unsigned int nid, struct node_hmem_attrs *hmem_attrs,
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unsigned access);
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#else
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static inline void node_add_cache(unsigned int nid,
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struct node_cache_attrs *cache_attrs)
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{
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}
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static inline void node_set_perf_attrs(unsigned int nid,
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struct node_hmem_attrs *hmem_attrs,
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unsigned access)
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{
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}
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#endif
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struct node {
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struct device dev;
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struct list_head access_list;
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#if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
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struct work_struct node_work;
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#endif
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#ifdef CONFIG_HMEM_REPORTING
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struct list_head cache_attrs;
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struct device *cache_dev;
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#endif
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};
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struct memory_block;
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extern struct node *node_devices[];
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typedef void (*node_registration_func_t)(struct node *);
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#if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_NUMA)
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extern int link_mem_sections(int nid, unsigned long start_pfn,
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unsigned long end_pfn);
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#else
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static inline int link_mem_sections(int nid, unsigned long start_pfn,
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unsigned long end_pfn)
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{
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return 0;
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}
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#endif
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extern void unregister_node(struct node *node);
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#ifdef CONFIG_NUMA
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/* Core of the node registration - only memory hotplug should use this */
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extern int __register_one_node(int nid);
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/* Registers an online node */
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static inline int register_one_node(int nid)
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{
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int error = 0;
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if (node_online(nid)) {
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struct pglist_data *pgdat = NODE_DATA(nid);
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unsigned long start_pfn = pgdat->node_start_pfn;
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unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
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error = __register_one_node(nid);
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if (error)
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return error;
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/* link memory sections under this node */
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error = link_mem_sections(nid, start_pfn, end_pfn);
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}
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return error;
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}
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extern void unregister_one_node(int nid);
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extern int register_cpu_under_node(unsigned int cpu, unsigned int nid);
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extern int unregister_cpu_under_node(unsigned int cpu, unsigned int nid);
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extern int register_mem_sect_under_node(struct memory_block *mem_blk,
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void *arg);
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extern int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
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unsigned long phys_index);
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extern int register_memory_node_under_compute_node(unsigned int mem_nid,
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unsigned int cpu_nid,
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unsigned access);
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#ifdef CONFIG_HUGETLBFS
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extern void register_hugetlbfs_with_node(node_registration_func_t doregister,
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node_registration_func_t unregister);
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#endif
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#else
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static inline int __register_one_node(int nid)
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{
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return 0;
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}
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static inline int register_one_node(int nid)
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{
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return 0;
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}
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static inline int unregister_one_node(int nid)
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{
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return 0;
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}
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static inline int register_cpu_under_node(unsigned int cpu, unsigned int nid)
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{
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return 0;
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}
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static inline int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
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{
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return 0;
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}
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static inline int register_mem_sect_under_node(struct memory_block *mem_blk,
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void *arg)
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{
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return 0;
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}
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static inline int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
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unsigned long phys_index)
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{
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return 0;
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}
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static inline void register_hugetlbfs_with_node(node_registration_func_t reg,
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node_registration_func_t unreg)
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{
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}
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#endif
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#define to_node(device) container_of(device, struct node, dev)
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#endif /* _LINUX_NODE_H_ */
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