08d9dbe72b
Systems may be constructed with various specialized nodes. Some nodes may provide memory, some provide compute devices that access and use that memory, and others may provide both. Nodes that provide memory are referred to as memory targets, and nodes that can initiate memory access are referred to as memory initiators. Memory targets will often have varying access characteristics from different initiators, and platforms may have ways to express those relationships. In preparation for these systems, provide interfaces for the kernel to export the memory relationship among different nodes memory targets and their initiators with symlinks to each other. If a system provides access locality for each initiator-target pair, nodes may be grouped into ranked access classes relative to other nodes. The new interface allows a subsystem to register relationships of varying classes if available and desired to be exported. A memory initiator may have multiple memory targets in the same access class. The target memory's initiators in a given class indicate the nodes access characteristics share the same performance relative to other linked initiator nodes. Each target within an initiator's access class, though, do not necessarily perform the same as each other. A memory target node may have multiple memory initiators. All linked initiators in a target's class have the same access characteristics to that target. The following example show the nodes' new sysfs hierarchy for a memory target node 'Y' with access class 0 from initiator node 'X': # symlinks -v /sys/devices/system/node/nodeX/access0/ relative: /sys/devices/system/node/nodeX/access0/targets/nodeY -> ../../nodeY # symlinks -v /sys/devices/system/node/nodeY/access0/ relative: /sys/devices/system/node/nodeY/access0/initiators/nodeX -> ../../nodeX The new attributes are added to the sysfs stable documentation. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Brice Goglin <Brice.Goglin@inria.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
129 lines
3.3 KiB
C
129 lines
3.3 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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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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};
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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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