1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _LINUX_MEMORY_TIERS_H
  3#define _LINUX_MEMORY_TIERS_H
  4
  5#include <linux/types.h>
  6#include <linux/nodemask.h>
  7#include <linux/kref.h>
  8#include <linux/mmzone.h>
  9#include <linux/notifier.h>
 10/*
 11 * Each tier cover a abstrace distance chunk size of 128
 12 */
 13#define MEMTIER_CHUNK_BITS	7
 14#define MEMTIER_CHUNK_SIZE	(1 << MEMTIER_CHUNK_BITS)
 15/*
 16 * Smaller abstract distance values imply faster (higher) memory tiers. Offset
 17 * the DRAM adistance so that we can accommodate devices with a slightly lower
 18 * adistance value (slightly faster) than default DRAM adistance to be part of
 19 * the same memory tier.
 20 */
 21#define MEMTIER_ADISTANCE_DRAM	((4 * MEMTIER_CHUNK_SIZE) + (MEMTIER_CHUNK_SIZE >> 1))
 22
 23struct memory_tier;
 24struct memory_dev_type {
 25	/* list of memory types that are part of same tier as this type */
 26	struct list_head tier_sibling;
 27	/* list of memory types that are managed by one driver */
 28	struct list_head list;
 29	/* abstract distance for this specific memory type */
 30	int adistance;
 31	/* Nodes of same abstract distance */
 32	nodemask_t nodes;
 33	struct kref kref;
 34};
 35
 36struct access_coordinate;
 37
 38#ifdef CONFIG_NUMA
 39extern bool numa_demotion_enabled;
 40extern struct memory_dev_type *default_dram_type;
 41struct memory_dev_type *alloc_memory_type(int adistance);
 42void put_memory_type(struct memory_dev_type *memtype);
 43void init_node_memory_type(int node, struct memory_dev_type *default_type);
 44void clear_node_memory_type(int node, struct memory_dev_type *memtype);
 45int register_mt_adistance_algorithm(struct notifier_block *nb);
 46int unregister_mt_adistance_algorithm(struct notifier_block *nb);
 47int mt_calc_adistance(int node, int *adist);
 48int mt_set_default_dram_perf(int nid, struct access_coordinate *perf,
 49			     const char *source);
 50int mt_perf_to_adistance(struct access_coordinate *perf, int *adist);
 51#ifdef CONFIG_MIGRATION
 52int next_demotion_node(int node);
 53void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets);
 54bool node_is_toptier(int node);
 55#else
 56static inline int next_demotion_node(int node)
 57{
 58	return NUMA_NO_NODE;
 59}
 60
 61static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
 62{
 63	*targets = NODE_MASK_NONE;
 64}
 65
 66static inline bool node_is_toptier(int node)
 67{
 68	return true;
 69}
 70#endif
 71
 72#else
 73
 74#define numa_demotion_enabled	false
 75#define default_dram_type	NULL
 76/*
 77 * CONFIG_NUMA implementation returns non NULL error.
 78 */
 79static inline struct memory_dev_type *alloc_memory_type(int adistance)
 80{
 81	return NULL;
 82}
 83
 84static inline void put_memory_type(struct memory_dev_type *memtype)
 85{
 86
 87}
 88
 89static inline void init_node_memory_type(int node, struct memory_dev_type *default_type)
 90{
 91
 92}
 93
 94static inline void clear_node_memory_type(int node, struct memory_dev_type *memtype)
 95{
 96
 97}
 98
 99static inline int next_demotion_node(int node)
100{
101	return NUMA_NO_NODE;
102}
103
104static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
105{
106	*targets = NODE_MASK_NONE;
107}
108
109static inline bool node_is_toptier(int node)
110{
111	return true;
112}
113
114static inline int register_mt_adistance_algorithm(struct notifier_block *nb)
115{
116	return 0;
117}
118
119static inline int unregister_mt_adistance_algorithm(struct notifier_block *nb)
120{
121	return 0;
122}
123
124static inline int mt_calc_adistance(int node, int *adist)
125{
126	return NOTIFY_DONE;
127}
128
129static inline int mt_set_default_dram_perf(int nid, struct access_coordinate *perf,
130					   const char *source)
131{
132	return -EIO;
133}
134
135static inline int mt_perf_to_adistance(struct access_coordinate *perf, int *adist)
136{
137	return -EIO;
138}
139#endif	/* CONFIG_NUMA */
140#endif  /* _LINUX_MEMORY_TIERS_H */