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 node_hmem_attrs;
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 node_hmem_attrs *perf,
49 const char *source);
50int mt_perf_to_adistance(struct node_hmem_attrs *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 node_hmem_attrs *perf,
130 const char *source)
131{
132 return -EIO;
133}
134
135static inline int mt_perf_to_adistance(struct node_hmem_attrs *perf, int *adist)
136{
137 return -EIO;
138}
139#endif /* CONFIG_NUMA */
140#endif /* _LINUX_MEMORY_TIERS_H */
141

source code of linux/include/linux/memory-tiers.h