Linux kernel mirror (for testing)
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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/*
10 * Each tier cover a abstrace distance chunk size of 128
11 */
12#define MEMTIER_CHUNK_BITS 7
13#define MEMTIER_CHUNK_SIZE (1 << MEMTIER_CHUNK_BITS)
14/*
15 * Smaller abstract distance values imply faster (higher) memory tiers. Offset
16 * the DRAM adistance so that we can accommodate devices with a slightly lower
17 * adistance value (slightly faster) than default DRAM adistance to be part of
18 * the same memory tier.
19 */
20#define MEMTIER_ADISTANCE_DRAM ((4 * MEMTIER_CHUNK_SIZE) + (MEMTIER_CHUNK_SIZE >> 1))
21
22struct memory_tier;
23struct memory_dev_type {
24 /* list of memory types that are part of same tier as this type */
25 struct list_head tier_sibiling;
26 /* abstract distance for this specific memory type */
27 int adistance;
28 /* Nodes of same abstract distance */
29 nodemask_t nodes;
30 struct kref kref;
31};
32
33#ifdef CONFIG_NUMA
34extern bool numa_demotion_enabled;
35struct memory_dev_type *alloc_memory_type(int adistance);
36void destroy_memory_type(struct memory_dev_type *memtype);
37void init_node_memory_type(int node, struct memory_dev_type *default_type);
38void clear_node_memory_type(int node, struct memory_dev_type *memtype);
39#ifdef CONFIG_MIGRATION
40int next_demotion_node(int node);
41void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets);
42bool node_is_toptier(int node);
43#else
44static inline int next_demotion_node(int node)
45{
46 return NUMA_NO_NODE;
47}
48
49static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
50{
51 *targets = NODE_MASK_NONE;
52}
53
54static inline bool node_is_toptier(int node)
55{
56 return true;
57}
58#endif
59
60#else
61
62#define numa_demotion_enabled false
63/*
64 * CONFIG_NUMA implementation returns non NULL error.
65 */
66static inline struct memory_dev_type *alloc_memory_type(int adistance)
67{
68 return NULL;
69}
70
71static inline void destroy_memory_type(struct memory_dev_type *memtype)
72{
73
74}
75
76static inline void init_node_memory_type(int node, struct memory_dev_type *default_type)
77{
78
79}
80
81static inline void clear_node_memory_type(int node, struct memory_dev_type *memtype)
82{
83
84}
85
86static inline int next_demotion_node(int node)
87{
88 return NUMA_NO_NODE;
89}
90
91static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
92{
93 *targets = NODE_MASK_NONE;
94}
95
96static inline bool node_is_toptier(int node)
97{
98 return true;
99}
100#endif /* CONFIG_NUMA */
101#endif /* _LINUX_MEMORY_TIERS_H */