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 #define MEMTIER_HOTPLUG_PRIO 100
22
23 struct memory_tier;
24 struct memory_dev_type {
25 /* list of memory types that are part of same tier as this type */
26 struct list_head tier_sibiling;
27 /* abstract distance for this specific memory type */
28 int adistance;
29 /* Nodes of same abstract distance */
30 nodemask_t nodes;
31 struct kref kref;
32 };
33
34 #ifdef CONFIG_NUMA
35 extern bool numa_demotion_enabled;
36 struct memory_dev_type *alloc_memory_type(int adistance);
37 void destroy_memory_type(struct memory_dev_type *memtype);
38 void init_node_memory_type(int node, struct memory_dev_type *default_type);
39 void clear_node_memory_type(int node, struct memory_dev_type *memtype);
40 #ifdef CONFIG_MIGRATION
41 int next_demotion_node(int node);
42 void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets);
43 bool node_is_toptier(int node);
44 #else
next_demotion_node(int node)45 static inline int next_demotion_node(int node)
46 {
47 return NUMA_NO_NODE;
48 }
49
node_get_allowed_targets(pg_data_t * pgdat,nodemask_t * targets)50 static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
51 {
52 *targets = NODE_MASK_NONE;
53 }
54
node_is_toptier(int node)55 static inline bool node_is_toptier(int node)
56 {
57 return true;
58 }
59 #endif
60
61 #else
62
63 #define numa_demotion_enabled false
64 /*
65 * CONFIG_NUMA implementation returns non NULL error.
66 */
alloc_memory_type(int adistance)67 static inline struct memory_dev_type *alloc_memory_type(int adistance)
68 {
69 return NULL;
70 }
71
destroy_memory_type(struct memory_dev_type * memtype)72 static inline void destroy_memory_type(struct memory_dev_type *memtype)
73 {
74
75 }
76
init_node_memory_type(int node,struct memory_dev_type * default_type)77 static inline void init_node_memory_type(int node, struct memory_dev_type *default_type)
78 {
79
80 }
81
clear_node_memory_type(int node,struct memory_dev_type * memtype)82 static inline void clear_node_memory_type(int node, struct memory_dev_type *memtype)
83 {
84
85 }
86
next_demotion_node(int node)87 static inline int next_demotion_node(int node)
88 {
89 return NUMA_NO_NODE;
90 }
91
node_get_allowed_targets(pg_data_t * pgdat,nodemask_t * targets)92 static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
93 {
94 *targets = NODE_MASK_NONE;
95 }
96
node_is_toptier(int node)97 static inline bool node_is_toptier(int node)
98 {
99 return true;
100 }
101 #endif /* CONFIG_NUMA */
102 #endif /* _LINUX_MEMORY_TIERS_H */
103