include/linux/memory-tiers.h

   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
  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_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
  36 struct access_coordinate;
  37
  38 #ifdef CONFIG_NUMA
  39 extern bool numa_demotion_enabled;
  40 extern struct memory_dev_type *default_dram_type;
  41 extern nodemask_t default_dram_nodes;
  42 struct memory_dev_type *alloc_memory_type(int adistance);
  43 void put_memory_type(struct memory_dev_type *memtype);
  44 void init_node_memory_type(int node, struct memory_dev_type *default_type);
  45 void clear_node_memory_type(int node, struct memory_dev_type *memtype);
  46 int register_mt_adistance_algorithm(struct notifier_block *nb);
  47 int unregister_mt_adistance_algorithm(struct notifier_block *nb);
  48 int mt_calc_adistance(int node, int *adist);
  49 int mt_set_default_dram_perf(int nid, struct access_coordinate *perf,
  50                              const char *source);
  51 int mt_perf_to_adistance(struct access_coordinate *perf, int *adist);
  52 struct memory_dev_type *mt_find_alloc_memory_type(int adist,
  53                                                   struct list_head *memory_types);
  54 void mt_put_memory_types(struct list_head *memory_types);
  55 #ifdef CONFIG_MIGRATION
  56 int next_demotion_node(int node);
  57 void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets);
  58 bool node_is_toptier(int node);
  59 #else
  60 static inline int next_demotion_node(int node)
  61 {
  62         return NUMA_NO_NODE;
  63 }
  64
  65 static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
  66 {
  67         *targets = NODE_MASK_NONE;
  68 }
  69
  70 static inline bool node_is_toptier(int node)
  71 {
  72         return true;
  73 }
  74 #endif
  75
  76 #else
  77
  78 #define numa_demotion_enabled   false
  79 #define default_dram_type       NULL
  80 #define default_dram_nodes      NODE_MASK_NONE
  81 /*
  82  * CONFIG_NUMA implementation returns non NULL error.
  83  */
  84 static inline struct memory_dev_type *alloc_memory_type(int adistance)
  85 {
  86         return NULL;
  87 }
  88
  89 static inline void put_memory_type(struct memory_dev_type *memtype)
  90 {
  91
  92 }
  93
  94 static inline void init_node_memory_type(int node, struct memory_dev_type *default_type)
  95 {
  96
  97 }
  98
  99 static inline void clear_node_memory_type(int node, struct memory_dev_type *memtype)
 100 {
 101
 102 }
 103
 104 static inline int next_demotion_node(int node)
 105 {
 106         return NUMA_NO_NODE;
 107 }
 108
 109 static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
 110 {
 111         *targets = NODE_MASK_NONE;
 112 }
 113
 114 static inline bool node_is_toptier(int node)
 115 {
 116         return true;
 117 }
 118
 119 static inline int register_mt_adistance_algorithm(struct notifier_block *nb)
 120 {
 121         return 0;
 122 }
 123
 124 static inline int unregister_mt_adistance_algorithm(struct notifier_block *nb)
 125 {
 126         return 0;
 127 }
 128
 129 static inline int mt_calc_adistance(int node, int *adist)
 130 {
 131         return NOTIFY_DONE;
 132 }
 133
 134 static inline int mt_set_default_dram_perf(int nid, struct access_coordinate *perf,
 135                                            const char *source)
 136 {
 137         return -EIO;
 138 }
 139
 140 static inline int mt_perf_to_adistance(struct access_coordinate *perf, int *adist)
 141 {
 142         return -EIO;
 143 }
 144
 145 static inline struct memory_dev_type *mt_find_alloc_memory_type(int adist,
 146                                                                 struct list_head *memory_types)
 147 {
 148         return NULL;
 149 }
 150
 151 static inline void mt_put_memory_types(struct list_head *memory_types)
 152 {
 153 }
 154 #endif  /* CONFIG_NUMA */
 155 #endif  /* _LINUX_MEMORY_TIERS_H */