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	((4L * 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;
 41extern nodemask_t default_dram_nodes;
 42struct memory_dev_type *alloc_memory_type(int adistance);
 43void put_memory_type(struct memory_dev_type *memtype);
 44void init_node_memory_type(int node, struct memory_dev_type *default_type);
 45void clear_node_memory_type(int node, struct memory_dev_type *memtype);
 46int register_mt_adistance_algorithm(struct notifier_block *nb);
 47int unregister_mt_adistance_algorithm(struct notifier_block *nb);
 48int mt_calc_adistance(int node, int *adist);
 49int mt_set_default_dram_perf(int nid, struct access_coordinate *perf,
 50			     const char *source);
 51int mt_perf_to_adistance(struct access_coordinate *perf, int *adist);
 52struct memory_dev_type *mt_find_alloc_memory_type(int adist,
 53						  struct list_head *memory_types);
 54void mt_put_memory_types(struct list_head *memory_types);
 55#ifdef CONFIG_MIGRATION
 56int next_demotion_node(int node);
 57void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets);
 58bool node_is_toptier(int node);
 59#else
 60static inline int next_demotion_node(int node)
 61{
 62	return NUMA_NO_NODE;
 63}
 64
 65static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
 66{
 67	*targets = NODE_MASK_NONE;
 68}
 69
 70static 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 */
 84static inline struct memory_dev_type *alloc_memory_type(int adistance)
 85{
 86	return NULL;
 87}
 88
 89static inline void put_memory_type(struct memory_dev_type *memtype)
 90{
 91
 92}
 93
 94static inline void init_node_memory_type(int node, struct memory_dev_type *default_type)
 95{
 96
 97}
 98
 99static inline void clear_node_memory_type(int node, struct memory_dev_type *memtype)
100{
101
102}
103
104static inline int next_demotion_node(int node)
105{
106	return NUMA_NO_NODE;
107}
108
109static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
110{
111	*targets = NODE_MASK_NONE;
112}
113
114static inline bool node_is_toptier(int node)
115{
116	return true;
117}
118
119static inline int register_mt_adistance_algorithm(struct notifier_block *nb)
120{
121	return 0;
122}
123
124static inline int unregister_mt_adistance_algorithm(struct notifier_block *nb)
125{
126	return 0;
127}
128
129static inline int mt_calc_adistance(int node, int *adist)
130{
131	return NOTIFY_DONE;
132}
133
134static inline int mt_set_default_dram_perf(int nid, struct access_coordinate *perf,
135					   const char *source)
136{
137	return -EIO;
138}
139
140static inline int mt_perf_to_adistance(struct access_coordinate *perf, int *adist)
141{
142	return -EIO;
143}
144
145static inline struct memory_dev_type *mt_find_alloc_memory_type(int adist,
146								struct list_head *memory_types)
147{
148	return NULL;
149}
150
151static inline void mt_put_memory_types(struct list_head *memory_types)
152{
153}
154#endif	/* CONFIG_NUMA */
155#endif  /* _LINUX_MEMORY_TIERS_H */