include/linux/memory.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * include/linux/memory.h - generic memory definition
   4  *
   5  * This is mainly for topological representation. We define the
   6  * basic "struct memory_block" here, which can be embedded in per-arch
   7  * definitions or NUMA information.
   8  *
   9  * Basic handling of the devices is done in drivers/base/memory.c
  10  * and system devices are handled in drivers/base/sys.c.
  11  *
  12  * Memory block are exported via sysfs in the class/memory/devices/
  13  * directory.
  14  *
  15  */
  16 #ifndef _LINUX_MEMORY_H_
  17 #define _LINUX_MEMORY_H_
  18
  19 #include <linux/node.h>
  20 #include <linux/compiler.h>
  21 #include <linux/mutex.h>
  22 #include <linux/notifier.h>
  23
  24 #define MIN_MEMORY_BLOCK_SIZE     (1UL << SECTION_SIZE_BITS)
  25
  26 /**
  27  * struct memory_group - a logical group of memory blocks
  28  * @nid: The node id for all memory blocks inside the memory group.
  29  * @blocks: List of all memory blocks belonging to this memory group.
  30  * @present_kernel_pages: Present (online) memory outside ZONE_MOVABLE of this
  31  *                        memory group.
  32  * @present_movable_pages: Present (online) memory in ZONE_MOVABLE of this
  33  *                         memory group.
  34  * @is_dynamic: The memory group type: static vs. dynamic
  35  * @s.max_pages: Valid with &memory_group.is_dynamic == false. The maximum
  36  *               number of pages we'll have in this static memory group.
  37  * @d.unit_pages: Valid with &memory_group.is_dynamic == true. Unit in pages
  38  *                in which memory is added/removed in this dynamic memory group.
  39  *                This granularity defines the alignment of a unit in physical
  40  *                address space; it has to be at least as big as a single
  41  *                memory block.
  42  *
  43  * A memory group logically groups memory blocks; each memory block
  44  * belongs to at most one memory group. A memory group corresponds to
  45  * a memory device, such as a DIMM or a NUMA node, which spans multiple
  46  * memory blocks and might even span multiple non-contiguous physical memory
  47  * ranges.
  48  *
  49  * Modification of members after registration is serialized by memory
  50  * hot(un)plug code.
  51  */
  52 struct memory_group {
  53         int nid;
  54         struct list_head memory_blocks;
  55         unsigned long present_kernel_pages;
  56         unsigned long present_movable_pages;
  57         bool is_dynamic;
  58         union {
  59                 struct {
  60                         unsigned long max_pages;
  61                 } s;
  62                 struct {
  63                         unsigned long unit_pages;
  64                 } d;
  65         };
  66 };
  67
  68 struct memory_block {
  69         unsigned long start_section_nr;
  70         unsigned long state;            /* serialized by the dev->lock */
  71         int online_type;                /* for passing data to online routine */
  72         int nid;                        /* NID for this memory block */
  73         struct device dev;
  74         /*
  75          * Number of vmemmap pages. These pages
  76          * lay at the beginning of the memory block.
  77          */
  78         unsigned long nr_vmemmap_pages;
  79         struct memory_group *group;     /* group (if any) for this block */
  80         struct list_head group_next;    /* next block inside memory group */
  81 };
  82
  83 int arch_get_memory_phys_device(unsigned long start_pfn);
  84 unsigned long memory_block_size_bytes(void);
  85 int set_memory_block_size_order(unsigned int order);
  86
  87 /* These states are exposed to userspace as text strings in sysfs */
  88 #define MEM_ONLINE              (1<<0) /* exposed to userspace */
  89 #define MEM_GOING_OFFLINE       (1<<1) /* exposed to userspace */
  90 #define MEM_OFFLINE             (1<<2) /* exposed to userspace */
  91 #define MEM_GOING_ONLINE        (1<<3)
  92 #define MEM_CANCEL_ONLINE       (1<<4)
  93 #define MEM_CANCEL_OFFLINE      (1<<5)
  94
  95 struct memory_notify {
  96         unsigned long start_pfn;
  97         unsigned long nr_pages;
  98         int status_change_nid_normal;
  99         int status_change_nid_high;
 100         int status_change_nid;
 101 };
 102
 103 struct notifier_block;
 104 struct mem_section;
 105
 106 /*
 107  * Priorities for the hotplug memory callback routines (stored in decreasing
 108  * order in the callback chain)
 109  */
 110 #define SLAB_CALLBACK_PRI       1
 111 #define IPC_CALLBACK_PRI        10
 112
 113 #ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
 114 static inline void memory_dev_init(void)
 115 {
 116         return;
 117 }
 118 static inline int register_memory_notifier(struct notifier_block *nb)
 119 {
 120         return 0;
 121 }
 122 static inline void unregister_memory_notifier(struct notifier_block *nb)
 123 {
 124 }
 125 static inline int memory_notify(unsigned long val, void *v)
 126 {
 127         return 0;
 128 }
 129 #else
 130 extern int register_memory_notifier(struct notifier_block *nb);
 131 extern void unregister_memory_notifier(struct notifier_block *nb);
 132 int create_memory_block_devices(unsigned long start, unsigned long size,
 133                                 unsigned long vmemmap_pages,
 134                                 struct memory_group *group);
 135 void remove_memory_block_devices(unsigned long start, unsigned long size);
 136 extern void memory_dev_init(void);
 137 extern int memory_notify(unsigned long val, void *v);
 138 extern struct memory_block *find_memory_block(unsigned long section_nr);
 139 typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
 140 extern int walk_memory_blocks(unsigned long start, unsigned long size,
 141                               void *arg, walk_memory_blocks_func_t func);
 142 extern int for_each_memory_block(void *arg, walk_memory_blocks_func_t func);
 143 #define CONFIG_MEM_BLOCK_SIZE   (PAGES_PER_SECTION<<PAGE_SHIFT)
 144
 145 extern int memory_group_register_static(int nid, unsigned long max_pages);
 146 extern int memory_group_register_dynamic(int nid, unsigned long unit_pages);
 147 extern int memory_group_unregister(int mgid);
 148 struct memory_group *memory_group_find_by_id(int mgid);
 149 typedef int (*walk_memory_groups_func_t)(struct memory_group *, void *);
 150 int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
 151                                struct memory_group *excluded, void *arg);
 152 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 153
 154 #ifdef CONFIG_MEMORY_HOTPLUG
 155 #define hotplug_memory_notifier(fn, pri) ({             \
 156         static __meminitdata struct notifier_block fn##_mem_nb =\
 157                 { .notifier_call = fn, .priority = pri };\
 158         register_memory_notifier(&fn##_mem_nb);                 \
 159 })
 160 #define register_hotmemory_notifier(nb)         register_memory_notifier(nb)
 161 #define unregister_hotmemory_notifier(nb)       unregister_memory_notifier(nb)
 162 #else
 163 #define hotplug_memory_notifier(fn, pri)        ({ 0; })
 164 /* These aren't inline functions due to a GCC bug. */
 165 #define register_hotmemory_notifier(nb)    ({ (void)(nb); 0; })
 166 #define unregister_hotmemory_notifier(nb)  ({ (void)(nb); })
 167 #endif
 168
 169 /*
 170  * Kernel text modification mutex, used for code patching. Users of this lock
 171  * can sleep.
 172  */
 173 extern struct mutex text_mutex;
 174
 175 #endif /* _LINUX_MEMORY_H_ */