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 struct memory_block {
  27         unsigned long start_section_nr;
  28         unsigned long state;            /* serialized by the dev->lock */
  29         int online_type;                /* for passing data to online routine */
  30         int phys_device;                /* to which fru does this belong? */
  31         struct device dev;
  32         int nid;                        /* NID for this memory block */
  33 };
  34
  35 int arch_get_memory_phys_device(unsigned long start_pfn);
  36 unsigned long memory_block_size_bytes(void);
  37 int set_memory_block_size_order(unsigned int order);
  38
  39 /* These states are exposed to userspace as text strings in sysfs */
  40 #define MEM_ONLINE              (1<<0) /* exposed to userspace */
  41 #define MEM_GOING_OFFLINE       (1<<1) /* exposed to userspace */
  42 #define MEM_OFFLINE             (1<<2) /* exposed to userspace */
  43 #define MEM_GOING_ONLINE        (1<<3)
  44 #define MEM_CANCEL_ONLINE       (1<<4)
  45 #define MEM_CANCEL_OFFLINE      (1<<5)
  46
  47 struct memory_notify {
  48         unsigned long start_pfn;
  49         unsigned long nr_pages;
  50         int status_change_nid_normal;
  51         int status_change_nid_high;
  52         int status_change_nid;
  53 };
  54
  55 struct notifier_block;
  56 struct mem_section;
  57
  58 /*
  59  * Priorities for the hotplug memory callback routines (stored in decreasing
  60  * order in the callback chain)
  61  */
  62 #define SLAB_CALLBACK_PRI       1
  63 #define IPC_CALLBACK_PRI        10
  64
  65 #ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
  66 static inline void memory_dev_init(void)
  67 {
  68         return;
  69 }
  70 static inline int register_memory_notifier(struct notifier_block *nb)
  71 {
  72         return 0;
  73 }
  74 static inline void unregister_memory_notifier(struct notifier_block *nb)
  75 {
  76 }
  77 static inline int memory_notify(unsigned long val, void *v)
  78 {
  79         return 0;
  80 }
  81 #else
  82 extern int register_memory_notifier(struct notifier_block *nb);
  83 extern void unregister_memory_notifier(struct notifier_block *nb);
  84 int create_memory_block_devices(unsigned long start, unsigned long size);
  85 void remove_memory_block_devices(unsigned long start, unsigned long size);
  86 extern void memory_dev_init(void);
  87 extern int memory_notify(unsigned long val, void *v);
  88 extern struct memory_block *find_memory_block(struct mem_section *);
  89 typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
  90 extern int walk_memory_blocks(unsigned long start, unsigned long size,
  91                               void *arg, walk_memory_blocks_func_t func);
  92 extern int for_each_memory_block(void *arg, walk_memory_blocks_func_t func);
  93 #define CONFIG_MEM_BLOCK_SIZE   (PAGES_PER_SECTION<<PAGE_SHIFT)
  94 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
  95
  96 #ifdef CONFIG_MEMORY_HOTPLUG
  97 #define hotplug_memory_notifier(fn, pri) ({             \
  98         static __meminitdata struct notifier_block fn##_mem_nb =\
  99                 { .notifier_call = fn, .priority = pri };\
 100         register_memory_notifier(&fn##_mem_nb);                 \
 101 })
 102 #define register_hotmemory_notifier(nb)         register_memory_notifier(nb)
 103 #define unregister_hotmemory_notifier(nb)       unregister_memory_notifier(nb)
 104 #else
 105 #define hotplug_memory_notifier(fn, pri)        ({ 0; })
 106 /* These aren't inline functions due to a GCC bug. */
 107 #define register_hotmemory_notifier(nb)    ({ (void)(nb); 0; })
 108 #define unregister_hotmemory_notifier(nb)  ({ (void)(nb); })
 109 #endif
 110
 111 /*
 112  * Kernel text modification mutex, used for code patching. Users of this lock
 113  * can sleep.
 114  */
 115 extern struct mutex text_mutex;
 116
 117 #endif /* _LINUX_MEMORY_H_ */