xref: /linux-6.15/include/linux/mm_types.h (revision b8bb7671)
1 #ifndef _LINUX_MM_TYPES_H
2 #define _LINUX_MM_TYPES_H
3 
4 #include <linux/auxvec.h>
5 #include <linux/types.h>
6 #include <linux/threads.h>
7 #include <linux/list.h>
8 #include <linux/spinlock.h>
9 #include <linux/prio_tree.h>
10 #include <linux/rbtree.h>
11 #include <linux/rwsem.h>
12 #include <linux/completion.h>
13 #include <linux/cpumask.h>
14 #include <linux/page-debug-flags.h>
15 #include <asm/page.h>
16 #include <asm/mmu.h>
17 
18 #ifndef AT_VECTOR_SIZE_ARCH
19 #define AT_VECTOR_SIZE_ARCH 0
20 #endif
21 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
22 
23 struct address_space;
24 
25 #define USE_SPLIT_PTLOCKS	(NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
26 
27 #if USE_SPLIT_PTLOCKS
28 typedef atomic_long_t mm_counter_t;
29 #else  /* !USE_SPLIT_PTLOCKS */
30 typedef unsigned long mm_counter_t;
31 #endif /* !USE_SPLIT_PTLOCKS */
32 
33 /*
34  * Each physical page in the system has a struct page associated with
35  * it to keep track of whatever it is we are using the page for at the
36  * moment. Note that we have no way to track which tasks are using
37  * a page, though if it is a pagecache page, rmap structures can tell us
38  * who is mapping it.
39  */
40 struct page {
41 	unsigned long flags;		/* Atomic flags, some possibly
42 					 * updated asynchronously */
43 	atomic_t _count;		/* Usage count, see below. */
44 	union {
45 		atomic_t _mapcount;	/* Count of ptes mapped in mms,
46 					 * to show when page is mapped
47 					 * & limit reverse map searches.
48 					 */
49 		struct {		/* SLUB */
50 			u16 inuse;
51 			u16 objects;
52 		};
53 	};
54 	union {
55 	    struct {
56 		unsigned long private;		/* Mapping-private opaque data:
57 					 	 * usually used for buffer_heads
58 						 * if PagePrivate set; used for
59 						 * swp_entry_t if PageSwapCache;
60 						 * indicates order in the buddy
61 						 * system if PG_buddy is set.
62 						 */
63 		struct address_space *mapping;	/* If low bit clear, points to
64 						 * inode address_space, or NULL.
65 						 * If page mapped as anonymous
66 						 * memory, low bit is set, and
67 						 * it points to anon_vma object:
68 						 * see PAGE_MAPPING_ANON below.
69 						 */
70 	    };
71 #if USE_SPLIT_PTLOCKS
72 	    spinlock_t ptl;
73 #endif
74 	    struct kmem_cache *slab;	/* SLUB: Pointer to slab */
75 	    struct page *first_page;	/* Compound tail pages */
76 	};
77 	union {
78 		pgoff_t index;		/* Our offset within mapping. */
79 		void *freelist;		/* SLUB: freelist req. slab lock */
80 	};
81 	struct list_head lru;		/* Pageout list, eg. active_list
82 					 * protected by zone->lru_lock !
83 					 */
84 	/*
85 	 * On machines where all RAM is mapped into kernel address space,
86 	 * we can simply calculate the virtual address. On machines with
87 	 * highmem some memory is mapped into kernel virtual memory
88 	 * dynamically, so we need a place to store that address.
89 	 * Note that this field could be 16 bits on x86 ... ;)
90 	 *
91 	 * Architectures with slow multiplication can define
92 	 * WANT_PAGE_VIRTUAL in asm/page.h
93 	 */
94 #if defined(WANT_PAGE_VIRTUAL)
95 	void *virtual;			/* Kernel virtual address (NULL if
96 					   not kmapped, ie. highmem) */
97 #endif /* WANT_PAGE_VIRTUAL */
98 };
99 
100 /*
101  * A region containing a mapping of a non-memory backed file under NOMMU
102  * conditions.  These are held in a global tree and are pinned by the VMAs that
103  * map parts of them.
104  */
105 struct vm_region {
106 	struct rb_node	vm_rb;		/* link in global region tree */
107 	unsigned long	vm_flags;	/* VMA vm_flags */
108 	unsigned long	vm_start;	/* start address of region */
109 	unsigned long	vm_end;		/* region initialised to here */
110 	unsigned long	vm_top;		/* region allocated to here */
111 	unsigned long	vm_pgoff;	/* the offset in vm_file corresponding to vm_start */
112 	struct file	*vm_file;	/* the backing file or NULL */
113 
114 	atomic_t	vm_usage;	/* region usage count */
115 };
116 
117 /*
118  * This struct defines a memory VMM memory area. There is one of these
119  * per VM-area/task.  A VM area is any part of the process virtual memory
120  * space that has a special rule for the page-fault handlers (ie a shared
121  * library, the executable area etc).
122  */
123 struct vm_area_struct {
124 	struct mm_struct * vm_mm;	/* The address space we belong to. */
125 	unsigned long vm_start;		/* Our start address within vm_mm. */
126 	unsigned long vm_end;		/* The first byte after our end address
127 					   within vm_mm. */
128 
129 	/* linked list of VM areas per task, sorted by address */
130 	struct vm_area_struct *vm_next;
131 
132 	pgprot_t vm_page_prot;		/* Access permissions of this VMA. */
133 	unsigned long vm_flags;		/* Flags, see mm.h. */
134 
135 	struct rb_node vm_rb;
136 
137 	/*
138 	 * For areas with an address space and backing store,
139 	 * linkage into the address_space->i_mmap prio tree, or
140 	 * linkage to the list of like vmas hanging off its node, or
141 	 * linkage of vma in the address_space->i_mmap_nonlinear list.
142 	 */
143 	union {
144 		struct {
145 			struct list_head list;
146 			void *parent;	/* aligns with prio_tree_node parent */
147 			struct vm_area_struct *head;
148 		} vm_set;
149 
150 		struct raw_prio_tree_node prio_tree_node;
151 	} shared;
152 
153 	/*
154 	 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
155 	 * list, after a COW of one of the file pages.	A MAP_SHARED vma
156 	 * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
157 	 * or brk vma (with NULL file) can only be in an anon_vma list.
158 	 */
159 	struct list_head anon_vma_node;	/* Serialized by anon_vma->lock */
160 	struct anon_vma *anon_vma;	/* Serialized by page_table_lock */
161 
162 	/* Function pointers to deal with this struct. */
163 	struct vm_operations_struct * vm_ops;
164 
165 	/* Information about our backing store: */
166 	unsigned long vm_pgoff;		/* Offset (within vm_file) in PAGE_SIZE
167 					   units, *not* PAGE_CACHE_SIZE */
168 	struct file * vm_file;		/* File we map to (can be NULL). */
169 	void * vm_private_data;		/* was vm_pte (shared mem) */
170 	unsigned long vm_truncate_count;/* truncate_count or restart_addr */
171 
172 #ifndef CONFIG_MMU
173 	struct vm_region *vm_region;	/* NOMMU mapping region */
174 #endif
175 #ifdef CONFIG_NUMA
176 	struct mempolicy *vm_policy;	/* NUMA policy for the VMA */
177 #endif
178 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
179 	unsigned long debug_flags;	/* Use atomic bitops on this */
180 #endif
181 };
182 
183 struct core_thread {
184 	struct task_struct *task;
185 	struct core_thread *next;
186 };
187 
188 struct core_state {
189 	atomic_t nr_threads;
190 	struct core_thread dumper;
191 	struct completion startup;
192 };
193 
194 struct mm_struct {
195 	struct vm_area_struct * mmap;		/* list of VMAs */
196 	struct rb_root mm_rb;
197 	struct vm_area_struct * mmap_cache;	/* last find_vma result */
198 	unsigned long (*get_unmapped_area) (struct file *filp,
199 				unsigned long addr, unsigned long len,
200 				unsigned long pgoff, unsigned long flags);
201 	void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
202 	unsigned long mmap_base;		/* base of mmap area */
203 	unsigned long task_size;		/* size of task vm space */
204 	unsigned long cached_hole_size; 	/* if non-zero, the largest hole below free_area_cache */
205 	unsigned long free_area_cache;		/* first hole of size cached_hole_size or larger */
206 	pgd_t * pgd;
207 	atomic_t mm_users;			/* How many users with user space? */
208 	atomic_t mm_count;			/* How many references to "struct mm_struct" (users count as 1) */
209 	int map_count;				/* number of VMAs */
210 	struct rw_semaphore mmap_sem;
211 	spinlock_t page_table_lock;		/* Protects page tables and some counters */
212 
213 	struct list_head mmlist;		/* List of maybe swapped mm's.	These are globally strung
214 						 * together off init_mm.mmlist, and are protected
215 						 * by mmlist_lock
216 						 */
217 
218 	/* Special counters, in some configurations protected by the
219 	 * page_table_lock, in other configurations by being atomic.
220 	 */
221 	mm_counter_t _file_rss;
222 	mm_counter_t _anon_rss;
223 
224 	unsigned long hiwater_rss;	/* High-watermark of RSS usage */
225 	unsigned long hiwater_vm;	/* High-water virtual memory usage */
226 
227 	unsigned long total_vm, locked_vm, shared_vm, exec_vm;
228 	unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
229 	unsigned long start_code, end_code, start_data, end_data;
230 	unsigned long start_brk, brk, start_stack;
231 	unsigned long arg_start, arg_end, env_start, env_end;
232 
233 	unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
234 
235 	cpumask_t cpu_vm_mask;
236 
237 	/* Architecture-specific MM context */
238 	mm_context_t context;
239 
240 	/* Swap token stuff */
241 	/*
242 	 * Last value of global fault stamp as seen by this process.
243 	 * In other words, this value gives an indication of how long
244 	 * it has been since this task got the token.
245 	 * Look at mm/thrash.c
246 	 */
247 	unsigned int faultstamp;
248 	unsigned int token_priority;
249 	unsigned int last_interval;
250 
251 	unsigned long flags; /* Must use atomic bitops to access the bits */
252 
253 	struct core_state *core_state; /* coredumping support */
254 
255 	/* aio bits */
256 	spinlock_t		ioctx_lock;
257 	struct hlist_head	ioctx_list;
258 
259 #ifdef CONFIG_MM_OWNER
260 	/*
261 	 * "owner" points to a task that is regarded as the canonical
262 	 * user/owner of this mm. All of the following must be true in
263 	 * order for it to be changed:
264 	 *
265 	 * current == mm->owner
266 	 * current->mm != mm
267 	 * new_owner->mm == mm
268 	 * new_owner->alloc_lock is held
269 	 */
270 	struct task_struct *owner;
271 #endif
272 
273 #ifdef CONFIG_PROC_FS
274 	/* store ref to file /proc/<pid>/exe symlink points to */
275 	struct file *exe_file;
276 	unsigned long num_exe_file_vmas;
277 #endif
278 #ifdef CONFIG_MMU_NOTIFIER
279 	struct mmu_notifier_mm *mmu_notifier_mm;
280 #endif
281 };
282 
283 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
284 #define mm_cpumask(mm) (&(mm)->cpu_vm_mask)
285 
286 #endif /* _LINUX_MM_TYPES_H */
287