1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MM_TYPES_H
3 #define _LINUX_MM_TYPES_H
5 #include <linux/mm_types_task.h>
7 #include <linux/auxvec.h>
8 #include <linux/list.h>
9 #include <linux/spinlock.h>
10 #include <linux/rbtree.h>
11 #include <linux/rwsem.h>
12 #include <linux/completion.h>
13 #include <linux/cpumask.h>
14 #include <linux/uprobes.h>
15 #include <linux/page-flags-layout.h>
16 #include <linux/workqueue.h>
20 #ifndef AT_VECTOR_SIZE_ARCH
21 #define AT_VECTOR_SIZE_ARCH 0
23 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
30 * Each physical page in the system has a struct page associated with
31 * it to keep track of whatever it is we are using the page for at the
32 * moment. Note that we have no way to track which tasks are using
33 * a page, though if it is a pagecache page, rmap structures can tell us
36 * The objects in struct page are organized in double word blocks in
37 * order to allows us to use atomic double word operations on portions
38 * of struct page. That is currently only used by slub but the arrangement
39 * allows the use of atomic double word operations on the flags/mapping
40 * and lru list pointers also.
43 /* First double word block */
44 unsigned long flags
; /* Atomic flags, some possibly
45 * updated asynchronously */
47 struct address_space
*mapping
; /* If low bit clear, points to
48 * inode address_space, or NULL.
49 * If page mapped as anonymous
50 * memory, low bit is set, and
51 * it points to anon_vma object
52 * or KSM private structure. See
53 * PAGE_MAPPING_ANON and
56 void *s_mem
; /* slab first object */
57 atomic_t compound_mapcount
; /* first tail page */
58 /* page_deferred_list().next -- second tail page */
61 /* Second double word */
63 pgoff_t index
; /* Our offset within mapping. */
64 void *freelist
; /* sl[aou]b first free object */
65 /* page_deferred_list().prev -- second tail page */
69 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
70 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
71 /* Used for cmpxchg_double in slub */
72 unsigned long counters
;
75 * Keep _refcount separate from slub cmpxchg_double data.
76 * As the rest of the double word is protected by slab_lock
77 * but _refcount is not.
85 * Count of ptes mapped in mms, to show when
86 * page is mapped & limit reverse map searches.
88 * Extra information about page type may be
89 * stored here for pages that are never mapped,
90 * in which case the value MUST BE <= -2.
91 * See page-flags.h for more details.
95 unsigned int active
; /* SLAB */
101 int units
; /* SLOB */
104 * Usage count, *USE WRAPPER FUNCTION* when manual
105 * accounting. See page_ref.h
112 * Third double word block
114 * WARNING: bit 0 of the first word encode PageTail(). That means
115 * the rest users of the storage space MUST NOT use the bit to
116 * avoid collision and false-positive PageTail().
119 struct list_head lru
; /* Pageout list, eg. active_list
120 * protected by zone_lru_lock !
121 * Can be used as a generic list
124 struct dev_pagemap
*pgmap
; /* ZONE_DEVICE pages are never on an
125 * lru or handled by a slab
126 * allocator, this points to the
127 * hosting device page map.
129 struct { /* slub per cpu partial pages */
130 struct page
*next
; /* Next partial slab */
132 int pages
; /* Nr of partial slabs left */
133 int pobjects
; /* Approximate # of objects */
140 struct rcu_head rcu_head
; /* Used by SLAB
141 * when destroying via RCU
143 /* Tail pages of compound page */
145 unsigned long compound_head
; /* If bit zero is set */
147 /* First tail page only */
150 * On 64 bit system we have enough space in struct page
151 * to encode compound_dtor and compound_order with
152 * unsigned int. It can help compiler generate better or
153 * smaller code on some archtectures.
155 unsigned int compound_dtor
;
156 unsigned int compound_order
;
158 unsigned short int compound_dtor
;
159 unsigned short int compound_order
;
163 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
165 unsigned long __pad
; /* do not overlay pmd_huge_pte
166 * with compound_head to avoid
167 * possible bit 0 collision.
169 pgtable_t pmd_huge_pte
; /* protected by page->ptl */
174 /* Remainder is not double word aligned */
176 unsigned long private; /* Mapping-private opaque data:
177 * usually used for buffer_heads
178 * if PagePrivate set; used for
179 * swp_entry_t if PageSwapCache;
180 * indicates order in the buddy
181 * system if PG_buddy is set.
183 #if USE_SPLIT_PTE_PTLOCKS
184 #if ALLOC_SPLIT_PTLOCKS
190 struct kmem_cache
*slab_cache
; /* SL[AU]B: Pointer to slab */
194 struct mem_cgroup
*mem_cgroup
;
198 * On machines where all RAM is mapped into kernel address space,
199 * we can simply calculate the virtual address. On machines with
200 * highmem some memory is mapped into kernel virtual memory
201 * dynamically, so we need a place to store that address.
202 * Note that this field could be 16 bits on x86 ... ;)
204 * Architectures with slow multiplication can define
205 * WANT_PAGE_VIRTUAL in asm/page.h
207 #if defined(WANT_PAGE_VIRTUAL)
208 void *virtual; /* Kernel virtual address (NULL if
209 not kmapped, ie. highmem) */
210 #endif /* WANT_PAGE_VIRTUAL */
212 #ifdef CONFIG_KMEMCHECK
214 * kmemcheck wants to track the status of each byte in a page; this
215 * is a pointer to such a status block. NULL if not tracked.
220 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
225 * The struct page can be forced to be double word aligned so that atomic ops
226 * on double words work. The SLUB allocator can make use of such a feature.
228 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
229 __aligned(2 * sizeof(unsigned long))
233 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
234 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
236 struct page_frag_cache
{
238 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
244 /* we maintain a pagecount bias, so that we dont dirty cache line
245 * containing page->_refcount every time we allocate a fragment.
247 unsigned int pagecnt_bias
;
251 typedef unsigned long vm_flags_t
;
254 * A region containing a mapping of a non-memory backed file under NOMMU
255 * conditions. These are held in a global tree and are pinned by the VMAs that
259 struct rb_node vm_rb
; /* link in global region tree */
260 vm_flags_t vm_flags
; /* VMA vm_flags */
261 unsigned long vm_start
; /* start address of region */
262 unsigned long vm_end
; /* region initialised to here */
263 unsigned long vm_top
; /* region allocated to here */
264 unsigned long vm_pgoff
; /* the offset in vm_file corresponding to vm_start */
265 struct file
*vm_file
; /* the backing file or NULL */
267 int vm_usage
; /* region usage count (access under nommu_region_sem) */
268 bool vm_icache_flushed
: 1; /* true if the icache has been flushed for
272 #ifdef CONFIG_USERFAULTFD
273 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
274 struct vm_userfaultfd_ctx
{
275 struct userfaultfd_ctx
*ctx
;
277 #else /* CONFIG_USERFAULTFD */
278 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
279 struct vm_userfaultfd_ctx
{};
280 #endif /* CONFIG_USERFAULTFD */
283 * This struct defines a memory VMM memory area. There is one of these
284 * per VM-area/task. A VM area is any part of the process virtual memory
285 * space that has a special rule for the page-fault handlers (ie a shared
286 * library, the executable area etc).
288 struct vm_area_struct
{
289 /* The first cache line has the info for VMA tree walking. */
291 unsigned long vm_start
; /* Our start address within vm_mm. */
292 unsigned long vm_end
; /* The first byte after our end address
295 /* linked list of VM areas per task, sorted by address */
296 struct vm_area_struct
*vm_next
, *vm_prev
;
298 struct rb_node vm_rb
;
301 * Largest free memory gap in bytes to the left of this VMA.
302 * Either between this VMA and vma->vm_prev, or between one of the
303 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
304 * get_unmapped_area find a free area of the right size.
306 unsigned long rb_subtree_gap
;
308 /* Second cache line starts here. */
310 struct mm_struct
*vm_mm
; /* The address space we belong to. */
311 pgprot_t vm_page_prot
; /* Access permissions of this VMA. */
312 unsigned long vm_flags
; /* Flags, see mm.h. */
315 * For areas with an address space and backing store,
316 * linkage into the address_space->i_mmap interval tree.
320 unsigned long rb_subtree_last
;
324 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
325 * list, after a COW of one of the file pages. A MAP_SHARED vma
326 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
327 * or brk vma (with NULL file) can only be in an anon_vma list.
329 struct list_head anon_vma_chain
; /* Serialized by mmap_sem &
331 struct anon_vma
*anon_vma
; /* Serialized by page_table_lock */
333 /* Function pointers to deal with this struct. */
334 const struct vm_operations_struct
*vm_ops
;
336 /* Information about our backing store: */
337 unsigned long vm_pgoff
; /* Offset (within vm_file) in PAGE_SIZE
339 struct file
* vm_file
; /* File we map to (can be NULL). */
340 void * vm_private_data
; /* was vm_pte (shared mem) */
342 atomic_long_t swap_readahead_info
;
344 struct vm_region
*vm_region
; /* NOMMU mapping region */
347 struct mempolicy
*vm_policy
; /* NUMA policy for the VMA */
349 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
;
350 } __randomize_layout
;
353 struct task_struct
*task
;
354 struct core_thread
*next
;
359 struct core_thread dumper
;
360 struct completion startup
;
365 struct vm_area_struct
*mmap
; /* list of VMAs */
366 struct rb_root mm_rb
;
367 u32 vmacache_seqnum
; /* per-thread vmacache */
369 unsigned long (*get_unmapped_area
) (struct file
*filp
,
370 unsigned long addr
, unsigned long len
,
371 unsigned long pgoff
, unsigned long flags
);
373 unsigned long mmap_base
; /* base of mmap area */
374 unsigned long mmap_legacy_base
; /* base of mmap area in bottom-up allocations */
375 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
376 /* Base adresses for compatible mmap() */
377 unsigned long mmap_compat_base
;
378 unsigned long mmap_compat_legacy_base
;
380 unsigned long task_size
; /* size of task vm space */
381 unsigned long highest_vm_end
; /* highest vma end address */
385 * @mm_users: The number of users including userspace.
387 * Use mmget()/mmget_not_zero()/mmput() to modify. When this drops
388 * to 0 (i.e. when the task exits and there are no other temporary
389 * reference holders), we also release a reference on @mm_count
390 * (which may then free the &struct mm_struct if @mm_count also
396 * @mm_count: The number of references to &struct mm_struct
397 * (@mm_users count as 1).
399 * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
400 * &struct mm_struct is freed.
404 atomic_long_t nr_ptes
; /* PTE page table pages */
405 #if CONFIG_PGTABLE_LEVELS > 2
406 atomic_long_t nr_pmds
; /* PMD page table pages */
408 #if CONFIG_PGTABLE_LEVELS > 3
409 atomic_long_t nr_puds
; /* PUD page table pages */
411 int map_count
; /* number of VMAs */
413 spinlock_t page_table_lock
; /* Protects page tables and some counters */
414 struct rw_semaphore mmap_sem
;
416 struct list_head mmlist
; /* List of maybe swapped mm's. These are globally strung
417 * together off init_mm.mmlist, and are protected
422 unsigned long hiwater_rss
; /* High-watermark of RSS usage */
423 unsigned long hiwater_vm
; /* High-water virtual memory usage */
425 unsigned long total_vm
; /* Total pages mapped */
426 unsigned long locked_vm
; /* Pages that have PG_mlocked set */
427 unsigned long pinned_vm
; /* Refcount permanently increased */
428 unsigned long data_vm
; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
429 unsigned long exec_vm
; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
430 unsigned long stack_vm
; /* VM_STACK */
431 unsigned long def_flags
;
432 unsigned long start_code
, end_code
, start_data
, end_data
;
433 unsigned long start_brk
, brk
, start_stack
;
434 unsigned long arg_start
, arg_end
, env_start
, env_end
;
436 unsigned long saved_auxv
[AT_VECTOR_SIZE
]; /* for /proc/PID/auxv */
439 * Special counters, in some configurations protected by the
440 * page_table_lock, in other configurations by being atomic.
442 struct mm_rss_stat rss_stat
;
444 struct linux_binfmt
*binfmt
;
446 cpumask_var_t cpu_vm_mask_var
;
448 /* Architecture-specific MM context */
449 mm_context_t context
;
451 unsigned long flags
; /* Must use atomic bitops to access the bits */
453 struct core_state
*core_state
; /* coredumping support */
454 #ifdef CONFIG_MEMBARRIER
455 atomic_t membarrier_state
;
458 spinlock_t ioctx_lock
;
459 struct kioctx_table __rcu
*ioctx_table
;
463 * "owner" points to a task that is regarded as the canonical
464 * user/owner of this mm. All of the following must be true in
465 * order for it to be changed:
467 * current == mm->owner
469 * new_owner->mm == mm
470 * new_owner->alloc_lock is held
472 struct task_struct __rcu
*owner
;
474 struct user_namespace
*user_ns
;
476 /* store ref to file /proc/<pid>/exe symlink points to */
477 struct file __rcu
*exe_file
;
478 #ifdef CONFIG_MMU_NOTIFIER
479 struct mmu_notifier_mm
*mmu_notifier_mm
;
481 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
482 pgtable_t pmd_huge_pte
; /* protected by page_table_lock */
484 #ifdef CONFIG_CPUMASK_OFFSTACK
485 struct cpumask cpumask_allocation
;
487 #ifdef CONFIG_NUMA_BALANCING
489 * numa_next_scan is the next time that the PTEs will be marked
490 * pte_numa. NUMA hinting faults will gather statistics and migrate
491 * pages to new nodes if necessary.
493 unsigned long numa_next_scan
;
495 /* Restart point for scanning and setting pte_numa */
496 unsigned long numa_scan_offset
;
498 /* numa_scan_seq prevents two threads setting pte_numa */
502 * An operation with batched TLB flushing is going on. Anything that
503 * can move process memory needs to flush the TLB when moving a
504 * PROT_NONE or PROT_NUMA mapped page.
506 atomic_t tlb_flush_pending
;
507 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
508 /* See flush_tlb_batched_pending() */
509 bool tlb_flush_batched
;
511 struct uprobes_state uprobes_state
;
512 #ifdef CONFIG_HUGETLB_PAGE
513 atomic_long_t hugetlb_usage
;
515 struct work_struct async_put_work
;
517 #if IS_ENABLED(CONFIG_HMM)
518 /* HMM needs to track a few things per mm */
521 } __randomize_layout
;
523 extern struct mm_struct init_mm
;
525 static inline void mm_init_cpumask(struct mm_struct
*mm
)
527 #ifdef CONFIG_CPUMASK_OFFSTACK
528 mm
->cpu_vm_mask_var
= &mm
->cpumask_allocation
;
530 cpumask_clear(mm
->cpu_vm_mask_var
);
533 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
534 static inline cpumask_t
*mm_cpumask(struct mm_struct
*mm
)
536 return mm
->cpu_vm_mask_var
;
540 extern void tlb_gather_mmu(struct mmu_gather
*tlb
, struct mm_struct
*mm
,
541 unsigned long start
, unsigned long end
);
542 extern void tlb_finish_mmu(struct mmu_gather
*tlb
,
543 unsigned long start
, unsigned long end
);
545 static inline void init_tlb_flush_pending(struct mm_struct
*mm
)
547 atomic_set(&mm
->tlb_flush_pending
, 0);
550 static inline void inc_tlb_flush_pending(struct mm_struct
*mm
)
552 atomic_inc(&mm
->tlb_flush_pending
);
554 * The only time this value is relevant is when there are indeed pages
555 * to flush. And we'll only flush pages after changing them, which
558 * So the ordering here is:
560 * atomic_inc(&mm->tlb_flush_pending);
567 * mm_tlb_flush_pending();
572 * atomic_dec(&mm->tlb_flush_pending);
574 * Where the increment if constrained by the PTL unlock, it thus
575 * ensures that the increment is visible if the PTE modification is
576 * visible. After all, if there is no PTE modification, nobody cares
577 * about TLB flushes either.
579 * This very much relies on users (mm_tlb_flush_pending() and
580 * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
581 * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
582 * locks (PPC) the unlock of one doesn't order against the lock of
585 * The decrement is ordered by the flush_tlb_range(), such that
586 * mm_tlb_flush_pending() will not return false unless all flushes have
591 static inline void dec_tlb_flush_pending(struct mm_struct
*mm
)
594 * See inc_tlb_flush_pending().
596 * This cannot be smp_mb__before_atomic() because smp_mb() simply does
597 * not order against TLB invalidate completion, which is what we need.
599 * Therefore we must rely on tlb_flush_*() to guarantee order.
601 atomic_dec(&mm
->tlb_flush_pending
);
604 static inline bool mm_tlb_flush_pending(struct mm_struct
*mm
)
607 * Must be called after having acquired the PTL; orders against that
608 * PTLs release and therefore ensures that if we observe the modified
609 * PTE we must also observe the increment from inc_tlb_flush_pending().
611 * That is, it only guarantees to return true if there is a flush
612 * pending for _this_ PTL.
614 return atomic_read(&mm
->tlb_flush_pending
);
617 static inline bool mm_tlb_flush_nested(struct mm_struct
*mm
)
620 * Similar to mm_tlb_flush_pending(), we must have acquired the PTL
621 * for which there is a TLB flush pending in order to guarantee
622 * we've seen both that PTE modification and the increment.
624 * (no requirement on actually still holding the PTL, that is irrelevant)
626 return atomic_read(&mm
->tlb_flush_pending
) > 1;
631 struct vm_special_mapping
{
632 const char *name
; /* The name, e.g. "[vdso]". */
635 * If .fault is not provided, this points to a
636 * NULL-terminated array of pages that back the special mapping.
638 * This must not be NULL unless .fault is provided.
643 * If non-NULL, then this is called to resolve page faults
644 * on the special mapping. If used, .pages is not checked.
646 int (*fault
)(const struct vm_special_mapping
*sm
,
647 struct vm_area_struct
*vma
,
648 struct vm_fault
*vmf
);
650 int (*mremap
)(const struct vm_special_mapping
*sm
,
651 struct vm_area_struct
*new_vma
);
654 enum tlb_flush_reason
{
655 TLB_FLUSH_ON_TASK_SWITCH
,
656 TLB_REMOTE_SHOOTDOWN
,
658 TLB_LOCAL_MM_SHOOTDOWN
,
660 NR_TLB_FLUSH_REASONS
,
664 * A swap entry has to fit into a "unsigned long", as the entry is hidden
665 * in the "index" field of the swapper address space.
671 #endif /* _LINUX_MM_TYPES_H */