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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Simple NUMA memory policy for the Linux kernel.
4 *
5 * Copyright 2003,2004 Andi Kleen, SuSE Labs.
6 * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc.
7 *
8 * NUMA policy allows the user to give hints in which node(s) memory should
9 * be allocated.
10 *
11 * Support four policies per VMA and per process:
12 *
13 * The VMA policy has priority over the process policy for a page fault.
14 *
15 * interleave Allocate memory interleaved over a set of nodes,
16 * with normal fallback if it fails.
17 * For VMA based allocations this interleaves based on the
18 * offset into the backing object or offset into the mapping
19 * for anonymous memory. For process policy an process counter
20 * is used.
21 *
22 * bind Only allocate memory on a specific set of nodes,
23 * no fallback.
24 * FIXME: memory is allocated starting with the first node
25 * to the last. It would be better if bind would truly restrict
26 * the allocation to memory nodes instead
27 *
28 * preferred Try a specific node first before normal fallback.
29 * As a special case NUMA_NO_NODE here means do the allocation
30 * on the local CPU. This is normally identical to default,
31 * but useful to set in a VMA when you have a non default
32 * process policy.
33 *
34 * default Allocate on the local node first, or when on a VMA
35 * use the process policy. This is what Linux always did
36 * in a NUMA aware kernel and still does by, ahem, default.
37 *
38 * The process policy is applied for most non interrupt memory allocations
39 * in that process' context. Interrupts ignore the policies and always
40 * try to allocate on the local CPU. The VMA policy is only applied for memory
41 * allocations for a VMA in the VM.
42 *
43 * Currently there are a few corner cases in swapping where the policy
44 * is not applied, but the majority should be handled. When process policy
45 * is used it is not remembered over swap outs/swap ins.
46 *
47 * Only the highest zone in the zone hierarchy gets policied. Allocations
48 * requesting a lower zone just use default policy. This implies that
49 * on systems with highmem kernel lowmem allocation don't get policied.
50 * Same with GFP_DMA allocations.
51 *
52 * For shmfs/tmpfs/hugetlbfs shared memory the policy is shared between
53 * all users and remembered even when nobody has memory mapped.
54 */
55
56/* Notebook:
57 fix mmap readahead to honour policy and enable policy for any page cache
58 object
59 statistics for bigpages
60 global policy for page cache? currently it uses process policy. Requires
61 first item above.
62 handle mremap for shared memory (currently ignored for the policy)
63 grows down?
64 make bind policy root only? It can trigger oom much faster and the
65 kernel is not always grateful with that.
66*/
67
68#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
69
70#include <linux/mempolicy.h>
71#include <linux/pagewalk.h>
72#include <linux/highmem.h>
73#include <linux/hugetlb.h>
74#include <linux/kernel.h>
75#include <linux/sched.h>
76#include <linux/sched/mm.h>
77#include <linux/sched/numa_balancing.h>
78#include <linux/sched/task.h>
79#include <linux/nodemask.h>
80#include <linux/cpuset.h>
81#include <linux/slab.h>
82#include <linux/string.h>
83#include <linux/export.h>
84#include <linux/nsproxy.h>
85#include <linux/interrupt.h>
86#include <linux/init.h>
87#include <linux/compat.h>
88#include <linux/ptrace.h>
89#include <linux/swap.h>
90#include <linux/seq_file.h>
91#include <linux/proc_fs.h>
92#include <linux/migrate.h>
93#include <linux/ksm.h>
94#include <linux/rmap.h>
95#include <linux/security.h>
96#include <linux/syscalls.h>
97#include <linux/ctype.h>
98#include <linux/mm_inline.h>
99#include <linux/mmu_notifier.h>
100#include <linux/printk.h>
101#include <linux/swapops.h>
102
103#include <asm/tlbflush.h>
104#include <linux/uaccess.h>
105
106#include "internal.h"
107
108/* Internal flags */
109#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
110#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
111
112static struct kmem_cache *policy_cache;
113static struct kmem_cache *sn_cache;
114
115/* Highest zone. An specific allocation for a zone below that is not
116 policied. */
117enum zone_type policy_zone = 0;
118
119/*
120 * run-time system-wide default policy => local allocation
121 */
122static struct mempolicy default_policy = {
123 .refcnt = ATOMIC_INIT(1), /* never free it */
124 .mode = MPOL_LOCAL,
125};
126
127static struct mempolicy preferred_node_policy[MAX_NUMNODES];
128
129/**
130 * numa_map_to_online_node - Find closest online node
131 * @node: Node id to start the search
132 *
133 * Lookup the next closest node by distance if @nid is not online.
134 */
135int numa_map_to_online_node(int node)
136{
137 int min_dist = INT_MAX, dist, n, min_node;
138
139 if (node == NUMA_NO_NODE || node_online(node))
140 return node;
141
142 min_node = node;
143 for_each_online_node(n) {
144 dist = node_distance(node, n);
145 if (dist < min_dist) {
146 min_dist = dist;
147 min_node = n;
148 }
149 }
150
151 return min_node;
152}
153EXPORT_SYMBOL_GPL(numa_map_to_online_node);
154
155struct mempolicy *get_task_policy(struct task_struct *p)
156{
157 struct mempolicy *pol = p->mempolicy;
158 int node;
159
160 if (pol)
161 return pol;
162
163 node = numa_node_id();
164 if (node != NUMA_NO_NODE) {
165 pol = &preferred_node_policy[node];
166 /* preferred_node_policy is not initialised early in boot */
167 if (pol->mode)
168 return pol;
169 }
170
171 return &default_policy;
172}
173
174static const struct mempolicy_operations {
175 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
176 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes);
177} mpol_ops[MPOL_MAX];
178
179static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
180{
181 return pol->flags & MPOL_MODE_FLAGS;
182}
183
184static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
185 const nodemask_t *rel)
186{
187 nodemask_t tmp;
188 nodes_fold(tmp, *orig, nodes_weight(*rel));
189 nodes_onto(*ret, tmp, *rel);
190}
191
192static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
193{
194 if (nodes_empty(*nodes))
195 return -EINVAL;
196 pol->nodes = *nodes;
197 return 0;
198}
199
200static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
201{
202 if (nodes_empty(*nodes))
203 return -EINVAL;
204
205 nodes_clear(pol->nodes);
206 node_set(first_node(*nodes), pol->nodes);
207 return 0;
208}
209
210static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
211{
212 if (nodes_empty(*nodes))
213 return -EINVAL;
214 pol->nodes = *nodes;
215 return 0;
216}
217
218/*
219 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
220 * any, for the new policy. mpol_new() has already validated the nodes
221 * parameter with respect to the policy mode and flags.
222 *
223 * Must be called holding task's alloc_lock to protect task's mems_allowed
224 * and mempolicy. May also be called holding the mmap_lock for write.
225 */
226static int mpol_set_nodemask(struct mempolicy *pol,
227 const nodemask_t *nodes, struct nodemask_scratch *nsc)
228{
229 int ret;
230
231 /*
232 * Default (pol==NULL) resp. local memory policies are not a
233 * subject of any remapping. They also do not need any special
234 * constructor.
235 */
236 if (!pol || pol->mode == MPOL_LOCAL)
237 return 0;
238
239 /* Check N_MEMORY */
240 nodes_and(nsc->mask1,
241 cpuset_current_mems_allowed, node_states[N_MEMORY]);
242
243 VM_BUG_ON(!nodes);
244
245 if (pol->flags & MPOL_F_RELATIVE_NODES)
246 mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1);
247 else
248 nodes_and(nsc->mask2, *nodes, nsc->mask1);
249
250 if (mpol_store_user_nodemask(pol))
251 pol->w.user_nodemask = *nodes;
252 else
253 pol->w.cpuset_mems_allowed = cpuset_current_mems_allowed;
254
255 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
256 return ret;
257}
258
259/*
260 * This function just creates a new policy, does some check and simple
261 * initialization. You must invoke mpol_set_nodemask() to set nodes.
262 */
263static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
264 nodemask_t *nodes)
265{
266 struct mempolicy *policy;
267
268 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
269 mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE);
270
271 if (mode == MPOL_DEFAULT) {
272 if (nodes && !nodes_empty(*nodes))
273 return ERR_PTR(-EINVAL);
274 return NULL;
275 }
276 VM_BUG_ON(!nodes);
277
278 /*
279 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
280 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
281 * All other modes require a valid pointer to a non-empty nodemask.
282 */
283 if (mode == MPOL_PREFERRED) {
284 if (nodes_empty(*nodes)) {
285 if (((flags & MPOL_F_STATIC_NODES) ||
286 (flags & MPOL_F_RELATIVE_NODES)))
287 return ERR_PTR(-EINVAL);
288
289 mode = MPOL_LOCAL;
290 }
291 } else if (mode == MPOL_LOCAL) {
292 if (!nodes_empty(*nodes) ||
293 (flags & MPOL_F_STATIC_NODES) ||
294 (flags & MPOL_F_RELATIVE_NODES))
295 return ERR_PTR(-EINVAL);
296 } else if (nodes_empty(*nodes))
297 return ERR_PTR(-EINVAL);
298 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
299 if (!policy)
300 return ERR_PTR(-ENOMEM);
301 atomic_set(&policy->refcnt, 1);
302 policy->mode = mode;
303 policy->flags = flags;
304
305 return policy;
306}
307
308/* Slow path of a mpol destructor. */
309void __mpol_put(struct mempolicy *p)
310{
311 if (!atomic_dec_and_test(&p->refcnt))
312 return;
313 kmem_cache_free(policy_cache, p);
314}
315
316static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes)
317{
318}
319
320static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
321{
322 nodemask_t tmp;
323
324 if (pol->flags & MPOL_F_STATIC_NODES)
325 nodes_and(tmp, pol->w.user_nodemask, *nodes);
326 else if (pol->flags & MPOL_F_RELATIVE_NODES)
327 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
328 else {
329 nodes_remap(tmp, pol->nodes, pol->w.cpuset_mems_allowed,
330 *nodes);
331 pol->w.cpuset_mems_allowed = *nodes;
332 }
333
334 if (nodes_empty(tmp))
335 tmp = *nodes;
336
337 pol->nodes = tmp;
338}
339
340static void mpol_rebind_preferred(struct mempolicy *pol,
341 const nodemask_t *nodes)
342{
343 pol->w.cpuset_mems_allowed = *nodes;
344}
345
346/*
347 * mpol_rebind_policy - Migrate a policy to a different set of nodes
348 *
349 * Per-vma policies are protected by mmap_lock. Allocations using per-task
350 * policies are protected by task->mems_allowed_seq to prevent a premature
351 * OOM/allocation failure due to parallel nodemask modification.
352 */
353static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask)
354{
355 if (!pol)
356 return;
357 if (!mpol_store_user_nodemask(pol) &&
358 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
359 return;
360
361 mpol_ops[pol->mode].rebind(pol, newmask);
362}
363
364/*
365 * Wrapper for mpol_rebind_policy() that just requires task
366 * pointer, and updates task mempolicy.
367 *
368 * Called with task's alloc_lock held.
369 */
370
371void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new)
372{
373 mpol_rebind_policy(tsk->mempolicy, new);
374}
375
376/*
377 * Rebind each vma in mm to new nodemask.
378 *
379 * Call holding a reference to mm. Takes mm->mmap_lock during call.
380 */
381
382void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
383{
384 struct vm_area_struct *vma;
385
386 mmap_write_lock(mm);
387 for (vma = mm->mmap; vma; vma = vma->vm_next)
388 mpol_rebind_policy(vma->vm_policy, new);
389 mmap_write_unlock(mm);
390}
391
392static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
393 [MPOL_DEFAULT] = {
394 .rebind = mpol_rebind_default,
395 },
396 [MPOL_INTERLEAVE] = {
397 .create = mpol_new_interleave,
398 .rebind = mpol_rebind_nodemask,
399 },
400 [MPOL_PREFERRED] = {
401 .create = mpol_new_preferred,
402 .rebind = mpol_rebind_preferred,
403 },
404 [MPOL_BIND] = {
405 .create = mpol_new_bind,
406 .rebind = mpol_rebind_nodemask,
407 },
408 [MPOL_LOCAL] = {
409 .rebind = mpol_rebind_default,
410 },
411};
412
413static int migrate_page_add(struct page *page, struct list_head *pagelist,
414 unsigned long flags);
415
416struct queue_pages {
417 struct list_head *pagelist;
418 unsigned long flags;
419 nodemask_t *nmask;
420 unsigned long start;
421 unsigned long end;
422 struct vm_area_struct *first;
423};
424
425/*
426 * Check if the page's nid is in qp->nmask.
427 *
428 * If MPOL_MF_INVERT is set in qp->flags, check if the nid is
429 * in the invert of qp->nmask.
430 */
431static inline bool queue_pages_required(struct page *page,
432 struct queue_pages *qp)
433{
434 int nid = page_to_nid(page);
435 unsigned long flags = qp->flags;
436
437 return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT);
438}
439
440/*
441 * queue_pages_pmd() has four possible return values:
442 * 0 - pages are placed on the right node or queued successfully, or
443 * special page is met, i.e. huge zero page.
444 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
445 * specified.
446 * 2 - THP was split.
447 * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an
448 * existing page was already on a node that does not follow the
449 * policy.
450 */
451static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
452 unsigned long end, struct mm_walk *walk)
453 __releases(ptl)
454{
455 int ret = 0;
456 struct page *page;
457 struct queue_pages *qp = walk->private;
458 unsigned long flags;
459
460 if (unlikely(is_pmd_migration_entry(*pmd))) {
461 ret = -EIO;
462 goto unlock;
463 }
464 page = pmd_page(*pmd);
465 if (is_huge_zero_page(page)) {
466 spin_unlock(ptl);
467 walk->action = ACTION_CONTINUE;
468 goto out;
469 }
470 if (!queue_pages_required(page, qp))
471 goto unlock;
472
473 flags = qp->flags;
474 /* go to thp migration */
475 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
476 if (!vma_migratable(walk->vma) ||
477 migrate_page_add(page, qp->pagelist, flags)) {
478 ret = 1;
479 goto unlock;
480 }
481 } else
482 ret = -EIO;
483unlock:
484 spin_unlock(ptl);
485out:
486 return ret;
487}
488
489/*
490 * Scan through pages checking if pages follow certain conditions,
491 * and move them to the pagelist if they do.
492 *
493 * queue_pages_pte_range() has three possible return values:
494 * 0 - pages are placed on the right node or queued successfully, or
495 * special page is met, i.e. zero page.
496 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
497 * specified.
498 * -EIO - only MPOL_MF_STRICT was specified and an existing page was already
499 * on a node that does not follow the policy.
500 */
501static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
502 unsigned long end, struct mm_walk *walk)
503{
504 struct vm_area_struct *vma = walk->vma;
505 struct page *page;
506 struct queue_pages *qp = walk->private;
507 unsigned long flags = qp->flags;
508 int ret;
509 bool has_unmovable = false;
510 pte_t *pte, *mapped_pte;
511 spinlock_t *ptl;
512
513 ptl = pmd_trans_huge_lock(pmd, vma);
514 if (ptl) {
515 ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
516 if (ret != 2)
517 return ret;
518 }
519 /* THP was split, fall through to pte walk */
520
521 if (pmd_trans_unstable(pmd))
522 return 0;
523
524 mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
525 for (; addr != end; pte++, addr += PAGE_SIZE) {
526 if (!pte_present(*pte))
527 continue;
528 page = vm_normal_page(vma, addr, *pte);
529 if (!page)
530 continue;
531 /*
532 * vm_normal_page() filters out zero pages, but there might
533 * still be PageReserved pages to skip, perhaps in a VDSO.
534 */
535 if (PageReserved(page))
536 continue;
537 if (!queue_pages_required(page, qp))
538 continue;
539 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
540 /* MPOL_MF_STRICT must be specified if we get here */
541 if (!vma_migratable(vma)) {
542 has_unmovable = true;
543 break;
544 }
545
546 /*
547 * Do not abort immediately since there may be
548 * temporary off LRU pages in the range. Still
549 * need migrate other LRU pages.
550 */
551 if (migrate_page_add(page, qp->pagelist, flags))
552 has_unmovable = true;
553 } else
554 break;
555 }
556 pte_unmap_unlock(mapped_pte, ptl);
557 cond_resched();
558
559 if (has_unmovable)
560 return 1;
561
562 return addr != end ? -EIO : 0;
563}
564
565static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
566 unsigned long addr, unsigned long end,
567 struct mm_walk *walk)
568{
569 int ret = 0;
570#ifdef CONFIG_HUGETLB_PAGE
571 struct queue_pages *qp = walk->private;
572 unsigned long flags = (qp->flags & MPOL_MF_VALID);
573 struct page *page;
574 spinlock_t *ptl;
575 pte_t entry;
576
577 ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
578 entry = huge_ptep_get(pte);
579 if (!pte_present(entry))
580 goto unlock;
581 page = pte_page(entry);
582 if (!queue_pages_required(page, qp))
583 goto unlock;
584
585 if (flags == MPOL_MF_STRICT) {
586 /*
587 * STRICT alone means only detecting misplaced page and no
588 * need to further check other vma.
589 */
590 ret = -EIO;
591 goto unlock;
592 }
593
594 if (!vma_migratable(walk->vma)) {
595 /*
596 * Must be STRICT with MOVE*, otherwise .test_walk() have
597 * stopped walking current vma.
598 * Detecting misplaced page but allow migrating pages which
599 * have been queued.
600 */
601 ret = 1;
602 goto unlock;
603 }
604
605 /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
606 if (flags & (MPOL_MF_MOVE_ALL) ||
607 (flags & MPOL_MF_MOVE && page_mapcount(page) == 1)) {
608 if (!isolate_huge_page(page, qp->pagelist) &&
609 (flags & MPOL_MF_STRICT))
610 /*
611 * Failed to isolate page but allow migrating pages
612 * which have been queued.
613 */
614 ret = 1;
615 }
616unlock:
617 spin_unlock(ptl);
618#else
619 BUG();
620#endif
621 return ret;
622}
623
624#ifdef CONFIG_NUMA_BALANCING
625/*
626 * This is used to mark a range of virtual addresses to be inaccessible.
627 * These are later cleared by a NUMA hinting fault. Depending on these
628 * faults, pages may be migrated for better NUMA placement.
629 *
630 * This is assuming that NUMA faults are handled using PROT_NONE. If
631 * an architecture makes a different choice, it will need further
632 * changes to the core.
633 */
634unsigned long change_prot_numa(struct vm_area_struct *vma,
635 unsigned long addr, unsigned long end)
636{
637 int nr_updated;
638
639 nr_updated = change_protection(vma, addr, end, PAGE_NONE, MM_CP_PROT_NUMA);
640 if (nr_updated)
641 count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
642
643 return nr_updated;
644}
645#else
646static unsigned long change_prot_numa(struct vm_area_struct *vma,
647 unsigned long addr, unsigned long end)
648{
649 return 0;
650}
651#endif /* CONFIG_NUMA_BALANCING */
652
653static int queue_pages_test_walk(unsigned long start, unsigned long end,
654 struct mm_walk *walk)
655{
656 struct vm_area_struct *vma = walk->vma;
657 struct queue_pages *qp = walk->private;
658 unsigned long endvma = vma->vm_end;
659 unsigned long flags = qp->flags;
660
661 /* range check first */
662 VM_BUG_ON_VMA(!range_in_vma(vma, start, end), vma);
663
664 if (!qp->first) {
665 qp->first = vma;
666 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
667 (qp->start < vma->vm_start))
668 /* hole at head side of range */
669 return -EFAULT;
670 }
671 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
672 ((vma->vm_end < qp->end) &&
673 (!vma->vm_next || vma->vm_end < vma->vm_next->vm_start)))
674 /* hole at middle or tail of range */
675 return -EFAULT;
676
677 /*
678 * Need check MPOL_MF_STRICT to return -EIO if possible
679 * regardless of vma_migratable
680 */
681 if (!vma_migratable(vma) &&
682 !(flags & MPOL_MF_STRICT))
683 return 1;
684
685 if (endvma > end)
686 endvma = end;
687
688 if (flags & MPOL_MF_LAZY) {
689 /* Similar to task_numa_work, skip inaccessible VMAs */
690 if (!is_vm_hugetlb_page(vma) && vma_is_accessible(vma) &&
691 !(vma->vm_flags & VM_MIXEDMAP))
692 change_prot_numa(vma, start, endvma);
693 return 1;
694 }
695
696 /* queue pages from current vma */
697 if (flags & MPOL_MF_VALID)
698 return 0;
699 return 1;
700}
701
702static const struct mm_walk_ops queue_pages_walk_ops = {
703 .hugetlb_entry = queue_pages_hugetlb,
704 .pmd_entry = queue_pages_pte_range,
705 .test_walk = queue_pages_test_walk,
706};
707
708/*
709 * Walk through page tables and collect pages to be migrated.
710 *
711 * If pages found in a given range are on a set of nodes (determined by
712 * @nodes and @flags,) it's isolated and queued to the pagelist which is
713 * passed via @private.
714 *
715 * queue_pages_range() has three possible return values:
716 * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
717 * specified.
718 * 0 - queue pages successfully or no misplaced page.
719 * errno - i.e. misplaced pages with MPOL_MF_STRICT specified (-EIO) or
720 * memory range specified by nodemask and maxnode points outside
721 * your accessible address space (-EFAULT)
722 */
723static int
724queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
725 nodemask_t *nodes, unsigned long flags,
726 struct list_head *pagelist)
727{
728 int err;
729 struct queue_pages qp = {
730 .pagelist = pagelist,
731 .flags = flags,
732 .nmask = nodes,
733 .start = start,
734 .end = end,
735 .first = NULL,
736 };
737
738 err = walk_page_range(mm, start, end, &queue_pages_walk_ops, &qp);
739
740 if (!qp.first)
741 /* whole range in hole */
742 err = -EFAULT;
743
744 return err;
745}
746
747/*
748 * Apply policy to a single VMA
749 * This must be called with the mmap_lock held for writing.
750 */
751static int vma_replace_policy(struct vm_area_struct *vma,
752 struct mempolicy *pol)
753{
754 int err;
755 struct mempolicy *old;
756 struct mempolicy *new;
757
758 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
759 vma->vm_start, vma->vm_end, vma->vm_pgoff,
760 vma->vm_ops, vma->vm_file,
761 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
762
763 new = mpol_dup(pol);
764 if (IS_ERR(new))
765 return PTR_ERR(new);
766
767 if (vma->vm_ops && vma->vm_ops->set_policy) {
768 err = vma->vm_ops->set_policy(vma, new);
769 if (err)
770 goto err_out;
771 }
772
773 old = vma->vm_policy;
774 vma->vm_policy = new; /* protected by mmap_lock */
775 mpol_put(old);
776
777 return 0;
778 err_out:
779 mpol_put(new);
780 return err;
781}
782
783/* Step 2: apply policy to a range and do splits. */
784static int mbind_range(struct mm_struct *mm, unsigned long start,
785 unsigned long end, struct mempolicy *new_pol)
786{
787 struct vm_area_struct *next;
788 struct vm_area_struct *prev;
789 struct vm_area_struct *vma;
790 int err = 0;
791 pgoff_t pgoff;
792 unsigned long vmstart;
793 unsigned long vmend;
794
795 vma = find_vma(mm, start);
796 VM_BUG_ON(!vma);
797
798 prev = vma->vm_prev;
799 if (start > vma->vm_start)
800 prev = vma;
801
802 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
803 next = vma->vm_next;
804 vmstart = max(start, vma->vm_start);
805 vmend = min(end, vma->vm_end);
806
807 if (mpol_equal(vma_policy(vma), new_pol))
808 continue;
809
810 pgoff = vma->vm_pgoff +
811 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
812 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
813 vma->anon_vma, vma->vm_file, pgoff,
814 new_pol, vma->vm_userfaultfd_ctx);
815 if (prev) {
816 vma = prev;
817 next = vma->vm_next;
818 if (mpol_equal(vma_policy(vma), new_pol))
819 continue;
820 /* vma_merge() joined vma && vma->next, case 8 */
821 goto replace;
822 }
823 if (vma->vm_start != vmstart) {
824 err = split_vma(vma->vm_mm, vma, vmstart, 1);
825 if (err)
826 goto out;
827 }
828 if (vma->vm_end != vmend) {
829 err = split_vma(vma->vm_mm, vma, vmend, 0);
830 if (err)
831 goto out;
832 }
833 replace:
834 err = vma_replace_policy(vma, new_pol);
835 if (err)
836 goto out;
837 }
838
839 out:
840 return err;
841}
842
843/* Set the process memory policy */
844static long do_set_mempolicy(unsigned short mode, unsigned short flags,
845 nodemask_t *nodes)
846{
847 struct mempolicy *new, *old;
848 NODEMASK_SCRATCH(scratch);
849 int ret;
850
851 if (!scratch)
852 return -ENOMEM;
853
854 new = mpol_new(mode, flags, nodes);
855 if (IS_ERR(new)) {
856 ret = PTR_ERR(new);
857 goto out;
858 }
859
860 ret = mpol_set_nodemask(new, nodes, scratch);
861 if (ret) {
862 mpol_put(new);
863 goto out;
864 }
865 task_lock(current);
866 old = current->mempolicy;
867 current->mempolicy = new;
868 if (new && new->mode == MPOL_INTERLEAVE)
869 current->il_prev = MAX_NUMNODES-1;
870 task_unlock(current);
871 mpol_put(old);
872 ret = 0;
873out:
874 NODEMASK_SCRATCH_FREE(scratch);
875 return ret;
876}
877
878/*
879 * Return nodemask for policy for get_mempolicy() query
880 *
881 * Called with task's alloc_lock held
882 */
883static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
884{
885 nodes_clear(*nodes);
886 if (p == &default_policy)
887 return;
888
889 switch (p->mode) {
890 case MPOL_BIND:
891 case MPOL_INTERLEAVE:
892 case MPOL_PREFERRED:
893 *nodes = p->nodes;
894 break;
895 case MPOL_LOCAL:
896 /* return empty node mask for local allocation */
897 break;
898 default:
899 BUG();
900 }
901}
902
903static int lookup_node(struct mm_struct *mm, unsigned long addr)
904{
905 struct page *p = NULL;
906 int err;
907
908 int locked = 1;
909 err = get_user_pages_locked(addr & PAGE_MASK, 1, 0, &p, &locked);
910 if (err > 0) {
911 err = page_to_nid(p);
912 put_page(p);
913 }
914 if (locked)
915 mmap_read_unlock(mm);
916 return err;
917}
918
919/* Retrieve NUMA policy */
920static long do_get_mempolicy(int *policy, nodemask_t *nmask,
921 unsigned long addr, unsigned long flags)
922{
923 int err;
924 struct mm_struct *mm = current->mm;
925 struct vm_area_struct *vma = NULL;
926 struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL;
927
928 if (flags &
929 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
930 return -EINVAL;
931
932 if (flags & MPOL_F_MEMS_ALLOWED) {
933 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
934 return -EINVAL;
935 *policy = 0; /* just so it's initialized */
936 task_lock(current);
937 *nmask = cpuset_current_mems_allowed;
938 task_unlock(current);
939 return 0;
940 }
941
942 if (flags & MPOL_F_ADDR) {
943 /*
944 * Do NOT fall back to task policy if the
945 * vma/shared policy at addr is NULL. We
946 * want to return MPOL_DEFAULT in this case.
947 */
948 mmap_read_lock(mm);
949 vma = vma_lookup(mm, addr);
950 if (!vma) {
951 mmap_read_unlock(mm);
952 return -EFAULT;
953 }
954 if (vma->vm_ops && vma->vm_ops->get_policy)
955 pol = vma->vm_ops->get_policy(vma, addr);
956 else
957 pol = vma->vm_policy;
958 } else if (addr)
959 return -EINVAL;
960
961 if (!pol)
962 pol = &default_policy; /* indicates default behavior */
963
964 if (flags & MPOL_F_NODE) {
965 if (flags & MPOL_F_ADDR) {
966 /*
967 * Take a refcount on the mpol, lookup_node()
968 * will drop the mmap_lock, so after calling
969 * lookup_node() only "pol" remains valid, "vma"
970 * is stale.
971 */
972 pol_refcount = pol;
973 vma = NULL;
974 mpol_get(pol);
975 err = lookup_node(mm, addr);
976 if (err < 0)
977 goto out;
978 *policy = err;
979 } else if (pol == current->mempolicy &&
980 pol->mode == MPOL_INTERLEAVE) {
981 *policy = next_node_in(current->il_prev, pol->nodes);
982 } else {
983 err = -EINVAL;
984 goto out;
985 }
986 } else {
987 *policy = pol == &default_policy ? MPOL_DEFAULT :
988 pol->mode;
989 /*
990 * Internal mempolicy flags must be masked off before exposing
991 * the policy to userspace.
992 */
993 *policy |= (pol->flags & MPOL_MODE_FLAGS);
994 }
995
996 err = 0;
997 if (nmask) {
998 if (mpol_store_user_nodemask(pol)) {
999 *nmask = pol->w.user_nodemask;
1000 } else {
1001 task_lock(current);
1002 get_policy_nodemask(pol, nmask);
1003 task_unlock(current);
1004 }
1005 }
1006
1007 out:
1008 mpol_cond_put(pol);
1009 if (vma)
1010 mmap_read_unlock(mm);
1011 if (pol_refcount)
1012 mpol_put(pol_refcount);
1013 return err;
1014}
1015
1016#ifdef CONFIG_MIGRATION
1017/*
1018 * page migration, thp tail pages can be passed.
1019 */
1020static int migrate_page_add(struct page *page, struct list_head *pagelist,
1021 unsigned long flags)
1022{
1023 struct page *head = compound_head(page);
1024 /*
1025 * Avoid migrating a page that is shared with others.
1026 */
1027 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(head) == 1) {
1028 if (!isolate_lru_page(head)) {
1029 list_add_tail(&head->lru, pagelist);
1030 mod_node_page_state(page_pgdat(head),
1031 NR_ISOLATED_ANON + page_is_file_lru(head),
1032 thp_nr_pages(head));
1033 } else if (flags & MPOL_MF_STRICT) {
1034 /*
1035 * Non-movable page may reach here. And, there may be
1036 * temporary off LRU pages or non-LRU movable pages.
1037 * Treat them as unmovable pages since they can't be
1038 * isolated, so they can't be moved at the moment. It
1039 * should return -EIO for this case too.
1040 */
1041 return -EIO;
1042 }
1043 }
1044
1045 return 0;
1046}
1047
1048/*
1049 * Migrate pages from one node to a target node.
1050 * Returns error or the number of pages not migrated.
1051 */
1052static int migrate_to_node(struct mm_struct *mm, int source, int dest,
1053 int flags)
1054{
1055 nodemask_t nmask;
1056 LIST_HEAD(pagelist);
1057 int err = 0;
1058 struct migration_target_control mtc = {
1059 .nid = dest,
1060 .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE,
1061 };
1062
1063 nodes_clear(nmask);
1064 node_set(source, nmask);
1065
1066 /*
1067 * This does not "check" the range but isolates all pages that
1068 * need migration. Between passing in the full user address
1069 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
1070 */
1071 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
1072 queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1073 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
1074
1075 if (!list_empty(&pagelist)) {
1076 err = migrate_pages(&pagelist, alloc_migration_target, NULL,
1077 (unsigned long)&mtc, MIGRATE_SYNC, MR_SYSCALL);
1078 if (err)
1079 putback_movable_pages(&pagelist);
1080 }
1081
1082 return err;
1083}
1084
1085/*
1086 * Move pages between the two nodesets so as to preserve the physical
1087 * layout as much as possible.
1088 *
1089 * Returns the number of page that could not be moved.
1090 */
1091int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1092 const nodemask_t *to, int flags)
1093{
1094 int busy = 0;
1095 int err = 0;
1096 nodemask_t tmp;
1097
1098 lru_cache_disable();
1099
1100 mmap_read_lock(mm);
1101
1102 /*
1103 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1104 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1105 * bit in 'tmp', and return that <source, dest> pair for migration.
1106 * The pair of nodemasks 'to' and 'from' define the map.
1107 *
1108 * If no pair of bits is found that way, fallback to picking some
1109 * pair of 'source' and 'dest' bits that are not the same. If the
1110 * 'source' and 'dest' bits are the same, this represents a node
1111 * that will be migrating to itself, so no pages need move.
1112 *
1113 * If no bits are left in 'tmp', or if all remaining bits left
1114 * in 'tmp' correspond to the same bit in 'to', return false
1115 * (nothing left to migrate).
1116 *
1117 * This lets us pick a pair of nodes to migrate between, such that
1118 * if possible the dest node is not already occupied by some other
1119 * source node, minimizing the risk of overloading the memory on a
1120 * node that would happen if we migrated incoming memory to a node
1121 * before migrating outgoing memory source that same node.
1122 *
1123 * A single scan of tmp is sufficient. As we go, we remember the
1124 * most recent <s, d> pair that moved (s != d). If we find a pair
1125 * that not only moved, but what's better, moved to an empty slot
1126 * (d is not set in tmp), then we break out then, with that pair.
1127 * Otherwise when we finish scanning from_tmp, we at least have the
1128 * most recent <s, d> pair that moved. If we get all the way through
1129 * the scan of tmp without finding any node that moved, much less
1130 * moved to an empty node, then there is nothing left worth migrating.
1131 */
1132
1133 tmp = *from;
1134 while (!nodes_empty(tmp)) {
1135 int s, d;
1136 int source = NUMA_NO_NODE;
1137 int dest = 0;
1138
1139 for_each_node_mask(s, tmp) {
1140
1141 /*
1142 * do_migrate_pages() tries to maintain the relative
1143 * node relationship of the pages established between
1144 * threads and memory areas.
1145 *
1146 * However if the number of source nodes is not equal to
1147 * the number of destination nodes we can not preserve
1148 * this node relative relationship. In that case, skip
1149 * copying memory from a node that is in the destination
1150 * mask.
1151 *
1152 * Example: [2,3,4] -> [3,4,5] moves everything.
1153 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1154 */
1155
1156 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1157 (node_isset(s, *to)))
1158 continue;
1159
1160 d = node_remap(s, *from, *to);
1161 if (s == d)
1162 continue;
1163
1164 source = s; /* Node moved. Memorize */
1165 dest = d;
1166
1167 /* dest not in remaining from nodes? */
1168 if (!node_isset(dest, tmp))
1169 break;
1170 }
1171 if (source == NUMA_NO_NODE)
1172 break;
1173
1174 node_clear(source, tmp);
1175 err = migrate_to_node(mm, source, dest, flags);
1176 if (err > 0)
1177 busy += err;
1178 if (err < 0)
1179 break;
1180 }
1181 mmap_read_unlock(mm);
1182
1183 lru_cache_enable();
1184 if (err < 0)
1185 return err;
1186 return busy;
1187
1188}
1189
1190/*
1191 * Allocate a new page for page migration based on vma policy.
1192 * Start by assuming the page is mapped by the same vma as contains @start.
1193 * Search forward from there, if not. N.B., this assumes that the
1194 * list of pages handed to migrate_pages()--which is how we get here--
1195 * is in virtual address order.
1196 */
1197static struct page *new_page(struct page *page, unsigned long start)
1198{
1199 struct vm_area_struct *vma;
1200 unsigned long address;
1201
1202 vma = find_vma(current->mm, start);
1203 while (vma) {
1204 address = page_address_in_vma(page, vma);
1205 if (address != -EFAULT)
1206 break;
1207 vma = vma->vm_next;
1208 }
1209
1210 if (PageHuge(page)) {
1211 return alloc_huge_page_vma(page_hstate(compound_head(page)),
1212 vma, address);
1213 } else if (PageTransHuge(page)) {
1214 struct page *thp;
1215
1216 thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
1217 HPAGE_PMD_ORDER);
1218 if (!thp)
1219 return NULL;
1220 prep_transhuge_page(thp);
1221 return thp;
1222 }
1223 /*
1224 * if !vma, alloc_page_vma() will use task or system default policy
1225 */
1226 return alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL,
1227 vma, address);
1228}
1229#else
1230
1231static int migrate_page_add(struct page *page, struct list_head *pagelist,
1232 unsigned long flags)
1233{
1234 return -EIO;
1235}
1236
1237int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1238 const nodemask_t *to, int flags)
1239{
1240 return -ENOSYS;
1241}
1242
1243static struct page *new_page(struct page *page, unsigned long start)
1244{
1245 return NULL;
1246}
1247#endif
1248
1249static long do_mbind(unsigned long start, unsigned long len,
1250 unsigned short mode, unsigned short mode_flags,
1251 nodemask_t *nmask, unsigned long flags)
1252{
1253 struct mm_struct *mm = current->mm;
1254 struct mempolicy *new;
1255 unsigned long end;
1256 int err;
1257 int ret;
1258 LIST_HEAD(pagelist);
1259
1260 if (flags & ~(unsigned long)MPOL_MF_VALID)
1261 return -EINVAL;
1262 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1263 return -EPERM;
1264
1265 if (start & ~PAGE_MASK)
1266 return -EINVAL;
1267
1268 if (mode == MPOL_DEFAULT)
1269 flags &= ~MPOL_MF_STRICT;
1270
1271 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1272 end = start + len;
1273
1274 if (end < start)
1275 return -EINVAL;
1276 if (end == start)
1277 return 0;
1278
1279 new = mpol_new(mode, mode_flags, nmask);
1280 if (IS_ERR(new))
1281 return PTR_ERR(new);
1282
1283 if (flags & MPOL_MF_LAZY)
1284 new->flags |= MPOL_F_MOF;
1285
1286 /*
1287 * If we are using the default policy then operation
1288 * on discontinuous address spaces is okay after all
1289 */
1290 if (!new)
1291 flags |= MPOL_MF_DISCONTIG_OK;
1292
1293 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1294 start, start + len, mode, mode_flags,
1295 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1296
1297 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1298
1299 lru_cache_disable();
1300 }
1301 {
1302 NODEMASK_SCRATCH(scratch);
1303 if (scratch) {
1304 mmap_write_lock(mm);
1305 err = mpol_set_nodemask(new, nmask, scratch);
1306 if (err)
1307 mmap_write_unlock(mm);
1308 } else
1309 err = -ENOMEM;
1310 NODEMASK_SCRATCH_FREE(scratch);
1311 }
1312 if (err)
1313 goto mpol_out;
1314
1315 ret = queue_pages_range(mm, start, end, nmask,
1316 flags | MPOL_MF_INVERT, &pagelist);
1317
1318 if (ret < 0) {
1319 err = ret;
1320 goto up_out;
1321 }
1322
1323 err = mbind_range(mm, start, end, new);
1324
1325 if (!err) {
1326 int nr_failed = 0;
1327
1328 if (!list_empty(&pagelist)) {
1329 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1330 nr_failed = migrate_pages(&pagelist, new_page, NULL,
1331 start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
1332 if (nr_failed)
1333 putback_movable_pages(&pagelist);
1334 }
1335
1336 if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
1337 err = -EIO;
1338 } else {
1339up_out:
1340 if (!list_empty(&pagelist))
1341 putback_movable_pages(&pagelist);
1342 }
1343
1344 mmap_write_unlock(mm);
1345mpol_out:
1346 mpol_put(new);
1347 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1348 lru_cache_enable();
1349 return err;
1350}
1351
1352/*
1353 * User space interface with variable sized bitmaps for nodelists.
1354 */
1355
1356/* Copy a node mask from user space. */
1357static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1358 unsigned long maxnode)
1359{
1360 unsigned long k;
1361 unsigned long t;
1362 unsigned long nlongs;
1363 unsigned long endmask;
1364
1365 --maxnode;
1366 nodes_clear(*nodes);
1367 if (maxnode == 0 || !nmask)
1368 return 0;
1369 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1370 return -EINVAL;
1371
1372 nlongs = BITS_TO_LONGS(maxnode);
1373 if ((maxnode % BITS_PER_LONG) == 0)
1374 endmask = ~0UL;
1375 else
1376 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1377
1378 /*
1379 * When the user specified more nodes than supported just check
1380 * if the non supported part is all zero.
1381 *
1382 * If maxnode have more longs than MAX_NUMNODES, check
1383 * the bits in that area first. And then go through to
1384 * check the rest bits which equal or bigger than MAX_NUMNODES.
1385 * Otherwise, just check bits [MAX_NUMNODES, maxnode).
1386 */
1387 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1388 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1389 if (get_user(t, nmask + k))
1390 return -EFAULT;
1391 if (k == nlongs - 1) {
1392 if (t & endmask)
1393 return -EINVAL;
1394 } else if (t)
1395 return -EINVAL;
1396 }
1397 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1398 endmask = ~0UL;
1399 }
1400
1401 if (maxnode > MAX_NUMNODES && MAX_NUMNODES % BITS_PER_LONG != 0) {
1402 unsigned long valid_mask = endmask;
1403
1404 valid_mask &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
1405 if (get_user(t, nmask + nlongs - 1))
1406 return -EFAULT;
1407 if (t & valid_mask)
1408 return -EINVAL;
1409 }
1410
1411 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1412 return -EFAULT;
1413 nodes_addr(*nodes)[nlongs-1] &= endmask;
1414 return 0;
1415}
1416
1417/* Copy a kernel node mask to user space */
1418static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1419 nodemask_t *nodes)
1420{
1421 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1422 unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long);
1423
1424 if (copy > nbytes) {
1425 if (copy > PAGE_SIZE)
1426 return -EINVAL;
1427 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1428 return -EFAULT;
1429 copy = nbytes;
1430 }
1431 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1432}
1433
1434/* Basic parameter sanity check used by both mbind() and set_mempolicy() */
1435static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)
1436{
1437 *flags = *mode & MPOL_MODE_FLAGS;
1438 *mode &= ~MPOL_MODE_FLAGS;
1439 if ((unsigned int)(*mode) >= MPOL_MAX)
1440 return -EINVAL;
1441 if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))
1442 return -EINVAL;
1443 if (*flags & MPOL_F_NUMA_BALANCING) {
1444 if (*mode != MPOL_BIND)
1445 return -EINVAL;
1446 *flags |= (MPOL_F_MOF | MPOL_F_MORON);
1447 }
1448 return 0;
1449}
1450
1451static long kernel_mbind(unsigned long start, unsigned long len,
1452 unsigned long mode, const unsigned long __user *nmask,
1453 unsigned long maxnode, unsigned int flags)
1454{
1455 unsigned short mode_flags;
1456 nodemask_t nodes;
1457 int lmode = mode;
1458 int err;
1459
1460 start = untagged_addr(start);
1461 err = sanitize_mpol_flags(&lmode, &mode_flags);
1462 if (err)
1463 return err;
1464
1465 err = get_nodes(&nodes, nmask, maxnode);
1466 if (err)
1467 return err;
1468
1469 return do_mbind(start, len, lmode, mode_flags, &nodes, flags);
1470}
1471
1472SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1473 unsigned long, mode, const unsigned long __user *, nmask,
1474 unsigned long, maxnode, unsigned int, flags)
1475{
1476 return kernel_mbind(start, len, mode, nmask, maxnode, flags);
1477}
1478
1479/* Set the process memory policy */
1480static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
1481 unsigned long maxnode)
1482{
1483 unsigned short mode_flags;
1484 nodemask_t nodes;
1485 int lmode = mode;
1486 int err;
1487
1488 err = sanitize_mpol_flags(&lmode, &mode_flags);
1489 if (err)
1490 return err;
1491
1492 err = get_nodes(&nodes, nmask, maxnode);
1493 if (err)
1494 return err;
1495
1496 return do_set_mempolicy(lmode, mode_flags, &nodes);
1497}
1498
1499SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
1500 unsigned long, maxnode)
1501{
1502 return kernel_set_mempolicy(mode, nmask, maxnode);
1503}
1504
1505static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
1506 const unsigned long __user *old_nodes,
1507 const unsigned long __user *new_nodes)
1508{
1509 struct mm_struct *mm = NULL;
1510 struct task_struct *task;
1511 nodemask_t task_nodes;
1512 int err;
1513 nodemask_t *old;
1514 nodemask_t *new;
1515 NODEMASK_SCRATCH(scratch);
1516
1517 if (!scratch)
1518 return -ENOMEM;
1519
1520 old = &scratch->mask1;
1521 new = &scratch->mask2;
1522
1523 err = get_nodes(old, old_nodes, maxnode);
1524 if (err)
1525 goto out;
1526
1527 err = get_nodes(new, new_nodes, maxnode);
1528 if (err)
1529 goto out;
1530
1531 /* Find the mm_struct */
1532 rcu_read_lock();
1533 task = pid ? find_task_by_vpid(pid) : current;
1534 if (!task) {
1535 rcu_read_unlock();
1536 err = -ESRCH;
1537 goto out;
1538 }
1539 get_task_struct(task);
1540
1541 err = -EINVAL;
1542
1543 /*
1544 * Check if this process has the right to modify the specified process.
1545 * Use the regular "ptrace_may_access()" checks.
1546 */
1547 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
1548 rcu_read_unlock();
1549 err = -EPERM;
1550 goto out_put;
1551 }
1552 rcu_read_unlock();
1553
1554 task_nodes = cpuset_mems_allowed(task);
1555 /* Is the user allowed to access the target nodes? */
1556 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1557 err = -EPERM;
1558 goto out_put;
1559 }
1560
1561 task_nodes = cpuset_mems_allowed(current);
1562 nodes_and(*new, *new, task_nodes);
1563 if (nodes_empty(*new))
1564 goto out_put;
1565
1566 err = security_task_movememory(task);
1567 if (err)
1568 goto out_put;
1569
1570 mm = get_task_mm(task);
1571 put_task_struct(task);
1572
1573 if (!mm) {
1574 err = -EINVAL;
1575 goto out;
1576 }
1577
1578 err = do_migrate_pages(mm, old, new,
1579 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1580
1581 mmput(mm);
1582out:
1583 NODEMASK_SCRATCH_FREE(scratch);
1584
1585 return err;
1586
1587out_put:
1588 put_task_struct(task);
1589 goto out;
1590
1591}
1592
1593SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1594 const unsigned long __user *, old_nodes,
1595 const unsigned long __user *, new_nodes)
1596{
1597 return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes);
1598}
1599
1600
1601/* Retrieve NUMA policy */
1602static int kernel_get_mempolicy(int __user *policy,
1603 unsigned long __user *nmask,
1604 unsigned long maxnode,
1605 unsigned long addr,
1606 unsigned long flags)
1607{
1608 int err;
1609 int pval;
1610 nodemask_t nodes;
1611
1612 if (nmask != NULL && maxnode < nr_node_ids)
1613 return -EINVAL;
1614
1615 addr = untagged_addr(addr);
1616
1617 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1618
1619 if (err)
1620 return err;
1621
1622 if (policy && put_user(pval, policy))
1623 return -EFAULT;
1624
1625 if (nmask)
1626 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1627
1628 return err;
1629}
1630
1631SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1632 unsigned long __user *, nmask, unsigned long, maxnode,
1633 unsigned long, addr, unsigned long, flags)
1634{
1635 return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags);
1636}
1637
1638#ifdef CONFIG_COMPAT
1639
1640COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1641 compat_ulong_t __user *, nmask,
1642 compat_ulong_t, maxnode,
1643 compat_ulong_t, addr, compat_ulong_t, flags)
1644{
1645 long err;
1646 unsigned long __user *nm = NULL;
1647 unsigned long nr_bits, alloc_size;
1648 DECLARE_BITMAP(bm, MAX_NUMNODES);
1649
1650 nr_bits = min_t(unsigned long, maxnode-1, nr_node_ids);
1651 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1652
1653 if (nmask)
1654 nm = compat_alloc_user_space(alloc_size);
1655
1656 err = kernel_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1657
1658 if (!err && nmask) {
1659 unsigned long copy_size;
1660 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1661 err = copy_from_user(bm, nm, copy_size);
1662 /* ensure entire bitmap is zeroed */
1663 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1664 err |= compat_put_bitmap(nmask, bm, nr_bits);
1665 }
1666
1667 return err;
1668}
1669
1670COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
1671 compat_ulong_t, maxnode)
1672{
1673 unsigned long __user *nm = NULL;
1674 unsigned long nr_bits, alloc_size;
1675 DECLARE_BITMAP(bm, MAX_NUMNODES);
1676
1677 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1678 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1679
1680 if (nmask) {
1681 if (compat_get_bitmap(bm, nmask, nr_bits))
1682 return -EFAULT;
1683 nm = compat_alloc_user_space(alloc_size);
1684 if (copy_to_user(nm, bm, alloc_size))
1685 return -EFAULT;
1686 }
1687
1688 return kernel_set_mempolicy(mode, nm, nr_bits+1);
1689}
1690
1691COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
1692 compat_ulong_t, mode, compat_ulong_t __user *, nmask,
1693 compat_ulong_t, maxnode, compat_ulong_t, flags)
1694{
1695 unsigned long __user *nm = NULL;
1696 unsigned long nr_bits, alloc_size;
1697 nodemask_t bm;
1698
1699 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1700 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1701
1702 if (nmask) {
1703 if (compat_get_bitmap(nodes_addr(bm), nmask, nr_bits))
1704 return -EFAULT;
1705 nm = compat_alloc_user_space(alloc_size);
1706 if (copy_to_user(nm, nodes_addr(bm), alloc_size))
1707 return -EFAULT;
1708 }
1709
1710 return kernel_mbind(start, len, mode, nm, nr_bits+1, flags);
1711}
1712
1713COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
1714 compat_ulong_t, maxnode,
1715 const compat_ulong_t __user *, old_nodes,
1716 const compat_ulong_t __user *, new_nodes)
1717{
1718 unsigned long __user *old = NULL;
1719 unsigned long __user *new = NULL;
1720 nodemask_t tmp_mask;
1721 unsigned long nr_bits;
1722 unsigned long size;
1723
1724 nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
1725 size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1726 if (old_nodes) {
1727 if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
1728 return -EFAULT;
1729 old = compat_alloc_user_space(new_nodes ? size * 2 : size);
1730 if (new_nodes)
1731 new = old + size / sizeof(unsigned long);
1732 if (copy_to_user(old, nodes_addr(tmp_mask), size))
1733 return -EFAULT;
1734 }
1735 if (new_nodes) {
1736 if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
1737 return -EFAULT;
1738 if (new == NULL)
1739 new = compat_alloc_user_space(size);
1740 if (copy_to_user(new, nodes_addr(tmp_mask), size))
1741 return -EFAULT;
1742 }
1743 return kernel_migrate_pages(pid, nr_bits + 1, old, new);
1744}
1745
1746#endif /* CONFIG_COMPAT */
1747
1748bool vma_migratable(struct vm_area_struct *vma)
1749{
1750 if (vma->vm_flags & (VM_IO | VM_PFNMAP))
1751 return false;
1752
1753 /*
1754 * DAX device mappings require predictable access latency, so avoid
1755 * incurring periodic faults.
1756 */
1757 if (vma_is_dax(vma))
1758 return false;
1759
1760 if (is_vm_hugetlb_page(vma) &&
1761 !hugepage_migration_supported(hstate_vma(vma)))
1762 return false;
1763
1764 /*
1765 * Migration allocates pages in the highest zone. If we cannot
1766 * do so then migration (at least from node to node) is not
1767 * possible.
1768 */
1769 if (vma->vm_file &&
1770 gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
1771 < policy_zone)
1772 return false;
1773 return true;
1774}
1775
1776struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
1777 unsigned long addr)
1778{
1779 struct mempolicy *pol = NULL;
1780
1781 if (vma) {
1782 if (vma->vm_ops && vma->vm_ops->get_policy) {
1783 pol = vma->vm_ops->get_policy(vma, addr);
1784 } else if (vma->vm_policy) {
1785 pol = vma->vm_policy;
1786
1787 /*
1788 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1789 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1790 * count on these policies which will be dropped by
1791 * mpol_cond_put() later
1792 */
1793 if (mpol_needs_cond_ref(pol))
1794 mpol_get(pol);
1795 }
1796 }
1797
1798 return pol;
1799}
1800
1801/*
1802 * get_vma_policy(@vma, @addr)
1803 * @vma: virtual memory area whose policy is sought
1804 * @addr: address in @vma for shared policy lookup
1805 *
1806 * Returns effective policy for a VMA at specified address.
1807 * Falls back to current->mempolicy or system default policy, as necessary.
1808 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1809 * count--added by the get_policy() vm_op, as appropriate--to protect against
1810 * freeing by another task. It is the caller's responsibility to free the
1811 * extra reference for shared policies.
1812 */
1813static struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
1814 unsigned long addr)
1815{
1816 struct mempolicy *pol = __get_vma_policy(vma, addr);
1817
1818 if (!pol)
1819 pol = get_task_policy(current);
1820
1821 return pol;
1822}
1823
1824bool vma_policy_mof(struct vm_area_struct *vma)
1825{
1826 struct mempolicy *pol;
1827
1828 if (vma->vm_ops && vma->vm_ops->get_policy) {
1829 bool ret = false;
1830
1831 pol = vma->vm_ops->get_policy(vma, vma->vm_start);
1832 if (pol && (pol->flags & MPOL_F_MOF))
1833 ret = true;
1834 mpol_cond_put(pol);
1835
1836 return ret;
1837 }
1838
1839 pol = vma->vm_policy;
1840 if (!pol)
1841 pol = get_task_policy(current);
1842
1843 return pol->flags & MPOL_F_MOF;
1844}
1845
1846static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1847{
1848 enum zone_type dynamic_policy_zone = policy_zone;
1849
1850 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1851
1852 /*
1853 * if policy->nodes has movable memory only,
1854 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1855 *
1856 * policy->nodes is intersect with node_states[N_MEMORY].
1857 * so if the following test fails, it implies
1858 * policy->nodes has movable memory only.
1859 */
1860 if (!nodes_intersects(policy->nodes, node_states[N_HIGH_MEMORY]))
1861 dynamic_policy_zone = ZONE_MOVABLE;
1862
1863 return zone >= dynamic_policy_zone;
1864}
1865
1866/*
1867 * Return a nodemask representing a mempolicy for filtering nodes for
1868 * page allocation
1869 */
1870nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1871{
1872 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1873 if (unlikely(policy->mode == MPOL_BIND) &&
1874 apply_policy_zone(policy, gfp_zone(gfp)) &&
1875 cpuset_nodemask_valid_mems_allowed(&policy->nodes))
1876 return &policy->nodes;
1877
1878 return NULL;
1879}
1880
1881/* Return the node id preferred by the given mempolicy, or the given id */
1882static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd)
1883{
1884 if (policy->mode == MPOL_PREFERRED) {
1885 nd = first_node(policy->nodes);
1886 } else {
1887 /*
1888 * __GFP_THISNODE shouldn't even be used with the bind policy
1889 * because we might easily break the expectation to stay on the
1890 * requested node and not break the policy.
1891 */
1892 WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE));
1893 }
1894
1895 return nd;
1896}
1897
1898/* Do dynamic interleaving for a process */
1899static unsigned interleave_nodes(struct mempolicy *policy)
1900{
1901 unsigned next;
1902 struct task_struct *me = current;
1903
1904 next = next_node_in(me->il_prev, policy->nodes);
1905 if (next < MAX_NUMNODES)
1906 me->il_prev = next;
1907 return next;
1908}
1909
1910/*
1911 * Depending on the memory policy provide a node from which to allocate the
1912 * next slab entry.
1913 */
1914unsigned int mempolicy_slab_node(void)
1915{
1916 struct mempolicy *policy;
1917 int node = numa_mem_id();
1918
1919 if (in_interrupt())
1920 return node;
1921
1922 policy = current->mempolicy;
1923 if (!policy)
1924 return node;
1925
1926 switch (policy->mode) {
1927 case MPOL_PREFERRED:
1928 return first_node(policy->nodes);
1929
1930 case MPOL_INTERLEAVE:
1931 return interleave_nodes(policy);
1932
1933 case MPOL_BIND: {
1934 struct zoneref *z;
1935
1936 /*
1937 * Follow bind policy behavior and start allocation at the
1938 * first node.
1939 */
1940 struct zonelist *zonelist;
1941 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1942 zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK];
1943 z = first_zones_zonelist(zonelist, highest_zoneidx,
1944 &policy->nodes);
1945 return z->zone ? zone_to_nid(z->zone) : node;
1946 }
1947 case MPOL_LOCAL:
1948 return node;
1949
1950 default:
1951 BUG();
1952 }
1953}
1954
1955/*
1956 * Do static interleaving for a VMA with known offset @n. Returns the n'th
1957 * node in pol->nodes (starting from n=0), wrapping around if n exceeds the
1958 * number of present nodes.
1959 */
1960static unsigned offset_il_node(struct mempolicy *pol, unsigned long n)
1961{
1962 nodemask_t nodemask = pol->nodes;
1963 unsigned int target, nnodes;
1964 int i;
1965 int nid;
1966 /*
1967 * The barrier will stabilize the nodemask in a register or on
1968 * the stack so that it will stop changing under the code.
1969 *
1970 * Between first_node() and next_node(), pol->nodes could be changed
1971 * by other threads. So we put pol->nodes in a local stack.
1972 */
1973 barrier();
1974
1975 nnodes = nodes_weight(nodemask);
1976 if (!nnodes)
1977 return numa_node_id();
1978 target = (unsigned int)n % nnodes;
1979 nid = first_node(nodemask);
1980 for (i = 0; i < target; i++)
1981 nid = next_node(nid, nodemask);
1982 return nid;
1983}
1984
1985/* Determine a node number for interleave */
1986static inline unsigned interleave_nid(struct mempolicy *pol,
1987 struct vm_area_struct *vma, unsigned long addr, int shift)
1988{
1989 if (vma) {
1990 unsigned long off;
1991
1992 /*
1993 * for small pages, there is no difference between
1994 * shift and PAGE_SHIFT, so the bit-shift is safe.
1995 * for huge pages, since vm_pgoff is in units of small
1996 * pages, we need to shift off the always 0 bits to get
1997 * a useful offset.
1998 */
1999 BUG_ON(shift < PAGE_SHIFT);
2000 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
2001 off += (addr - vma->vm_start) >> shift;
2002 return offset_il_node(pol, off);
2003 } else
2004 return interleave_nodes(pol);
2005}
2006
2007#ifdef CONFIG_HUGETLBFS
2008/*
2009 * huge_node(@vma, @addr, @gfp_flags, @mpol)
2010 * @vma: virtual memory area whose policy is sought
2011 * @addr: address in @vma for shared policy lookup and interleave policy
2012 * @gfp_flags: for requested zone
2013 * @mpol: pointer to mempolicy pointer for reference counted mempolicy
2014 * @nodemask: pointer to nodemask pointer for MPOL_BIND nodemask
2015 *
2016 * Returns a nid suitable for a huge page allocation and a pointer
2017 * to the struct mempolicy for conditional unref after allocation.
2018 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
2019 * @nodemask for filtering the zonelist.
2020 *
2021 * Must be protected by read_mems_allowed_begin()
2022 */
2023int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags,
2024 struct mempolicy **mpol, nodemask_t **nodemask)
2025{
2026 int nid;
2027
2028 *mpol = get_vma_policy(vma, addr);
2029 *nodemask = NULL; /* assume !MPOL_BIND */
2030
2031 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
2032 nid = interleave_nid(*mpol, vma, addr,
2033 huge_page_shift(hstate_vma(vma)));
2034 } else {
2035 nid = policy_node(gfp_flags, *mpol, numa_node_id());
2036 if ((*mpol)->mode == MPOL_BIND)
2037 *nodemask = &(*mpol)->nodes;
2038 }
2039 return nid;
2040}
2041
2042/*
2043 * init_nodemask_of_mempolicy
2044 *
2045 * If the current task's mempolicy is "default" [NULL], return 'false'
2046 * to indicate default policy. Otherwise, extract the policy nodemask
2047 * for 'bind' or 'interleave' policy into the argument nodemask, or
2048 * initialize the argument nodemask to contain the single node for
2049 * 'preferred' or 'local' policy and return 'true' to indicate presence
2050 * of non-default mempolicy.
2051 *
2052 * We don't bother with reference counting the mempolicy [mpol_get/put]
2053 * because the current task is examining it's own mempolicy and a task's
2054 * mempolicy is only ever changed by the task itself.
2055 *
2056 * N.B., it is the caller's responsibility to free a returned nodemask.
2057 */
2058bool init_nodemask_of_mempolicy(nodemask_t *mask)
2059{
2060 struct mempolicy *mempolicy;
2061
2062 if (!(mask && current->mempolicy))
2063 return false;
2064
2065 task_lock(current);
2066 mempolicy = current->mempolicy;
2067 switch (mempolicy->mode) {
2068 case MPOL_PREFERRED:
2069 case MPOL_BIND:
2070 case MPOL_INTERLEAVE:
2071 *mask = mempolicy->nodes;
2072 break;
2073
2074 case MPOL_LOCAL:
2075 init_nodemask_of_node(mask, numa_node_id());
2076 break;
2077
2078 default:
2079 BUG();
2080 }
2081 task_unlock(current);
2082
2083 return true;
2084}
2085#endif
2086
2087/*
2088 * mempolicy_in_oom_domain
2089 *
2090 * If tsk's mempolicy is "bind", check for intersection between mask and
2091 * the policy nodemask. Otherwise, return true for all other policies
2092 * including "interleave", as a tsk with "interleave" policy may have
2093 * memory allocated from all nodes in system.
2094 *
2095 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
2096 */
2097bool mempolicy_in_oom_domain(struct task_struct *tsk,
2098 const nodemask_t *mask)
2099{
2100 struct mempolicy *mempolicy;
2101 bool ret = true;
2102
2103 if (!mask)
2104 return ret;
2105
2106 task_lock(tsk);
2107 mempolicy = tsk->mempolicy;
2108 if (mempolicy && mempolicy->mode == MPOL_BIND)
2109 ret = nodes_intersects(mempolicy->nodes, *mask);
2110 task_unlock(tsk);
2111
2112 return ret;
2113}
2114
2115/* Allocate a page in interleaved policy.
2116 Own path because it needs to do special accounting. */
2117static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
2118 unsigned nid)
2119{
2120 struct page *page;
2121
2122 page = __alloc_pages(gfp, order, nid, NULL);
2123 /* skip NUMA_INTERLEAVE_HIT counter update if numa stats is disabled */
2124 if (!static_branch_likely(&vm_numa_stat_key))
2125 return page;
2126 if (page && page_to_nid(page) == nid) {
2127 preempt_disable();
2128 __count_numa_event(page_zone(page), NUMA_INTERLEAVE_HIT);
2129 preempt_enable();
2130 }
2131 return page;
2132}
2133
2134/**
2135 * alloc_pages_vma - Allocate a page for a VMA.
2136 * @gfp: GFP flags.
2137 * @order: Order of the GFP allocation.
2138 * @vma: Pointer to VMA or NULL if not available.
2139 * @addr: Virtual address of the allocation. Must be inside @vma.
2140 * @node: Which node to prefer for allocation (modulo policy).
2141 * @hugepage: For hugepages try only the preferred node if possible.
2142 *
2143 * Allocate a page for a specific address in @vma, using the appropriate
2144 * NUMA policy. When @vma is not NULL the caller must hold the mmap_lock
2145 * of the mm_struct of the VMA to prevent it from going away. Should be
2146 * used for all allocations for pages that will be mapped into user space.
2147 *
2148 * Return: The page on success or NULL if allocation fails.
2149 */
2150struct page *alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
2151 unsigned long addr, int node, bool hugepage)
2152{
2153 struct mempolicy *pol;
2154 struct page *page;
2155 int preferred_nid;
2156 nodemask_t *nmask;
2157
2158 pol = get_vma_policy(vma, addr);
2159
2160 if (pol->mode == MPOL_INTERLEAVE) {
2161 unsigned nid;
2162
2163 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2164 mpol_cond_put(pol);
2165 page = alloc_page_interleave(gfp, order, nid);
2166 goto out;
2167 }
2168
2169 if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
2170 int hpage_node = node;
2171
2172 /*
2173 * For hugepage allocation and non-interleave policy which
2174 * allows the current node (or other explicitly preferred
2175 * node) we only try to allocate from the current/preferred
2176 * node and don't fall back to other nodes, as the cost of
2177 * remote accesses would likely offset THP benefits.
2178 *
2179 * If the policy is interleave, or does not allow the current
2180 * node in its nodemask, we allocate the standard way.
2181 */
2182 if (pol->mode == MPOL_PREFERRED)
2183 hpage_node = first_node(pol->nodes);
2184
2185 nmask = policy_nodemask(gfp, pol);
2186 if (!nmask || node_isset(hpage_node, *nmask)) {
2187 mpol_cond_put(pol);
2188 /*
2189 * First, try to allocate THP only on local node, but
2190 * don't reclaim unnecessarily, just compact.
2191 */
2192 page = __alloc_pages_node(hpage_node,
2193 gfp | __GFP_THISNODE | __GFP_NORETRY, order);
2194
2195 /*
2196 * If hugepage allocations are configured to always
2197 * synchronous compact or the vma has been madvised
2198 * to prefer hugepage backing, retry allowing remote
2199 * memory with both reclaim and compact as well.
2200 */
2201 if (!page && (gfp & __GFP_DIRECT_RECLAIM))
2202 page = __alloc_pages_node(hpage_node,
2203 gfp, order);
2204
2205 goto out;
2206 }
2207 }
2208
2209 nmask = policy_nodemask(gfp, pol);
2210 preferred_nid = policy_node(gfp, pol, node);
2211 page = __alloc_pages(gfp, order, preferred_nid, nmask);
2212 mpol_cond_put(pol);
2213out:
2214 return page;
2215}
2216EXPORT_SYMBOL(alloc_pages_vma);
2217
2218/**
2219 * alloc_pages - Allocate pages.
2220 * @gfp: GFP flags.
2221 * @order: Power of two of number of pages to allocate.
2222 *
2223 * Allocate 1 << @order contiguous pages. The physical address of the
2224 * first page is naturally aligned (eg an order-3 allocation will be aligned
2225 * to a multiple of 8 * PAGE_SIZE bytes). The NUMA policy of the current
2226 * process is honoured when in process context.
2227 *
2228 * Context: Can be called from any context, providing the appropriate GFP
2229 * flags are used.
2230 * Return: The page on success or NULL if allocation fails.
2231 */
2232struct page *alloc_pages(gfp_t gfp, unsigned order)
2233{
2234 struct mempolicy *pol = &default_policy;
2235 struct page *page;
2236
2237 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2238 pol = get_task_policy(current);
2239
2240 /*
2241 * No reference counting needed for current->mempolicy
2242 * nor system default_policy
2243 */
2244 if (pol->mode == MPOL_INTERLEAVE)
2245 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
2246 else
2247 page = __alloc_pages(gfp, order,
2248 policy_node(gfp, pol, numa_node_id()),
2249 policy_nodemask(gfp, pol));
2250
2251 return page;
2252}
2253EXPORT_SYMBOL(alloc_pages);
2254
2255int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
2256{
2257 struct mempolicy *pol = mpol_dup(vma_policy(src));
2258
2259 if (IS_ERR(pol))
2260 return PTR_ERR(pol);
2261 dst->vm_policy = pol;
2262 return 0;
2263}
2264
2265/*
2266 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2267 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2268 * with the mems_allowed returned by cpuset_mems_allowed(). This
2269 * keeps mempolicies cpuset relative after its cpuset moves. See
2270 * further kernel/cpuset.c update_nodemask().
2271 *
2272 * current's mempolicy may be rebinded by the other task(the task that changes
2273 * cpuset's mems), so we needn't do rebind work for current task.
2274 */
2275
2276/* Slow path of a mempolicy duplicate */
2277struct mempolicy *__mpol_dup(struct mempolicy *old)
2278{
2279 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2280
2281 if (!new)
2282 return ERR_PTR(-ENOMEM);
2283
2284 /* task's mempolicy is protected by alloc_lock */
2285 if (old == current->mempolicy) {
2286 task_lock(current);
2287 *new = *old;
2288 task_unlock(current);
2289 } else
2290 *new = *old;
2291
2292 if (current_cpuset_is_being_rebound()) {
2293 nodemask_t mems = cpuset_mems_allowed(current);
2294 mpol_rebind_policy(new, &mems);
2295 }
2296 atomic_set(&new->refcnt, 1);
2297 return new;
2298}
2299
2300/* Slow path of a mempolicy comparison */
2301bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2302{
2303 if (!a || !b)
2304 return false;
2305 if (a->mode != b->mode)
2306 return false;
2307 if (a->flags != b->flags)
2308 return false;
2309 if (mpol_store_user_nodemask(a))
2310 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2311 return false;
2312
2313 switch (a->mode) {
2314 case MPOL_BIND:
2315 case MPOL_INTERLEAVE:
2316 case MPOL_PREFERRED:
2317 return !!nodes_equal(a->nodes, b->nodes);
2318 case MPOL_LOCAL:
2319 return true;
2320 default:
2321 BUG();
2322 return false;
2323 }
2324}
2325
2326/*
2327 * Shared memory backing store policy support.
2328 *
2329 * Remember policies even when nobody has shared memory mapped.
2330 * The policies are kept in Red-Black tree linked from the inode.
2331 * They are protected by the sp->lock rwlock, which should be held
2332 * for any accesses to the tree.
2333 */
2334
2335/*
2336 * lookup first element intersecting start-end. Caller holds sp->lock for
2337 * reading or for writing
2338 */
2339static struct sp_node *
2340sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2341{
2342 struct rb_node *n = sp->root.rb_node;
2343
2344 while (n) {
2345 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2346
2347 if (start >= p->end)
2348 n = n->rb_right;
2349 else if (end <= p->start)
2350 n = n->rb_left;
2351 else
2352 break;
2353 }
2354 if (!n)
2355 return NULL;
2356 for (;;) {
2357 struct sp_node *w = NULL;
2358 struct rb_node *prev = rb_prev(n);
2359 if (!prev)
2360 break;
2361 w = rb_entry(prev, struct sp_node, nd);
2362 if (w->end <= start)
2363 break;
2364 n = prev;
2365 }
2366 return rb_entry(n, struct sp_node, nd);
2367}
2368
2369/*
2370 * Insert a new shared policy into the list. Caller holds sp->lock for
2371 * writing.
2372 */
2373static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2374{
2375 struct rb_node **p = &sp->root.rb_node;
2376 struct rb_node *parent = NULL;
2377 struct sp_node *nd;
2378
2379 while (*p) {
2380 parent = *p;
2381 nd = rb_entry(parent, struct sp_node, nd);
2382 if (new->start < nd->start)
2383 p = &(*p)->rb_left;
2384 else if (new->end > nd->end)
2385 p = &(*p)->rb_right;
2386 else
2387 BUG();
2388 }
2389 rb_link_node(&new->nd, parent, p);
2390 rb_insert_color(&new->nd, &sp->root);
2391 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2392 new->policy ? new->policy->mode : 0);
2393}
2394
2395/* Find shared policy intersecting idx */
2396struct mempolicy *
2397mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2398{
2399 struct mempolicy *pol = NULL;
2400 struct sp_node *sn;
2401
2402 if (!sp->root.rb_node)
2403 return NULL;
2404 read_lock(&sp->lock);
2405 sn = sp_lookup(sp, idx, idx+1);
2406 if (sn) {
2407 mpol_get(sn->policy);
2408 pol = sn->policy;
2409 }
2410 read_unlock(&sp->lock);
2411 return pol;
2412}
2413
2414static void sp_free(struct sp_node *n)
2415{
2416 mpol_put(n->policy);
2417 kmem_cache_free(sn_cache, n);
2418}
2419
2420/**
2421 * mpol_misplaced - check whether current page node is valid in policy
2422 *
2423 * @page: page to be checked
2424 * @vma: vm area where page mapped
2425 * @addr: virtual address where page mapped
2426 *
2427 * Lookup current policy node id for vma,addr and "compare to" page's
2428 * node id. Policy determination "mimics" alloc_page_vma().
2429 * Called from fault path where we know the vma and faulting address.
2430 *
2431 * Return: -1 if the page is in a node that is valid for this policy, or a
2432 * suitable node ID to allocate a replacement page from.
2433 */
2434int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
2435{
2436 struct mempolicy *pol;
2437 struct zoneref *z;
2438 int curnid = page_to_nid(page);
2439 unsigned long pgoff;
2440 int thiscpu = raw_smp_processor_id();
2441 int thisnid = cpu_to_node(thiscpu);
2442 int polnid = NUMA_NO_NODE;
2443 int ret = -1;
2444
2445 pol = get_vma_policy(vma, addr);
2446 if (!(pol->flags & MPOL_F_MOF))
2447 goto out;
2448
2449 switch (pol->mode) {
2450 case MPOL_INTERLEAVE:
2451 pgoff = vma->vm_pgoff;
2452 pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
2453 polnid = offset_il_node(pol, pgoff);
2454 break;
2455
2456 case MPOL_PREFERRED:
2457 polnid = first_node(pol->nodes);
2458 break;
2459
2460 case MPOL_LOCAL:
2461 polnid = numa_node_id();
2462 break;
2463
2464 case MPOL_BIND:
2465 /* Optimize placement among multiple nodes via NUMA balancing */
2466 if (pol->flags & MPOL_F_MORON) {
2467 if (node_isset(thisnid, pol->nodes))
2468 break;
2469 goto out;
2470 }
2471
2472 /*
2473 * allows binding to multiple nodes.
2474 * use current page if in policy nodemask,
2475 * else select nearest allowed node, if any.
2476 * If no allowed nodes, use current [!misplaced].
2477 */
2478 if (node_isset(curnid, pol->nodes))
2479 goto out;
2480 z = first_zones_zonelist(
2481 node_zonelist(numa_node_id(), GFP_HIGHUSER),
2482 gfp_zone(GFP_HIGHUSER),
2483 &pol->nodes);
2484 polnid = zone_to_nid(z->zone);
2485 break;
2486
2487 default:
2488 BUG();
2489 }
2490
2491 /* Migrate the page towards the node whose CPU is referencing it */
2492 if (pol->flags & MPOL_F_MORON) {
2493 polnid = thisnid;
2494
2495 if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
2496 goto out;
2497 }
2498
2499 if (curnid != polnid)
2500 ret = polnid;
2501out:
2502 mpol_cond_put(pol);
2503
2504 return ret;
2505}
2506
2507/*
2508 * Drop the (possibly final) reference to task->mempolicy. It needs to be
2509 * dropped after task->mempolicy is set to NULL so that any allocation done as
2510 * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed
2511 * policy.
2512 */
2513void mpol_put_task_policy(struct task_struct *task)
2514{
2515 struct mempolicy *pol;
2516
2517 task_lock(task);
2518 pol = task->mempolicy;
2519 task->mempolicy = NULL;
2520 task_unlock(task);
2521 mpol_put(pol);
2522}
2523
2524static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2525{
2526 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2527 rb_erase(&n->nd, &sp->root);
2528 sp_free(n);
2529}
2530
2531static void sp_node_init(struct sp_node *node, unsigned long start,
2532 unsigned long end, struct mempolicy *pol)
2533{
2534 node->start = start;
2535 node->end = end;
2536 node->policy = pol;
2537}
2538
2539static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2540 struct mempolicy *pol)
2541{
2542 struct sp_node *n;
2543 struct mempolicy *newpol;
2544
2545 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2546 if (!n)
2547 return NULL;
2548
2549 newpol = mpol_dup(pol);
2550 if (IS_ERR(newpol)) {
2551 kmem_cache_free(sn_cache, n);
2552 return NULL;
2553 }
2554 newpol->flags |= MPOL_F_SHARED;
2555 sp_node_init(n, start, end, newpol);
2556
2557 return n;
2558}
2559
2560/* Replace a policy range. */
2561static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2562 unsigned long end, struct sp_node *new)
2563{
2564 struct sp_node *n;
2565 struct sp_node *n_new = NULL;
2566 struct mempolicy *mpol_new = NULL;
2567 int ret = 0;
2568
2569restart:
2570 write_lock(&sp->lock);
2571 n = sp_lookup(sp, start, end);
2572 /* Take care of old policies in the same range. */
2573 while (n && n->start < end) {
2574 struct rb_node *next = rb_next(&n->nd);
2575 if (n->start >= start) {
2576 if (n->end <= end)
2577 sp_delete(sp, n);
2578 else
2579 n->start = end;
2580 } else {
2581 /* Old policy spanning whole new range. */
2582 if (n->end > end) {
2583 if (!n_new)
2584 goto alloc_new;
2585
2586 *mpol_new = *n->policy;
2587 atomic_set(&mpol_new->refcnt, 1);
2588 sp_node_init(n_new, end, n->end, mpol_new);
2589 n->end = start;
2590 sp_insert(sp, n_new);
2591 n_new = NULL;
2592 mpol_new = NULL;
2593 break;
2594 } else
2595 n->end = start;
2596 }
2597 if (!next)
2598 break;
2599 n = rb_entry(next, struct sp_node, nd);
2600 }
2601 if (new)
2602 sp_insert(sp, new);
2603 write_unlock(&sp->lock);
2604 ret = 0;
2605
2606err_out:
2607 if (mpol_new)
2608 mpol_put(mpol_new);
2609 if (n_new)
2610 kmem_cache_free(sn_cache, n_new);
2611
2612 return ret;
2613
2614alloc_new:
2615 write_unlock(&sp->lock);
2616 ret = -ENOMEM;
2617 n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2618 if (!n_new)
2619 goto err_out;
2620 mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2621 if (!mpol_new)
2622 goto err_out;
2623 goto restart;
2624}
2625
2626/**
2627 * mpol_shared_policy_init - initialize shared policy for inode
2628 * @sp: pointer to inode shared policy
2629 * @mpol: struct mempolicy to install
2630 *
2631 * Install non-NULL @mpol in inode's shared policy rb-tree.
2632 * On entry, the current task has a reference on a non-NULL @mpol.
2633 * This must be released on exit.
2634 * This is called at get_inode() calls and we can use GFP_KERNEL.
2635 */
2636void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2637{
2638 int ret;
2639
2640 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2641 rwlock_init(&sp->lock);
2642
2643 if (mpol) {
2644 struct vm_area_struct pvma;
2645 struct mempolicy *new;
2646 NODEMASK_SCRATCH(scratch);
2647
2648 if (!scratch)
2649 goto put_mpol;
2650 /* contextualize the tmpfs mount point mempolicy */
2651 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2652 if (IS_ERR(new))
2653 goto free_scratch; /* no valid nodemask intersection */
2654
2655 task_lock(current);
2656 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2657 task_unlock(current);
2658 if (ret)
2659 goto put_new;
2660
2661 /* Create pseudo-vma that contains just the policy */
2662 vma_init(&pvma, NULL);
2663 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2664 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2665
2666put_new:
2667 mpol_put(new); /* drop initial ref */
2668free_scratch:
2669 NODEMASK_SCRATCH_FREE(scratch);
2670put_mpol:
2671 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2672 }
2673}
2674
2675int mpol_set_shared_policy(struct shared_policy *info,
2676 struct vm_area_struct *vma, struct mempolicy *npol)
2677{
2678 int err;
2679 struct sp_node *new = NULL;
2680 unsigned long sz = vma_pages(vma);
2681
2682 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2683 vma->vm_pgoff,
2684 sz, npol ? npol->mode : -1,
2685 npol ? npol->flags : -1,
2686 npol ? nodes_addr(npol->nodes)[0] : NUMA_NO_NODE);
2687
2688 if (npol) {
2689 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2690 if (!new)
2691 return -ENOMEM;
2692 }
2693 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2694 if (err && new)
2695 sp_free(new);
2696 return err;
2697}
2698
2699/* Free a backing policy store on inode delete. */
2700void mpol_free_shared_policy(struct shared_policy *p)
2701{
2702 struct sp_node *n;
2703 struct rb_node *next;
2704
2705 if (!p->root.rb_node)
2706 return;
2707 write_lock(&p->lock);
2708 next = rb_first(&p->root);
2709 while (next) {
2710 n = rb_entry(next, struct sp_node, nd);
2711 next = rb_next(&n->nd);
2712 sp_delete(p, n);
2713 }
2714 write_unlock(&p->lock);
2715}
2716
2717#ifdef CONFIG_NUMA_BALANCING
2718static int __initdata numabalancing_override;
2719
2720static void __init check_numabalancing_enable(void)
2721{
2722 bool numabalancing_default = false;
2723
2724 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2725 numabalancing_default = true;
2726
2727 /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
2728 if (numabalancing_override)
2729 set_numabalancing_state(numabalancing_override == 1);
2730
2731 if (num_online_nodes() > 1 && !numabalancing_override) {
2732 pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n",
2733 numabalancing_default ? "Enabling" : "Disabling");
2734 set_numabalancing_state(numabalancing_default);
2735 }
2736}
2737
2738static int __init setup_numabalancing(char *str)
2739{
2740 int ret = 0;
2741 if (!str)
2742 goto out;
2743
2744 if (!strcmp(str, "enable")) {
2745 numabalancing_override = 1;
2746 ret = 1;
2747 } else if (!strcmp(str, "disable")) {
2748 numabalancing_override = -1;
2749 ret = 1;
2750 }
2751out:
2752 if (!ret)
2753 pr_warn("Unable to parse numa_balancing=\n");
2754
2755 return ret;
2756}
2757__setup("numa_balancing=", setup_numabalancing);
2758#else
2759static inline void __init check_numabalancing_enable(void)
2760{
2761}
2762#endif /* CONFIG_NUMA_BALANCING */
2763
2764/* assumes fs == KERNEL_DS */
2765void __init numa_policy_init(void)
2766{
2767 nodemask_t interleave_nodes;
2768 unsigned long largest = 0;
2769 int nid, prefer = 0;
2770
2771 policy_cache = kmem_cache_create("numa_policy",
2772 sizeof(struct mempolicy),
2773 0, SLAB_PANIC, NULL);
2774
2775 sn_cache = kmem_cache_create("shared_policy_node",
2776 sizeof(struct sp_node),
2777 0, SLAB_PANIC, NULL);
2778
2779 for_each_node(nid) {
2780 preferred_node_policy[nid] = (struct mempolicy) {
2781 .refcnt = ATOMIC_INIT(1),
2782 .mode = MPOL_PREFERRED,
2783 .flags = MPOL_F_MOF | MPOL_F_MORON,
2784 .nodes = nodemask_of_node(nid),
2785 };
2786 }
2787
2788 /*
2789 * Set interleaving policy for system init. Interleaving is only
2790 * enabled across suitably sized nodes (default is >= 16MB), or
2791 * fall back to the largest node if they're all smaller.
2792 */
2793 nodes_clear(interleave_nodes);
2794 for_each_node_state(nid, N_MEMORY) {
2795 unsigned long total_pages = node_present_pages(nid);
2796
2797 /* Preserve the largest node */
2798 if (largest < total_pages) {
2799 largest = total_pages;
2800 prefer = nid;
2801 }
2802
2803 /* Interleave this node? */
2804 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2805 node_set(nid, interleave_nodes);
2806 }
2807
2808 /* All too small, use the largest */
2809 if (unlikely(nodes_empty(interleave_nodes)))
2810 node_set(prefer, interleave_nodes);
2811
2812 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2813 pr_err("%s: interleaving failed\n", __func__);
2814
2815 check_numabalancing_enable();
2816}
2817
2818/* Reset policy of current process to default */
2819void numa_default_policy(void)
2820{
2821 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2822}
2823
2824/*
2825 * Parse and format mempolicy from/to strings
2826 */
2827
2828static const char * const policy_modes[] =
2829{
2830 [MPOL_DEFAULT] = "default",
2831 [MPOL_PREFERRED] = "prefer",
2832 [MPOL_BIND] = "bind",
2833 [MPOL_INTERLEAVE] = "interleave",
2834 [MPOL_LOCAL] = "local",
2835};
2836
2837
2838#ifdef CONFIG_TMPFS
2839/**
2840 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2841 * @str: string containing mempolicy to parse
2842 * @mpol: pointer to struct mempolicy pointer, returned on success.
2843 *
2844 * Format of input:
2845 * <mode>[=<flags>][:<nodelist>]
2846 *
2847 * On success, returns 0, else 1
2848 */
2849int mpol_parse_str(char *str, struct mempolicy **mpol)
2850{
2851 struct mempolicy *new = NULL;
2852 unsigned short mode_flags;
2853 nodemask_t nodes;
2854 char *nodelist = strchr(str, ':');
2855 char *flags = strchr(str, '=');
2856 int err = 1, mode;
2857
2858 if (flags)
2859 *flags++ = '\0'; /* terminate mode string */
2860
2861 if (nodelist) {
2862 /* NUL-terminate mode or flags string */
2863 *nodelist++ = '\0';
2864 if (nodelist_parse(nodelist, nodes))
2865 goto out;
2866 if (!nodes_subset(nodes, node_states[N_MEMORY]))
2867 goto out;
2868 } else
2869 nodes_clear(nodes);
2870
2871 mode = match_string(policy_modes, MPOL_MAX, str);
2872 if (mode < 0)
2873 goto out;
2874
2875 switch (mode) {
2876 case MPOL_PREFERRED:
2877 /*
2878 * Insist on a nodelist of one node only, although later
2879 * we use first_node(nodes) to grab a single node, so here
2880 * nodelist (or nodes) cannot be empty.
2881 */
2882 if (nodelist) {
2883 char *rest = nodelist;
2884 while (isdigit(*rest))
2885 rest++;
2886 if (*rest)
2887 goto out;
2888 if (nodes_empty(nodes))
2889 goto out;
2890 }
2891 break;
2892 case MPOL_INTERLEAVE:
2893 /*
2894 * Default to online nodes with memory if no nodelist
2895 */
2896 if (!nodelist)
2897 nodes = node_states[N_MEMORY];
2898 break;
2899 case MPOL_LOCAL:
2900 /*
2901 * Don't allow a nodelist; mpol_new() checks flags
2902 */
2903 if (nodelist)
2904 goto out;
2905 break;
2906 case MPOL_DEFAULT:
2907 /*
2908 * Insist on a empty nodelist
2909 */
2910 if (!nodelist)
2911 err = 0;
2912 goto out;
2913 case MPOL_BIND:
2914 /*
2915 * Insist on a nodelist
2916 */
2917 if (!nodelist)
2918 goto out;
2919 }
2920
2921 mode_flags = 0;
2922 if (flags) {
2923 /*
2924 * Currently, we only support two mutually exclusive
2925 * mode flags.
2926 */
2927 if (!strcmp(flags, "static"))
2928 mode_flags |= MPOL_F_STATIC_NODES;
2929 else if (!strcmp(flags, "relative"))
2930 mode_flags |= MPOL_F_RELATIVE_NODES;
2931 else
2932 goto out;
2933 }
2934
2935 new = mpol_new(mode, mode_flags, &nodes);
2936 if (IS_ERR(new))
2937 goto out;
2938
2939 /*
2940 * Save nodes for mpol_to_str() to show the tmpfs mount options
2941 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
2942 */
2943 if (mode != MPOL_PREFERRED) {
2944 new->nodes = nodes;
2945 } else if (nodelist) {
2946 nodes_clear(new->nodes);
2947 node_set(first_node(nodes), new->nodes);
2948 } else {
2949 new->mode = MPOL_LOCAL;
2950 }
2951
2952 /*
2953 * Save nodes for contextualization: this will be used to "clone"
2954 * the mempolicy in a specific context [cpuset] at a later time.
2955 */
2956 new->w.user_nodemask = nodes;
2957
2958 err = 0;
2959
2960out:
2961 /* Restore string for error message */
2962 if (nodelist)
2963 *--nodelist = ':';
2964 if (flags)
2965 *--flags = '=';
2966 if (!err)
2967 *mpol = new;
2968 return err;
2969}
2970#endif /* CONFIG_TMPFS */
2971
2972/**
2973 * mpol_to_str - format a mempolicy structure for printing
2974 * @buffer: to contain formatted mempolicy string
2975 * @maxlen: length of @buffer
2976 * @pol: pointer to mempolicy to be formatted
2977 *
2978 * Convert @pol into a string. If @buffer is too short, truncate the string.
2979 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
2980 * longest flag, "relative", and to display at least a few node ids.
2981 */
2982void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
2983{
2984 char *p = buffer;
2985 nodemask_t nodes = NODE_MASK_NONE;
2986 unsigned short mode = MPOL_DEFAULT;
2987 unsigned short flags = 0;
2988
2989 if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
2990 mode = pol->mode;
2991 flags = pol->flags;
2992 }
2993
2994 switch (mode) {
2995 case MPOL_DEFAULT:
2996 case MPOL_LOCAL:
2997 break;
2998 case MPOL_PREFERRED:
2999 case MPOL_BIND:
3000 case MPOL_INTERLEAVE:
3001 nodes = pol->nodes;
3002 break;
3003 default:
3004 WARN_ON_ONCE(1);
3005 snprintf(p, maxlen, "unknown");
3006 return;
3007 }
3008
3009 p += snprintf(p, maxlen, "%s", policy_modes[mode]);
3010
3011 if (flags & MPOL_MODE_FLAGS) {
3012 p += snprintf(p, buffer + maxlen - p, "=");
3013
3014 /*
3015 * Currently, the only defined flags are mutually exclusive
3016 */
3017 if (flags & MPOL_F_STATIC_NODES)
3018 p += snprintf(p, buffer + maxlen - p, "static");
3019 else if (flags & MPOL_F_RELATIVE_NODES)
3020 p += snprintf(p, buffer + maxlen - p, "relative");
3021 }
3022
3023 if (!nodes_empty(nodes))
3024 p += scnprintf(p, buffer + maxlen - p, ":%*pbl",
3025 nodemask_pr_args(&nodes));
3026}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Simple NUMA memory policy for the Linux kernel.
4 *
5 * Copyright 2003,2004 Andi Kleen, SuSE Labs.
6 * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc.
7 *
8 * NUMA policy allows the user to give hints in which node(s) memory should
9 * be allocated.
10 *
11 * Support four policies per VMA and per process:
12 *
13 * The VMA policy has priority over the process policy for a page fault.
14 *
15 * interleave Allocate memory interleaved over a set of nodes,
16 * with normal fallback if it fails.
17 * For VMA based allocations this interleaves based on the
18 * offset into the backing object or offset into the mapping
19 * for anonymous memory. For process policy an process counter
20 * is used.
21 *
22 * bind Only allocate memory on a specific set of nodes,
23 * no fallback.
24 * FIXME: memory is allocated starting with the first node
25 * to the last. It would be better if bind would truly restrict
26 * the allocation to memory nodes instead
27 *
28 * preferred Try a specific node first before normal fallback.
29 * As a special case NUMA_NO_NODE here means do the allocation
30 * on the local CPU. This is normally identical to default,
31 * but useful to set in a VMA when you have a non default
32 * process policy.
33 *
34 * preferred many Try a set of nodes first before normal fallback. This is
35 * similar to preferred without the special case.
36 *
37 * default Allocate on the local node first, or when on a VMA
38 * use the process policy. This is what Linux always did
39 * in a NUMA aware kernel and still does by, ahem, default.
40 *
41 * The process policy is applied for most non interrupt memory allocations
42 * in that process' context. Interrupts ignore the policies and always
43 * try to allocate on the local CPU. The VMA policy is only applied for memory
44 * allocations for a VMA in the VM.
45 *
46 * Currently there are a few corner cases in swapping where the policy
47 * is not applied, but the majority should be handled. When process policy
48 * is used it is not remembered over swap outs/swap ins.
49 *
50 * Only the highest zone in the zone hierarchy gets policied. Allocations
51 * requesting a lower zone just use default policy. This implies that
52 * on systems with highmem kernel lowmem allocation don't get policied.
53 * Same with GFP_DMA allocations.
54 *
55 * For shmfs/tmpfs/hugetlbfs shared memory the policy is shared between
56 * all users and remembered even when nobody has memory mapped.
57 */
58
59/* Notebook:
60 fix mmap readahead to honour policy and enable policy for any page cache
61 object
62 statistics for bigpages
63 global policy for page cache? currently it uses process policy. Requires
64 first item above.
65 handle mremap for shared memory (currently ignored for the policy)
66 grows down?
67 make bind policy root only? It can trigger oom much faster and the
68 kernel is not always grateful with that.
69*/
70
71#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
72
73#include <linux/mempolicy.h>
74#include <linux/pagewalk.h>
75#include <linux/highmem.h>
76#include <linux/hugetlb.h>
77#include <linux/kernel.h>
78#include <linux/sched.h>
79#include <linux/sched/mm.h>
80#include <linux/sched/numa_balancing.h>
81#include <linux/sched/task.h>
82#include <linux/nodemask.h>
83#include <linux/cpuset.h>
84#include <linux/slab.h>
85#include <linux/string.h>
86#include <linux/export.h>
87#include <linux/nsproxy.h>
88#include <linux/interrupt.h>
89#include <linux/init.h>
90#include <linux/compat.h>
91#include <linux/ptrace.h>
92#include <linux/swap.h>
93#include <linux/seq_file.h>
94#include <linux/proc_fs.h>
95#include <linux/migrate.h>
96#include <linux/ksm.h>
97#include <linux/rmap.h>
98#include <linux/security.h>
99#include <linux/syscalls.h>
100#include <linux/ctype.h>
101#include <linux/mm_inline.h>
102#include <linux/mmu_notifier.h>
103#include <linux/printk.h>
104#include <linux/swapops.h>
105
106#include <asm/tlbflush.h>
107#include <asm/tlb.h>
108#include <linux/uaccess.h>
109
110#include "internal.h"
111
112/* Internal flags */
113#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
114#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
115
116static struct kmem_cache *policy_cache;
117static struct kmem_cache *sn_cache;
118
119/* Highest zone. An specific allocation for a zone below that is not
120 policied. */
121enum zone_type policy_zone = 0;
122
123/*
124 * run-time system-wide default policy => local allocation
125 */
126static struct mempolicy default_policy = {
127 .refcnt = ATOMIC_INIT(1), /* never free it */
128 .mode = MPOL_LOCAL,
129};
130
131static struct mempolicy preferred_node_policy[MAX_NUMNODES];
132
133/**
134 * numa_map_to_online_node - Find closest online node
135 * @node: Node id to start the search
136 *
137 * Lookup the next closest node by distance if @nid is not online.
138 *
139 * Return: this @node if it is online, otherwise the closest node by distance
140 */
141int numa_map_to_online_node(int node)
142{
143 int min_dist = INT_MAX, dist, n, min_node;
144
145 if (node == NUMA_NO_NODE || node_online(node))
146 return node;
147
148 min_node = node;
149 for_each_online_node(n) {
150 dist = node_distance(node, n);
151 if (dist < min_dist) {
152 min_dist = dist;
153 min_node = n;
154 }
155 }
156
157 return min_node;
158}
159EXPORT_SYMBOL_GPL(numa_map_to_online_node);
160
161struct mempolicy *get_task_policy(struct task_struct *p)
162{
163 struct mempolicy *pol = p->mempolicy;
164 int node;
165
166 if (pol)
167 return pol;
168
169 node = numa_node_id();
170 if (node != NUMA_NO_NODE) {
171 pol = &preferred_node_policy[node];
172 /* preferred_node_policy is not initialised early in boot */
173 if (pol->mode)
174 return pol;
175 }
176
177 return &default_policy;
178}
179
180static const struct mempolicy_operations {
181 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
182 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes);
183} mpol_ops[MPOL_MAX];
184
185static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
186{
187 return pol->flags & MPOL_MODE_FLAGS;
188}
189
190static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
191 const nodemask_t *rel)
192{
193 nodemask_t tmp;
194 nodes_fold(tmp, *orig, nodes_weight(*rel));
195 nodes_onto(*ret, tmp, *rel);
196}
197
198static int mpol_new_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
199{
200 if (nodes_empty(*nodes))
201 return -EINVAL;
202 pol->nodes = *nodes;
203 return 0;
204}
205
206static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
207{
208 if (nodes_empty(*nodes))
209 return -EINVAL;
210
211 nodes_clear(pol->nodes);
212 node_set(first_node(*nodes), pol->nodes);
213 return 0;
214}
215
216/*
217 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
218 * any, for the new policy. mpol_new() has already validated the nodes
219 * parameter with respect to the policy mode and flags.
220 *
221 * Must be called holding task's alloc_lock to protect task's mems_allowed
222 * and mempolicy. May also be called holding the mmap_lock for write.
223 */
224static int mpol_set_nodemask(struct mempolicy *pol,
225 const nodemask_t *nodes, struct nodemask_scratch *nsc)
226{
227 int ret;
228
229 /*
230 * Default (pol==NULL) resp. local memory policies are not a
231 * subject of any remapping. They also do not need any special
232 * constructor.
233 */
234 if (!pol || pol->mode == MPOL_LOCAL)
235 return 0;
236
237 /* Check N_MEMORY */
238 nodes_and(nsc->mask1,
239 cpuset_current_mems_allowed, node_states[N_MEMORY]);
240
241 VM_BUG_ON(!nodes);
242
243 if (pol->flags & MPOL_F_RELATIVE_NODES)
244 mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1);
245 else
246 nodes_and(nsc->mask2, *nodes, nsc->mask1);
247
248 if (mpol_store_user_nodemask(pol))
249 pol->w.user_nodemask = *nodes;
250 else
251 pol->w.cpuset_mems_allowed = cpuset_current_mems_allowed;
252
253 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
254 return ret;
255}
256
257/*
258 * This function just creates a new policy, does some check and simple
259 * initialization. You must invoke mpol_set_nodemask() to set nodes.
260 */
261static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
262 nodemask_t *nodes)
263{
264 struct mempolicy *policy;
265
266 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
267 mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE);
268
269 if (mode == MPOL_DEFAULT) {
270 if (nodes && !nodes_empty(*nodes))
271 return ERR_PTR(-EINVAL);
272 return NULL;
273 }
274 VM_BUG_ON(!nodes);
275
276 /*
277 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
278 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
279 * All other modes require a valid pointer to a non-empty nodemask.
280 */
281 if (mode == MPOL_PREFERRED) {
282 if (nodes_empty(*nodes)) {
283 if (((flags & MPOL_F_STATIC_NODES) ||
284 (flags & MPOL_F_RELATIVE_NODES)))
285 return ERR_PTR(-EINVAL);
286
287 mode = MPOL_LOCAL;
288 }
289 } else if (mode == MPOL_LOCAL) {
290 if (!nodes_empty(*nodes) ||
291 (flags & MPOL_F_STATIC_NODES) ||
292 (flags & MPOL_F_RELATIVE_NODES))
293 return ERR_PTR(-EINVAL);
294 } else if (nodes_empty(*nodes))
295 return ERR_PTR(-EINVAL);
296 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
297 if (!policy)
298 return ERR_PTR(-ENOMEM);
299 atomic_set(&policy->refcnt, 1);
300 policy->mode = mode;
301 policy->flags = flags;
302 policy->home_node = NUMA_NO_NODE;
303
304 return policy;
305}
306
307/* Slow path of a mpol destructor. */
308void __mpol_put(struct mempolicy *p)
309{
310 if (!atomic_dec_and_test(&p->refcnt))
311 return;
312 kmem_cache_free(policy_cache, p);
313}
314
315static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes)
316{
317}
318
319static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
320{
321 nodemask_t tmp;
322
323 if (pol->flags & MPOL_F_STATIC_NODES)
324 nodes_and(tmp, pol->w.user_nodemask, *nodes);
325 else if (pol->flags & MPOL_F_RELATIVE_NODES)
326 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
327 else {
328 nodes_remap(tmp, pol->nodes, pol->w.cpuset_mems_allowed,
329 *nodes);
330 pol->w.cpuset_mems_allowed = *nodes;
331 }
332
333 if (nodes_empty(tmp))
334 tmp = *nodes;
335
336 pol->nodes = tmp;
337}
338
339static void mpol_rebind_preferred(struct mempolicy *pol,
340 const nodemask_t *nodes)
341{
342 pol->w.cpuset_mems_allowed = *nodes;
343}
344
345/*
346 * mpol_rebind_policy - Migrate a policy to a different set of nodes
347 *
348 * Per-vma policies are protected by mmap_lock. Allocations using per-task
349 * policies are protected by task->mems_allowed_seq to prevent a premature
350 * OOM/allocation failure due to parallel nodemask modification.
351 */
352static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask)
353{
354 if (!pol || pol->mode == MPOL_LOCAL)
355 return;
356 if (!mpol_store_user_nodemask(pol) &&
357 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
358 return;
359
360 mpol_ops[pol->mode].rebind(pol, newmask);
361}
362
363/*
364 * Wrapper for mpol_rebind_policy() that just requires task
365 * pointer, and updates task mempolicy.
366 *
367 * Called with task's alloc_lock held.
368 */
369
370void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new)
371{
372 mpol_rebind_policy(tsk->mempolicy, new);
373}
374
375/*
376 * Rebind each vma in mm to new nodemask.
377 *
378 * Call holding a reference to mm. Takes mm->mmap_lock during call.
379 */
380
381void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
382{
383 struct vm_area_struct *vma;
384 VMA_ITERATOR(vmi, mm, 0);
385
386 mmap_write_lock(mm);
387 for_each_vma(vmi, vma)
388 mpol_rebind_policy(vma->vm_policy, new);
389 mmap_write_unlock(mm);
390}
391
392static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
393 [MPOL_DEFAULT] = {
394 .rebind = mpol_rebind_default,
395 },
396 [MPOL_INTERLEAVE] = {
397 .create = mpol_new_nodemask,
398 .rebind = mpol_rebind_nodemask,
399 },
400 [MPOL_PREFERRED] = {
401 .create = mpol_new_preferred,
402 .rebind = mpol_rebind_preferred,
403 },
404 [MPOL_BIND] = {
405 .create = mpol_new_nodemask,
406 .rebind = mpol_rebind_nodemask,
407 },
408 [MPOL_LOCAL] = {
409 .rebind = mpol_rebind_default,
410 },
411 [MPOL_PREFERRED_MANY] = {
412 .create = mpol_new_nodemask,
413 .rebind = mpol_rebind_preferred,
414 },
415};
416
417static int migrate_page_add(struct page *page, struct list_head *pagelist,
418 unsigned long flags);
419
420struct queue_pages {
421 struct list_head *pagelist;
422 unsigned long flags;
423 nodemask_t *nmask;
424 unsigned long start;
425 unsigned long end;
426 struct vm_area_struct *first;
427};
428
429/*
430 * Check if the page's nid is in qp->nmask.
431 *
432 * If MPOL_MF_INVERT is set in qp->flags, check if the nid is
433 * in the invert of qp->nmask.
434 */
435static inline bool queue_pages_required(struct page *page,
436 struct queue_pages *qp)
437{
438 int nid = page_to_nid(page);
439 unsigned long flags = qp->flags;
440
441 return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT);
442}
443
444/*
445 * queue_pages_pmd() has three possible return values:
446 * 0 - pages are placed on the right node or queued successfully, or
447 * special page is met, i.e. huge zero page.
448 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
449 * specified.
450 * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an
451 * existing page was already on a node that does not follow the
452 * policy.
453 */
454static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
455 unsigned long end, struct mm_walk *walk)
456 __releases(ptl)
457{
458 int ret = 0;
459 struct page *page;
460 struct queue_pages *qp = walk->private;
461 unsigned long flags;
462
463 if (unlikely(is_pmd_migration_entry(*pmd))) {
464 ret = -EIO;
465 goto unlock;
466 }
467 page = pmd_page(*pmd);
468 if (is_huge_zero_page(page)) {
469 walk->action = ACTION_CONTINUE;
470 goto unlock;
471 }
472 if (!queue_pages_required(page, qp))
473 goto unlock;
474
475 flags = qp->flags;
476 /* go to thp migration */
477 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
478 if (!vma_migratable(walk->vma) ||
479 migrate_page_add(page, qp->pagelist, flags)) {
480 ret = 1;
481 goto unlock;
482 }
483 } else
484 ret = -EIO;
485unlock:
486 spin_unlock(ptl);
487 return ret;
488}
489
490/*
491 * Scan through pages checking if pages follow certain conditions,
492 * and move them to the pagelist if they do.
493 *
494 * queue_pages_pte_range() has three possible return values:
495 * 0 - pages are placed on the right node or queued successfully, or
496 * special page is met, i.e. zero page.
497 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
498 * specified.
499 * -EIO - only MPOL_MF_STRICT was specified and an existing page was already
500 * on a node that does not follow the policy.
501 */
502static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
503 unsigned long end, struct mm_walk *walk)
504{
505 struct vm_area_struct *vma = walk->vma;
506 struct page *page;
507 struct queue_pages *qp = walk->private;
508 unsigned long flags = qp->flags;
509 bool has_unmovable = false;
510 pte_t *pte, *mapped_pte;
511 spinlock_t *ptl;
512
513 ptl = pmd_trans_huge_lock(pmd, vma);
514 if (ptl)
515 return queue_pages_pmd(pmd, ptl, addr, end, walk);
516
517 if (pmd_trans_unstable(pmd))
518 return 0;
519
520 mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
521 for (; addr != end; pte++, addr += PAGE_SIZE) {
522 if (!pte_present(*pte))
523 continue;
524 page = vm_normal_page(vma, addr, *pte);
525 if (!page || is_zone_device_page(page))
526 continue;
527 /*
528 * vm_normal_page() filters out zero pages, but there might
529 * still be PageReserved pages to skip, perhaps in a VDSO.
530 */
531 if (PageReserved(page))
532 continue;
533 if (!queue_pages_required(page, qp))
534 continue;
535 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
536 /* MPOL_MF_STRICT must be specified if we get here */
537 if (!vma_migratable(vma)) {
538 has_unmovable = true;
539 break;
540 }
541
542 /*
543 * Do not abort immediately since there may be
544 * temporary off LRU pages in the range. Still
545 * need migrate other LRU pages.
546 */
547 if (migrate_page_add(page, qp->pagelist, flags))
548 has_unmovable = true;
549 } else
550 break;
551 }
552 pte_unmap_unlock(mapped_pte, ptl);
553 cond_resched();
554
555 if (has_unmovable)
556 return 1;
557
558 return addr != end ? -EIO : 0;
559}
560
561static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
562 unsigned long addr, unsigned long end,
563 struct mm_walk *walk)
564{
565 int ret = 0;
566#ifdef CONFIG_HUGETLB_PAGE
567 struct queue_pages *qp = walk->private;
568 unsigned long flags = (qp->flags & MPOL_MF_VALID);
569 struct page *page;
570 spinlock_t *ptl;
571 pte_t entry;
572
573 ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
574 entry = huge_ptep_get(pte);
575 if (!pte_present(entry))
576 goto unlock;
577 page = pte_page(entry);
578 if (!queue_pages_required(page, qp))
579 goto unlock;
580
581 if (flags == MPOL_MF_STRICT) {
582 /*
583 * STRICT alone means only detecting misplaced page and no
584 * need to further check other vma.
585 */
586 ret = -EIO;
587 goto unlock;
588 }
589
590 if (!vma_migratable(walk->vma)) {
591 /*
592 * Must be STRICT with MOVE*, otherwise .test_walk() have
593 * stopped walking current vma.
594 * Detecting misplaced page but allow migrating pages which
595 * have been queued.
596 */
597 ret = 1;
598 goto unlock;
599 }
600
601 /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
602 if (flags & (MPOL_MF_MOVE_ALL) ||
603 (flags & MPOL_MF_MOVE && page_mapcount(page) == 1 &&
604 !hugetlb_pmd_shared(pte))) {
605 if (isolate_hugetlb(page, qp->pagelist) &&
606 (flags & MPOL_MF_STRICT))
607 /*
608 * Failed to isolate page but allow migrating pages
609 * which have been queued.
610 */
611 ret = 1;
612 }
613unlock:
614 spin_unlock(ptl);
615#else
616 BUG();
617#endif
618 return ret;
619}
620
621#ifdef CONFIG_NUMA_BALANCING
622/*
623 * This is used to mark a range of virtual addresses to be inaccessible.
624 * These are later cleared by a NUMA hinting fault. Depending on these
625 * faults, pages may be migrated for better NUMA placement.
626 *
627 * This is assuming that NUMA faults are handled using PROT_NONE. If
628 * an architecture makes a different choice, it will need further
629 * changes to the core.
630 */
631unsigned long change_prot_numa(struct vm_area_struct *vma,
632 unsigned long addr, unsigned long end)
633{
634 struct mmu_gather tlb;
635 int nr_updated;
636
637 tlb_gather_mmu(&tlb, vma->vm_mm);
638
639 nr_updated = change_protection(&tlb, vma, addr, end, PAGE_NONE,
640 MM_CP_PROT_NUMA);
641 if (nr_updated)
642 count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
643
644 tlb_finish_mmu(&tlb);
645
646 return nr_updated;
647}
648#else
649static unsigned long change_prot_numa(struct vm_area_struct *vma,
650 unsigned long addr, unsigned long end)
651{
652 return 0;
653}
654#endif /* CONFIG_NUMA_BALANCING */
655
656static int queue_pages_test_walk(unsigned long start, unsigned long end,
657 struct mm_walk *walk)
658{
659 struct vm_area_struct *next, *vma = walk->vma;
660 struct queue_pages *qp = walk->private;
661 unsigned long endvma = vma->vm_end;
662 unsigned long flags = qp->flags;
663
664 /* range check first */
665 VM_BUG_ON_VMA(!range_in_vma(vma, start, end), vma);
666
667 if (!qp->first) {
668 qp->first = vma;
669 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
670 (qp->start < vma->vm_start))
671 /* hole at head side of range */
672 return -EFAULT;
673 }
674 next = find_vma(vma->vm_mm, vma->vm_end);
675 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
676 ((vma->vm_end < qp->end) &&
677 (!next || vma->vm_end < next->vm_start)))
678 /* hole at middle or tail of range */
679 return -EFAULT;
680
681 /*
682 * Need check MPOL_MF_STRICT to return -EIO if possible
683 * regardless of vma_migratable
684 */
685 if (!vma_migratable(vma) &&
686 !(flags & MPOL_MF_STRICT))
687 return 1;
688
689 if (endvma > end)
690 endvma = end;
691
692 if (flags & MPOL_MF_LAZY) {
693 /* Similar to task_numa_work, skip inaccessible VMAs */
694 if (!is_vm_hugetlb_page(vma) && vma_is_accessible(vma) &&
695 !(vma->vm_flags & VM_MIXEDMAP))
696 change_prot_numa(vma, start, endvma);
697 return 1;
698 }
699
700 /* queue pages from current vma */
701 if (flags & MPOL_MF_VALID)
702 return 0;
703 return 1;
704}
705
706static const struct mm_walk_ops queue_pages_walk_ops = {
707 .hugetlb_entry = queue_pages_hugetlb,
708 .pmd_entry = queue_pages_pte_range,
709 .test_walk = queue_pages_test_walk,
710};
711
712/*
713 * Walk through page tables and collect pages to be migrated.
714 *
715 * If pages found in a given range are on a set of nodes (determined by
716 * @nodes and @flags,) it's isolated and queued to the pagelist which is
717 * passed via @private.
718 *
719 * queue_pages_range() has three possible return values:
720 * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
721 * specified.
722 * 0 - queue pages successfully or no misplaced page.
723 * errno - i.e. misplaced pages with MPOL_MF_STRICT specified (-EIO) or
724 * memory range specified by nodemask and maxnode points outside
725 * your accessible address space (-EFAULT)
726 */
727static int
728queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
729 nodemask_t *nodes, unsigned long flags,
730 struct list_head *pagelist)
731{
732 int err;
733 struct queue_pages qp = {
734 .pagelist = pagelist,
735 .flags = flags,
736 .nmask = nodes,
737 .start = start,
738 .end = end,
739 .first = NULL,
740 };
741
742 err = walk_page_range(mm, start, end, &queue_pages_walk_ops, &qp);
743
744 if (!qp.first)
745 /* whole range in hole */
746 err = -EFAULT;
747
748 return err;
749}
750
751/*
752 * Apply policy to a single VMA
753 * This must be called with the mmap_lock held for writing.
754 */
755static int vma_replace_policy(struct vm_area_struct *vma,
756 struct mempolicy *pol)
757{
758 int err;
759 struct mempolicy *old;
760 struct mempolicy *new;
761
762 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
763 vma->vm_start, vma->vm_end, vma->vm_pgoff,
764 vma->vm_ops, vma->vm_file,
765 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
766
767 new = mpol_dup(pol);
768 if (IS_ERR(new))
769 return PTR_ERR(new);
770
771 if (vma->vm_ops && vma->vm_ops->set_policy) {
772 err = vma->vm_ops->set_policy(vma, new);
773 if (err)
774 goto err_out;
775 }
776
777 old = vma->vm_policy;
778 vma->vm_policy = new; /* protected by mmap_lock */
779 mpol_put(old);
780
781 return 0;
782 err_out:
783 mpol_put(new);
784 return err;
785}
786
787/* Step 2: apply policy to a range and do splits. */
788static int mbind_range(struct mm_struct *mm, unsigned long start,
789 unsigned long end, struct mempolicy *new_pol)
790{
791 MA_STATE(mas, &mm->mm_mt, start, start);
792 struct vm_area_struct *prev;
793 struct vm_area_struct *vma;
794 int err = 0;
795 pgoff_t pgoff;
796
797 prev = mas_prev(&mas, 0);
798 if (unlikely(!prev))
799 mas_set(&mas, start);
800
801 vma = mas_find(&mas, end - 1);
802 if (WARN_ON(!vma))
803 return 0;
804
805 if (start > vma->vm_start)
806 prev = vma;
807
808 for (; vma; vma = mas_next(&mas, end - 1)) {
809 unsigned long vmstart = max(start, vma->vm_start);
810 unsigned long vmend = min(end, vma->vm_end);
811
812 if (mpol_equal(vma_policy(vma), new_pol))
813 goto next;
814
815 pgoff = vma->vm_pgoff +
816 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
817 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
818 vma->anon_vma, vma->vm_file, pgoff,
819 new_pol, vma->vm_userfaultfd_ctx,
820 anon_vma_name(vma));
821 if (prev) {
822 /* vma_merge() invalidated the mas */
823 mas_pause(&mas);
824 vma = prev;
825 goto replace;
826 }
827 if (vma->vm_start != vmstart) {
828 err = split_vma(vma->vm_mm, vma, vmstart, 1);
829 if (err)
830 goto out;
831 /* split_vma() invalidated the mas */
832 mas_pause(&mas);
833 }
834 if (vma->vm_end != vmend) {
835 err = split_vma(vma->vm_mm, vma, vmend, 0);
836 if (err)
837 goto out;
838 /* split_vma() invalidated the mas */
839 mas_pause(&mas);
840 }
841replace:
842 err = vma_replace_policy(vma, new_pol);
843 if (err)
844 goto out;
845next:
846 prev = vma;
847 }
848
849out:
850 return err;
851}
852
853/* Set the process memory policy */
854static long do_set_mempolicy(unsigned short mode, unsigned short flags,
855 nodemask_t *nodes)
856{
857 struct mempolicy *new, *old;
858 NODEMASK_SCRATCH(scratch);
859 int ret;
860
861 if (!scratch)
862 return -ENOMEM;
863
864 new = mpol_new(mode, flags, nodes);
865 if (IS_ERR(new)) {
866 ret = PTR_ERR(new);
867 goto out;
868 }
869
870 task_lock(current);
871 ret = mpol_set_nodemask(new, nodes, scratch);
872 if (ret) {
873 task_unlock(current);
874 mpol_put(new);
875 goto out;
876 }
877
878 old = current->mempolicy;
879 current->mempolicy = new;
880 if (new && new->mode == MPOL_INTERLEAVE)
881 current->il_prev = MAX_NUMNODES-1;
882 task_unlock(current);
883 mpol_put(old);
884 ret = 0;
885out:
886 NODEMASK_SCRATCH_FREE(scratch);
887 return ret;
888}
889
890/*
891 * Return nodemask for policy for get_mempolicy() query
892 *
893 * Called with task's alloc_lock held
894 */
895static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
896{
897 nodes_clear(*nodes);
898 if (p == &default_policy)
899 return;
900
901 switch (p->mode) {
902 case MPOL_BIND:
903 case MPOL_INTERLEAVE:
904 case MPOL_PREFERRED:
905 case MPOL_PREFERRED_MANY:
906 *nodes = p->nodes;
907 break;
908 case MPOL_LOCAL:
909 /* return empty node mask for local allocation */
910 break;
911 default:
912 BUG();
913 }
914}
915
916static int lookup_node(struct mm_struct *mm, unsigned long addr)
917{
918 struct page *p = NULL;
919 int ret;
920
921 ret = get_user_pages_fast(addr & PAGE_MASK, 1, 0, &p);
922 if (ret > 0) {
923 ret = page_to_nid(p);
924 put_page(p);
925 }
926 return ret;
927}
928
929/* Retrieve NUMA policy */
930static long do_get_mempolicy(int *policy, nodemask_t *nmask,
931 unsigned long addr, unsigned long flags)
932{
933 int err;
934 struct mm_struct *mm = current->mm;
935 struct vm_area_struct *vma = NULL;
936 struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL;
937
938 if (flags &
939 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
940 return -EINVAL;
941
942 if (flags & MPOL_F_MEMS_ALLOWED) {
943 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
944 return -EINVAL;
945 *policy = 0; /* just so it's initialized */
946 task_lock(current);
947 *nmask = cpuset_current_mems_allowed;
948 task_unlock(current);
949 return 0;
950 }
951
952 if (flags & MPOL_F_ADDR) {
953 /*
954 * Do NOT fall back to task policy if the
955 * vma/shared policy at addr is NULL. We
956 * want to return MPOL_DEFAULT in this case.
957 */
958 mmap_read_lock(mm);
959 vma = vma_lookup(mm, addr);
960 if (!vma) {
961 mmap_read_unlock(mm);
962 return -EFAULT;
963 }
964 if (vma->vm_ops && vma->vm_ops->get_policy)
965 pol = vma->vm_ops->get_policy(vma, addr);
966 else
967 pol = vma->vm_policy;
968 } else if (addr)
969 return -EINVAL;
970
971 if (!pol)
972 pol = &default_policy; /* indicates default behavior */
973
974 if (flags & MPOL_F_NODE) {
975 if (flags & MPOL_F_ADDR) {
976 /*
977 * Take a refcount on the mpol, because we are about to
978 * drop the mmap_lock, after which only "pol" remains
979 * valid, "vma" is stale.
980 */
981 pol_refcount = pol;
982 vma = NULL;
983 mpol_get(pol);
984 mmap_read_unlock(mm);
985 err = lookup_node(mm, addr);
986 if (err < 0)
987 goto out;
988 *policy = err;
989 } else if (pol == current->mempolicy &&
990 pol->mode == MPOL_INTERLEAVE) {
991 *policy = next_node_in(current->il_prev, pol->nodes);
992 } else {
993 err = -EINVAL;
994 goto out;
995 }
996 } else {
997 *policy = pol == &default_policy ? MPOL_DEFAULT :
998 pol->mode;
999 /*
1000 * Internal mempolicy flags must be masked off before exposing
1001 * the policy to userspace.
1002 */
1003 *policy |= (pol->flags & MPOL_MODE_FLAGS);
1004 }
1005
1006 err = 0;
1007 if (nmask) {
1008 if (mpol_store_user_nodemask(pol)) {
1009 *nmask = pol->w.user_nodemask;
1010 } else {
1011 task_lock(current);
1012 get_policy_nodemask(pol, nmask);
1013 task_unlock(current);
1014 }
1015 }
1016
1017 out:
1018 mpol_cond_put(pol);
1019 if (vma)
1020 mmap_read_unlock(mm);
1021 if (pol_refcount)
1022 mpol_put(pol_refcount);
1023 return err;
1024}
1025
1026#ifdef CONFIG_MIGRATION
1027/*
1028 * page migration, thp tail pages can be passed.
1029 */
1030static int migrate_page_add(struct page *page, struct list_head *pagelist,
1031 unsigned long flags)
1032{
1033 struct page *head = compound_head(page);
1034 /*
1035 * Avoid migrating a page that is shared with others.
1036 */
1037 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(head) == 1) {
1038 if (!isolate_lru_page(head)) {
1039 list_add_tail(&head->lru, pagelist);
1040 mod_node_page_state(page_pgdat(head),
1041 NR_ISOLATED_ANON + page_is_file_lru(head),
1042 thp_nr_pages(head));
1043 } else if (flags & MPOL_MF_STRICT) {
1044 /*
1045 * Non-movable page may reach here. And, there may be
1046 * temporary off LRU pages or non-LRU movable pages.
1047 * Treat them as unmovable pages since they can't be
1048 * isolated, so they can't be moved at the moment. It
1049 * should return -EIO for this case too.
1050 */
1051 return -EIO;
1052 }
1053 }
1054
1055 return 0;
1056}
1057
1058/*
1059 * Migrate pages from one node to a target node.
1060 * Returns error or the number of pages not migrated.
1061 */
1062static int migrate_to_node(struct mm_struct *mm, int source, int dest,
1063 int flags)
1064{
1065 nodemask_t nmask;
1066 struct vm_area_struct *vma;
1067 LIST_HEAD(pagelist);
1068 int err = 0;
1069 struct migration_target_control mtc = {
1070 .nid = dest,
1071 .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE,
1072 };
1073
1074 nodes_clear(nmask);
1075 node_set(source, nmask);
1076
1077 /*
1078 * This does not "check" the range but isolates all pages that
1079 * need migration. Between passing in the full user address
1080 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
1081 */
1082 vma = find_vma(mm, 0);
1083 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
1084 queue_pages_range(mm, vma->vm_start, mm->task_size, &nmask,
1085 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
1086
1087 if (!list_empty(&pagelist)) {
1088 err = migrate_pages(&pagelist, alloc_migration_target, NULL,
1089 (unsigned long)&mtc, MIGRATE_SYNC, MR_SYSCALL, NULL);
1090 if (err)
1091 putback_movable_pages(&pagelist);
1092 }
1093
1094 return err;
1095}
1096
1097/*
1098 * Move pages between the two nodesets so as to preserve the physical
1099 * layout as much as possible.
1100 *
1101 * Returns the number of page that could not be moved.
1102 */
1103int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1104 const nodemask_t *to, int flags)
1105{
1106 int busy = 0;
1107 int err = 0;
1108 nodemask_t tmp;
1109
1110 lru_cache_disable();
1111
1112 mmap_read_lock(mm);
1113
1114 /*
1115 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1116 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1117 * bit in 'tmp', and return that <source, dest> pair for migration.
1118 * The pair of nodemasks 'to' and 'from' define the map.
1119 *
1120 * If no pair of bits is found that way, fallback to picking some
1121 * pair of 'source' and 'dest' bits that are not the same. If the
1122 * 'source' and 'dest' bits are the same, this represents a node
1123 * that will be migrating to itself, so no pages need move.
1124 *
1125 * If no bits are left in 'tmp', or if all remaining bits left
1126 * in 'tmp' correspond to the same bit in 'to', return false
1127 * (nothing left to migrate).
1128 *
1129 * This lets us pick a pair of nodes to migrate between, such that
1130 * if possible the dest node is not already occupied by some other
1131 * source node, minimizing the risk of overloading the memory on a
1132 * node that would happen if we migrated incoming memory to a node
1133 * before migrating outgoing memory source that same node.
1134 *
1135 * A single scan of tmp is sufficient. As we go, we remember the
1136 * most recent <s, d> pair that moved (s != d). If we find a pair
1137 * that not only moved, but what's better, moved to an empty slot
1138 * (d is not set in tmp), then we break out then, with that pair.
1139 * Otherwise when we finish scanning from_tmp, we at least have the
1140 * most recent <s, d> pair that moved. If we get all the way through
1141 * the scan of tmp without finding any node that moved, much less
1142 * moved to an empty node, then there is nothing left worth migrating.
1143 */
1144
1145 tmp = *from;
1146 while (!nodes_empty(tmp)) {
1147 int s, d;
1148 int source = NUMA_NO_NODE;
1149 int dest = 0;
1150
1151 for_each_node_mask(s, tmp) {
1152
1153 /*
1154 * do_migrate_pages() tries to maintain the relative
1155 * node relationship of the pages established between
1156 * threads and memory areas.
1157 *
1158 * However if the number of source nodes is not equal to
1159 * the number of destination nodes we can not preserve
1160 * this node relative relationship. In that case, skip
1161 * copying memory from a node that is in the destination
1162 * mask.
1163 *
1164 * Example: [2,3,4] -> [3,4,5] moves everything.
1165 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1166 */
1167
1168 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1169 (node_isset(s, *to)))
1170 continue;
1171
1172 d = node_remap(s, *from, *to);
1173 if (s == d)
1174 continue;
1175
1176 source = s; /* Node moved. Memorize */
1177 dest = d;
1178
1179 /* dest not in remaining from nodes? */
1180 if (!node_isset(dest, tmp))
1181 break;
1182 }
1183 if (source == NUMA_NO_NODE)
1184 break;
1185
1186 node_clear(source, tmp);
1187 err = migrate_to_node(mm, source, dest, flags);
1188 if (err > 0)
1189 busy += err;
1190 if (err < 0)
1191 break;
1192 }
1193 mmap_read_unlock(mm);
1194
1195 lru_cache_enable();
1196 if (err < 0)
1197 return err;
1198 return busy;
1199
1200}
1201
1202/*
1203 * Allocate a new page for page migration based on vma policy.
1204 * Start by assuming the page is mapped by the same vma as contains @start.
1205 * Search forward from there, if not. N.B., this assumes that the
1206 * list of pages handed to migrate_pages()--which is how we get here--
1207 * is in virtual address order.
1208 */
1209static struct page *new_page(struct page *page, unsigned long start)
1210{
1211 struct folio *dst, *src = page_folio(page);
1212 struct vm_area_struct *vma;
1213 unsigned long address;
1214 VMA_ITERATOR(vmi, current->mm, start);
1215 gfp_t gfp = GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL;
1216
1217 for_each_vma(vmi, vma) {
1218 address = page_address_in_vma(page, vma);
1219 if (address != -EFAULT)
1220 break;
1221 }
1222
1223 if (folio_test_hugetlb(src))
1224 return alloc_huge_page_vma(page_hstate(&src->page),
1225 vma, address);
1226
1227 if (folio_test_large(src))
1228 gfp = GFP_TRANSHUGE;
1229
1230 /*
1231 * if !vma, vma_alloc_folio() will use task or system default policy
1232 */
1233 dst = vma_alloc_folio(gfp, folio_order(src), vma, address,
1234 folio_test_large(src));
1235 return &dst->page;
1236}
1237#else
1238
1239static int migrate_page_add(struct page *page, struct list_head *pagelist,
1240 unsigned long flags)
1241{
1242 return -EIO;
1243}
1244
1245int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1246 const nodemask_t *to, int flags)
1247{
1248 return -ENOSYS;
1249}
1250
1251static struct page *new_page(struct page *page, unsigned long start)
1252{
1253 return NULL;
1254}
1255#endif
1256
1257static long do_mbind(unsigned long start, unsigned long len,
1258 unsigned short mode, unsigned short mode_flags,
1259 nodemask_t *nmask, unsigned long flags)
1260{
1261 struct mm_struct *mm = current->mm;
1262 struct mempolicy *new;
1263 unsigned long end;
1264 int err;
1265 int ret;
1266 LIST_HEAD(pagelist);
1267
1268 if (flags & ~(unsigned long)MPOL_MF_VALID)
1269 return -EINVAL;
1270 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1271 return -EPERM;
1272
1273 if (start & ~PAGE_MASK)
1274 return -EINVAL;
1275
1276 if (mode == MPOL_DEFAULT)
1277 flags &= ~MPOL_MF_STRICT;
1278
1279 len = PAGE_ALIGN(len);
1280 end = start + len;
1281
1282 if (end < start)
1283 return -EINVAL;
1284 if (end == start)
1285 return 0;
1286
1287 new = mpol_new(mode, mode_flags, nmask);
1288 if (IS_ERR(new))
1289 return PTR_ERR(new);
1290
1291 if (flags & MPOL_MF_LAZY)
1292 new->flags |= MPOL_F_MOF;
1293
1294 /*
1295 * If we are using the default policy then operation
1296 * on discontinuous address spaces is okay after all
1297 */
1298 if (!new)
1299 flags |= MPOL_MF_DISCONTIG_OK;
1300
1301 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1302 start, start + len, mode, mode_flags,
1303 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1304
1305 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1306
1307 lru_cache_disable();
1308 }
1309 {
1310 NODEMASK_SCRATCH(scratch);
1311 if (scratch) {
1312 mmap_write_lock(mm);
1313 err = mpol_set_nodemask(new, nmask, scratch);
1314 if (err)
1315 mmap_write_unlock(mm);
1316 } else
1317 err = -ENOMEM;
1318 NODEMASK_SCRATCH_FREE(scratch);
1319 }
1320 if (err)
1321 goto mpol_out;
1322
1323 ret = queue_pages_range(mm, start, end, nmask,
1324 flags | MPOL_MF_INVERT, &pagelist);
1325
1326 if (ret < 0) {
1327 err = ret;
1328 goto up_out;
1329 }
1330
1331 err = mbind_range(mm, start, end, new);
1332
1333 if (!err) {
1334 int nr_failed = 0;
1335
1336 if (!list_empty(&pagelist)) {
1337 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1338 nr_failed = migrate_pages(&pagelist, new_page, NULL,
1339 start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND, NULL);
1340 if (nr_failed)
1341 putback_movable_pages(&pagelist);
1342 }
1343
1344 if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
1345 err = -EIO;
1346 } else {
1347up_out:
1348 if (!list_empty(&pagelist))
1349 putback_movable_pages(&pagelist);
1350 }
1351
1352 mmap_write_unlock(mm);
1353mpol_out:
1354 mpol_put(new);
1355 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1356 lru_cache_enable();
1357 return err;
1358}
1359
1360/*
1361 * User space interface with variable sized bitmaps for nodelists.
1362 */
1363static int get_bitmap(unsigned long *mask, const unsigned long __user *nmask,
1364 unsigned long maxnode)
1365{
1366 unsigned long nlongs = BITS_TO_LONGS(maxnode);
1367 int ret;
1368
1369 if (in_compat_syscall())
1370 ret = compat_get_bitmap(mask,
1371 (const compat_ulong_t __user *)nmask,
1372 maxnode);
1373 else
1374 ret = copy_from_user(mask, nmask,
1375 nlongs * sizeof(unsigned long));
1376
1377 if (ret)
1378 return -EFAULT;
1379
1380 if (maxnode % BITS_PER_LONG)
1381 mask[nlongs - 1] &= (1UL << (maxnode % BITS_PER_LONG)) - 1;
1382
1383 return 0;
1384}
1385
1386/* Copy a node mask from user space. */
1387static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1388 unsigned long maxnode)
1389{
1390 --maxnode;
1391 nodes_clear(*nodes);
1392 if (maxnode == 0 || !nmask)
1393 return 0;
1394 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1395 return -EINVAL;
1396
1397 /*
1398 * When the user specified more nodes than supported just check
1399 * if the non supported part is all zero, one word at a time,
1400 * starting at the end.
1401 */
1402 while (maxnode > MAX_NUMNODES) {
1403 unsigned long bits = min_t(unsigned long, maxnode, BITS_PER_LONG);
1404 unsigned long t;
1405
1406 if (get_bitmap(&t, &nmask[(maxnode - 1) / BITS_PER_LONG], bits))
1407 return -EFAULT;
1408
1409 if (maxnode - bits >= MAX_NUMNODES) {
1410 maxnode -= bits;
1411 } else {
1412 maxnode = MAX_NUMNODES;
1413 t &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
1414 }
1415 if (t)
1416 return -EINVAL;
1417 }
1418
1419 return get_bitmap(nodes_addr(*nodes), nmask, maxnode);
1420}
1421
1422/* Copy a kernel node mask to user space */
1423static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1424 nodemask_t *nodes)
1425{
1426 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1427 unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long);
1428 bool compat = in_compat_syscall();
1429
1430 if (compat)
1431 nbytes = BITS_TO_COMPAT_LONGS(nr_node_ids) * sizeof(compat_long_t);
1432
1433 if (copy > nbytes) {
1434 if (copy > PAGE_SIZE)
1435 return -EINVAL;
1436 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1437 return -EFAULT;
1438 copy = nbytes;
1439 maxnode = nr_node_ids;
1440 }
1441
1442 if (compat)
1443 return compat_put_bitmap((compat_ulong_t __user *)mask,
1444 nodes_addr(*nodes), maxnode);
1445
1446 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1447}
1448
1449/* Basic parameter sanity check used by both mbind() and set_mempolicy() */
1450static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)
1451{
1452 *flags = *mode & MPOL_MODE_FLAGS;
1453 *mode &= ~MPOL_MODE_FLAGS;
1454
1455 if ((unsigned int)(*mode) >= MPOL_MAX)
1456 return -EINVAL;
1457 if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))
1458 return -EINVAL;
1459 if (*flags & MPOL_F_NUMA_BALANCING) {
1460 if (*mode != MPOL_BIND)
1461 return -EINVAL;
1462 *flags |= (MPOL_F_MOF | MPOL_F_MORON);
1463 }
1464 return 0;
1465}
1466
1467static long kernel_mbind(unsigned long start, unsigned long len,
1468 unsigned long mode, const unsigned long __user *nmask,
1469 unsigned long maxnode, unsigned int flags)
1470{
1471 unsigned short mode_flags;
1472 nodemask_t nodes;
1473 int lmode = mode;
1474 int err;
1475
1476 start = untagged_addr(start);
1477 err = sanitize_mpol_flags(&lmode, &mode_flags);
1478 if (err)
1479 return err;
1480
1481 err = get_nodes(&nodes, nmask, maxnode);
1482 if (err)
1483 return err;
1484
1485 return do_mbind(start, len, lmode, mode_flags, &nodes, flags);
1486}
1487
1488SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, len,
1489 unsigned long, home_node, unsigned long, flags)
1490{
1491 struct mm_struct *mm = current->mm;
1492 struct vm_area_struct *vma;
1493 struct mempolicy *new;
1494 unsigned long vmstart;
1495 unsigned long vmend;
1496 unsigned long end;
1497 int err = -ENOENT;
1498 VMA_ITERATOR(vmi, mm, start);
1499
1500 start = untagged_addr(start);
1501 if (start & ~PAGE_MASK)
1502 return -EINVAL;
1503 /*
1504 * flags is used for future extension if any.
1505 */
1506 if (flags != 0)
1507 return -EINVAL;
1508
1509 /*
1510 * Check home_node is online to avoid accessing uninitialized
1511 * NODE_DATA.
1512 */
1513 if (home_node >= MAX_NUMNODES || !node_online(home_node))
1514 return -EINVAL;
1515
1516 len = PAGE_ALIGN(len);
1517 end = start + len;
1518
1519 if (end < start)
1520 return -EINVAL;
1521 if (end == start)
1522 return 0;
1523 mmap_write_lock(mm);
1524 for_each_vma_range(vmi, vma, end) {
1525 vmstart = max(start, vma->vm_start);
1526 vmend = min(end, vma->vm_end);
1527 new = mpol_dup(vma_policy(vma));
1528 if (IS_ERR(new)) {
1529 err = PTR_ERR(new);
1530 break;
1531 }
1532 /*
1533 * Only update home node if there is an existing vma policy
1534 */
1535 if (!new)
1536 continue;
1537
1538 /*
1539 * If any vma in the range got policy other than MPOL_BIND
1540 * or MPOL_PREFERRED_MANY we return error. We don't reset
1541 * the home node for vmas we already updated before.
1542 */
1543 if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
1544 mpol_put(new);
1545 err = -EOPNOTSUPP;
1546 break;
1547 }
1548
1549 new->home_node = home_node;
1550 err = mbind_range(mm, vmstart, vmend, new);
1551 mpol_put(new);
1552 if (err)
1553 break;
1554 }
1555 mmap_write_unlock(mm);
1556 return err;
1557}
1558
1559SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1560 unsigned long, mode, const unsigned long __user *, nmask,
1561 unsigned long, maxnode, unsigned int, flags)
1562{
1563 return kernel_mbind(start, len, mode, nmask, maxnode, flags);
1564}
1565
1566/* Set the process memory policy */
1567static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
1568 unsigned long maxnode)
1569{
1570 unsigned short mode_flags;
1571 nodemask_t nodes;
1572 int lmode = mode;
1573 int err;
1574
1575 err = sanitize_mpol_flags(&lmode, &mode_flags);
1576 if (err)
1577 return err;
1578
1579 err = get_nodes(&nodes, nmask, maxnode);
1580 if (err)
1581 return err;
1582
1583 return do_set_mempolicy(lmode, mode_flags, &nodes);
1584}
1585
1586SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
1587 unsigned long, maxnode)
1588{
1589 return kernel_set_mempolicy(mode, nmask, maxnode);
1590}
1591
1592static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
1593 const unsigned long __user *old_nodes,
1594 const unsigned long __user *new_nodes)
1595{
1596 struct mm_struct *mm = NULL;
1597 struct task_struct *task;
1598 nodemask_t task_nodes;
1599 int err;
1600 nodemask_t *old;
1601 nodemask_t *new;
1602 NODEMASK_SCRATCH(scratch);
1603
1604 if (!scratch)
1605 return -ENOMEM;
1606
1607 old = &scratch->mask1;
1608 new = &scratch->mask2;
1609
1610 err = get_nodes(old, old_nodes, maxnode);
1611 if (err)
1612 goto out;
1613
1614 err = get_nodes(new, new_nodes, maxnode);
1615 if (err)
1616 goto out;
1617
1618 /* Find the mm_struct */
1619 rcu_read_lock();
1620 task = pid ? find_task_by_vpid(pid) : current;
1621 if (!task) {
1622 rcu_read_unlock();
1623 err = -ESRCH;
1624 goto out;
1625 }
1626 get_task_struct(task);
1627
1628 err = -EINVAL;
1629
1630 /*
1631 * Check if this process has the right to modify the specified process.
1632 * Use the regular "ptrace_may_access()" checks.
1633 */
1634 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
1635 rcu_read_unlock();
1636 err = -EPERM;
1637 goto out_put;
1638 }
1639 rcu_read_unlock();
1640
1641 task_nodes = cpuset_mems_allowed(task);
1642 /* Is the user allowed to access the target nodes? */
1643 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1644 err = -EPERM;
1645 goto out_put;
1646 }
1647
1648 task_nodes = cpuset_mems_allowed(current);
1649 nodes_and(*new, *new, task_nodes);
1650 if (nodes_empty(*new))
1651 goto out_put;
1652
1653 err = security_task_movememory(task);
1654 if (err)
1655 goto out_put;
1656
1657 mm = get_task_mm(task);
1658 put_task_struct(task);
1659
1660 if (!mm) {
1661 err = -EINVAL;
1662 goto out;
1663 }
1664
1665 err = do_migrate_pages(mm, old, new,
1666 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1667
1668 mmput(mm);
1669out:
1670 NODEMASK_SCRATCH_FREE(scratch);
1671
1672 return err;
1673
1674out_put:
1675 put_task_struct(task);
1676 goto out;
1677
1678}
1679
1680SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1681 const unsigned long __user *, old_nodes,
1682 const unsigned long __user *, new_nodes)
1683{
1684 return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes);
1685}
1686
1687
1688/* Retrieve NUMA policy */
1689static int kernel_get_mempolicy(int __user *policy,
1690 unsigned long __user *nmask,
1691 unsigned long maxnode,
1692 unsigned long addr,
1693 unsigned long flags)
1694{
1695 int err;
1696 int pval;
1697 nodemask_t nodes;
1698
1699 if (nmask != NULL && maxnode < nr_node_ids)
1700 return -EINVAL;
1701
1702 addr = untagged_addr(addr);
1703
1704 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1705
1706 if (err)
1707 return err;
1708
1709 if (policy && put_user(pval, policy))
1710 return -EFAULT;
1711
1712 if (nmask)
1713 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1714
1715 return err;
1716}
1717
1718SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1719 unsigned long __user *, nmask, unsigned long, maxnode,
1720 unsigned long, addr, unsigned long, flags)
1721{
1722 return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags);
1723}
1724
1725bool vma_migratable(struct vm_area_struct *vma)
1726{
1727 if (vma->vm_flags & (VM_IO | VM_PFNMAP))
1728 return false;
1729
1730 /*
1731 * DAX device mappings require predictable access latency, so avoid
1732 * incurring periodic faults.
1733 */
1734 if (vma_is_dax(vma))
1735 return false;
1736
1737 if (is_vm_hugetlb_page(vma) &&
1738 !hugepage_migration_supported(hstate_vma(vma)))
1739 return false;
1740
1741 /*
1742 * Migration allocates pages in the highest zone. If we cannot
1743 * do so then migration (at least from node to node) is not
1744 * possible.
1745 */
1746 if (vma->vm_file &&
1747 gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
1748 < policy_zone)
1749 return false;
1750 return true;
1751}
1752
1753struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
1754 unsigned long addr)
1755{
1756 struct mempolicy *pol = NULL;
1757
1758 if (vma) {
1759 if (vma->vm_ops && vma->vm_ops->get_policy) {
1760 pol = vma->vm_ops->get_policy(vma, addr);
1761 } else if (vma->vm_policy) {
1762 pol = vma->vm_policy;
1763
1764 /*
1765 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1766 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1767 * count on these policies which will be dropped by
1768 * mpol_cond_put() later
1769 */
1770 if (mpol_needs_cond_ref(pol))
1771 mpol_get(pol);
1772 }
1773 }
1774
1775 return pol;
1776}
1777
1778/*
1779 * get_vma_policy(@vma, @addr)
1780 * @vma: virtual memory area whose policy is sought
1781 * @addr: address in @vma for shared policy lookup
1782 *
1783 * Returns effective policy for a VMA at specified address.
1784 * Falls back to current->mempolicy or system default policy, as necessary.
1785 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1786 * count--added by the get_policy() vm_op, as appropriate--to protect against
1787 * freeing by another task. It is the caller's responsibility to free the
1788 * extra reference for shared policies.
1789 */
1790static struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
1791 unsigned long addr)
1792{
1793 struct mempolicy *pol = __get_vma_policy(vma, addr);
1794
1795 if (!pol)
1796 pol = get_task_policy(current);
1797
1798 return pol;
1799}
1800
1801bool vma_policy_mof(struct vm_area_struct *vma)
1802{
1803 struct mempolicy *pol;
1804
1805 if (vma->vm_ops && vma->vm_ops->get_policy) {
1806 bool ret = false;
1807
1808 pol = vma->vm_ops->get_policy(vma, vma->vm_start);
1809 if (pol && (pol->flags & MPOL_F_MOF))
1810 ret = true;
1811 mpol_cond_put(pol);
1812
1813 return ret;
1814 }
1815
1816 pol = vma->vm_policy;
1817 if (!pol)
1818 pol = get_task_policy(current);
1819
1820 return pol->flags & MPOL_F_MOF;
1821}
1822
1823bool apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1824{
1825 enum zone_type dynamic_policy_zone = policy_zone;
1826
1827 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1828
1829 /*
1830 * if policy->nodes has movable memory only,
1831 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1832 *
1833 * policy->nodes is intersect with node_states[N_MEMORY].
1834 * so if the following test fails, it implies
1835 * policy->nodes has movable memory only.
1836 */
1837 if (!nodes_intersects(policy->nodes, node_states[N_HIGH_MEMORY]))
1838 dynamic_policy_zone = ZONE_MOVABLE;
1839
1840 return zone >= dynamic_policy_zone;
1841}
1842
1843/*
1844 * Return a nodemask representing a mempolicy for filtering nodes for
1845 * page allocation
1846 */
1847nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1848{
1849 int mode = policy->mode;
1850
1851 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1852 if (unlikely(mode == MPOL_BIND) &&
1853 apply_policy_zone(policy, gfp_zone(gfp)) &&
1854 cpuset_nodemask_valid_mems_allowed(&policy->nodes))
1855 return &policy->nodes;
1856
1857 if (mode == MPOL_PREFERRED_MANY)
1858 return &policy->nodes;
1859
1860 return NULL;
1861}
1862
1863/*
1864 * Return the preferred node id for 'prefer' mempolicy, and return
1865 * the given id for all other policies.
1866 *
1867 * policy_node() is always coupled with policy_nodemask(), which
1868 * secures the nodemask limit for 'bind' and 'prefer-many' policy.
1869 */
1870static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd)
1871{
1872 if (policy->mode == MPOL_PREFERRED) {
1873 nd = first_node(policy->nodes);
1874 } else {
1875 /*
1876 * __GFP_THISNODE shouldn't even be used with the bind policy
1877 * because we might easily break the expectation to stay on the
1878 * requested node and not break the policy.
1879 */
1880 WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE));
1881 }
1882
1883 if ((policy->mode == MPOL_BIND ||
1884 policy->mode == MPOL_PREFERRED_MANY) &&
1885 policy->home_node != NUMA_NO_NODE)
1886 return policy->home_node;
1887
1888 return nd;
1889}
1890
1891/* Do dynamic interleaving for a process */
1892static unsigned interleave_nodes(struct mempolicy *policy)
1893{
1894 unsigned next;
1895 struct task_struct *me = current;
1896
1897 next = next_node_in(me->il_prev, policy->nodes);
1898 if (next < MAX_NUMNODES)
1899 me->il_prev = next;
1900 return next;
1901}
1902
1903/*
1904 * Depending on the memory policy provide a node from which to allocate the
1905 * next slab entry.
1906 */
1907unsigned int mempolicy_slab_node(void)
1908{
1909 struct mempolicy *policy;
1910 int node = numa_mem_id();
1911
1912 if (!in_task())
1913 return node;
1914
1915 policy = current->mempolicy;
1916 if (!policy)
1917 return node;
1918
1919 switch (policy->mode) {
1920 case MPOL_PREFERRED:
1921 return first_node(policy->nodes);
1922
1923 case MPOL_INTERLEAVE:
1924 return interleave_nodes(policy);
1925
1926 case MPOL_BIND:
1927 case MPOL_PREFERRED_MANY:
1928 {
1929 struct zoneref *z;
1930
1931 /*
1932 * Follow bind policy behavior and start allocation at the
1933 * first node.
1934 */
1935 struct zonelist *zonelist;
1936 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1937 zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK];
1938 z = first_zones_zonelist(zonelist, highest_zoneidx,
1939 &policy->nodes);
1940 return z->zone ? zone_to_nid(z->zone) : node;
1941 }
1942 case MPOL_LOCAL:
1943 return node;
1944
1945 default:
1946 BUG();
1947 }
1948}
1949
1950/*
1951 * Do static interleaving for a VMA with known offset @n. Returns the n'th
1952 * node in pol->nodes (starting from n=0), wrapping around if n exceeds the
1953 * number of present nodes.
1954 */
1955static unsigned offset_il_node(struct mempolicy *pol, unsigned long n)
1956{
1957 nodemask_t nodemask = pol->nodes;
1958 unsigned int target, nnodes;
1959 int i;
1960 int nid;
1961 /*
1962 * The barrier will stabilize the nodemask in a register or on
1963 * the stack so that it will stop changing under the code.
1964 *
1965 * Between first_node() and next_node(), pol->nodes could be changed
1966 * by other threads. So we put pol->nodes in a local stack.
1967 */
1968 barrier();
1969
1970 nnodes = nodes_weight(nodemask);
1971 if (!nnodes)
1972 return numa_node_id();
1973 target = (unsigned int)n % nnodes;
1974 nid = first_node(nodemask);
1975 for (i = 0; i < target; i++)
1976 nid = next_node(nid, nodemask);
1977 return nid;
1978}
1979
1980/* Determine a node number for interleave */
1981static inline unsigned interleave_nid(struct mempolicy *pol,
1982 struct vm_area_struct *vma, unsigned long addr, int shift)
1983{
1984 if (vma) {
1985 unsigned long off;
1986
1987 /*
1988 * for small pages, there is no difference between
1989 * shift and PAGE_SHIFT, so the bit-shift is safe.
1990 * for huge pages, since vm_pgoff is in units of small
1991 * pages, we need to shift off the always 0 bits to get
1992 * a useful offset.
1993 */
1994 BUG_ON(shift < PAGE_SHIFT);
1995 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1996 off += (addr - vma->vm_start) >> shift;
1997 return offset_il_node(pol, off);
1998 } else
1999 return interleave_nodes(pol);
2000}
2001
2002#ifdef CONFIG_HUGETLBFS
2003/*
2004 * huge_node(@vma, @addr, @gfp_flags, @mpol)
2005 * @vma: virtual memory area whose policy is sought
2006 * @addr: address in @vma for shared policy lookup and interleave policy
2007 * @gfp_flags: for requested zone
2008 * @mpol: pointer to mempolicy pointer for reference counted mempolicy
2009 * @nodemask: pointer to nodemask pointer for 'bind' and 'prefer-many' policy
2010 *
2011 * Returns a nid suitable for a huge page allocation and a pointer
2012 * to the struct mempolicy for conditional unref after allocation.
2013 * If the effective policy is 'bind' or 'prefer-many', returns a pointer
2014 * to the mempolicy's @nodemask for filtering the zonelist.
2015 *
2016 * Must be protected by read_mems_allowed_begin()
2017 */
2018int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags,
2019 struct mempolicy **mpol, nodemask_t **nodemask)
2020{
2021 int nid;
2022 int mode;
2023
2024 *mpol = get_vma_policy(vma, addr);
2025 *nodemask = NULL;
2026 mode = (*mpol)->mode;
2027
2028 if (unlikely(mode == MPOL_INTERLEAVE)) {
2029 nid = interleave_nid(*mpol, vma, addr,
2030 huge_page_shift(hstate_vma(vma)));
2031 } else {
2032 nid = policy_node(gfp_flags, *mpol, numa_node_id());
2033 if (mode == MPOL_BIND || mode == MPOL_PREFERRED_MANY)
2034 *nodemask = &(*mpol)->nodes;
2035 }
2036 return nid;
2037}
2038
2039/*
2040 * init_nodemask_of_mempolicy
2041 *
2042 * If the current task's mempolicy is "default" [NULL], return 'false'
2043 * to indicate default policy. Otherwise, extract the policy nodemask
2044 * for 'bind' or 'interleave' policy into the argument nodemask, or
2045 * initialize the argument nodemask to contain the single node for
2046 * 'preferred' or 'local' policy and return 'true' to indicate presence
2047 * of non-default mempolicy.
2048 *
2049 * We don't bother with reference counting the mempolicy [mpol_get/put]
2050 * because the current task is examining it's own mempolicy and a task's
2051 * mempolicy is only ever changed by the task itself.
2052 *
2053 * N.B., it is the caller's responsibility to free a returned nodemask.
2054 */
2055bool init_nodemask_of_mempolicy(nodemask_t *mask)
2056{
2057 struct mempolicy *mempolicy;
2058
2059 if (!(mask && current->mempolicy))
2060 return false;
2061
2062 task_lock(current);
2063 mempolicy = current->mempolicy;
2064 switch (mempolicy->mode) {
2065 case MPOL_PREFERRED:
2066 case MPOL_PREFERRED_MANY:
2067 case MPOL_BIND:
2068 case MPOL_INTERLEAVE:
2069 *mask = mempolicy->nodes;
2070 break;
2071
2072 case MPOL_LOCAL:
2073 init_nodemask_of_node(mask, numa_node_id());
2074 break;
2075
2076 default:
2077 BUG();
2078 }
2079 task_unlock(current);
2080
2081 return true;
2082}
2083#endif
2084
2085/*
2086 * mempolicy_in_oom_domain
2087 *
2088 * If tsk's mempolicy is "bind", check for intersection between mask and
2089 * the policy nodemask. Otherwise, return true for all other policies
2090 * including "interleave", as a tsk with "interleave" policy may have
2091 * memory allocated from all nodes in system.
2092 *
2093 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
2094 */
2095bool mempolicy_in_oom_domain(struct task_struct *tsk,
2096 const nodemask_t *mask)
2097{
2098 struct mempolicy *mempolicy;
2099 bool ret = true;
2100
2101 if (!mask)
2102 return ret;
2103
2104 task_lock(tsk);
2105 mempolicy = tsk->mempolicy;
2106 if (mempolicy && mempolicy->mode == MPOL_BIND)
2107 ret = nodes_intersects(mempolicy->nodes, *mask);
2108 task_unlock(tsk);
2109
2110 return ret;
2111}
2112
2113/* Allocate a page in interleaved policy.
2114 Own path because it needs to do special accounting. */
2115static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
2116 unsigned nid)
2117{
2118 struct page *page;
2119
2120 page = __alloc_pages(gfp, order, nid, NULL);
2121 /* skip NUMA_INTERLEAVE_HIT counter update if numa stats is disabled */
2122 if (!static_branch_likely(&vm_numa_stat_key))
2123 return page;
2124 if (page && page_to_nid(page) == nid) {
2125 preempt_disable();
2126 __count_numa_event(page_zone(page), NUMA_INTERLEAVE_HIT);
2127 preempt_enable();
2128 }
2129 return page;
2130}
2131
2132static struct page *alloc_pages_preferred_many(gfp_t gfp, unsigned int order,
2133 int nid, struct mempolicy *pol)
2134{
2135 struct page *page;
2136 gfp_t preferred_gfp;
2137
2138 /*
2139 * This is a two pass approach. The first pass will only try the
2140 * preferred nodes but skip the direct reclaim and allow the
2141 * allocation to fail, while the second pass will try all the
2142 * nodes in system.
2143 */
2144 preferred_gfp = gfp | __GFP_NOWARN;
2145 preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
2146 page = __alloc_pages(preferred_gfp, order, nid, &pol->nodes);
2147 if (!page)
2148 page = __alloc_pages(gfp, order, nid, NULL);
2149
2150 return page;
2151}
2152
2153/**
2154 * vma_alloc_folio - Allocate a folio for a VMA.
2155 * @gfp: GFP flags.
2156 * @order: Order of the folio.
2157 * @vma: Pointer to VMA or NULL if not available.
2158 * @addr: Virtual address of the allocation. Must be inside @vma.
2159 * @hugepage: For hugepages try only the preferred node if possible.
2160 *
2161 * Allocate a folio for a specific address in @vma, using the appropriate
2162 * NUMA policy. When @vma is not NULL the caller must hold the mmap_lock
2163 * of the mm_struct of the VMA to prevent it from going away. Should be
2164 * used for all allocations for folios that will be mapped into user space.
2165 *
2166 * Return: The folio on success or NULL if allocation fails.
2167 */
2168struct folio *vma_alloc_folio(gfp_t gfp, int order, struct vm_area_struct *vma,
2169 unsigned long addr, bool hugepage)
2170{
2171 struct mempolicy *pol;
2172 int node = numa_node_id();
2173 struct folio *folio;
2174 int preferred_nid;
2175 nodemask_t *nmask;
2176
2177 pol = get_vma_policy(vma, addr);
2178
2179 if (pol->mode == MPOL_INTERLEAVE) {
2180 struct page *page;
2181 unsigned nid;
2182
2183 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2184 mpol_cond_put(pol);
2185 gfp |= __GFP_COMP;
2186 page = alloc_page_interleave(gfp, order, nid);
2187 if (page && order > 1)
2188 prep_transhuge_page(page);
2189 folio = (struct folio *)page;
2190 goto out;
2191 }
2192
2193 if (pol->mode == MPOL_PREFERRED_MANY) {
2194 struct page *page;
2195
2196 node = policy_node(gfp, pol, node);
2197 gfp |= __GFP_COMP;
2198 page = alloc_pages_preferred_many(gfp, order, node, pol);
2199 mpol_cond_put(pol);
2200 if (page && order > 1)
2201 prep_transhuge_page(page);
2202 folio = (struct folio *)page;
2203 goto out;
2204 }
2205
2206 if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
2207 int hpage_node = node;
2208
2209 /*
2210 * For hugepage allocation and non-interleave policy which
2211 * allows the current node (or other explicitly preferred
2212 * node) we only try to allocate from the current/preferred
2213 * node and don't fall back to other nodes, as the cost of
2214 * remote accesses would likely offset THP benefits.
2215 *
2216 * If the policy is interleave or does not allow the current
2217 * node in its nodemask, we allocate the standard way.
2218 */
2219 if (pol->mode == MPOL_PREFERRED)
2220 hpage_node = first_node(pol->nodes);
2221
2222 nmask = policy_nodemask(gfp, pol);
2223 if (!nmask || node_isset(hpage_node, *nmask)) {
2224 mpol_cond_put(pol);
2225 /*
2226 * First, try to allocate THP only on local node, but
2227 * don't reclaim unnecessarily, just compact.
2228 */
2229 folio = __folio_alloc_node(gfp | __GFP_THISNODE |
2230 __GFP_NORETRY, order, hpage_node);
2231
2232 /*
2233 * If hugepage allocations are configured to always
2234 * synchronous compact or the vma has been madvised
2235 * to prefer hugepage backing, retry allowing remote
2236 * memory with both reclaim and compact as well.
2237 */
2238 if (!folio && (gfp & __GFP_DIRECT_RECLAIM))
2239 folio = __folio_alloc(gfp, order, hpage_node,
2240 nmask);
2241
2242 goto out;
2243 }
2244 }
2245
2246 nmask = policy_nodemask(gfp, pol);
2247 preferred_nid = policy_node(gfp, pol, node);
2248 folio = __folio_alloc(gfp, order, preferred_nid, nmask);
2249 mpol_cond_put(pol);
2250out:
2251 return folio;
2252}
2253EXPORT_SYMBOL(vma_alloc_folio);
2254
2255/**
2256 * alloc_pages - Allocate pages.
2257 * @gfp: GFP flags.
2258 * @order: Power of two of number of pages to allocate.
2259 *
2260 * Allocate 1 << @order contiguous pages. The physical address of the
2261 * first page is naturally aligned (eg an order-3 allocation will be aligned
2262 * to a multiple of 8 * PAGE_SIZE bytes). The NUMA policy of the current
2263 * process is honoured when in process context.
2264 *
2265 * Context: Can be called from any context, providing the appropriate GFP
2266 * flags are used.
2267 * Return: The page on success or NULL if allocation fails.
2268 */
2269struct page *alloc_pages(gfp_t gfp, unsigned order)
2270{
2271 struct mempolicy *pol = &default_policy;
2272 struct page *page;
2273
2274 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2275 pol = get_task_policy(current);
2276
2277 /*
2278 * No reference counting needed for current->mempolicy
2279 * nor system default_policy
2280 */
2281 if (pol->mode == MPOL_INTERLEAVE)
2282 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
2283 else if (pol->mode == MPOL_PREFERRED_MANY)
2284 page = alloc_pages_preferred_many(gfp, order,
2285 policy_node(gfp, pol, numa_node_id()), pol);
2286 else
2287 page = __alloc_pages(gfp, order,
2288 policy_node(gfp, pol, numa_node_id()),
2289 policy_nodemask(gfp, pol));
2290
2291 return page;
2292}
2293EXPORT_SYMBOL(alloc_pages);
2294
2295struct folio *folio_alloc(gfp_t gfp, unsigned order)
2296{
2297 struct page *page = alloc_pages(gfp | __GFP_COMP, order);
2298
2299 if (page && order > 1)
2300 prep_transhuge_page(page);
2301 return (struct folio *)page;
2302}
2303EXPORT_SYMBOL(folio_alloc);
2304
2305static unsigned long alloc_pages_bulk_array_interleave(gfp_t gfp,
2306 struct mempolicy *pol, unsigned long nr_pages,
2307 struct page **page_array)
2308{
2309 int nodes;
2310 unsigned long nr_pages_per_node;
2311 int delta;
2312 int i;
2313 unsigned long nr_allocated;
2314 unsigned long total_allocated = 0;
2315
2316 nodes = nodes_weight(pol->nodes);
2317 nr_pages_per_node = nr_pages / nodes;
2318 delta = nr_pages - nodes * nr_pages_per_node;
2319
2320 for (i = 0; i < nodes; i++) {
2321 if (delta) {
2322 nr_allocated = __alloc_pages_bulk(gfp,
2323 interleave_nodes(pol), NULL,
2324 nr_pages_per_node + 1, NULL,
2325 page_array);
2326 delta--;
2327 } else {
2328 nr_allocated = __alloc_pages_bulk(gfp,
2329 interleave_nodes(pol), NULL,
2330 nr_pages_per_node, NULL, page_array);
2331 }
2332
2333 page_array += nr_allocated;
2334 total_allocated += nr_allocated;
2335 }
2336
2337 return total_allocated;
2338}
2339
2340static unsigned long alloc_pages_bulk_array_preferred_many(gfp_t gfp, int nid,
2341 struct mempolicy *pol, unsigned long nr_pages,
2342 struct page **page_array)
2343{
2344 gfp_t preferred_gfp;
2345 unsigned long nr_allocated = 0;
2346
2347 preferred_gfp = gfp | __GFP_NOWARN;
2348 preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
2349
2350 nr_allocated = __alloc_pages_bulk(preferred_gfp, nid, &pol->nodes,
2351 nr_pages, NULL, page_array);
2352
2353 if (nr_allocated < nr_pages)
2354 nr_allocated += __alloc_pages_bulk(gfp, numa_node_id(), NULL,
2355 nr_pages - nr_allocated, NULL,
2356 page_array + nr_allocated);
2357 return nr_allocated;
2358}
2359
2360/* alloc pages bulk and mempolicy should be considered at the
2361 * same time in some situation such as vmalloc.
2362 *
2363 * It can accelerate memory allocation especially interleaving
2364 * allocate memory.
2365 */
2366unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp,
2367 unsigned long nr_pages, struct page **page_array)
2368{
2369 struct mempolicy *pol = &default_policy;
2370
2371 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2372 pol = get_task_policy(current);
2373
2374 if (pol->mode == MPOL_INTERLEAVE)
2375 return alloc_pages_bulk_array_interleave(gfp, pol,
2376 nr_pages, page_array);
2377
2378 if (pol->mode == MPOL_PREFERRED_MANY)
2379 return alloc_pages_bulk_array_preferred_many(gfp,
2380 numa_node_id(), pol, nr_pages, page_array);
2381
2382 return __alloc_pages_bulk(gfp, policy_node(gfp, pol, numa_node_id()),
2383 policy_nodemask(gfp, pol), nr_pages, NULL,
2384 page_array);
2385}
2386
2387int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
2388{
2389 struct mempolicy *pol = mpol_dup(vma_policy(src));
2390
2391 if (IS_ERR(pol))
2392 return PTR_ERR(pol);
2393 dst->vm_policy = pol;
2394 return 0;
2395}
2396
2397/*
2398 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2399 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2400 * with the mems_allowed returned by cpuset_mems_allowed(). This
2401 * keeps mempolicies cpuset relative after its cpuset moves. See
2402 * further kernel/cpuset.c update_nodemask().
2403 *
2404 * current's mempolicy may be rebinded by the other task(the task that changes
2405 * cpuset's mems), so we needn't do rebind work for current task.
2406 */
2407
2408/* Slow path of a mempolicy duplicate */
2409struct mempolicy *__mpol_dup(struct mempolicy *old)
2410{
2411 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2412
2413 if (!new)
2414 return ERR_PTR(-ENOMEM);
2415
2416 /* task's mempolicy is protected by alloc_lock */
2417 if (old == current->mempolicy) {
2418 task_lock(current);
2419 *new = *old;
2420 task_unlock(current);
2421 } else
2422 *new = *old;
2423
2424 if (current_cpuset_is_being_rebound()) {
2425 nodemask_t mems = cpuset_mems_allowed(current);
2426 mpol_rebind_policy(new, &mems);
2427 }
2428 atomic_set(&new->refcnt, 1);
2429 return new;
2430}
2431
2432/* Slow path of a mempolicy comparison */
2433bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2434{
2435 if (!a || !b)
2436 return false;
2437 if (a->mode != b->mode)
2438 return false;
2439 if (a->flags != b->flags)
2440 return false;
2441 if (a->home_node != b->home_node)
2442 return false;
2443 if (mpol_store_user_nodemask(a))
2444 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2445 return false;
2446
2447 switch (a->mode) {
2448 case MPOL_BIND:
2449 case MPOL_INTERLEAVE:
2450 case MPOL_PREFERRED:
2451 case MPOL_PREFERRED_MANY:
2452 return !!nodes_equal(a->nodes, b->nodes);
2453 case MPOL_LOCAL:
2454 return true;
2455 default:
2456 BUG();
2457 return false;
2458 }
2459}
2460
2461/*
2462 * Shared memory backing store policy support.
2463 *
2464 * Remember policies even when nobody has shared memory mapped.
2465 * The policies are kept in Red-Black tree linked from the inode.
2466 * They are protected by the sp->lock rwlock, which should be held
2467 * for any accesses to the tree.
2468 */
2469
2470/*
2471 * lookup first element intersecting start-end. Caller holds sp->lock for
2472 * reading or for writing
2473 */
2474static struct sp_node *
2475sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2476{
2477 struct rb_node *n = sp->root.rb_node;
2478
2479 while (n) {
2480 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2481
2482 if (start >= p->end)
2483 n = n->rb_right;
2484 else if (end <= p->start)
2485 n = n->rb_left;
2486 else
2487 break;
2488 }
2489 if (!n)
2490 return NULL;
2491 for (;;) {
2492 struct sp_node *w = NULL;
2493 struct rb_node *prev = rb_prev(n);
2494 if (!prev)
2495 break;
2496 w = rb_entry(prev, struct sp_node, nd);
2497 if (w->end <= start)
2498 break;
2499 n = prev;
2500 }
2501 return rb_entry(n, struct sp_node, nd);
2502}
2503
2504/*
2505 * Insert a new shared policy into the list. Caller holds sp->lock for
2506 * writing.
2507 */
2508static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2509{
2510 struct rb_node **p = &sp->root.rb_node;
2511 struct rb_node *parent = NULL;
2512 struct sp_node *nd;
2513
2514 while (*p) {
2515 parent = *p;
2516 nd = rb_entry(parent, struct sp_node, nd);
2517 if (new->start < nd->start)
2518 p = &(*p)->rb_left;
2519 else if (new->end > nd->end)
2520 p = &(*p)->rb_right;
2521 else
2522 BUG();
2523 }
2524 rb_link_node(&new->nd, parent, p);
2525 rb_insert_color(&new->nd, &sp->root);
2526 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2527 new->policy ? new->policy->mode : 0);
2528}
2529
2530/* Find shared policy intersecting idx */
2531struct mempolicy *
2532mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2533{
2534 struct mempolicy *pol = NULL;
2535 struct sp_node *sn;
2536
2537 if (!sp->root.rb_node)
2538 return NULL;
2539 read_lock(&sp->lock);
2540 sn = sp_lookup(sp, idx, idx+1);
2541 if (sn) {
2542 mpol_get(sn->policy);
2543 pol = sn->policy;
2544 }
2545 read_unlock(&sp->lock);
2546 return pol;
2547}
2548
2549static void sp_free(struct sp_node *n)
2550{
2551 mpol_put(n->policy);
2552 kmem_cache_free(sn_cache, n);
2553}
2554
2555/**
2556 * mpol_misplaced - check whether current page node is valid in policy
2557 *
2558 * @page: page to be checked
2559 * @vma: vm area where page mapped
2560 * @addr: virtual address where page mapped
2561 *
2562 * Lookup current policy node id for vma,addr and "compare to" page's
2563 * node id. Policy determination "mimics" alloc_page_vma().
2564 * Called from fault path where we know the vma and faulting address.
2565 *
2566 * Return: NUMA_NO_NODE if the page is in a node that is valid for this
2567 * policy, or a suitable node ID to allocate a replacement page from.
2568 */
2569int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
2570{
2571 struct mempolicy *pol;
2572 struct zoneref *z;
2573 int curnid = page_to_nid(page);
2574 unsigned long pgoff;
2575 int thiscpu = raw_smp_processor_id();
2576 int thisnid = cpu_to_node(thiscpu);
2577 int polnid = NUMA_NO_NODE;
2578 int ret = NUMA_NO_NODE;
2579
2580 pol = get_vma_policy(vma, addr);
2581 if (!(pol->flags & MPOL_F_MOF))
2582 goto out;
2583
2584 switch (pol->mode) {
2585 case MPOL_INTERLEAVE:
2586 pgoff = vma->vm_pgoff;
2587 pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
2588 polnid = offset_il_node(pol, pgoff);
2589 break;
2590
2591 case MPOL_PREFERRED:
2592 if (node_isset(curnid, pol->nodes))
2593 goto out;
2594 polnid = first_node(pol->nodes);
2595 break;
2596
2597 case MPOL_LOCAL:
2598 polnid = numa_node_id();
2599 break;
2600
2601 case MPOL_BIND:
2602 /* Optimize placement among multiple nodes via NUMA balancing */
2603 if (pol->flags & MPOL_F_MORON) {
2604 if (node_isset(thisnid, pol->nodes))
2605 break;
2606 goto out;
2607 }
2608 fallthrough;
2609
2610 case MPOL_PREFERRED_MANY:
2611 /*
2612 * use current page if in policy nodemask,
2613 * else select nearest allowed node, if any.
2614 * If no allowed nodes, use current [!misplaced].
2615 */
2616 if (node_isset(curnid, pol->nodes))
2617 goto out;
2618 z = first_zones_zonelist(
2619 node_zonelist(numa_node_id(), GFP_HIGHUSER),
2620 gfp_zone(GFP_HIGHUSER),
2621 &pol->nodes);
2622 polnid = zone_to_nid(z->zone);
2623 break;
2624
2625 default:
2626 BUG();
2627 }
2628
2629 /* Migrate the page towards the node whose CPU is referencing it */
2630 if (pol->flags & MPOL_F_MORON) {
2631 polnid = thisnid;
2632
2633 if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
2634 goto out;
2635 }
2636
2637 if (curnid != polnid)
2638 ret = polnid;
2639out:
2640 mpol_cond_put(pol);
2641
2642 return ret;
2643}
2644
2645/*
2646 * Drop the (possibly final) reference to task->mempolicy. It needs to be
2647 * dropped after task->mempolicy is set to NULL so that any allocation done as
2648 * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed
2649 * policy.
2650 */
2651void mpol_put_task_policy(struct task_struct *task)
2652{
2653 struct mempolicy *pol;
2654
2655 task_lock(task);
2656 pol = task->mempolicy;
2657 task->mempolicy = NULL;
2658 task_unlock(task);
2659 mpol_put(pol);
2660}
2661
2662static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2663{
2664 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2665 rb_erase(&n->nd, &sp->root);
2666 sp_free(n);
2667}
2668
2669static void sp_node_init(struct sp_node *node, unsigned long start,
2670 unsigned long end, struct mempolicy *pol)
2671{
2672 node->start = start;
2673 node->end = end;
2674 node->policy = pol;
2675}
2676
2677static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2678 struct mempolicy *pol)
2679{
2680 struct sp_node *n;
2681 struct mempolicy *newpol;
2682
2683 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2684 if (!n)
2685 return NULL;
2686
2687 newpol = mpol_dup(pol);
2688 if (IS_ERR(newpol)) {
2689 kmem_cache_free(sn_cache, n);
2690 return NULL;
2691 }
2692 newpol->flags |= MPOL_F_SHARED;
2693 sp_node_init(n, start, end, newpol);
2694
2695 return n;
2696}
2697
2698/* Replace a policy range. */
2699static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2700 unsigned long end, struct sp_node *new)
2701{
2702 struct sp_node *n;
2703 struct sp_node *n_new = NULL;
2704 struct mempolicy *mpol_new = NULL;
2705 int ret = 0;
2706
2707restart:
2708 write_lock(&sp->lock);
2709 n = sp_lookup(sp, start, end);
2710 /* Take care of old policies in the same range. */
2711 while (n && n->start < end) {
2712 struct rb_node *next = rb_next(&n->nd);
2713 if (n->start >= start) {
2714 if (n->end <= end)
2715 sp_delete(sp, n);
2716 else
2717 n->start = end;
2718 } else {
2719 /* Old policy spanning whole new range. */
2720 if (n->end > end) {
2721 if (!n_new)
2722 goto alloc_new;
2723
2724 *mpol_new = *n->policy;
2725 atomic_set(&mpol_new->refcnt, 1);
2726 sp_node_init(n_new, end, n->end, mpol_new);
2727 n->end = start;
2728 sp_insert(sp, n_new);
2729 n_new = NULL;
2730 mpol_new = NULL;
2731 break;
2732 } else
2733 n->end = start;
2734 }
2735 if (!next)
2736 break;
2737 n = rb_entry(next, struct sp_node, nd);
2738 }
2739 if (new)
2740 sp_insert(sp, new);
2741 write_unlock(&sp->lock);
2742 ret = 0;
2743
2744err_out:
2745 if (mpol_new)
2746 mpol_put(mpol_new);
2747 if (n_new)
2748 kmem_cache_free(sn_cache, n_new);
2749
2750 return ret;
2751
2752alloc_new:
2753 write_unlock(&sp->lock);
2754 ret = -ENOMEM;
2755 n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2756 if (!n_new)
2757 goto err_out;
2758 mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2759 if (!mpol_new)
2760 goto err_out;
2761 atomic_set(&mpol_new->refcnt, 1);
2762 goto restart;
2763}
2764
2765/**
2766 * mpol_shared_policy_init - initialize shared policy for inode
2767 * @sp: pointer to inode shared policy
2768 * @mpol: struct mempolicy to install
2769 *
2770 * Install non-NULL @mpol in inode's shared policy rb-tree.
2771 * On entry, the current task has a reference on a non-NULL @mpol.
2772 * This must be released on exit.
2773 * This is called at get_inode() calls and we can use GFP_KERNEL.
2774 */
2775void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2776{
2777 int ret;
2778
2779 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2780 rwlock_init(&sp->lock);
2781
2782 if (mpol) {
2783 struct vm_area_struct pvma;
2784 struct mempolicy *new;
2785 NODEMASK_SCRATCH(scratch);
2786
2787 if (!scratch)
2788 goto put_mpol;
2789 /* contextualize the tmpfs mount point mempolicy */
2790 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2791 if (IS_ERR(new))
2792 goto free_scratch; /* no valid nodemask intersection */
2793
2794 task_lock(current);
2795 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2796 task_unlock(current);
2797 if (ret)
2798 goto put_new;
2799
2800 /* Create pseudo-vma that contains just the policy */
2801 vma_init(&pvma, NULL);
2802 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2803 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2804
2805put_new:
2806 mpol_put(new); /* drop initial ref */
2807free_scratch:
2808 NODEMASK_SCRATCH_FREE(scratch);
2809put_mpol:
2810 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2811 }
2812}
2813
2814int mpol_set_shared_policy(struct shared_policy *info,
2815 struct vm_area_struct *vma, struct mempolicy *npol)
2816{
2817 int err;
2818 struct sp_node *new = NULL;
2819 unsigned long sz = vma_pages(vma);
2820
2821 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2822 vma->vm_pgoff,
2823 sz, npol ? npol->mode : -1,
2824 npol ? npol->flags : -1,
2825 npol ? nodes_addr(npol->nodes)[0] : NUMA_NO_NODE);
2826
2827 if (npol) {
2828 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2829 if (!new)
2830 return -ENOMEM;
2831 }
2832 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2833 if (err && new)
2834 sp_free(new);
2835 return err;
2836}
2837
2838/* Free a backing policy store on inode delete. */
2839void mpol_free_shared_policy(struct shared_policy *p)
2840{
2841 struct sp_node *n;
2842 struct rb_node *next;
2843
2844 if (!p->root.rb_node)
2845 return;
2846 write_lock(&p->lock);
2847 next = rb_first(&p->root);
2848 while (next) {
2849 n = rb_entry(next, struct sp_node, nd);
2850 next = rb_next(&n->nd);
2851 sp_delete(p, n);
2852 }
2853 write_unlock(&p->lock);
2854}
2855
2856#ifdef CONFIG_NUMA_BALANCING
2857static int __initdata numabalancing_override;
2858
2859static void __init check_numabalancing_enable(void)
2860{
2861 bool numabalancing_default = false;
2862
2863 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2864 numabalancing_default = true;
2865
2866 /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
2867 if (numabalancing_override)
2868 set_numabalancing_state(numabalancing_override == 1);
2869
2870 if (num_online_nodes() > 1 && !numabalancing_override) {
2871 pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n",
2872 numabalancing_default ? "Enabling" : "Disabling");
2873 set_numabalancing_state(numabalancing_default);
2874 }
2875}
2876
2877static int __init setup_numabalancing(char *str)
2878{
2879 int ret = 0;
2880 if (!str)
2881 goto out;
2882
2883 if (!strcmp(str, "enable")) {
2884 numabalancing_override = 1;
2885 ret = 1;
2886 } else if (!strcmp(str, "disable")) {
2887 numabalancing_override = -1;
2888 ret = 1;
2889 }
2890out:
2891 if (!ret)
2892 pr_warn("Unable to parse numa_balancing=\n");
2893
2894 return ret;
2895}
2896__setup("numa_balancing=", setup_numabalancing);
2897#else
2898static inline void __init check_numabalancing_enable(void)
2899{
2900}
2901#endif /* CONFIG_NUMA_BALANCING */
2902
2903/* assumes fs == KERNEL_DS */
2904void __init numa_policy_init(void)
2905{
2906 nodemask_t interleave_nodes;
2907 unsigned long largest = 0;
2908 int nid, prefer = 0;
2909
2910 policy_cache = kmem_cache_create("numa_policy",
2911 sizeof(struct mempolicy),
2912 0, SLAB_PANIC, NULL);
2913
2914 sn_cache = kmem_cache_create("shared_policy_node",
2915 sizeof(struct sp_node),
2916 0, SLAB_PANIC, NULL);
2917
2918 for_each_node(nid) {
2919 preferred_node_policy[nid] = (struct mempolicy) {
2920 .refcnt = ATOMIC_INIT(1),
2921 .mode = MPOL_PREFERRED,
2922 .flags = MPOL_F_MOF | MPOL_F_MORON,
2923 .nodes = nodemask_of_node(nid),
2924 };
2925 }
2926
2927 /*
2928 * Set interleaving policy for system init. Interleaving is only
2929 * enabled across suitably sized nodes (default is >= 16MB), or
2930 * fall back to the largest node if they're all smaller.
2931 */
2932 nodes_clear(interleave_nodes);
2933 for_each_node_state(nid, N_MEMORY) {
2934 unsigned long total_pages = node_present_pages(nid);
2935
2936 /* Preserve the largest node */
2937 if (largest < total_pages) {
2938 largest = total_pages;
2939 prefer = nid;
2940 }
2941
2942 /* Interleave this node? */
2943 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2944 node_set(nid, interleave_nodes);
2945 }
2946
2947 /* All too small, use the largest */
2948 if (unlikely(nodes_empty(interleave_nodes)))
2949 node_set(prefer, interleave_nodes);
2950
2951 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2952 pr_err("%s: interleaving failed\n", __func__);
2953
2954 check_numabalancing_enable();
2955}
2956
2957/* Reset policy of current process to default */
2958void numa_default_policy(void)
2959{
2960 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2961}
2962
2963/*
2964 * Parse and format mempolicy from/to strings
2965 */
2966
2967static const char * const policy_modes[] =
2968{
2969 [MPOL_DEFAULT] = "default",
2970 [MPOL_PREFERRED] = "prefer",
2971 [MPOL_BIND] = "bind",
2972 [MPOL_INTERLEAVE] = "interleave",
2973 [MPOL_LOCAL] = "local",
2974 [MPOL_PREFERRED_MANY] = "prefer (many)",
2975};
2976
2977
2978#ifdef CONFIG_TMPFS
2979/**
2980 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2981 * @str: string containing mempolicy to parse
2982 * @mpol: pointer to struct mempolicy pointer, returned on success.
2983 *
2984 * Format of input:
2985 * <mode>[=<flags>][:<nodelist>]
2986 *
2987 * Return: %0 on success, else %1
2988 */
2989int mpol_parse_str(char *str, struct mempolicy **mpol)
2990{
2991 struct mempolicy *new = NULL;
2992 unsigned short mode_flags;
2993 nodemask_t nodes;
2994 char *nodelist = strchr(str, ':');
2995 char *flags = strchr(str, '=');
2996 int err = 1, mode;
2997
2998 if (flags)
2999 *flags++ = '\0'; /* terminate mode string */
3000
3001 if (nodelist) {
3002 /* NUL-terminate mode or flags string */
3003 *nodelist++ = '\0';
3004 if (nodelist_parse(nodelist, nodes))
3005 goto out;
3006 if (!nodes_subset(nodes, node_states[N_MEMORY]))
3007 goto out;
3008 } else
3009 nodes_clear(nodes);
3010
3011 mode = match_string(policy_modes, MPOL_MAX, str);
3012 if (mode < 0)
3013 goto out;
3014
3015 switch (mode) {
3016 case MPOL_PREFERRED:
3017 /*
3018 * Insist on a nodelist of one node only, although later
3019 * we use first_node(nodes) to grab a single node, so here
3020 * nodelist (or nodes) cannot be empty.
3021 */
3022 if (nodelist) {
3023 char *rest = nodelist;
3024 while (isdigit(*rest))
3025 rest++;
3026 if (*rest)
3027 goto out;
3028 if (nodes_empty(nodes))
3029 goto out;
3030 }
3031 break;
3032 case MPOL_INTERLEAVE:
3033 /*
3034 * Default to online nodes with memory if no nodelist
3035 */
3036 if (!nodelist)
3037 nodes = node_states[N_MEMORY];
3038 break;
3039 case MPOL_LOCAL:
3040 /*
3041 * Don't allow a nodelist; mpol_new() checks flags
3042 */
3043 if (nodelist)
3044 goto out;
3045 break;
3046 case MPOL_DEFAULT:
3047 /*
3048 * Insist on a empty nodelist
3049 */
3050 if (!nodelist)
3051 err = 0;
3052 goto out;
3053 case MPOL_PREFERRED_MANY:
3054 case MPOL_BIND:
3055 /*
3056 * Insist on a nodelist
3057 */
3058 if (!nodelist)
3059 goto out;
3060 }
3061
3062 mode_flags = 0;
3063 if (flags) {
3064 /*
3065 * Currently, we only support two mutually exclusive
3066 * mode flags.
3067 */
3068 if (!strcmp(flags, "static"))
3069 mode_flags |= MPOL_F_STATIC_NODES;
3070 else if (!strcmp(flags, "relative"))
3071 mode_flags |= MPOL_F_RELATIVE_NODES;
3072 else
3073 goto out;
3074 }
3075
3076 new = mpol_new(mode, mode_flags, &nodes);
3077 if (IS_ERR(new))
3078 goto out;
3079
3080 /*
3081 * Save nodes for mpol_to_str() to show the tmpfs mount options
3082 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
3083 */
3084 if (mode != MPOL_PREFERRED) {
3085 new->nodes = nodes;
3086 } else if (nodelist) {
3087 nodes_clear(new->nodes);
3088 node_set(first_node(nodes), new->nodes);
3089 } else {
3090 new->mode = MPOL_LOCAL;
3091 }
3092
3093 /*
3094 * Save nodes for contextualization: this will be used to "clone"
3095 * the mempolicy in a specific context [cpuset] at a later time.
3096 */
3097 new->w.user_nodemask = nodes;
3098
3099 err = 0;
3100
3101out:
3102 /* Restore string for error message */
3103 if (nodelist)
3104 *--nodelist = ':';
3105 if (flags)
3106 *--flags = '=';
3107 if (!err)
3108 *mpol = new;
3109 return err;
3110}
3111#endif /* CONFIG_TMPFS */
3112
3113/**
3114 * mpol_to_str - format a mempolicy structure for printing
3115 * @buffer: to contain formatted mempolicy string
3116 * @maxlen: length of @buffer
3117 * @pol: pointer to mempolicy to be formatted
3118 *
3119 * Convert @pol into a string. If @buffer is too short, truncate the string.
3120 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
3121 * longest flag, "relative", and to display at least a few node ids.
3122 */
3123void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
3124{
3125 char *p = buffer;
3126 nodemask_t nodes = NODE_MASK_NONE;
3127 unsigned short mode = MPOL_DEFAULT;
3128 unsigned short flags = 0;
3129
3130 if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
3131 mode = pol->mode;
3132 flags = pol->flags;
3133 }
3134
3135 switch (mode) {
3136 case MPOL_DEFAULT:
3137 case MPOL_LOCAL:
3138 break;
3139 case MPOL_PREFERRED:
3140 case MPOL_PREFERRED_MANY:
3141 case MPOL_BIND:
3142 case MPOL_INTERLEAVE:
3143 nodes = pol->nodes;
3144 break;
3145 default:
3146 WARN_ON_ONCE(1);
3147 snprintf(p, maxlen, "unknown");
3148 return;
3149 }
3150
3151 p += snprintf(p, maxlen, "%s", policy_modes[mode]);
3152
3153 if (flags & MPOL_MODE_FLAGS) {
3154 p += snprintf(p, buffer + maxlen - p, "=");
3155
3156 /*
3157 * Currently, the only defined flags are mutually exclusive
3158 */
3159 if (flags & MPOL_F_STATIC_NODES)
3160 p += snprintf(p, buffer + maxlen - p, "static");
3161 else if (flags & MPOL_F_RELATIVE_NODES)
3162 p += snprintf(p, buffer + maxlen - p, "relative");
3163 }
3164
3165 if (!nodes_empty(nodes))
3166 p += scnprintf(p, buffer + maxlen - p, ":%*pbl",
3167 nodemask_pr_args(&nodes));
3168}