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