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1/*
2 * Simple NUMA memory policy for the Linux kernel.
3 *
4 * Copyright 2003,2004 Andi Kleen, SuSE Labs.
5 * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc.
6 * Subject to the GNU Public License, version 2.
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/mm.h>
72#include <linux/highmem.h>
73#include <linux/hugetlb.h>
74#include <linux/kernel.h>
75#include <linux/sched.h>
76#include <linux/nodemask.h>
77#include <linux/cpuset.h>
78#include <linux/slab.h>
79#include <linux/string.h>
80#include <linux/export.h>
81#include <linux/nsproxy.h>
82#include <linux/interrupt.h>
83#include <linux/init.h>
84#include <linux/compat.h>
85#include <linux/swap.h>
86#include <linux/seq_file.h>
87#include <linux/proc_fs.h>
88#include <linux/migrate.h>
89#include <linux/ksm.h>
90#include <linux/rmap.h>
91#include <linux/security.h>
92#include <linux/syscalls.h>
93#include <linux/ctype.h>
94#include <linux/mm_inline.h>
95#include <linux/mmu_notifier.h>
96#include <linux/printk.h>
97
98#include <asm/tlbflush.h>
99#include <asm/uaccess.h>
100#include <linux/random.h>
101
102#include "internal.h"
103
104/* Internal flags */
105#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
106#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
107
108static struct kmem_cache *policy_cache;
109static struct kmem_cache *sn_cache;
110
111/* Highest zone. An specific allocation for a zone below that is not
112 policied. */
113enum zone_type policy_zone = 0;
114
115/*
116 * run-time system-wide default policy => local allocation
117 */
118static struct mempolicy default_policy = {
119 .refcnt = ATOMIC_INIT(1), /* never free it */
120 .mode = MPOL_PREFERRED,
121 .flags = MPOL_F_LOCAL,
122};
123
124static struct mempolicy preferred_node_policy[MAX_NUMNODES];
125
126struct mempolicy *get_task_policy(struct task_struct *p)
127{
128 struct mempolicy *pol = p->mempolicy;
129 int node;
130
131 if (pol)
132 return pol;
133
134 node = numa_node_id();
135 if (node != NUMA_NO_NODE) {
136 pol = &preferred_node_policy[node];
137 /* preferred_node_policy is not initialised early in boot */
138 if (pol->mode)
139 return pol;
140 }
141
142 return &default_policy;
143}
144
145static const struct mempolicy_operations {
146 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
147 /*
148 * If read-side task has no lock to protect task->mempolicy, write-side
149 * task will rebind the task->mempolicy by two step. The first step is
150 * setting all the newly nodes, and the second step is cleaning all the
151 * disallowed nodes. In this way, we can avoid finding no node to alloc
152 * page.
153 * If we have a lock to protect task->mempolicy in read-side, we do
154 * rebind directly.
155 *
156 * step:
157 * MPOL_REBIND_ONCE - do rebind work at once
158 * MPOL_REBIND_STEP1 - set all the newly nodes
159 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
160 */
161 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes,
162 enum mpol_rebind_step step);
163} mpol_ops[MPOL_MAX];
164
165static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
166{
167 return pol->flags & MPOL_MODE_FLAGS;
168}
169
170static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
171 const nodemask_t *rel)
172{
173 nodemask_t tmp;
174 nodes_fold(tmp, *orig, nodes_weight(*rel));
175 nodes_onto(*ret, tmp, *rel);
176}
177
178static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
179{
180 if (nodes_empty(*nodes))
181 return -EINVAL;
182 pol->v.nodes = *nodes;
183 return 0;
184}
185
186static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
187{
188 if (!nodes)
189 pol->flags |= MPOL_F_LOCAL; /* local allocation */
190 else if (nodes_empty(*nodes))
191 return -EINVAL; /* no allowed nodes */
192 else
193 pol->v.preferred_node = first_node(*nodes);
194 return 0;
195}
196
197static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
198{
199 if (nodes_empty(*nodes))
200 return -EINVAL;
201 pol->v.nodes = *nodes;
202 return 0;
203}
204
205/*
206 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
207 * any, for the new policy. mpol_new() has already validated the nodes
208 * parameter with respect to the policy mode and flags. But, we need to
209 * handle an empty nodemask with MPOL_PREFERRED here.
210 *
211 * Must be called holding task's alloc_lock to protect task's mems_allowed
212 * and mempolicy. May also be called holding the mmap_semaphore for write.
213 */
214static int mpol_set_nodemask(struct mempolicy *pol,
215 const nodemask_t *nodes, struct nodemask_scratch *nsc)
216{
217 int ret;
218
219 /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
220 if (pol == NULL)
221 return 0;
222 /* Check N_MEMORY */
223 nodes_and(nsc->mask1,
224 cpuset_current_mems_allowed, node_states[N_MEMORY]);
225
226 VM_BUG_ON(!nodes);
227 if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
228 nodes = NULL; /* explicit local allocation */
229 else {
230 if (pol->flags & MPOL_F_RELATIVE_NODES)
231 mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1);
232 else
233 nodes_and(nsc->mask2, *nodes, nsc->mask1);
234
235 if (mpol_store_user_nodemask(pol))
236 pol->w.user_nodemask = *nodes;
237 else
238 pol->w.cpuset_mems_allowed =
239 cpuset_current_mems_allowed;
240 }
241
242 if (nodes)
243 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
244 else
245 ret = mpol_ops[pol->mode].create(pol, NULL);
246 return ret;
247}
248
249/*
250 * This function just creates a new policy, does some check and simple
251 * initialization. You must invoke mpol_set_nodemask() to set nodes.
252 */
253static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
254 nodemask_t *nodes)
255{
256 struct mempolicy *policy;
257
258 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
259 mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE);
260
261 if (mode == MPOL_DEFAULT) {
262 if (nodes && !nodes_empty(*nodes))
263 return ERR_PTR(-EINVAL);
264 return NULL;
265 }
266 VM_BUG_ON(!nodes);
267
268 /*
269 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
270 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
271 * All other modes require a valid pointer to a non-empty nodemask.
272 */
273 if (mode == MPOL_PREFERRED) {
274 if (nodes_empty(*nodes)) {
275 if (((flags & MPOL_F_STATIC_NODES) ||
276 (flags & MPOL_F_RELATIVE_NODES)))
277 return ERR_PTR(-EINVAL);
278 }
279 } else if (mode == MPOL_LOCAL) {
280 if (!nodes_empty(*nodes))
281 return ERR_PTR(-EINVAL);
282 mode = MPOL_PREFERRED;
283 } else if (nodes_empty(*nodes))
284 return ERR_PTR(-EINVAL);
285 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
286 if (!policy)
287 return ERR_PTR(-ENOMEM);
288 atomic_set(&policy->refcnt, 1);
289 policy->mode = mode;
290 policy->flags = flags;
291
292 return policy;
293}
294
295/* Slow path of a mpol destructor. */
296void __mpol_put(struct mempolicy *p)
297{
298 if (!atomic_dec_and_test(&p->refcnt))
299 return;
300 kmem_cache_free(policy_cache, p);
301}
302
303static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes,
304 enum mpol_rebind_step step)
305{
306}
307
308/*
309 * step:
310 * MPOL_REBIND_ONCE - do rebind work at once
311 * MPOL_REBIND_STEP1 - set all the newly nodes
312 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
313 */
314static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes,
315 enum mpol_rebind_step step)
316{
317 nodemask_t tmp;
318
319 if (pol->flags & MPOL_F_STATIC_NODES)
320 nodes_and(tmp, pol->w.user_nodemask, *nodes);
321 else if (pol->flags & MPOL_F_RELATIVE_NODES)
322 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
323 else {
324 /*
325 * if step == 1, we use ->w.cpuset_mems_allowed to cache the
326 * result
327 */
328 if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP1) {
329 nodes_remap(tmp, pol->v.nodes,
330 pol->w.cpuset_mems_allowed, *nodes);
331 pol->w.cpuset_mems_allowed = step ? tmp : *nodes;
332 } else if (step == MPOL_REBIND_STEP2) {
333 tmp = pol->w.cpuset_mems_allowed;
334 pol->w.cpuset_mems_allowed = *nodes;
335 } else
336 BUG();
337 }
338
339 if (nodes_empty(tmp))
340 tmp = *nodes;
341
342 if (step == MPOL_REBIND_STEP1)
343 nodes_or(pol->v.nodes, pol->v.nodes, tmp);
344 else if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP2)
345 pol->v.nodes = tmp;
346 else
347 BUG();
348
349 if (!node_isset(current->il_next, tmp)) {
350 current->il_next = next_node(current->il_next, tmp);
351 if (current->il_next >= MAX_NUMNODES)
352 current->il_next = first_node(tmp);
353 if (current->il_next >= MAX_NUMNODES)
354 current->il_next = numa_node_id();
355 }
356}
357
358static void mpol_rebind_preferred(struct mempolicy *pol,
359 const nodemask_t *nodes,
360 enum mpol_rebind_step step)
361{
362 nodemask_t tmp;
363
364 if (pol->flags & MPOL_F_STATIC_NODES) {
365 int node = first_node(pol->w.user_nodemask);
366
367 if (node_isset(node, *nodes)) {
368 pol->v.preferred_node = node;
369 pol->flags &= ~MPOL_F_LOCAL;
370 } else
371 pol->flags |= MPOL_F_LOCAL;
372 } else if (pol->flags & MPOL_F_RELATIVE_NODES) {
373 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
374 pol->v.preferred_node = first_node(tmp);
375 } else if (!(pol->flags & MPOL_F_LOCAL)) {
376 pol->v.preferred_node = node_remap(pol->v.preferred_node,
377 pol->w.cpuset_mems_allowed,
378 *nodes);
379 pol->w.cpuset_mems_allowed = *nodes;
380 }
381}
382
383/*
384 * mpol_rebind_policy - Migrate a policy to a different set of nodes
385 *
386 * If read-side task has no lock to protect task->mempolicy, write-side
387 * task will rebind the task->mempolicy by two step. The first step is
388 * setting all the newly nodes, and the second step is cleaning all the
389 * disallowed nodes. In this way, we can avoid finding no node to alloc
390 * page.
391 * If we have a lock to protect task->mempolicy in read-side, we do
392 * rebind directly.
393 *
394 * step:
395 * MPOL_REBIND_ONCE - do rebind work at once
396 * MPOL_REBIND_STEP1 - set all the newly nodes
397 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
398 */
399static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask,
400 enum mpol_rebind_step step)
401{
402 if (!pol)
403 return;
404 if (!mpol_store_user_nodemask(pol) && step == MPOL_REBIND_ONCE &&
405 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
406 return;
407
408 if (step == MPOL_REBIND_STEP1 && (pol->flags & MPOL_F_REBINDING))
409 return;
410
411 if (step == MPOL_REBIND_STEP2 && !(pol->flags & MPOL_F_REBINDING))
412 BUG();
413
414 if (step == MPOL_REBIND_STEP1)
415 pol->flags |= MPOL_F_REBINDING;
416 else if (step == MPOL_REBIND_STEP2)
417 pol->flags &= ~MPOL_F_REBINDING;
418 else if (step >= MPOL_REBIND_NSTEP)
419 BUG();
420
421 mpol_ops[pol->mode].rebind(pol, newmask, step);
422}
423
424/*
425 * Wrapper for mpol_rebind_policy() that just requires task
426 * pointer, and updates task mempolicy.
427 *
428 * Called with task's alloc_lock held.
429 */
430
431void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new,
432 enum mpol_rebind_step step)
433{
434 mpol_rebind_policy(tsk->mempolicy, new, step);
435}
436
437/*
438 * Rebind each vma in mm to new nodemask.
439 *
440 * Call holding a reference to mm. Takes mm->mmap_sem during call.
441 */
442
443void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
444{
445 struct vm_area_struct *vma;
446
447 down_write(&mm->mmap_sem);
448 for (vma = mm->mmap; vma; vma = vma->vm_next)
449 mpol_rebind_policy(vma->vm_policy, new, MPOL_REBIND_ONCE);
450 up_write(&mm->mmap_sem);
451}
452
453static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
454 [MPOL_DEFAULT] = {
455 .rebind = mpol_rebind_default,
456 },
457 [MPOL_INTERLEAVE] = {
458 .create = mpol_new_interleave,
459 .rebind = mpol_rebind_nodemask,
460 },
461 [MPOL_PREFERRED] = {
462 .create = mpol_new_preferred,
463 .rebind = mpol_rebind_preferred,
464 },
465 [MPOL_BIND] = {
466 .create = mpol_new_bind,
467 .rebind = mpol_rebind_nodemask,
468 },
469};
470
471static void migrate_page_add(struct page *page, struct list_head *pagelist,
472 unsigned long flags);
473
474struct queue_pages {
475 struct list_head *pagelist;
476 unsigned long flags;
477 nodemask_t *nmask;
478 struct vm_area_struct *prev;
479};
480
481/*
482 * Scan through pages checking if pages follow certain conditions,
483 * and move them to the pagelist if they do.
484 */
485static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
486 unsigned long end, struct mm_walk *walk)
487{
488 struct vm_area_struct *vma = walk->vma;
489 struct page *page;
490 struct queue_pages *qp = walk->private;
491 unsigned long flags = qp->flags;
492 int nid, ret;
493 pte_t *pte;
494 spinlock_t *ptl;
495
496 if (pmd_trans_huge(*pmd)) {
497 ptl = pmd_lock(walk->mm, pmd);
498 if (pmd_trans_huge(*pmd)) {
499 page = pmd_page(*pmd);
500 if (is_huge_zero_page(page)) {
501 spin_unlock(ptl);
502 split_huge_pmd(vma, pmd, addr);
503 } else {
504 get_page(page);
505 spin_unlock(ptl);
506 lock_page(page);
507 ret = split_huge_page(page);
508 unlock_page(page);
509 put_page(page);
510 if (ret)
511 return 0;
512 }
513 } else {
514 spin_unlock(ptl);
515 }
516 }
517
518retry:
519 pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
520 for (; addr != end; pte++, addr += PAGE_SIZE) {
521 if (!pte_present(*pte))
522 continue;
523 page = vm_normal_page(vma, addr, *pte);
524 if (!page)
525 continue;
526 /*
527 * vm_normal_page() filters out zero pages, but there might
528 * still be PageReserved pages to skip, perhaps in a VDSO.
529 */
530 if (PageReserved(page))
531 continue;
532 nid = page_to_nid(page);
533 if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
534 continue;
535 if (PageTransCompound(page) && PageAnon(page)) {
536 get_page(page);
537 pte_unmap_unlock(pte, ptl);
538 lock_page(page);
539 ret = split_huge_page(page);
540 unlock_page(page);
541 put_page(page);
542 /* Failed to split -- skip. */
543 if (ret) {
544 pte = pte_offset_map_lock(walk->mm, pmd,
545 addr, &ptl);
546 continue;
547 }
548 goto retry;
549 }
550
551 migrate_page_add(page, qp->pagelist, flags);
552 }
553 pte_unmap_unlock(pte - 1, ptl);
554 cond_resched();
555 return 0;
556}
557
558static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
559 unsigned long addr, unsigned long end,
560 struct mm_walk *walk)
561{
562#ifdef CONFIG_HUGETLB_PAGE
563 struct queue_pages *qp = walk->private;
564 unsigned long flags = qp->flags;
565 int nid;
566 struct page *page;
567 spinlock_t *ptl;
568 pte_t entry;
569
570 ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
571 entry = huge_ptep_get(pte);
572 if (!pte_present(entry))
573 goto unlock;
574 page = pte_page(entry);
575 nid = page_to_nid(page);
576 if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
577 goto unlock;
578 /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
579 if (flags & (MPOL_MF_MOVE_ALL) ||
580 (flags & MPOL_MF_MOVE && page_mapcount(page) == 1))
581 isolate_huge_page(page, qp->pagelist);
582unlock:
583 spin_unlock(ptl);
584#else
585 BUG();
586#endif
587 return 0;
588}
589
590#ifdef CONFIG_NUMA_BALANCING
591/*
592 * This is used to mark a range of virtual addresses to be inaccessible.
593 * These are later cleared by a NUMA hinting fault. Depending on these
594 * faults, pages may be migrated for better NUMA placement.
595 *
596 * This is assuming that NUMA faults are handled using PROT_NONE. If
597 * an architecture makes a different choice, it will need further
598 * changes to the core.
599 */
600unsigned long change_prot_numa(struct vm_area_struct *vma,
601 unsigned long addr, unsigned long end)
602{
603 int nr_updated;
604
605 nr_updated = change_protection(vma, addr, end, PAGE_NONE, 0, 1);
606 if (nr_updated)
607 count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
608
609 return nr_updated;
610}
611#else
612static unsigned long change_prot_numa(struct vm_area_struct *vma,
613 unsigned long addr, unsigned long end)
614{
615 return 0;
616}
617#endif /* CONFIG_NUMA_BALANCING */
618
619static int queue_pages_test_walk(unsigned long start, unsigned long end,
620 struct mm_walk *walk)
621{
622 struct vm_area_struct *vma = walk->vma;
623 struct queue_pages *qp = walk->private;
624 unsigned long endvma = vma->vm_end;
625 unsigned long flags = qp->flags;
626
627 if (!vma_migratable(vma))
628 return 1;
629
630 if (endvma > end)
631 endvma = end;
632 if (vma->vm_start > start)
633 start = vma->vm_start;
634
635 if (!(flags & MPOL_MF_DISCONTIG_OK)) {
636 if (!vma->vm_next && vma->vm_end < end)
637 return -EFAULT;
638 if (qp->prev && qp->prev->vm_end < vma->vm_start)
639 return -EFAULT;
640 }
641
642 qp->prev = vma;
643
644 if (flags & MPOL_MF_LAZY) {
645 /* Similar to task_numa_work, skip inaccessible VMAs */
646 if (!is_vm_hugetlb_page(vma) &&
647 (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) &&
648 !(vma->vm_flags & VM_MIXEDMAP))
649 change_prot_numa(vma, start, endvma);
650 return 1;
651 }
652
653 /* queue pages from current vma */
654 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
655 return 0;
656 return 1;
657}
658
659/*
660 * Walk through page tables and collect pages to be migrated.
661 *
662 * If pages found in a given range are on a set of nodes (determined by
663 * @nodes and @flags,) it's isolated and queued to the pagelist which is
664 * passed via @private.)
665 */
666static int
667queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
668 nodemask_t *nodes, unsigned long flags,
669 struct list_head *pagelist)
670{
671 struct queue_pages qp = {
672 .pagelist = pagelist,
673 .flags = flags,
674 .nmask = nodes,
675 .prev = NULL,
676 };
677 struct mm_walk queue_pages_walk = {
678 .hugetlb_entry = queue_pages_hugetlb,
679 .pmd_entry = queue_pages_pte_range,
680 .test_walk = queue_pages_test_walk,
681 .mm = mm,
682 .private = &qp,
683 };
684
685 return walk_page_range(start, end, &queue_pages_walk);
686}
687
688/*
689 * Apply policy to a single VMA
690 * This must be called with the mmap_sem held for writing.
691 */
692static int vma_replace_policy(struct vm_area_struct *vma,
693 struct mempolicy *pol)
694{
695 int err;
696 struct mempolicy *old;
697 struct mempolicy *new;
698
699 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
700 vma->vm_start, vma->vm_end, vma->vm_pgoff,
701 vma->vm_ops, vma->vm_file,
702 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
703
704 new = mpol_dup(pol);
705 if (IS_ERR(new))
706 return PTR_ERR(new);
707
708 if (vma->vm_ops && vma->vm_ops->set_policy) {
709 err = vma->vm_ops->set_policy(vma, new);
710 if (err)
711 goto err_out;
712 }
713
714 old = vma->vm_policy;
715 vma->vm_policy = new; /* protected by mmap_sem */
716 mpol_put(old);
717
718 return 0;
719 err_out:
720 mpol_put(new);
721 return err;
722}
723
724/* Step 2: apply policy to a range and do splits. */
725static int mbind_range(struct mm_struct *mm, unsigned long start,
726 unsigned long end, struct mempolicy *new_pol)
727{
728 struct vm_area_struct *next;
729 struct vm_area_struct *prev;
730 struct vm_area_struct *vma;
731 int err = 0;
732 pgoff_t pgoff;
733 unsigned long vmstart;
734 unsigned long vmend;
735
736 vma = find_vma(mm, start);
737 if (!vma || vma->vm_start > start)
738 return -EFAULT;
739
740 prev = vma->vm_prev;
741 if (start > vma->vm_start)
742 prev = vma;
743
744 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
745 next = vma->vm_next;
746 vmstart = max(start, vma->vm_start);
747 vmend = min(end, vma->vm_end);
748
749 if (mpol_equal(vma_policy(vma), new_pol))
750 continue;
751
752 pgoff = vma->vm_pgoff +
753 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
754 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
755 vma->anon_vma, vma->vm_file, pgoff,
756 new_pol, vma->vm_userfaultfd_ctx);
757 if (prev) {
758 vma = prev;
759 next = vma->vm_next;
760 if (mpol_equal(vma_policy(vma), new_pol))
761 continue;
762 /* vma_merge() joined vma && vma->next, case 8 */
763 goto replace;
764 }
765 if (vma->vm_start != vmstart) {
766 err = split_vma(vma->vm_mm, vma, vmstart, 1);
767 if (err)
768 goto out;
769 }
770 if (vma->vm_end != vmend) {
771 err = split_vma(vma->vm_mm, vma, vmend, 0);
772 if (err)
773 goto out;
774 }
775 replace:
776 err = vma_replace_policy(vma, new_pol);
777 if (err)
778 goto out;
779 }
780
781 out:
782 return err;
783}
784
785/* Set the process memory policy */
786static long do_set_mempolicy(unsigned short mode, unsigned short flags,
787 nodemask_t *nodes)
788{
789 struct mempolicy *new, *old;
790 NODEMASK_SCRATCH(scratch);
791 int ret;
792
793 if (!scratch)
794 return -ENOMEM;
795
796 new = mpol_new(mode, flags, nodes);
797 if (IS_ERR(new)) {
798 ret = PTR_ERR(new);
799 goto out;
800 }
801
802 task_lock(current);
803 ret = mpol_set_nodemask(new, nodes, scratch);
804 if (ret) {
805 task_unlock(current);
806 mpol_put(new);
807 goto out;
808 }
809 old = current->mempolicy;
810 current->mempolicy = new;
811 if (new && new->mode == MPOL_INTERLEAVE &&
812 nodes_weight(new->v.nodes))
813 current->il_next = first_node(new->v.nodes);
814 task_unlock(current);
815 mpol_put(old);
816 ret = 0;
817out:
818 NODEMASK_SCRATCH_FREE(scratch);
819 return ret;
820}
821
822/*
823 * Return nodemask for policy for get_mempolicy() query
824 *
825 * Called with task's alloc_lock held
826 */
827static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
828{
829 nodes_clear(*nodes);
830 if (p == &default_policy)
831 return;
832
833 switch (p->mode) {
834 case MPOL_BIND:
835 /* Fall through */
836 case MPOL_INTERLEAVE:
837 *nodes = p->v.nodes;
838 break;
839 case MPOL_PREFERRED:
840 if (!(p->flags & MPOL_F_LOCAL))
841 node_set(p->v.preferred_node, *nodes);
842 /* else return empty node mask for local allocation */
843 break;
844 default:
845 BUG();
846 }
847}
848
849static int lookup_node(unsigned long addr)
850{
851 struct page *p;
852 int err;
853
854 err = get_user_pages(addr & PAGE_MASK, 1, 0, 0, &p, NULL);
855 if (err >= 0) {
856 err = page_to_nid(p);
857 put_page(p);
858 }
859 return err;
860}
861
862/* Retrieve NUMA policy */
863static long do_get_mempolicy(int *policy, nodemask_t *nmask,
864 unsigned long addr, unsigned long flags)
865{
866 int err;
867 struct mm_struct *mm = current->mm;
868 struct vm_area_struct *vma = NULL;
869 struct mempolicy *pol = current->mempolicy;
870
871 if (flags &
872 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
873 return -EINVAL;
874
875 if (flags & MPOL_F_MEMS_ALLOWED) {
876 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
877 return -EINVAL;
878 *policy = 0; /* just so it's initialized */
879 task_lock(current);
880 *nmask = cpuset_current_mems_allowed;
881 task_unlock(current);
882 return 0;
883 }
884
885 if (flags & MPOL_F_ADDR) {
886 /*
887 * Do NOT fall back to task policy if the
888 * vma/shared policy at addr is NULL. We
889 * want to return MPOL_DEFAULT in this case.
890 */
891 down_read(&mm->mmap_sem);
892 vma = find_vma_intersection(mm, addr, addr+1);
893 if (!vma) {
894 up_read(&mm->mmap_sem);
895 return -EFAULT;
896 }
897 if (vma->vm_ops && vma->vm_ops->get_policy)
898 pol = vma->vm_ops->get_policy(vma, addr);
899 else
900 pol = vma->vm_policy;
901 } else if (addr)
902 return -EINVAL;
903
904 if (!pol)
905 pol = &default_policy; /* indicates default behavior */
906
907 if (flags & MPOL_F_NODE) {
908 if (flags & MPOL_F_ADDR) {
909 err = lookup_node(addr);
910 if (err < 0)
911 goto out;
912 *policy = err;
913 } else if (pol == current->mempolicy &&
914 pol->mode == MPOL_INTERLEAVE) {
915 *policy = current->il_next;
916 } else {
917 err = -EINVAL;
918 goto out;
919 }
920 } else {
921 *policy = pol == &default_policy ? MPOL_DEFAULT :
922 pol->mode;
923 /*
924 * Internal mempolicy flags must be masked off before exposing
925 * the policy to userspace.
926 */
927 *policy |= (pol->flags & MPOL_MODE_FLAGS);
928 }
929
930 if (vma) {
931 up_read(¤t->mm->mmap_sem);
932 vma = NULL;
933 }
934
935 err = 0;
936 if (nmask) {
937 if (mpol_store_user_nodemask(pol)) {
938 *nmask = pol->w.user_nodemask;
939 } else {
940 task_lock(current);
941 get_policy_nodemask(pol, nmask);
942 task_unlock(current);
943 }
944 }
945
946 out:
947 mpol_cond_put(pol);
948 if (vma)
949 up_read(¤t->mm->mmap_sem);
950 return err;
951}
952
953#ifdef CONFIG_MIGRATION
954/*
955 * page migration
956 */
957static void migrate_page_add(struct page *page, struct list_head *pagelist,
958 unsigned long flags)
959{
960 /*
961 * Avoid migrating a page that is shared with others.
962 */
963 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
964 if (!isolate_lru_page(page)) {
965 list_add_tail(&page->lru, pagelist);
966 inc_zone_page_state(page, NR_ISOLATED_ANON +
967 page_is_file_cache(page));
968 }
969 }
970}
971
972static struct page *new_node_page(struct page *page, unsigned long node, int **x)
973{
974 if (PageHuge(page))
975 return alloc_huge_page_node(page_hstate(compound_head(page)),
976 node);
977 else
978 return __alloc_pages_node(node, GFP_HIGHUSER_MOVABLE |
979 __GFP_THISNODE, 0);
980}
981
982/*
983 * Migrate pages from one node to a target node.
984 * Returns error or the number of pages not migrated.
985 */
986static int migrate_to_node(struct mm_struct *mm, int source, int dest,
987 int flags)
988{
989 nodemask_t nmask;
990 LIST_HEAD(pagelist);
991 int err = 0;
992
993 nodes_clear(nmask);
994 node_set(source, nmask);
995
996 /*
997 * This does not "check" the range but isolates all pages that
998 * need migration. Between passing in the full user address
999 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
1000 */
1001 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
1002 queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1003 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
1004
1005 if (!list_empty(&pagelist)) {
1006 err = migrate_pages(&pagelist, new_node_page, NULL, dest,
1007 MIGRATE_SYNC, MR_SYSCALL);
1008 if (err)
1009 putback_movable_pages(&pagelist);
1010 }
1011
1012 return err;
1013}
1014
1015/*
1016 * Move pages between the two nodesets so as to preserve the physical
1017 * layout as much as possible.
1018 *
1019 * Returns the number of page that could not be moved.
1020 */
1021int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1022 const nodemask_t *to, int flags)
1023{
1024 int busy = 0;
1025 int err;
1026 nodemask_t tmp;
1027
1028 err = migrate_prep();
1029 if (err)
1030 return err;
1031
1032 down_read(&mm->mmap_sem);
1033
1034 /*
1035 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1036 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1037 * bit in 'tmp', and return that <source, dest> pair for migration.
1038 * The pair of nodemasks 'to' and 'from' define the map.
1039 *
1040 * If no pair of bits is found that way, fallback to picking some
1041 * pair of 'source' and 'dest' bits that are not the same. If the
1042 * 'source' and 'dest' bits are the same, this represents a node
1043 * that will be migrating to itself, so no pages need move.
1044 *
1045 * If no bits are left in 'tmp', or if all remaining bits left
1046 * in 'tmp' correspond to the same bit in 'to', return false
1047 * (nothing left to migrate).
1048 *
1049 * This lets us pick a pair of nodes to migrate between, such that
1050 * if possible the dest node is not already occupied by some other
1051 * source node, minimizing the risk of overloading the memory on a
1052 * node that would happen if we migrated incoming memory to a node
1053 * before migrating outgoing memory source that same node.
1054 *
1055 * A single scan of tmp is sufficient. As we go, we remember the
1056 * most recent <s, d> pair that moved (s != d). If we find a pair
1057 * that not only moved, but what's better, moved to an empty slot
1058 * (d is not set in tmp), then we break out then, with that pair.
1059 * Otherwise when we finish scanning from_tmp, we at least have the
1060 * most recent <s, d> pair that moved. If we get all the way through
1061 * the scan of tmp without finding any node that moved, much less
1062 * moved to an empty node, then there is nothing left worth migrating.
1063 */
1064
1065 tmp = *from;
1066 while (!nodes_empty(tmp)) {
1067 int s,d;
1068 int source = NUMA_NO_NODE;
1069 int dest = 0;
1070
1071 for_each_node_mask(s, tmp) {
1072
1073 /*
1074 * do_migrate_pages() tries to maintain the relative
1075 * node relationship of the pages established between
1076 * threads and memory areas.
1077 *
1078 * However if the number of source nodes is not equal to
1079 * the number of destination nodes we can not preserve
1080 * this node relative relationship. In that case, skip
1081 * copying memory from a node that is in the destination
1082 * mask.
1083 *
1084 * Example: [2,3,4] -> [3,4,5] moves everything.
1085 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1086 */
1087
1088 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1089 (node_isset(s, *to)))
1090 continue;
1091
1092 d = node_remap(s, *from, *to);
1093 if (s == d)
1094 continue;
1095
1096 source = s; /* Node moved. Memorize */
1097 dest = d;
1098
1099 /* dest not in remaining from nodes? */
1100 if (!node_isset(dest, tmp))
1101 break;
1102 }
1103 if (source == NUMA_NO_NODE)
1104 break;
1105
1106 node_clear(source, tmp);
1107 err = migrate_to_node(mm, source, dest, flags);
1108 if (err > 0)
1109 busy += err;
1110 if (err < 0)
1111 break;
1112 }
1113 up_read(&mm->mmap_sem);
1114 if (err < 0)
1115 return err;
1116 return busy;
1117
1118}
1119
1120/*
1121 * Allocate a new page for page migration based on vma policy.
1122 * Start by assuming the page is mapped by the same vma as contains @start.
1123 * Search forward from there, if not. N.B., this assumes that the
1124 * list of pages handed to migrate_pages()--which is how we get here--
1125 * is in virtual address order.
1126 */
1127static struct page *new_page(struct page *page, unsigned long start, int **x)
1128{
1129 struct vm_area_struct *vma;
1130 unsigned long uninitialized_var(address);
1131
1132 vma = find_vma(current->mm, start);
1133 while (vma) {
1134 address = page_address_in_vma(page, vma);
1135 if (address != -EFAULT)
1136 break;
1137 vma = vma->vm_next;
1138 }
1139
1140 if (PageHuge(page)) {
1141 BUG_ON(!vma);
1142 return alloc_huge_page_noerr(vma, address, 1);
1143 }
1144 /*
1145 * if !vma, alloc_page_vma() will use task or system default policy
1146 */
1147 return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1148}
1149#else
1150
1151static void migrate_page_add(struct page *page, struct list_head *pagelist,
1152 unsigned long flags)
1153{
1154}
1155
1156int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1157 const nodemask_t *to, int flags)
1158{
1159 return -ENOSYS;
1160}
1161
1162static struct page *new_page(struct page *page, unsigned long start, int **x)
1163{
1164 return NULL;
1165}
1166#endif
1167
1168static long do_mbind(unsigned long start, unsigned long len,
1169 unsigned short mode, unsigned short mode_flags,
1170 nodemask_t *nmask, unsigned long flags)
1171{
1172 struct mm_struct *mm = current->mm;
1173 struct mempolicy *new;
1174 unsigned long end;
1175 int err;
1176 LIST_HEAD(pagelist);
1177
1178 if (flags & ~(unsigned long)MPOL_MF_VALID)
1179 return -EINVAL;
1180 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1181 return -EPERM;
1182
1183 if (start & ~PAGE_MASK)
1184 return -EINVAL;
1185
1186 if (mode == MPOL_DEFAULT)
1187 flags &= ~MPOL_MF_STRICT;
1188
1189 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1190 end = start + len;
1191
1192 if (end < start)
1193 return -EINVAL;
1194 if (end == start)
1195 return 0;
1196
1197 new = mpol_new(mode, mode_flags, nmask);
1198 if (IS_ERR(new))
1199 return PTR_ERR(new);
1200
1201 if (flags & MPOL_MF_LAZY)
1202 new->flags |= MPOL_F_MOF;
1203
1204 /*
1205 * If we are using the default policy then operation
1206 * on discontinuous address spaces is okay after all
1207 */
1208 if (!new)
1209 flags |= MPOL_MF_DISCONTIG_OK;
1210
1211 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1212 start, start + len, mode, mode_flags,
1213 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1214
1215 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1216
1217 err = migrate_prep();
1218 if (err)
1219 goto mpol_out;
1220 }
1221 {
1222 NODEMASK_SCRATCH(scratch);
1223 if (scratch) {
1224 down_write(&mm->mmap_sem);
1225 task_lock(current);
1226 err = mpol_set_nodemask(new, nmask, scratch);
1227 task_unlock(current);
1228 if (err)
1229 up_write(&mm->mmap_sem);
1230 } else
1231 err = -ENOMEM;
1232 NODEMASK_SCRATCH_FREE(scratch);
1233 }
1234 if (err)
1235 goto mpol_out;
1236
1237 err = queue_pages_range(mm, start, end, nmask,
1238 flags | MPOL_MF_INVERT, &pagelist);
1239 if (!err)
1240 err = mbind_range(mm, start, end, new);
1241
1242 if (!err) {
1243 int nr_failed = 0;
1244
1245 if (!list_empty(&pagelist)) {
1246 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1247 nr_failed = migrate_pages(&pagelist, new_page, NULL,
1248 start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
1249 if (nr_failed)
1250 putback_movable_pages(&pagelist);
1251 }
1252
1253 if (nr_failed && (flags & MPOL_MF_STRICT))
1254 err = -EIO;
1255 } else
1256 putback_movable_pages(&pagelist);
1257
1258 up_write(&mm->mmap_sem);
1259 mpol_out:
1260 mpol_put(new);
1261 return err;
1262}
1263
1264/*
1265 * User space interface with variable sized bitmaps for nodelists.
1266 */
1267
1268/* Copy a node mask from user space. */
1269static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1270 unsigned long maxnode)
1271{
1272 unsigned long k;
1273 unsigned long nlongs;
1274 unsigned long endmask;
1275
1276 --maxnode;
1277 nodes_clear(*nodes);
1278 if (maxnode == 0 || !nmask)
1279 return 0;
1280 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1281 return -EINVAL;
1282
1283 nlongs = BITS_TO_LONGS(maxnode);
1284 if ((maxnode % BITS_PER_LONG) == 0)
1285 endmask = ~0UL;
1286 else
1287 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1288
1289 /* When the user specified more nodes than supported just check
1290 if the non supported part is all zero. */
1291 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1292 if (nlongs > PAGE_SIZE/sizeof(long))
1293 return -EINVAL;
1294 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1295 unsigned long t;
1296 if (get_user(t, nmask + k))
1297 return -EFAULT;
1298 if (k == nlongs - 1) {
1299 if (t & endmask)
1300 return -EINVAL;
1301 } else if (t)
1302 return -EINVAL;
1303 }
1304 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1305 endmask = ~0UL;
1306 }
1307
1308 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1309 return -EFAULT;
1310 nodes_addr(*nodes)[nlongs-1] &= endmask;
1311 return 0;
1312}
1313
1314/* Copy a kernel node mask to user space */
1315static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1316 nodemask_t *nodes)
1317{
1318 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1319 const int nbytes = BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long);
1320
1321 if (copy > nbytes) {
1322 if (copy > PAGE_SIZE)
1323 return -EINVAL;
1324 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1325 return -EFAULT;
1326 copy = nbytes;
1327 }
1328 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1329}
1330
1331SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1332 unsigned long, mode, const unsigned long __user *, nmask,
1333 unsigned long, maxnode, unsigned, flags)
1334{
1335 nodemask_t nodes;
1336 int err;
1337 unsigned short mode_flags;
1338
1339 mode_flags = mode & MPOL_MODE_FLAGS;
1340 mode &= ~MPOL_MODE_FLAGS;
1341 if (mode >= MPOL_MAX)
1342 return -EINVAL;
1343 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1344 (mode_flags & MPOL_F_RELATIVE_NODES))
1345 return -EINVAL;
1346 err = get_nodes(&nodes, nmask, maxnode);
1347 if (err)
1348 return err;
1349 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1350}
1351
1352/* Set the process memory policy */
1353SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
1354 unsigned long, maxnode)
1355{
1356 int err;
1357 nodemask_t nodes;
1358 unsigned short flags;
1359
1360 flags = mode & MPOL_MODE_FLAGS;
1361 mode &= ~MPOL_MODE_FLAGS;
1362 if ((unsigned int)mode >= MPOL_MAX)
1363 return -EINVAL;
1364 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1365 return -EINVAL;
1366 err = get_nodes(&nodes, nmask, maxnode);
1367 if (err)
1368 return err;
1369 return do_set_mempolicy(mode, flags, &nodes);
1370}
1371
1372SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1373 const unsigned long __user *, old_nodes,
1374 const unsigned long __user *, new_nodes)
1375{
1376 const struct cred *cred = current_cred(), *tcred;
1377 struct mm_struct *mm = NULL;
1378 struct task_struct *task;
1379 nodemask_t task_nodes;
1380 int err;
1381 nodemask_t *old;
1382 nodemask_t *new;
1383 NODEMASK_SCRATCH(scratch);
1384
1385 if (!scratch)
1386 return -ENOMEM;
1387
1388 old = &scratch->mask1;
1389 new = &scratch->mask2;
1390
1391 err = get_nodes(old, old_nodes, maxnode);
1392 if (err)
1393 goto out;
1394
1395 err = get_nodes(new, new_nodes, maxnode);
1396 if (err)
1397 goto out;
1398
1399 /* Find the mm_struct */
1400 rcu_read_lock();
1401 task = pid ? find_task_by_vpid(pid) : current;
1402 if (!task) {
1403 rcu_read_unlock();
1404 err = -ESRCH;
1405 goto out;
1406 }
1407 get_task_struct(task);
1408
1409 err = -EINVAL;
1410
1411 /*
1412 * Check if this process has the right to modify the specified
1413 * process. The right exists if the process has administrative
1414 * capabilities, superuser privileges or the same
1415 * userid as the target process.
1416 */
1417 tcred = __task_cred(task);
1418 if (!uid_eq(cred->euid, tcred->suid) && !uid_eq(cred->euid, tcred->uid) &&
1419 !uid_eq(cred->uid, tcred->suid) && !uid_eq(cred->uid, tcred->uid) &&
1420 !capable(CAP_SYS_NICE)) {
1421 rcu_read_unlock();
1422 err = -EPERM;
1423 goto out_put;
1424 }
1425 rcu_read_unlock();
1426
1427 task_nodes = cpuset_mems_allowed(task);
1428 /* Is the user allowed to access the target nodes? */
1429 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1430 err = -EPERM;
1431 goto out_put;
1432 }
1433
1434 if (!nodes_subset(*new, node_states[N_MEMORY])) {
1435 err = -EINVAL;
1436 goto out_put;
1437 }
1438
1439 err = security_task_movememory(task);
1440 if (err)
1441 goto out_put;
1442
1443 mm = get_task_mm(task);
1444 put_task_struct(task);
1445
1446 if (!mm) {
1447 err = -EINVAL;
1448 goto out;
1449 }
1450
1451 err = do_migrate_pages(mm, old, new,
1452 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1453
1454 mmput(mm);
1455out:
1456 NODEMASK_SCRATCH_FREE(scratch);
1457
1458 return err;
1459
1460out_put:
1461 put_task_struct(task);
1462 goto out;
1463
1464}
1465
1466
1467/* Retrieve NUMA policy */
1468SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1469 unsigned long __user *, nmask, unsigned long, maxnode,
1470 unsigned long, addr, unsigned long, flags)
1471{
1472 int err;
1473 int uninitialized_var(pval);
1474 nodemask_t nodes;
1475
1476 if (nmask != NULL && maxnode < MAX_NUMNODES)
1477 return -EINVAL;
1478
1479 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1480
1481 if (err)
1482 return err;
1483
1484 if (policy && put_user(pval, policy))
1485 return -EFAULT;
1486
1487 if (nmask)
1488 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1489
1490 return err;
1491}
1492
1493#ifdef CONFIG_COMPAT
1494
1495COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1496 compat_ulong_t __user *, nmask,
1497 compat_ulong_t, maxnode,
1498 compat_ulong_t, addr, compat_ulong_t, flags)
1499{
1500 long err;
1501 unsigned long __user *nm = NULL;
1502 unsigned long nr_bits, alloc_size;
1503 DECLARE_BITMAP(bm, MAX_NUMNODES);
1504
1505 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1506 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1507
1508 if (nmask)
1509 nm = compat_alloc_user_space(alloc_size);
1510
1511 err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1512
1513 if (!err && nmask) {
1514 unsigned long copy_size;
1515 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1516 err = copy_from_user(bm, nm, copy_size);
1517 /* ensure entire bitmap is zeroed */
1518 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1519 err |= compat_put_bitmap(nmask, bm, nr_bits);
1520 }
1521
1522 return err;
1523}
1524
1525COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
1526 compat_ulong_t, maxnode)
1527{
1528 long err = 0;
1529 unsigned long __user *nm = NULL;
1530 unsigned long nr_bits, alloc_size;
1531 DECLARE_BITMAP(bm, MAX_NUMNODES);
1532
1533 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1534 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1535
1536 if (nmask) {
1537 err = compat_get_bitmap(bm, nmask, nr_bits);
1538 nm = compat_alloc_user_space(alloc_size);
1539 err |= copy_to_user(nm, bm, alloc_size);
1540 }
1541
1542 if (err)
1543 return -EFAULT;
1544
1545 return sys_set_mempolicy(mode, nm, nr_bits+1);
1546}
1547
1548COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
1549 compat_ulong_t, mode, compat_ulong_t __user *, nmask,
1550 compat_ulong_t, maxnode, compat_ulong_t, flags)
1551{
1552 long err = 0;
1553 unsigned long __user *nm = NULL;
1554 unsigned long nr_bits, alloc_size;
1555 nodemask_t bm;
1556
1557 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1558 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1559
1560 if (nmask) {
1561 err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
1562 nm = compat_alloc_user_space(alloc_size);
1563 err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
1564 }
1565
1566 if (err)
1567 return -EFAULT;
1568
1569 return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
1570}
1571
1572#endif
1573
1574struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
1575 unsigned long addr)
1576{
1577 struct mempolicy *pol = NULL;
1578
1579 if (vma) {
1580 if (vma->vm_ops && vma->vm_ops->get_policy) {
1581 pol = vma->vm_ops->get_policy(vma, addr);
1582 } else if (vma->vm_policy) {
1583 pol = vma->vm_policy;
1584
1585 /*
1586 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1587 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1588 * count on these policies which will be dropped by
1589 * mpol_cond_put() later
1590 */
1591 if (mpol_needs_cond_ref(pol))
1592 mpol_get(pol);
1593 }
1594 }
1595
1596 return pol;
1597}
1598
1599/*
1600 * get_vma_policy(@vma, @addr)
1601 * @vma: virtual memory area whose policy is sought
1602 * @addr: address in @vma for shared policy lookup
1603 *
1604 * Returns effective policy for a VMA at specified address.
1605 * Falls back to current->mempolicy or system default policy, as necessary.
1606 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1607 * count--added by the get_policy() vm_op, as appropriate--to protect against
1608 * freeing by another task. It is the caller's responsibility to free the
1609 * extra reference for shared policies.
1610 */
1611static struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
1612 unsigned long addr)
1613{
1614 struct mempolicy *pol = __get_vma_policy(vma, addr);
1615
1616 if (!pol)
1617 pol = get_task_policy(current);
1618
1619 return pol;
1620}
1621
1622bool vma_policy_mof(struct vm_area_struct *vma)
1623{
1624 struct mempolicy *pol;
1625
1626 if (vma->vm_ops && vma->vm_ops->get_policy) {
1627 bool ret = false;
1628
1629 pol = vma->vm_ops->get_policy(vma, vma->vm_start);
1630 if (pol && (pol->flags & MPOL_F_MOF))
1631 ret = true;
1632 mpol_cond_put(pol);
1633
1634 return ret;
1635 }
1636
1637 pol = vma->vm_policy;
1638 if (!pol)
1639 pol = get_task_policy(current);
1640
1641 return pol->flags & MPOL_F_MOF;
1642}
1643
1644static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1645{
1646 enum zone_type dynamic_policy_zone = policy_zone;
1647
1648 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1649
1650 /*
1651 * if policy->v.nodes has movable memory only,
1652 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1653 *
1654 * policy->v.nodes is intersect with node_states[N_MEMORY].
1655 * so if the following test faile, it implies
1656 * policy->v.nodes has movable memory only.
1657 */
1658 if (!nodes_intersects(policy->v.nodes, node_states[N_HIGH_MEMORY]))
1659 dynamic_policy_zone = ZONE_MOVABLE;
1660
1661 return zone >= dynamic_policy_zone;
1662}
1663
1664/*
1665 * Return a nodemask representing a mempolicy for filtering nodes for
1666 * page allocation
1667 */
1668static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1669{
1670 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1671 if (unlikely(policy->mode == MPOL_BIND) &&
1672 apply_policy_zone(policy, gfp_zone(gfp)) &&
1673 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1674 return &policy->v.nodes;
1675
1676 return NULL;
1677}
1678
1679/* Return a zonelist indicated by gfp for node representing a mempolicy */
1680static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
1681 int nd)
1682{
1683 switch (policy->mode) {
1684 case MPOL_PREFERRED:
1685 if (!(policy->flags & MPOL_F_LOCAL))
1686 nd = policy->v.preferred_node;
1687 break;
1688 case MPOL_BIND:
1689 /*
1690 * Normally, MPOL_BIND allocations are node-local within the
1691 * allowed nodemask. However, if __GFP_THISNODE is set and the
1692 * current node isn't part of the mask, we use the zonelist for
1693 * the first node in the mask instead.
1694 */
1695 if (unlikely(gfp & __GFP_THISNODE) &&
1696 unlikely(!node_isset(nd, policy->v.nodes)))
1697 nd = first_node(policy->v.nodes);
1698 break;
1699 default:
1700 BUG();
1701 }
1702 return node_zonelist(nd, gfp);
1703}
1704
1705/* Do dynamic interleaving for a process */
1706static unsigned interleave_nodes(struct mempolicy *policy)
1707{
1708 unsigned nid, next;
1709 struct task_struct *me = current;
1710
1711 nid = me->il_next;
1712 next = next_node(nid, policy->v.nodes);
1713 if (next >= MAX_NUMNODES)
1714 next = first_node(policy->v.nodes);
1715 if (next < MAX_NUMNODES)
1716 me->il_next = next;
1717 return nid;
1718}
1719
1720/*
1721 * Depending on the memory policy provide a node from which to allocate the
1722 * next slab entry.
1723 */
1724unsigned int mempolicy_slab_node(void)
1725{
1726 struct mempolicy *policy;
1727 int node = numa_mem_id();
1728
1729 if (in_interrupt())
1730 return node;
1731
1732 policy = current->mempolicy;
1733 if (!policy || policy->flags & MPOL_F_LOCAL)
1734 return node;
1735
1736 switch (policy->mode) {
1737 case MPOL_PREFERRED:
1738 /*
1739 * handled MPOL_F_LOCAL above
1740 */
1741 return policy->v.preferred_node;
1742
1743 case MPOL_INTERLEAVE:
1744 return interleave_nodes(policy);
1745
1746 case MPOL_BIND: {
1747 /*
1748 * Follow bind policy behavior and start allocation at the
1749 * first node.
1750 */
1751 struct zonelist *zonelist;
1752 struct zone *zone;
1753 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1754 zonelist = &NODE_DATA(node)->node_zonelists[0];
1755 (void)first_zones_zonelist(zonelist, highest_zoneidx,
1756 &policy->v.nodes,
1757 &zone);
1758 return zone ? zone->node : node;
1759 }
1760
1761 default:
1762 BUG();
1763 }
1764}
1765
1766/* Do static interleaving for a VMA with known offset. */
1767static unsigned offset_il_node(struct mempolicy *pol,
1768 struct vm_area_struct *vma, unsigned long off)
1769{
1770 unsigned nnodes = nodes_weight(pol->v.nodes);
1771 unsigned target;
1772 int c;
1773 int nid = NUMA_NO_NODE;
1774
1775 if (!nnodes)
1776 return numa_node_id();
1777 target = (unsigned int)off % nnodes;
1778 c = 0;
1779 do {
1780 nid = next_node(nid, pol->v.nodes);
1781 c++;
1782 } while (c <= target);
1783 return nid;
1784}
1785
1786/* Determine a node number for interleave */
1787static inline unsigned interleave_nid(struct mempolicy *pol,
1788 struct vm_area_struct *vma, unsigned long addr, int shift)
1789{
1790 if (vma) {
1791 unsigned long off;
1792
1793 /*
1794 * for small pages, there is no difference between
1795 * shift and PAGE_SHIFT, so the bit-shift is safe.
1796 * for huge pages, since vm_pgoff is in units of small
1797 * pages, we need to shift off the always 0 bits to get
1798 * a useful offset.
1799 */
1800 BUG_ON(shift < PAGE_SHIFT);
1801 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1802 off += (addr - vma->vm_start) >> shift;
1803 return offset_il_node(pol, vma, off);
1804 } else
1805 return interleave_nodes(pol);
1806}
1807
1808/*
1809 * Return the bit number of a random bit set in the nodemask.
1810 * (returns NUMA_NO_NODE if nodemask is empty)
1811 */
1812int node_random(const nodemask_t *maskp)
1813{
1814 int w, bit = NUMA_NO_NODE;
1815
1816 w = nodes_weight(*maskp);
1817 if (w)
1818 bit = bitmap_ord_to_pos(maskp->bits,
1819 get_random_int() % w, MAX_NUMNODES);
1820 return bit;
1821}
1822
1823#ifdef CONFIG_HUGETLBFS
1824/*
1825 * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
1826 * @vma: virtual memory area whose policy is sought
1827 * @addr: address in @vma for shared policy lookup and interleave policy
1828 * @gfp_flags: for requested zone
1829 * @mpol: pointer to mempolicy pointer for reference counted mempolicy
1830 * @nodemask: pointer to nodemask pointer for MPOL_BIND nodemask
1831 *
1832 * Returns a zonelist suitable for a huge page allocation and a pointer
1833 * to the struct mempolicy for conditional unref after allocation.
1834 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1835 * @nodemask for filtering the zonelist.
1836 *
1837 * Must be protected by read_mems_allowed_begin()
1838 */
1839struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1840 gfp_t gfp_flags, struct mempolicy **mpol,
1841 nodemask_t **nodemask)
1842{
1843 struct zonelist *zl;
1844
1845 *mpol = get_vma_policy(vma, addr);
1846 *nodemask = NULL; /* assume !MPOL_BIND */
1847
1848 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1849 zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1850 huge_page_shift(hstate_vma(vma))), gfp_flags);
1851 } else {
1852 zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1853 if ((*mpol)->mode == MPOL_BIND)
1854 *nodemask = &(*mpol)->v.nodes;
1855 }
1856 return zl;
1857}
1858
1859/*
1860 * init_nodemask_of_mempolicy
1861 *
1862 * If the current task's mempolicy is "default" [NULL], return 'false'
1863 * to indicate default policy. Otherwise, extract the policy nodemask
1864 * for 'bind' or 'interleave' policy into the argument nodemask, or
1865 * initialize the argument nodemask to contain the single node for
1866 * 'preferred' or 'local' policy and return 'true' to indicate presence
1867 * of non-default mempolicy.
1868 *
1869 * We don't bother with reference counting the mempolicy [mpol_get/put]
1870 * because the current task is examining it's own mempolicy and a task's
1871 * mempolicy is only ever changed by the task itself.
1872 *
1873 * N.B., it is the caller's responsibility to free a returned nodemask.
1874 */
1875bool init_nodemask_of_mempolicy(nodemask_t *mask)
1876{
1877 struct mempolicy *mempolicy;
1878 int nid;
1879
1880 if (!(mask && current->mempolicy))
1881 return false;
1882
1883 task_lock(current);
1884 mempolicy = current->mempolicy;
1885 switch (mempolicy->mode) {
1886 case MPOL_PREFERRED:
1887 if (mempolicy->flags & MPOL_F_LOCAL)
1888 nid = numa_node_id();
1889 else
1890 nid = mempolicy->v.preferred_node;
1891 init_nodemask_of_node(mask, nid);
1892 break;
1893
1894 case MPOL_BIND:
1895 /* Fall through */
1896 case MPOL_INTERLEAVE:
1897 *mask = mempolicy->v.nodes;
1898 break;
1899
1900 default:
1901 BUG();
1902 }
1903 task_unlock(current);
1904
1905 return true;
1906}
1907#endif
1908
1909/*
1910 * mempolicy_nodemask_intersects
1911 *
1912 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
1913 * policy. Otherwise, check for intersection between mask and the policy
1914 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
1915 * policy, always return true since it may allocate elsewhere on fallback.
1916 *
1917 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
1918 */
1919bool mempolicy_nodemask_intersects(struct task_struct *tsk,
1920 const nodemask_t *mask)
1921{
1922 struct mempolicy *mempolicy;
1923 bool ret = true;
1924
1925 if (!mask)
1926 return ret;
1927 task_lock(tsk);
1928 mempolicy = tsk->mempolicy;
1929 if (!mempolicy)
1930 goto out;
1931
1932 switch (mempolicy->mode) {
1933 case MPOL_PREFERRED:
1934 /*
1935 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
1936 * allocate from, they may fallback to other nodes when oom.
1937 * Thus, it's possible for tsk to have allocated memory from
1938 * nodes in mask.
1939 */
1940 break;
1941 case MPOL_BIND:
1942 case MPOL_INTERLEAVE:
1943 ret = nodes_intersects(mempolicy->v.nodes, *mask);
1944 break;
1945 default:
1946 BUG();
1947 }
1948out:
1949 task_unlock(tsk);
1950 return ret;
1951}
1952
1953/* Allocate a page in interleaved policy.
1954 Own path because it needs to do special accounting. */
1955static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
1956 unsigned nid)
1957{
1958 struct zonelist *zl;
1959 struct page *page;
1960
1961 zl = node_zonelist(nid, gfp);
1962 page = __alloc_pages(gfp, order, zl);
1963 if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1964 inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
1965 return page;
1966}
1967
1968/**
1969 * alloc_pages_vma - Allocate a page for a VMA.
1970 *
1971 * @gfp:
1972 * %GFP_USER user allocation.
1973 * %GFP_KERNEL kernel allocations,
1974 * %GFP_HIGHMEM highmem/user allocations,
1975 * %GFP_FS allocation should not call back into a file system.
1976 * %GFP_ATOMIC don't sleep.
1977 *
1978 * @order:Order of the GFP allocation.
1979 * @vma: Pointer to VMA or NULL if not available.
1980 * @addr: Virtual Address of the allocation. Must be inside the VMA.
1981 * @node: Which node to prefer for allocation (modulo policy).
1982 * @hugepage: for hugepages try only the preferred node if possible
1983 *
1984 * This function allocates a page from the kernel page pool and applies
1985 * a NUMA policy associated with the VMA or the current process.
1986 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
1987 * mm_struct of the VMA to prevent it from going away. Should be used for
1988 * all allocations for pages that will be mapped into user space. Returns
1989 * NULL when no page can be allocated.
1990 */
1991struct page *
1992alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
1993 unsigned long addr, int node, bool hugepage)
1994{
1995 struct mempolicy *pol;
1996 struct page *page;
1997 unsigned int cpuset_mems_cookie;
1998 struct zonelist *zl;
1999 nodemask_t *nmask;
2000
2001retry_cpuset:
2002 pol = get_vma_policy(vma, addr);
2003 cpuset_mems_cookie = read_mems_allowed_begin();
2004
2005 if (pol->mode == MPOL_INTERLEAVE) {
2006 unsigned nid;
2007
2008 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2009 mpol_cond_put(pol);
2010 page = alloc_page_interleave(gfp, order, nid);
2011 goto out;
2012 }
2013
2014 if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
2015 int hpage_node = node;
2016
2017 /*
2018 * For hugepage allocation and non-interleave policy which
2019 * allows the current node (or other explicitly preferred
2020 * node) we only try to allocate from the current/preferred
2021 * node and don't fall back to other nodes, as the cost of
2022 * remote accesses would likely offset THP benefits.
2023 *
2024 * If the policy is interleave, or does not allow the current
2025 * node in its nodemask, we allocate the standard way.
2026 */
2027 if (pol->mode == MPOL_PREFERRED &&
2028 !(pol->flags & MPOL_F_LOCAL))
2029 hpage_node = pol->v.preferred_node;
2030
2031 nmask = policy_nodemask(gfp, pol);
2032 if (!nmask || node_isset(hpage_node, *nmask)) {
2033 mpol_cond_put(pol);
2034 page = __alloc_pages_node(hpage_node,
2035 gfp | __GFP_THISNODE, order);
2036 goto out;
2037 }
2038 }
2039
2040 nmask = policy_nodemask(gfp, pol);
2041 zl = policy_zonelist(gfp, pol, node);
2042 mpol_cond_put(pol);
2043 page = __alloc_pages_nodemask(gfp, order, zl, nmask);
2044out:
2045 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
2046 goto retry_cpuset;
2047 return page;
2048}
2049
2050/**
2051 * alloc_pages_current - Allocate pages.
2052 *
2053 * @gfp:
2054 * %GFP_USER user allocation,
2055 * %GFP_KERNEL kernel allocation,
2056 * %GFP_HIGHMEM highmem allocation,
2057 * %GFP_FS don't call back into a file system.
2058 * %GFP_ATOMIC don't sleep.
2059 * @order: Power of two of allocation size in pages. 0 is a single page.
2060 *
2061 * Allocate a page from the kernel page pool. When not in
2062 * interrupt context and apply the current process NUMA policy.
2063 * Returns NULL when no page can be allocated.
2064 *
2065 * Don't call cpuset_update_task_memory_state() unless
2066 * 1) it's ok to take cpuset_sem (can WAIT), and
2067 * 2) allocating for current task (not interrupt).
2068 */
2069struct page *alloc_pages_current(gfp_t gfp, unsigned order)
2070{
2071 struct mempolicy *pol = &default_policy;
2072 struct page *page;
2073 unsigned int cpuset_mems_cookie;
2074
2075 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2076 pol = get_task_policy(current);
2077
2078retry_cpuset:
2079 cpuset_mems_cookie = read_mems_allowed_begin();
2080
2081 /*
2082 * No reference counting needed for current->mempolicy
2083 * nor system default_policy
2084 */
2085 if (pol->mode == MPOL_INTERLEAVE)
2086 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
2087 else
2088 page = __alloc_pages_nodemask(gfp, order,
2089 policy_zonelist(gfp, pol, numa_node_id()),
2090 policy_nodemask(gfp, pol));
2091
2092 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
2093 goto retry_cpuset;
2094
2095 return page;
2096}
2097EXPORT_SYMBOL(alloc_pages_current);
2098
2099int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
2100{
2101 struct mempolicy *pol = mpol_dup(vma_policy(src));
2102
2103 if (IS_ERR(pol))
2104 return PTR_ERR(pol);
2105 dst->vm_policy = pol;
2106 return 0;
2107}
2108
2109/*
2110 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2111 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2112 * with the mems_allowed returned by cpuset_mems_allowed(). This
2113 * keeps mempolicies cpuset relative after its cpuset moves. See
2114 * further kernel/cpuset.c update_nodemask().
2115 *
2116 * current's mempolicy may be rebinded by the other task(the task that changes
2117 * cpuset's mems), so we needn't do rebind work for current task.
2118 */
2119
2120/* Slow path of a mempolicy duplicate */
2121struct mempolicy *__mpol_dup(struct mempolicy *old)
2122{
2123 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2124
2125 if (!new)
2126 return ERR_PTR(-ENOMEM);
2127
2128 /* task's mempolicy is protected by alloc_lock */
2129 if (old == current->mempolicy) {
2130 task_lock(current);
2131 *new = *old;
2132 task_unlock(current);
2133 } else
2134 *new = *old;
2135
2136 if (current_cpuset_is_being_rebound()) {
2137 nodemask_t mems = cpuset_mems_allowed(current);
2138 if (new->flags & MPOL_F_REBINDING)
2139 mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
2140 else
2141 mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
2142 }
2143 atomic_set(&new->refcnt, 1);
2144 return new;
2145}
2146
2147/* Slow path of a mempolicy comparison */
2148bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2149{
2150 if (!a || !b)
2151 return false;
2152 if (a->mode != b->mode)
2153 return false;
2154 if (a->flags != b->flags)
2155 return false;
2156 if (mpol_store_user_nodemask(a))
2157 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2158 return false;
2159
2160 switch (a->mode) {
2161 case MPOL_BIND:
2162 /* Fall through */
2163 case MPOL_INTERLEAVE:
2164 return !!nodes_equal(a->v.nodes, b->v.nodes);
2165 case MPOL_PREFERRED:
2166 return a->v.preferred_node == b->v.preferred_node;
2167 default:
2168 BUG();
2169 return false;
2170 }
2171}
2172
2173/*
2174 * Shared memory backing store policy support.
2175 *
2176 * Remember policies even when nobody has shared memory mapped.
2177 * The policies are kept in Red-Black tree linked from the inode.
2178 * They are protected by the sp->lock rwlock, which should be held
2179 * for any accesses to the tree.
2180 */
2181
2182/*
2183 * lookup first element intersecting start-end. Caller holds sp->lock for
2184 * reading or for writing
2185 */
2186static struct sp_node *
2187sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2188{
2189 struct rb_node *n = sp->root.rb_node;
2190
2191 while (n) {
2192 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2193
2194 if (start >= p->end)
2195 n = n->rb_right;
2196 else if (end <= p->start)
2197 n = n->rb_left;
2198 else
2199 break;
2200 }
2201 if (!n)
2202 return NULL;
2203 for (;;) {
2204 struct sp_node *w = NULL;
2205 struct rb_node *prev = rb_prev(n);
2206 if (!prev)
2207 break;
2208 w = rb_entry(prev, struct sp_node, nd);
2209 if (w->end <= start)
2210 break;
2211 n = prev;
2212 }
2213 return rb_entry(n, struct sp_node, nd);
2214}
2215
2216/*
2217 * Insert a new shared policy into the list. Caller holds sp->lock for
2218 * writing.
2219 */
2220static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2221{
2222 struct rb_node **p = &sp->root.rb_node;
2223 struct rb_node *parent = NULL;
2224 struct sp_node *nd;
2225
2226 while (*p) {
2227 parent = *p;
2228 nd = rb_entry(parent, struct sp_node, nd);
2229 if (new->start < nd->start)
2230 p = &(*p)->rb_left;
2231 else if (new->end > nd->end)
2232 p = &(*p)->rb_right;
2233 else
2234 BUG();
2235 }
2236 rb_link_node(&new->nd, parent, p);
2237 rb_insert_color(&new->nd, &sp->root);
2238 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2239 new->policy ? new->policy->mode : 0);
2240}
2241
2242/* Find shared policy intersecting idx */
2243struct mempolicy *
2244mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2245{
2246 struct mempolicy *pol = NULL;
2247 struct sp_node *sn;
2248
2249 if (!sp->root.rb_node)
2250 return NULL;
2251 read_lock(&sp->lock);
2252 sn = sp_lookup(sp, idx, idx+1);
2253 if (sn) {
2254 mpol_get(sn->policy);
2255 pol = sn->policy;
2256 }
2257 read_unlock(&sp->lock);
2258 return pol;
2259}
2260
2261static void sp_free(struct sp_node *n)
2262{
2263 mpol_put(n->policy);
2264 kmem_cache_free(sn_cache, n);
2265}
2266
2267/**
2268 * mpol_misplaced - check whether current page node is valid in policy
2269 *
2270 * @page: page to be checked
2271 * @vma: vm area where page mapped
2272 * @addr: virtual address where page mapped
2273 *
2274 * Lookup current policy node id for vma,addr and "compare to" page's
2275 * node id.
2276 *
2277 * Returns:
2278 * -1 - not misplaced, page is in the right node
2279 * node - node id where the page should be
2280 *
2281 * Policy determination "mimics" alloc_page_vma().
2282 * Called from fault path where we know the vma and faulting address.
2283 */
2284int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
2285{
2286 struct mempolicy *pol;
2287 struct zone *zone;
2288 int curnid = page_to_nid(page);
2289 unsigned long pgoff;
2290 int thiscpu = raw_smp_processor_id();
2291 int thisnid = cpu_to_node(thiscpu);
2292 int polnid = -1;
2293 int ret = -1;
2294
2295 BUG_ON(!vma);
2296
2297 pol = get_vma_policy(vma, addr);
2298 if (!(pol->flags & MPOL_F_MOF))
2299 goto out;
2300
2301 switch (pol->mode) {
2302 case MPOL_INTERLEAVE:
2303 BUG_ON(addr >= vma->vm_end);
2304 BUG_ON(addr < vma->vm_start);
2305
2306 pgoff = vma->vm_pgoff;
2307 pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
2308 polnid = offset_il_node(pol, vma, pgoff);
2309 break;
2310
2311 case MPOL_PREFERRED:
2312 if (pol->flags & MPOL_F_LOCAL)
2313 polnid = numa_node_id();
2314 else
2315 polnid = pol->v.preferred_node;
2316 break;
2317
2318 case MPOL_BIND:
2319 /*
2320 * allows binding to multiple nodes.
2321 * use current page if in policy nodemask,
2322 * else select nearest allowed node, if any.
2323 * If no allowed nodes, use current [!misplaced].
2324 */
2325 if (node_isset(curnid, pol->v.nodes))
2326 goto out;
2327 (void)first_zones_zonelist(
2328 node_zonelist(numa_node_id(), GFP_HIGHUSER),
2329 gfp_zone(GFP_HIGHUSER),
2330 &pol->v.nodes, &zone);
2331 polnid = zone->node;
2332 break;
2333
2334 default:
2335 BUG();
2336 }
2337
2338 /* Migrate the page towards the node whose CPU is referencing it */
2339 if (pol->flags & MPOL_F_MORON) {
2340 polnid = thisnid;
2341
2342 if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
2343 goto out;
2344 }
2345
2346 if (curnid != polnid)
2347 ret = polnid;
2348out:
2349 mpol_cond_put(pol);
2350
2351 return ret;
2352}
2353
2354static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2355{
2356 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2357 rb_erase(&n->nd, &sp->root);
2358 sp_free(n);
2359}
2360
2361static void sp_node_init(struct sp_node *node, unsigned long start,
2362 unsigned long end, struct mempolicy *pol)
2363{
2364 node->start = start;
2365 node->end = end;
2366 node->policy = pol;
2367}
2368
2369static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2370 struct mempolicy *pol)
2371{
2372 struct sp_node *n;
2373 struct mempolicy *newpol;
2374
2375 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2376 if (!n)
2377 return NULL;
2378
2379 newpol = mpol_dup(pol);
2380 if (IS_ERR(newpol)) {
2381 kmem_cache_free(sn_cache, n);
2382 return NULL;
2383 }
2384 newpol->flags |= MPOL_F_SHARED;
2385 sp_node_init(n, start, end, newpol);
2386
2387 return n;
2388}
2389
2390/* Replace a policy range. */
2391static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2392 unsigned long end, struct sp_node *new)
2393{
2394 struct sp_node *n;
2395 struct sp_node *n_new = NULL;
2396 struct mempolicy *mpol_new = NULL;
2397 int ret = 0;
2398
2399restart:
2400 write_lock(&sp->lock);
2401 n = sp_lookup(sp, start, end);
2402 /* Take care of old policies in the same range. */
2403 while (n && n->start < end) {
2404 struct rb_node *next = rb_next(&n->nd);
2405 if (n->start >= start) {
2406 if (n->end <= end)
2407 sp_delete(sp, n);
2408 else
2409 n->start = end;
2410 } else {
2411 /* Old policy spanning whole new range. */
2412 if (n->end > end) {
2413 if (!n_new)
2414 goto alloc_new;
2415
2416 *mpol_new = *n->policy;
2417 atomic_set(&mpol_new->refcnt, 1);
2418 sp_node_init(n_new, end, n->end, mpol_new);
2419 n->end = start;
2420 sp_insert(sp, n_new);
2421 n_new = NULL;
2422 mpol_new = NULL;
2423 break;
2424 } else
2425 n->end = start;
2426 }
2427 if (!next)
2428 break;
2429 n = rb_entry(next, struct sp_node, nd);
2430 }
2431 if (new)
2432 sp_insert(sp, new);
2433 write_unlock(&sp->lock);
2434 ret = 0;
2435
2436err_out:
2437 if (mpol_new)
2438 mpol_put(mpol_new);
2439 if (n_new)
2440 kmem_cache_free(sn_cache, n_new);
2441
2442 return ret;
2443
2444alloc_new:
2445 write_unlock(&sp->lock);
2446 ret = -ENOMEM;
2447 n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2448 if (!n_new)
2449 goto err_out;
2450 mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2451 if (!mpol_new)
2452 goto err_out;
2453 goto restart;
2454}
2455
2456/**
2457 * mpol_shared_policy_init - initialize shared policy for inode
2458 * @sp: pointer to inode shared policy
2459 * @mpol: struct mempolicy to install
2460 *
2461 * Install non-NULL @mpol in inode's shared policy rb-tree.
2462 * On entry, the current task has a reference on a non-NULL @mpol.
2463 * This must be released on exit.
2464 * This is called at get_inode() calls and we can use GFP_KERNEL.
2465 */
2466void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2467{
2468 int ret;
2469
2470 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2471 rwlock_init(&sp->lock);
2472
2473 if (mpol) {
2474 struct vm_area_struct pvma;
2475 struct mempolicy *new;
2476 NODEMASK_SCRATCH(scratch);
2477
2478 if (!scratch)
2479 goto put_mpol;
2480 /* contextualize the tmpfs mount point mempolicy */
2481 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2482 if (IS_ERR(new))
2483 goto free_scratch; /* no valid nodemask intersection */
2484
2485 task_lock(current);
2486 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2487 task_unlock(current);
2488 if (ret)
2489 goto put_new;
2490
2491 /* Create pseudo-vma that contains just the policy */
2492 memset(&pvma, 0, sizeof(struct vm_area_struct));
2493 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2494 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2495
2496put_new:
2497 mpol_put(new); /* drop initial ref */
2498free_scratch:
2499 NODEMASK_SCRATCH_FREE(scratch);
2500put_mpol:
2501 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2502 }
2503}
2504
2505int mpol_set_shared_policy(struct shared_policy *info,
2506 struct vm_area_struct *vma, struct mempolicy *npol)
2507{
2508 int err;
2509 struct sp_node *new = NULL;
2510 unsigned long sz = vma_pages(vma);
2511
2512 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2513 vma->vm_pgoff,
2514 sz, npol ? npol->mode : -1,
2515 npol ? npol->flags : -1,
2516 npol ? nodes_addr(npol->v.nodes)[0] : NUMA_NO_NODE);
2517
2518 if (npol) {
2519 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2520 if (!new)
2521 return -ENOMEM;
2522 }
2523 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2524 if (err && new)
2525 sp_free(new);
2526 return err;
2527}
2528
2529/* Free a backing policy store on inode delete. */
2530void mpol_free_shared_policy(struct shared_policy *p)
2531{
2532 struct sp_node *n;
2533 struct rb_node *next;
2534
2535 if (!p->root.rb_node)
2536 return;
2537 write_lock(&p->lock);
2538 next = rb_first(&p->root);
2539 while (next) {
2540 n = rb_entry(next, struct sp_node, nd);
2541 next = rb_next(&n->nd);
2542 sp_delete(p, n);
2543 }
2544 write_unlock(&p->lock);
2545}
2546
2547#ifdef CONFIG_NUMA_BALANCING
2548static int __initdata numabalancing_override;
2549
2550static void __init check_numabalancing_enable(void)
2551{
2552 bool numabalancing_default = false;
2553
2554 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2555 numabalancing_default = true;
2556
2557 /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
2558 if (numabalancing_override)
2559 set_numabalancing_state(numabalancing_override == 1);
2560
2561 if (num_online_nodes() > 1 && !numabalancing_override) {
2562 pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n",
2563 numabalancing_default ? "Enabling" : "Disabling");
2564 set_numabalancing_state(numabalancing_default);
2565 }
2566}
2567
2568static int __init setup_numabalancing(char *str)
2569{
2570 int ret = 0;
2571 if (!str)
2572 goto out;
2573
2574 if (!strcmp(str, "enable")) {
2575 numabalancing_override = 1;
2576 ret = 1;
2577 } else if (!strcmp(str, "disable")) {
2578 numabalancing_override = -1;
2579 ret = 1;
2580 }
2581out:
2582 if (!ret)
2583 pr_warn("Unable to parse numa_balancing=\n");
2584
2585 return ret;
2586}
2587__setup("numa_balancing=", setup_numabalancing);
2588#else
2589static inline void __init check_numabalancing_enable(void)
2590{
2591}
2592#endif /* CONFIG_NUMA_BALANCING */
2593
2594/* assumes fs == KERNEL_DS */
2595void __init numa_policy_init(void)
2596{
2597 nodemask_t interleave_nodes;
2598 unsigned long largest = 0;
2599 int nid, prefer = 0;
2600
2601 policy_cache = kmem_cache_create("numa_policy",
2602 sizeof(struct mempolicy),
2603 0, SLAB_PANIC, NULL);
2604
2605 sn_cache = kmem_cache_create("shared_policy_node",
2606 sizeof(struct sp_node),
2607 0, SLAB_PANIC, NULL);
2608
2609 for_each_node(nid) {
2610 preferred_node_policy[nid] = (struct mempolicy) {
2611 .refcnt = ATOMIC_INIT(1),
2612 .mode = MPOL_PREFERRED,
2613 .flags = MPOL_F_MOF | MPOL_F_MORON,
2614 .v = { .preferred_node = nid, },
2615 };
2616 }
2617
2618 /*
2619 * Set interleaving policy for system init. Interleaving is only
2620 * enabled across suitably sized nodes (default is >= 16MB), or
2621 * fall back to the largest node if they're all smaller.
2622 */
2623 nodes_clear(interleave_nodes);
2624 for_each_node_state(nid, N_MEMORY) {
2625 unsigned long total_pages = node_present_pages(nid);
2626
2627 /* Preserve the largest node */
2628 if (largest < total_pages) {
2629 largest = total_pages;
2630 prefer = nid;
2631 }
2632
2633 /* Interleave this node? */
2634 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2635 node_set(nid, interleave_nodes);
2636 }
2637
2638 /* All too small, use the largest */
2639 if (unlikely(nodes_empty(interleave_nodes)))
2640 node_set(prefer, interleave_nodes);
2641
2642 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2643 pr_err("%s: interleaving failed\n", __func__);
2644
2645 check_numabalancing_enable();
2646}
2647
2648/* Reset policy of current process to default */
2649void numa_default_policy(void)
2650{
2651 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2652}
2653
2654/*
2655 * Parse and format mempolicy from/to strings
2656 */
2657
2658/*
2659 * "local" is implemented internally by MPOL_PREFERRED with MPOL_F_LOCAL flag.
2660 */
2661static const char * const policy_modes[] =
2662{
2663 [MPOL_DEFAULT] = "default",
2664 [MPOL_PREFERRED] = "prefer",
2665 [MPOL_BIND] = "bind",
2666 [MPOL_INTERLEAVE] = "interleave",
2667 [MPOL_LOCAL] = "local",
2668};
2669
2670
2671#ifdef CONFIG_TMPFS
2672/**
2673 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2674 * @str: string containing mempolicy to parse
2675 * @mpol: pointer to struct mempolicy pointer, returned on success.
2676 *
2677 * Format of input:
2678 * <mode>[=<flags>][:<nodelist>]
2679 *
2680 * On success, returns 0, else 1
2681 */
2682int mpol_parse_str(char *str, struct mempolicy **mpol)
2683{
2684 struct mempolicy *new = NULL;
2685 unsigned short mode;
2686 unsigned short mode_flags;
2687 nodemask_t nodes;
2688 char *nodelist = strchr(str, ':');
2689 char *flags = strchr(str, '=');
2690 int err = 1;
2691
2692 if (nodelist) {
2693 /* NUL-terminate mode or flags string */
2694 *nodelist++ = '\0';
2695 if (nodelist_parse(nodelist, nodes))
2696 goto out;
2697 if (!nodes_subset(nodes, node_states[N_MEMORY]))
2698 goto out;
2699 } else
2700 nodes_clear(nodes);
2701
2702 if (flags)
2703 *flags++ = '\0'; /* terminate mode string */
2704
2705 for (mode = 0; mode < MPOL_MAX; mode++) {
2706 if (!strcmp(str, policy_modes[mode])) {
2707 break;
2708 }
2709 }
2710 if (mode >= MPOL_MAX)
2711 goto out;
2712
2713 switch (mode) {
2714 case MPOL_PREFERRED:
2715 /*
2716 * Insist on a nodelist of one node only
2717 */
2718 if (nodelist) {
2719 char *rest = nodelist;
2720 while (isdigit(*rest))
2721 rest++;
2722 if (*rest)
2723 goto out;
2724 }
2725 break;
2726 case MPOL_INTERLEAVE:
2727 /*
2728 * Default to online nodes with memory if no nodelist
2729 */
2730 if (!nodelist)
2731 nodes = node_states[N_MEMORY];
2732 break;
2733 case MPOL_LOCAL:
2734 /*
2735 * Don't allow a nodelist; mpol_new() checks flags
2736 */
2737 if (nodelist)
2738 goto out;
2739 mode = MPOL_PREFERRED;
2740 break;
2741 case MPOL_DEFAULT:
2742 /*
2743 * Insist on a empty nodelist
2744 */
2745 if (!nodelist)
2746 err = 0;
2747 goto out;
2748 case MPOL_BIND:
2749 /*
2750 * Insist on a nodelist
2751 */
2752 if (!nodelist)
2753 goto out;
2754 }
2755
2756 mode_flags = 0;
2757 if (flags) {
2758 /*
2759 * Currently, we only support two mutually exclusive
2760 * mode flags.
2761 */
2762 if (!strcmp(flags, "static"))
2763 mode_flags |= MPOL_F_STATIC_NODES;
2764 else if (!strcmp(flags, "relative"))
2765 mode_flags |= MPOL_F_RELATIVE_NODES;
2766 else
2767 goto out;
2768 }
2769
2770 new = mpol_new(mode, mode_flags, &nodes);
2771 if (IS_ERR(new))
2772 goto out;
2773
2774 /*
2775 * Save nodes for mpol_to_str() to show the tmpfs mount options
2776 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
2777 */
2778 if (mode != MPOL_PREFERRED)
2779 new->v.nodes = nodes;
2780 else if (nodelist)
2781 new->v.preferred_node = first_node(nodes);
2782 else
2783 new->flags |= MPOL_F_LOCAL;
2784
2785 /*
2786 * Save nodes for contextualization: this will be used to "clone"
2787 * the mempolicy in a specific context [cpuset] at a later time.
2788 */
2789 new->w.user_nodemask = nodes;
2790
2791 err = 0;
2792
2793out:
2794 /* Restore string for error message */
2795 if (nodelist)
2796 *--nodelist = ':';
2797 if (flags)
2798 *--flags = '=';
2799 if (!err)
2800 *mpol = new;
2801 return err;
2802}
2803#endif /* CONFIG_TMPFS */
2804
2805/**
2806 * mpol_to_str - format a mempolicy structure for printing
2807 * @buffer: to contain formatted mempolicy string
2808 * @maxlen: length of @buffer
2809 * @pol: pointer to mempolicy to be formatted
2810 *
2811 * Convert @pol into a string. If @buffer is too short, truncate the string.
2812 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
2813 * longest flag, "relative", and to display at least a few node ids.
2814 */
2815void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
2816{
2817 char *p = buffer;
2818 nodemask_t nodes = NODE_MASK_NONE;
2819 unsigned short mode = MPOL_DEFAULT;
2820 unsigned short flags = 0;
2821
2822 if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
2823 mode = pol->mode;
2824 flags = pol->flags;
2825 }
2826
2827 switch (mode) {
2828 case MPOL_DEFAULT:
2829 break;
2830 case MPOL_PREFERRED:
2831 if (flags & MPOL_F_LOCAL)
2832 mode = MPOL_LOCAL;
2833 else
2834 node_set(pol->v.preferred_node, nodes);
2835 break;
2836 case MPOL_BIND:
2837 case MPOL_INTERLEAVE:
2838 nodes = pol->v.nodes;
2839 break;
2840 default:
2841 WARN_ON_ONCE(1);
2842 snprintf(p, maxlen, "unknown");
2843 return;
2844 }
2845
2846 p += snprintf(p, maxlen, "%s", policy_modes[mode]);
2847
2848 if (flags & MPOL_MODE_FLAGS) {
2849 p += snprintf(p, buffer + maxlen - p, "=");
2850
2851 /*
2852 * Currently, the only defined flags are mutually exclusive
2853 */
2854 if (flags & MPOL_F_STATIC_NODES)
2855 p += snprintf(p, buffer + maxlen - p, "static");
2856 else if (flags & MPOL_F_RELATIVE_NODES)
2857 p += snprintf(p, buffer + maxlen - p, "relative");
2858 }
2859
2860 if (!nodes_empty(nodes))
2861 p += scnprintf(p, buffer + maxlen - p, ":%*pbl",
2862 nodemask_pr_args(&nodes));
2863}
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}