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