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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Simple NUMA memory policy for the Linux kernel.
4 *
5 * Copyright 2003,2004 Andi Kleen, SuSE Labs.
6 * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc.
7 *
8 * NUMA policy allows the user to give hints in which node(s) memory should
9 * be allocated.
10 *
11 * Support four policies per VMA and per process:
12 *
13 * The VMA policy has priority over the process policy for a page fault.
14 *
15 * interleave Allocate memory interleaved over a set of nodes,
16 * with normal fallback if it fails.
17 * For VMA based allocations this interleaves based on the
18 * offset into the backing object or offset into the mapping
19 * for anonymous memory. For process policy an process counter
20 * is used.
21 *
22 * bind Only allocate memory on a specific set of nodes,
23 * no fallback.
24 * FIXME: memory is allocated starting with the first node
25 * to the last. It would be better if bind would truly restrict
26 * the allocation to memory nodes instead
27 *
28 * preferred Try a specific node first before normal fallback.
29 * As a special case NUMA_NO_NODE here means do the allocation
30 * on the local CPU. This is normally identical to default,
31 * but useful to set in a VMA when you have a non default
32 * process policy.
33 *
34 * default Allocate on the local node first, or when on a VMA
35 * use the process policy. This is what Linux always did
36 * in a NUMA aware kernel and still does by, ahem, default.
37 *
38 * The process policy is applied for most non interrupt memory allocations
39 * in that process' context. Interrupts ignore the policies and always
40 * try to allocate on the local CPU. The VMA policy is only applied for memory
41 * allocations for a VMA in the VM.
42 *
43 * Currently there are a few corner cases in swapping where the policy
44 * is not applied, but the majority should be handled. When process policy
45 * is used it is not remembered over swap outs/swap ins.
46 *
47 * Only the highest zone in the zone hierarchy gets policied. Allocations
48 * requesting a lower zone just use default policy. This implies that
49 * on systems with highmem kernel lowmem allocation don't get policied.
50 * Same with GFP_DMA allocations.
51 *
52 * For shmfs/tmpfs/hugetlbfs shared memory the policy is shared between
53 * all users and remembered even when nobody has memory mapped.
54 */
55
56/* Notebook:
57 fix mmap readahead to honour policy and enable policy for any page cache
58 object
59 statistics for bigpages
60 global policy for page cache? currently it uses process policy. Requires
61 first item above.
62 handle mremap for shared memory (currently ignored for the policy)
63 grows down?
64 make bind policy root only? It can trigger oom much faster and the
65 kernel is not always grateful with that.
66*/
67
68#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
69
70#include <linux/mempolicy.h>
71#include <linux/pagewalk.h>
72#include <linux/highmem.h>
73#include <linux/hugetlb.h>
74#include <linux/kernel.h>
75#include <linux/sched.h>
76#include <linux/sched/mm.h>
77#include <linux/sched/numa_balancing.h>
78#include <linux/sched/task.h>
79#include <linux/nodemask.h>
80#include <linux/cpuset.h>
81#include <linux/slab.h>
82#include <linux/string.h>
83#include <linux/export.h>
84#include <linux/nsproxy.h>
85#include <linux/interrupt.h>
86#include <linux/init.h>
87#include <linux/compat.h>
88#include <linux/ptrace.h>
89#include <linux/swap.h>
90#include <linux/seq_file.h>
91#include <linux/proc_fs.h>
92#include <linux/migrate.h>
93#include <linux/ksm.h>
94#include <linux/rmap.h>
95#include <linux/security.h>
96#include <linux/syscalls.h>
97#include <linux/ctype.h>
98#include <linux/mm_inline.h>
99#include <linux/mmu_notifier.h>
100#include <linux/printk.h>
101#include <linux/swapops.h>
102
103#include <asm/tlbflush.h>
104#include <linux/uaccess.h>
105
106#include "internal.h"
107
108/* Internal flags */
109#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
110#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
111
112static struct kmem_cache *policy_cache;
113static struct kmem_cache *sn_cache;
114
115/* Highest zone. An specific allocation for a zone below that is not
116 policied. */
117enum zone_type policy_zone = 0;
118
119/*
120 * run-time system-wide default policy => local allocation
121 */
122static struct mempolicy default_policy = {
123 .refcnt = ATOMIC_INIT(1), /* never free it */
124 .mode = MPOL_LOCAL,
125};
126
127static struct mempolicy preferred_node_policy[MAX_NUMNODES];
128
129/**
130 * numa_map_to_online_node - Find closest online node
131 * @node: Node id to start the search
132 *
133 * Lookup the next closest node by distance if @nid is not online.
134 */
135int numa_map_to_online_node(int node)
136{
137 int min_dist = INT_MAX, dist, n, min_node;
138
139 if (node == NUMA_NO_NODE || node_online(node))
140 return node;
141
142 min_node = node;
143 for_each_online_node(n) {
144 dist = node_distance(node, n);
145 if (dist < min_dist) {
146 min_dist = dist;
147 min_node = n;
148 }
149 }
150
151 return min_node;
152}
153EXPORT_SYMBOL_GPL(numa_map_to_online_node);
154
155struct mempolicy *get_task_policy(struct task_struct *p)
156{
157 struct mempolicy *pol = p->mempolicy;
158 int node;
159
160 if (pol)
161 return pol;
162
163 node = numa_node_id();
164 if (node != NUMA_NO_NODE) {
165 pol = &preferred_node_policy[node];
166 /* preferred_node_policy is not initialised early in boot */
167 if (pol->mode)
168 return pol;
169 }
170
171 return &default_policy;
172}
173
174static const struct mempolicy_operations {
175 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
176 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes);
177} mpol_ops[MPOL_MAX];
178
179static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
180{
181 return pol->flags & MPOL_MODE_FLAGS;
182}
183
184static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
185 const nodemask_t *rel)
186{
187 nodemask_t tmp;
188 nodes_fold(tmp, *orig, nodes_weight(*rel));
189 nodes_onto(*ret, tmp, *rel);
190}
191
192static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
193{
194 if (nodes_empty(*nodes))
195 return -EINVAL;
196 pol->nodes = *nodes;
197 return 0;
198}
199
200static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
201{
202 if (nodes_empty(*nodes))
203 return -EINVAL;
204
205 nodes_clear(pol->nodes);
206 node_set(first_node(*nodes), pol->nodes);
207 return 0;
208}
209
210static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
211{
212 if (nodes_empty(*nodes))
213 return -EINVAL;
214 pol->nodes = *nodes;
215 return 0;
216}
217
218/*
219 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
220 * any, for the new policy. mpol_new() has already validated the nodes
221 * parameter with respect to the policy mode and flags.
222 *
223 * Must be called holding task's alloc_lock to protect task's mems_allowed
224 * and mempolicy. May also be called holding the mmap_lock for write.
225 */
226static int mpol_set_nodemask(struct mempolicy *pol,
227 const nodemask_t *nodes, struct nodemask_scratch *nsc)
228{
229 int ret;
230
231 /*
232 * Default (pol==NULL) resp. local memory policies are not a
233 * subject of any remapping. They also do not need any special
234 * constructor.
235 */
236 if (!pol || pol->mode == MPOL_LOCAL)
237 return 0;
238
239 /* Check N_MEMORY */
240 nodes_and(nsc->mask1,
241 cpuset_current_mems_allowed, node_states[N_MEMORY]);
242
243 VM_BUG_ON(!nodes);
244
245 if (pol->flags & MPOL_F_RELATIVE_NODES)
246 mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1);
247 else
248 nodes_and(nsc->mask2, *nodes, nsc->mask1);
249
250 if (mpol_store_user_nodemask(pol))
251 pol->w.user_nodemask = *nodes;
252 else
253 pol->w.cpuset_mems_allowed = cpuset_current_mems_allowed;
254
255 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
256 return ret;
257}
258
259/*
260 * This function just creates a new policy, does some check and simple
261 * initialization. You must invoke mpol_set_nodemask() to set nodes.
262 */
263static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
264 nodemask_t *nodes)
265{
266 struct mempolicy *policy;
267
268 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
269 mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE);
270
271 if (mode == MPOL_DEFAULT) {
272 if (nodes && !nodes_empty(*nodes))
273 return ERR_PTR(-EINVAL);
274 return NULL;
275 }
276 VM_BUG_ON(!nodes);
277
278 /*
279 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
280 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
281 * All other modes require a valid pointer to a non-empty nodemask.
282 */
283 if (mode == MPOL_PREFERRED) {
284 if (nodes_empty(*nodes)) {
285 if (((flags & MPOL_F_STATIC_NODES) ||
286 (flags & MPOL_F_RELATIVE_NODES)))
287 return ERR_PTR(-EINVAL);
288
289 mode = MPOL_LOCAL;
290 }
291 } else if (mode == MPOL_LOCAL) {
292 if (!nodes_empty(*nodes) ||
293 (flags & MPOL_F_STATIC_NODES) ||
294 (flags & MPOL_F_RELATIVE_NODES))
295 return ERR_PTR(-EINVAL);
296 } else if (nodes_empty(*nodes))
297 return ERR_PTR(-EINVAL);
298 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
299 if (!policy)
300 return ERR_PTR(-ENOMEM);
301 atomic_set(&policy->refcnt, 1);
302 policy->mode = mode;
303 policy->flags = flags;
304
305 return policy;
306}
307
308/* Slow path of a mpol destructor. */
309void __mpol_put(struct mempolicy *p)
310{
311 if (!atomic_dec_and_test(&p->refcnt))
312 return;
313 kmem_cache_free(policy_cache, p);
314}
315
316static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes)
317{
318}
319
320static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
321{
322 nodemask_t tmp;
323
324 if (pol->flags & MPOL_F_STATIC_NODES)
325 nodes_and(tmp, pol->w.user_nodemask, *nodes);
326 else if (pol->flags & MPOL_F_RELATIVE_NODES)
327 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
328 else {
329 nodes_remap(tmp, pol->nodes, pol->w.cpuset_mems_allowed,
330 *nodes);
331 pol->w.cpuset_mems_allowed = *nodes;
332 }
333
334 if (nodes_empty(tmp))
335 tmp = *nodes;
336
337 pol->nodes = tmp;
338}
339
340static void mpol_rebind_preferred(struct mempolicy *pol,
341 const nodemask_t *nodes)
342{
343 pol->w.cpuset_mems_allowed = *nodes;
344}
345
346/*
347 * mpol_rebind_policy - Migrate a policy to a different set of nodes
348 *
349 * Per-vma policies are protected by mmap_lock. Allocations using per-task
350 * policies are protected by task->mems_allowed_seq to prevent a premature
351 * OOM/allocation failure due to parallel nodemask modification.
352 */
353static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask)
354{
355 if (!pol)
356 return;
357 if (!mpol_store_user_nodemask(pol) &&
358 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
359 return;
360
361 mpol_ops[pol->mode].rebind(pol, newmask);
362}
363
364/*
365 * Wrapper for mpol_rebind_policy() that just requires task
366 * pointer, and updates task mempolicy.
367 *
368 * Called with task's alloc_lock held.
369 */
370
371void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new)
372{
373 mpol_rebind_policy(tsk->mempolicy, new);
374}
375
376/*
377 * Rebind each vma in mm to new nodemask.
378 *
379 * Call holding a reference to mm. Takes mm->mmap_lock during call.
380 */
381
382void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
383{
384 struct vm_area_struct *vma;
385
386 mmap_write_lock(mm);
387 for (vma = mm->mmap; vma; vma = vma->vm_next)
388 mpol_rebind_policy(vma->vm_policy, new);
389 mmap_write_unlock(mm);
390}
391
392static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
393 [MPOL_DEFAULT] = {
394 .rebind = mpol_rebind_default,
395 },
396 [MPOL_INTERLEAVE] = {
397 .create = mpol_new_interleave,
398 .rebind = mpol_rebind_nodemask,
399 },
400 [MPOL_PREFERRED] = {
401 .create = mpol_new_preferred,
402 .rebind = mpol_rebind_preferred,
403 },
404 [MPOL_BIND] = {
405 .create = mpol_new_bind,
406 .rebind = mpol_rebind_nodemask,
407 },
408 [MPOL_LOCAL] = {
409 .rebind = mpol_rebind_default,
410 },
411};
412
413static int migrate_page_add(struct page *page, struct list_head *pagelist,
414 unsigned long flags);
415
416struct queue_pages {
417 struct list_head *pagelist;
418 unsigned long flags;
419 nodemask_t *nmask;
420 unsigned long start;
421 unsigned long end;
422 struct vm_area_struct *first;
423};
424
425/*
426 * Check if the page's nid is in qp->nmask.
427 *
428 * If MPOL_MF_INVERT is set in qp->flags, check if the nid is
429 * in the invert of qp->nmask.
430 */
431static inline bool queue_pages_required(struct page *page,
432 struct queue_pages *qp)
433{
434 int nid = page_to_nid(page);
435 unsigned long flags = qp->flags;
436
437 return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT);
438}
439
440/*
441 * queue_pages_pmd() has four possible return values:
442 * 0 - pages are placed on the right node or queued successfully, or
443 * special page is met, i.e. huge zero page.
444 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
445 * specified.
446 * 2 - THP was split.
447 * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an
448 * existing page was already on a node that does not follow the
449 * policy.
450 */
451static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
452 unsigned long end, struct mm_walk *walk)
453 __releases(ptl)
454{
455 int ret = 0;
456 struct page *page;
457 struct queue_pages *qp = walk->private;
458 unsigned long flags;
459
460 if (unlikely(is_pmd_migration_entry(*pmd))) {
461 ret = -EIO;
462 goto unlock;
463 }
464 page = pmd_page(*pmd);
465 if (is_huge_zero_page(page)) {
466 spin_unlock(ptl);
467 walk->action = ACTION_CONTINUE;
468 goto out;
469 }
470 if (!queue_pages_required(page, qp))
471 goto unlock;
472
473 flags = qp->flags;
474 /* go to thp migration */
475 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
476 if (!vma_migratable(walk->vma) ||
477 migrate_page_add(page, qp->pagelist, flags)) {
478 ret = 1;
479 goto unlock;
480 }
481 } else
482 ret = -EIO;
483unlock:
484 spin_unlock(ptl);
485out:
486 return ret;
487}
488
489/*
490 * Scan through pages checking if pages follow certain conditions,
491 * and move them to the pagelist if they do.
492 *
493 * queue_pages_pte_range() has three possible return values:
494 * 0 - pages are placed on the right node or queued successfully, or
495 * special page is met, i.e. zero page.
496 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
497 * specified.
498 * -EIO - only MPOL_MF_STRICT was specified and an existing page was already
499 * on a node that does not follow the policy.
500 */
501static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
502 unsigned long end, struct mm_walk *walk)
503{
504 struct vm_area_struct *vma = walk->vma;
505 struct page *page;
506 struct queue_pages *qp = walk->private;
507 unsigned long flags = qp->flags;
508 int ret;
509 bool has_unmovable = false;
510 pte_t *pte, *mapped_pte;
511 spinlock_t *ptl;
512
513 ptl = pmd_trans_huge_lock(pmd, vma);
514 if (ptl) {
515 ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
516 if (ret != 2)
517 return ret;
518 }
519 /* THP was split, fall through to pte walk */
520
521 if (pmd_trans_unstable(pmd))
522 return 0;
523
524 mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
525 for (; addr != end; pte++, addr += PAGE_SIZE) {
526 if (!pte_present(*pte))
527 continue;
528 page = vm_normal_page(vma, addr, *pte);
529 if (!page)
530 continue;
531 /*
532 * vm_normal_page() filters out zero pages, but there might
533 * still be PageReserved pages to skip, perhaps in a VDSO.
534 */
535 if (PageReserved(page))
536 continue;
537 if (!queue_pages_required(page, qp))
538 continue;
539 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
540 /* MPOL_MF_STRICT must be specified if we get here */
541 if (!vma_migratable(vma)) {
542 has_unmovable = true;
543 break;
544 }
545
546 /*
547 * Do not abort immediately since there may be
548 * temporary off LRU pages in the range. Still
549 * need migrate other LRU pages.
550 */
551 if (migrate_page_add(page, qp->pagelist, flags))
552 has_unmovable = true;
553 } else
554 break;
555 }
556 pte_unmap_unlock(mapped_pte, ptl);
557 cond_resched();
558
559 if (has_unmovable)
560 return 1;
561
562 return addr != end ? -EIO : 0;
563}
564
565static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
566 unsigned long addr, unsigned long end,
567 struct mm_walk *walk)
568{
569 int ret = 0;
570#ifdef CONFIG_HUGETLB_PAGE
571 struct queue_pages *qp = walk->private;
572 unsigned long flags = (qp->flags & MPOL_MF_VALID);
573 struct page *page;
574 spinlock_t *ptl;
575 pte_t entry;
576
577 ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
578 entry = huge_ptep_get(pte);
579 if (!pte_present(entry))
580 goto unlock;
581 page = pte_page(entry);
582 if (!queue_pages_required(page, qp))
583 goto unlock;
584
585 if (flags == MPOL_MF_STRICT) {
586 /*
587 * STRICT alone means only detecting misplaced page and no
588 * need to further check other vma.
589 */
590 ret = -EIO;
591 goto unlock;
592 }
593
594 if (!vma_migratable(walk->vma)) {
595 /*
596 * Must be STRICT with MOVE*, otherwise .test_walk() have
597 * stopped walking current vma.
598 * Detecting misplaced page but allow migrating pages which
599 * have been queued.
600 */
601 ret = 1;
602 goto unlock;
603 }
604
605 /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
606 if (flags & (MPOL_MF_MOVE_ALL) ||
607 (flags & MPOL_MF_MOVE && page_mapcount(page) == 1)) {
608 if (!isolate_huge_page(page, qp->pagelist) &&
609 (flags & MPOL_MF_STRICT))
610 /*
611 * Failed to isolate page but allow migrating pages
612 * which have been queued.
613 */
614 ret = 1;
615 }
616unlock:
617 spin_unlock(ptl);
618#else
619 BUG();
620#endif
621 return ret;
622}
623
624#ifdef CONFIG_NUMA_BALANCING
625/*
626 * This is used to mark a range of virtual addresses to be inaccessible.
627 * These are later cleared by a NUMA hinting fault. Depending on these
628 * faults, pages may be migrated for better NUMA placement.
629 *
630 * This is assuming that NUMA faults are handled using PROT_NONE. If
631 * an architecture makes a different choice, it will need further
632 * changes to the core.
633 */
634unsigned long change_prot_numa(struct vm_area_struct *vma,
635 unsigned long addr, unsigned long end)
636{
637 int nr_updated;
638
639 nr_updated = change_protection(vma, addr, end, PAGE_NONE, MM_CP_PROT_NUMA);
640 if (nr_updated)
641 count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
642
643 return nr_updated;
644}
645#else
646static unsigned long change_prot_numa(struct vm_area_struct *vma,
647 unsigned long addr, unsigned long end)
648{
649 return 0;
650}
651#endif /* CONFIG_NUMA_BALANCING */
652
653static int queue_pages_test_walk(unsigned long start, unsigned long end,
654 struct mm_walk *walk)
655{
656 struct vm_area_struct *vma = walk->vma;
657 struct queue_pages *qp = walk->private;
658 unsigned long endvma = vma->vm_end;
659 unsigned long flags = qp->flags;
660
661 /* range check first */
662 VM_BUG_ON_VMA(!range_in_vma(vma, start, end), vma);
663
664 if (!qp->first) {
665 qp->first = vma;
666 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
667 (qp->start < vma->vm_start))
668 /* hole at head side of range */
669 return -EFAULT;
670 }
671 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
672 ((vma->vm_end < qp->end) &&
673 (!vma->vm_next || vma->vm_end < vma->vm_next->vm_start)))
674 /* hole at middle or tail of range */
675 return -EFAULT;
676
677 /*
678 * Need check MPOL_MF_STRICT to return -EIO if possible
679 * regardless of vma_migratable
680 */
681 if (!vma_migratable(vma) &&
682 !(flags & MPOL_MF_STRICT))
683 return 1;
684
685 if (endvma > end)
686 endvma = end;
687
688 if (flags & MPOL_MF_LAZY) {
689 /* Similar to task_numa_work, skip inaccessible VMAs */
690 if (!is_vm_hugetlb_page(vma) && vma_is_accessible(vma) &&
691 !(vma->vm_flags & VM_MIXEDMAP))
692 change_prot_numa(vma, start, endvma);
693 return 1;
694 }
695
696 /* queue pages from current vma */
697 if (flags & MPOL_MF_VALID)
698 return 0;
699 return 1;
700}
701
702static const struct mm_walk_ops queue_pages_walk_ops = {
703 .hugetlb_entry = queue_pages_hugetlb,
704 .pmd_entry = queue_pages_pte_range,
705 .test_walk = queue_pages_test_walk,
706};
707
708/*
709 * Walk through page tables and collect pages to be migrated.
710 *
711 * If pages found in a given range are on a set of nodes (determined by
712 * @nodes and @flags,) it's isolated and queued to the pagelist which is
713 * passed via @private.
714 *
715 * queue_pages_range() has three possible return values:
716 * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
717 * specified.
718 * 0 - queue pages successfully or no misplaced page.
719 * errno - i.e. misplaced pages with MPOL_MF_STRICT specified (-EIO) or
720 * memory range specified by nodemask and maxnode points outside
721 * your accessible address space (-EFAULT)
722 */
723static int
724queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
725 nodemask_t *nodes, unsigned long flags,
726 struct list_head *pagelist)
727{
728 int err;
729 struct queue_pages qp = {
730 .pagelist = pagelist,
731 .flags = flags,
732 .nmask = nodes,
733 .start = start,
734 .end = end,
735 .first = NULL,
736 };
737
738 err = walk_page_range(mm, start, end, &queue_pages_walk_ops, &qp);
739
740 if (!qp.first)
741 /* whole range in hole */
742 err = -EFAULT;
743
744 return err;
745}
746
747/*
748 * Apply policy to a single VMA
749 * This must be called with the mmap_lock held for writing.
750 */
751static int vma_replace_policy(struct vm_area_struct *vma,
752 struct mempolicy *pol)
753{
754 int err;
755 struct mempolicy *old;
756 struct mempolicy *new;
757
758 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
759 vma->vm_start, vma->vm_end, vma->vm_pgoff,
760 vma->vm_ops, vma->vm_file,
761 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
762
763 new = mpol_dup(pol);
764 if (IS_ERR(new))
765 return PTR_ERR(new);
766
767 if (vma->vm_ops && vma->vm_ops->set_policy) {
768 err = vma->vm_ops->set_policy(vma, new);
769 if (err)
770 goto err_out;
771 }
772
773 old = vma->vm_policy;
774 vma->vm_policy = new; /* protected by mmap_lock */
775 mpol_put(old);
776
777 return 0;
778 err_out:
779 mpol_put(new);
780 return err;
781}
782
783/* Step 2: apply policy to a range and do splits. */
784static int mbind_range(struct mm_struct *mm, unsigned long start,
785 unsigned long end, struct mempolicy *new_pol)
786{
787 struct vm_area_struct *next;
788 struct vm_area_struct *prev;
789 struct vm_area_struct *vma;
790 int err = 0;
791 pgoff_t pgoff;
792 unsigned long vmstart;
793 unsigned long vmend;
794
795 vma = find_vma(mm, start);
796 VM_BUG_ON(!vma);
797
798 prev = vma->vm_prev;
799 if (start > vma->vm_start)
800 prev = vma;
801
802 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
803 next = vma->vm_next;
804 vmstart = max(start, vma->vm_start);
805 vmend = min(end, vma->vm_end);
806
807 if (mpol_equal(vma_policy(vma), new_pol))
808 continue;
809
810 pgoff = vma->vm_pgoff +
811 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
812 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
813 vma->anon_vma, vma->vm_file, pgoff,
814 new_pol, vma->vm_userfaultfd_ctx);
815 if (prev) {
816 vma = prev;
817 next = vma->vm_next;
818 if (mpol_equal(vma_policy(vma), new_pol))
819 continue;
820 /* vma_merge() joined vma && vma->next, case 8 */
821 goto replace;
822 }
823 if (vma->vm_start != vmstart) {
824 err = split_vma(vma->vm_mm, vma, vmstart, 1);
825 if (err)
826 goto out;
827 }
828 if (vma->vm_end != vmend) {
829 err = split_vma(vma->vm_mm, vma, vmend, 0);
830 if (err)
831 goto out;
832 }
833 replace:
834 err = vma_replace_policy(vma, new_pol);
835 if (err)
836 goto out;
837 }
838
839 out:
840 return err;
841}
842
843/* Set the process memory policy */
844static long do_set_mempolicy(unsigned short mode, unsigned short flags,
845 nodemask_t *nodes)
846{
847 struct mempolicy *new, *old;
848 NODEMASK_SCRATCH(scratch);
849 int ret;
850
851 if (!scratch)
852 return -ENOMEM;
853
854 new = mpol_new(mode, flags, nodes);
855 if (IS_ERR(new)) {
856 ret = PTR_ERR(new);
857 goto out;
858 }
859
860 ret = mpol_set_nodemask(new, nodes, scratch);
861 if (ret) {
862 mpol_put(new);
863 goto out;
864 }
865 task_lock(current);
866 old = current->mempolicy;
867 current->mempolicy = new;
868 if (new && new->mode == MPOL_INTERLEAVE)
869 current->il_prev = MAX_NUMNODES-1;
870 task_unlock(current);
871 mpol_put(old);
872 ret = 0;
873out:
874 NODEMASK_SCRATCH_FREE(scratch);
875 return ret;
876}
877
878/*
879 * Return nodemask for policy for get_mempolicy() query
880 *
881 * Called with task's alloc_lock held
882 */
883static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
884{
885 nodes_clear(*nodes);
886 if (p == &default_policy)
887 return;
888
889 switch (p->mode) {
890 case MPOL_BIND:
891 case MPOL_INTERLEAVE:
892 case MPOL_PREFERRED:
893 *nodes = p->nodes;
894 break;
895 case MPOL_LOCAL:
896 /* return empty node mask for local allocation */
897 break;
898 default:
899 BUG();
900 }
901}
902
903static int lookup_node(struct mm_struct *mm, unsigned long addr)
904{
905 struct page *p = NULL;
906 int err;
907
908 int locked = 1;
909 err = get_user_pages_locked(addr & PAGE_MASK, 1, 0, &p, &locked);
910 if (err > 0) {
911 err = page_to_nid(p);
912 put_page(p);
913 }
914 if (locked)
915 mmap_read_unlock(mm);
916 return err;
917}
918
919/* Retrieve NUMA policy */
920static long do_get_mempolicy(int *policy, nodemask_t *nmask,
921 unsigned long addr, unsigned long flags)
922{
923 int err;
924 struct mm_struct *mm = current->mm;
925 struct vm_area_struct *vma = NULL;
926 struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL;
927
928 if (flags &
929 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
930 return -EINVAL;
931
932 if (flags & MPOL_F_MEMS_ALLOWED) {
933 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
934 return -EINVAL;
935 *policy = 0; /* just so it's initialized */
936 task_lock(current);
937 *nmask = cpuset_current_mems_allowed;
938 task_unlock(current);
939 return 0;
940 }
941
942 if (flags & MPOL_F_ADDR) {
943 /*
944 * Do NOT fall back to task policy if the
945 * vma/shared policy at addr is NULL. We
946 * want to return MPOL_DEFAULT in this case.
947 */
948 mmap_read_lock(mm);
949 vma = vma_lookup(mm, addr);
950 if (!vma) {
951 mmap_read_unlock(mm);
952 return -EFAULT;
953 }
954 if (vma->vm_ops && vma->vm_ops->get_policy)
955 pol = vma->vm_ops->get_policy(vma, addr);
956 else
957 pol = vma->vm_policy;
958 } else if (addr)
959 return -EINVAL;
960
961 if (!pol)
962 pol = &default_policy; /* indicates default behavior */
963
964 if (flags & MPOL_F_NODE) {
965 if (flags & MPOL_F_ADDR) {
966 /*
967 * Take a refcount on the mpol, lookup_node()
968 * will drop the mmap_lock, so after calling
969 * lookup_node() only "pol" remains valid, "vma"
970 * is stale.
971 */
972 pol_refcount = pol;
973 vma = NULL;
974 mpol_get(pol);
975 err = lookup_node(mm, addr);
976 if (err < 0)
977 goto out;
978 *policy = err;
979 } else if (pol == current->mempolicy &&
980 pol->mode == MPOL_INTERLEAVE) {
981 *policy = next_node_in(current->il_prev, pol->nodes);
982 } else {
983 err = -EINVAL;
984 goto out;
985 }
986 } else {
987 *policy = pol == &default_policy ? MPOL_DEFAULT :
988 pol->mode;
989 /*
990 * Internal mempolicy flags must be masked off before exposing
991 * the policy to userspace.
992 */
993 *policy |= (pol->flags & MPOL_MODE_FLAGS);
994 }
995
996 err = 0;
997 if (nmask) {
998 if (mpol_store_user_nodemask(pol)) {
999 *nmask = pol->w.user_nodemask;
1000 } else {
1001 task_lock(current);
1002 get_policy_nodemask(pol, nmask);
1003 task_unlock(current);
1004 }
1005 }
1006
1007 out:
1008 mpol_cond_put(pol);
1009 if (vma)
1010 mmap_read_unlock(mm);
1011 if (pol_refcount)
1012 mpol_put(pol_refcount);
1013 return err;
1014}
1015
1016#ifdef CONFIG_MIGRATION
1017/*
1018 * page migration, thp tail pages can be passed.
1019 */
1020static int migrate_page_add(struct page *page, struct list_head *pagelist,
1021 unsigned long flags)
1022{
1023 struct page *head = compound_head(page);
1024 /*
1025 * Avoid migrating a page that is shared with others.
1026 */
1027 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(head) == 1) {
1028 if (!isolate_lru_page(head)) {
1029 list_add_tail(&head->lru, pagelist);
1030 mod_node_page_state(page_pgdat(head),
1031 NR_ISOLATED_ANON + page_is_file_lru(head),
1032 thp_nr_pages(head));
1033 } else if (flags & MPOL_MF_STRICT) {
1034 /*
1035 * Non-movable page may reach here. And, there may be
1036 * temporary off LRU pages or non-LRU movable pages.
1037 * Treat them as unmovable pages since they can't be
1038 * isolated, so they can't be moved at the moment. It
1039 * should return -EIO for this case too.
1040 */
1041 return -EIO;
1042 }
1043 }
1044
1045 return 0;
1046}
1047
1048/*
1049 * Migrate pages from one node to a target node.
1050 * Returns error or the number of pages not migrated.
1051 */
1052static int migrate_to_node(struct mm_struct *mm, int source, int dest,
1053 int flags)
1054{
1055 nodemask_t nmask;
1056 LIST_HEAD(pagelist);
1057 int err = 0;
1058 struct migration_target_control mtc = {
1059 .nid = dest,
1060 .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE,
1061 };
1062
1063 nodes_clear(nmask);
1064 node_set(source, nmask);
1065
1066 /*
1067 * This does not "check" the range but isolates all pages that
1068 * need migration. Between passing in the full user address
1069 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
1070 */
1071 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
1072 queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1073 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
1074
1075 if (!list_empty(&pagelist)) {
1076 err = migrate_pages(&pagelist, alloc_migration_target, NULL,
1077 (unsigned long)&mtc, MIGRATE_SYNC, MR_SYSCALL);
1078 if (err)
1079 putback_movable_pages(&pagelist);
1080 }
1081
1082 return err;
1083}
1084
1085/*
1086 * Move pages between the two nodesets so as to preserve the physical
1087 * layout as much as possible.
1088 *
1089 * Returns the number of page that could not be moved.
1090 */
1091int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1092 const nodemask_t *to, int flags)
1093{
1094 int busy = 0;
1095 int err = 0;
1096 nodemask_t tmp;
1097
1098 lru_cache_disable();
1099
1100 mmap_read_lock(mm);
1101
1102 /*
1103 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1104 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1105 * bit in 'tmp', and return that <source, dest> pair for migration.
1106 * The pair of nodemasks 'to' and 'from' define the map.
1107 *
1108 * If no pair of bits is found that way, fallback to picking some
1109 * pair of 'source' and 'dest' bits that are not the same. If the
1110 * 'source' and 'dest' bits are the same, this represents a node
1111 * that will be migrating to itself, so no pages need move.
1112 *
1113 * If no bits are left in 'tmp', or if all remaining bits left
1114 * in 'tmp' correspond to the same bit in 'to', return false
1115 * (nothing left to migrate).
1116 *
1117 * This lets us pick a pair of nodes to migrate between, such that
1118 * if possible the dest node is not already occupied by some other
1119 * source node, minimizing the risk of overloading the memory on a
1120 * node that would happen if we migrated incoming memory to a node
1121 * before migrating outgoing memory source that same node.
1122 *
1123 * A single scan of tmp is sufficient. As we go, we remember the
1124 * most recent <s, d> pair that moved (s != d). If we find a pair
1125 * that not only moved, but what's better, moved to an empty slot
1126 * (d is not set in tmp), then we break out then, with that pair.
1127 * Otherwise when we finish scanning from_tmp, we at least have the
1128 * most recent <s, d> pair that moved. If we get all the way through
1129 * the scan of tmp without finding any node that moved, much less
1130 * moved to an empty node, then there is nothing left worth migrating.
1131 */
1132
1133 tmp = *from;
1134 while (!nodes_empty(tmp)) {
1135 int s, d;
1136 int source = NUMA_NO_NODE;
1137 int dest = 0;
1138
1139 for_each_node_mask(s, tmp) {
1140
1141 /*
1142 * do_migrate_pages() tries to maintain the relative
1143 * node relationship of the pages established between
1144 * threads and memory areas.
1145 *
1146 * However if the number of source nodes is not equal to
1147 * the number of destination nodes we can not preserve
1148 * this node relative relationship. In that case, skip
1149 * copying memory from a node that is in the destination
1150 * mask.
1151 *
1152 * Example: [2,3,4] -> [3,4,5] moves everything.
1153 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1154 */
1155
1156 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1157 (node_isset(s, *to)))
1158 continue;
1159
1160 d = node_remap(s, *from, *to);
1161 if (s == d)
1162 continue;
1163
1164 source = s; /* Node moved. Memorize */
1165 dest = d;
1166
1167 /* dest not in remaining from nodes? */
1168 if (!node_isset(dest, tmp))
1169 break;
1170 }
1171 if (source == NUMA_NO_NODE)
1172 break;
1173
1174 node_clear(source, tmp);
1175 err = migrate_to_node(mm, source, dest, flags);
1176 if (err > 0)
1177 busy += err;
1178 if (err < 0)
1179 break;
1180 }
1181 mmap_read_unlock(mm);
1182
1183 lru_cache_enable();
1184 if (err < 0)
1185 return err;
1186 return busy;
1187
1188}
1189
1190/*
1191 * Allocate a new page for page migration based on vma policy.
1192 * Start by assuming the page is mapped by the same vma as contains @start.
1193 * Search forward from there, if not. N.B., this assumes that the
1194 * list of pages handed to migrate_pages()--which is how we get here--
1195 * is in virtual address order.
1196 */
1197static struct page *new_page(struct page *page, unsigned long start)
1198{
1199 struct vm_area_struct *vma;
1200 unsigned long address;
1201
1202 vma = find_vma(current->mm, start);
1203 while (vma) {
1204 address = page_address_in_vma(page, vma);
1205 if (address != -EFAULT)
1206 break;
1207 vma = vma->vm_next;
1208 }
1209
1210 if (PageHuge(page)) {
1211 return alloc_huge_page_vma(page_hstate(compound_head(page)),
1212 vma, address);
1213 } else if (PageTransHuge(page)) {
1214 struct page *thp;
1215
1216 thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
1217 HPAGE_PMD_ORDER);
1218 if (!thp)
1219 return NULL;
1220 prep_transhuge_page(thp);
1221 return thp;
1222 }
1223 /*
1224 * if !vma, alloc_page_vma() will use task or system default policy
1225 */
1226 return alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL,
1227 vma, address);
1228}
1229#else
1230
1231static int migrate_page_add(struct page *page, struct list_head *pagelist,
1232 unsigned long flags)
1233{
1234 return -EIO;
1235}
1236
1237int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1238 const nodemask_t *to, int flags)
1239{
1240 return -ENOSYS;
1241}
1242
1243static struct page *new_page(struct page *page, unsigned long start)
1244{
1245 return NULL;
1246}
1247#endif
1248
1249static long do_mbind(unsigned long start, unsigned long len,
1250 unsigned short mode, unsigned short mode_flags,
1251 nodemask_t *nmask, unsigned long flags)
1252{
1253 struct mm_struct *mm = current->mm;
1254 struct mempolicy *new;
1255 unsigned long end;
1256 int err;
1257 int ret;
1258 LIST_HEAD(pagelist);
1259
1260 if (flags & ~(unsigned long)MPOL_MF_VALID)
1261 return -EINVAL;
1262 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1263 return -EPERM;
1264
1265 if (start & ~PAGE_MASK)
1266 return -EINVAL;
1267
1268 if (mode == MPOL_DEFAULT)
1269 flags &= ~MPOL_MF_STRICT;
1270
1271 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1272 end = start + len;
1273
1274 if (end < start)
1275 return -EINVAL;
1276 if (end == start)
1277 return 0;
1278
1279 new = mpol_new(mode, mode_flags, nmask);
1280 if (IS_ERR(new))
1281 return PTR_ERR(new);
1282
1283 if (flags & MPOL_MF_LAZY)
1284 new->flags |= MPOL_F_MOF;
1285
1286 /*
1287 * If we are using the default policy then operation
1288 * on discontinuous address spaces is okay after all
1289 */
1290 if (!new)
1291 flags |= MPOL_MF_DISCONTIG_OK;
1292
1293 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1294 start, start + len, mode, mode_flags,
1295 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1296
1297 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1298
1299 lru_cache_disable();
1300 }
1301 {
1302 NODEMASK_SCRATCH(scratch);
1303 if (scratch) {
1304 mmap_write_lock(mm);
1305 err = mpol_set_nodemask(new, nmask, scratch);
1306 if (err)
1307 mmap_write_unlock(mm);
1308 } else
1309 err = -ENOMEM;
1310 NODEMASK_SCRATCH_FREE(scratch);
1311 }
1312 if (err)
1313 goto mpol_out;
1314
1315 ret = queue_pages_range(mm, start, end, nmask,
1316 flags | MPOL_MF_INVERT, &pagelist);
1317
1318 if (ret < 0) {
1319 err = ret;
1320 goto up_out;
1321 }
1322
1323 err = mbind_range(mm, start, end, new);
1324
1325 if (!err) {
1326 int nr_failed = 0;
1327
1328 if (!list_empty(&pagelist)) {
1329 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1330 nr_failed = migrate_pages(&pagelist, new_page, NULL,
1331 start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
1332 if (nr_failed)
1333 putback_movable_pages(&pagelist);
1334 }
1335
1336 if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
1337 err = -EIO;
1338 } else {
1339up_out:
1340 if (!list_empty(&pagelist))
1341 putback_movable_pages(&pagelist);
1342 }
1343
1344 mmap_write_unlock(mm);
1345mpol_out:
1346 mpol_put(new);
1347 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1348 lru_cache_enable();
1349 return err;
1350}
1351
1352/*
1353 * User space interface with variable sized bitmaps for nodelists.
1354 */
1355
1356/* Copy a node mask from user space. */
1357static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1358 unsigned long maxnode)
1359{
1360 unsigned long k;
1361 unsigned long t;
1362 unsigned long nlongs;
1363 unsigned long endmask;
1364
1365 --maxnode;
1366 nodes_clear(*nodes);
1367 if (maxnode == 0 || !nmask)
1368 return 0;
1369 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1370 return -EINVAL;
1371
1372 nlongs = BITS_TO_LONGS(maxnode);
1373 if ((maxnode % BITS_PER_LONG) == 0)
1374 endmask = ~0UL;
1375 else
1376 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1377
1378 /*
1379 * When the user specified more nodes than supported just check
1380 * if the non supported part is all zero.
1381 *
1382 * If maxnode have more longs than MAX_NUMNODES, check
1383 * the bits in that area first. And then go through to
1384 * check the rest bits which equal or bigger than MAX_NUMNODES.
1385 * Otherwise, just check bits [MAX_NUMNODES, maxnode).
1386 */
1387 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1388 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1389 if (get_user(t, nmask + k))
1390 return -EFAULT;
1391 if (k == nlongs - 1) {
1392 if (t & endmask)
1393 return -EINVAL;
1394 } else if (t)
1395 return -EINVAL;
1396 }
1397 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1398 endmask = ~0UL;
1399 }
1400
1401 if (maxnode > MAX_NUMNODES && MAX_NUMNODES % BITS_PER_LONG != 0) {
1402 unsigned long valid_mask = endmask;
1403
1404 valid_mask &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
1405 if (get_user(t, nmask + nlongs - 1))
1406 return -EFAULT;
1407 if (t & valid_mask)
1408 return -EINVAL;
1409 }
1410
1411 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1412 return -EFAULT;
1413 nodes_addr(*nodes)[nlongs-1] &= endmask;
1414 return 0;
1415}
1416
1417/* Copy a kernel node mask to user space */
1418static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1419 nodemask_t *nodes)
1420{
1421 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1422 unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long);
1423
1424 if (copy > nbytes) {
1425 if (copy > PAGE_SIZE)
1426 return -EINVAL;
1427 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1428 return -EFAULT;
1429 copy = nbytes;
1430 }
1431 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1432}
1433
1434/* Basic parameter sanity check used by both mbind() and set_mempolicy() */
1435static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)
1436{
1437 *flags = *mode & MPOL_MODE_FLAGS;
1438 *mode &= ~MPOL_MODE_FLAGS;
1439 if ((unsigned int)(*mode) >= MPOL_MAX)
1440 return -EINVAL;
1441 if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))
1442 return -EINVAL;
1443 if (*flags & MPOL_F_NUMA_BALANCING) {
1444 if (*mode != MPOL_BIND)
1445 return -EINVAL;
1446 *flags |= (MPOL_F_MOF | MPOL_F_MORON);
1447 }
1448 return 0;
1449}
1450
1451static long kernel_mbind(unsigned long start, unsigned long len,
1452 unsigned long mode, const unsigned long __user *nmask,
1453 unsigned long maxnode, unsigned int flags)
1454{
1455 unsigned short mode_flags;
1456 nodemask_t nodes;
1457 int lmode = mode;
1458 int err;
1459
1460 start = untagged_addr(start);
1461 err = sanitize_mpol_flags(&lmode, &mode_flags);
1462 if (err)
1463 return err;
1464
1465 err = get_nodes(&nodes, nmask, maxnode);
1466 if (err)
1467 return err;
1468
1469 return do_mbind(start, len, lmode, mode_flags, &nodes, flags);
1470}
1471
1472SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1473 unsigned long, mode, const unsigned long __user *, nmask,
1474 unsigned long, maxnode, unsigned int, flags)
1475{
1476 return kernel_mbind(start, len, mode, nmask, maxnode, flags);
1477}
1478
1479/* Set the process memory policy */
1480static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
1481 unsigned long maxnode)
1482{
1483 unsigned short mode_flags;
1484 nodemask_t nodes;
1485 int lmode = mode;
1486 int err;
1487
1488 err = sanitize_mpol_flags(&lmode, &mode_flags);
1489 if (err)
1490 return err;
1491
1492 err = get_nodes(&nodes, nmask, maxnode);
1493 if (err)
1494 return err;
1495
1496 return do_set_mempolicy(lmode, mode_flags, &nodes);
1497}
1498
1499SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
1500 unsigned long, maxnode)
1501{
1502 return kernel_set_mempolicy(mode, nmask, maxnode);
1503}
1504
1505static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
1506 const unsigned long __user *old_nodes,
1507 const unsigned long __user *new_nodes)
1508{
1509 struct mm_struct *mm = NULL;
1510 struct task_struct *task;
1511 nodemask_t task_nodes;
1512 int err;
1513 nodemask_t *old;
1514 nodemask_t *new;
1515 NODEMASK_SCRATCH(scratch);
1516
1517 if (!scratch)
1518 return -ENOMEM;
1519
1520 old = &scratch->mask1;
1521 new = &scratch->mask2;
1522
1523 err = get_nodes(old, old_nodes, maxnode);
1524 if (err)
1525 goto out;
1526
1527 err = get_nodes(new, new_nodes, maxnode);
1528 if (err)
1529 goto out;
1530
1531 /* Find the mm_struct */
1532 rcu_read_lock();
1533 task = pid ? find_task_by_vpid(pid) : current;
1534 if (!task) {
1535 rcu_read_unlock();
1536 err = -ESRCH;
1537 goto out;
1538 }
1539 get_task_struct(task);
1540
1541 err = -EINVAL;
1542
1543 /*
1544 * Check if this process has the right to modify the specified process.
1545 * Use the regular "ptrace_may_access()" checks.
1546 */
1547 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
1548 rcu_read_unlock();
1549 err = -EPERM;
1550 goto out_put;
1551 }
1552 rcu_read_unlock();
1553
1554 task_nodes = cpuset_mems_allowed(task);
1555 /* Is the user allowed to access the target nodes? */
1556 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1557 err = -EPERM;
1558 goto out_put;
1559 }
1560
1561 task_nodes = cpuset_mems_allowed(current);
1562 nodes_and(*new, *new, task_nodes);
1563 if (nodes_empty(*new))
1564 goto out_put;
1565
1566 err = security_task_movememory(task);
1567 if (err)
1568 goto out_put;
1569
1570 mm = get_task_mm(task);
1571 put_task_struct(task);
1572
1573 if (!mm) {
1574 err = -EINVAL;
1575 goto out;
1576 }
1577
1578 err = do_migrate_pages(mm, old, new,
1579 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1580
1581 mmput(mm);
1582out:
1583 NODEMASK_SCRATCH_FREE(scratch);
1584
1585 return err;
1586
1587out_put:
1588 put_task_struct(task);
1589 goto out;
1590
1591}
1592
1593SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1594 const unsigned long __user *, old_nodes,
1595 const unsigned long __user *, new_nodes)
1596{
1597 return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes);
1598}
1599
1600
1601/* Retrieve NUMA policy */
1602static int kernel_get_mempolicy(int __user *policy,
1603 unsigned long __user *nmask,
1604 unsigned long maxnode,
1605 unsigned long addr,
1606 unsigned long flags)
1607{
1608 int err;
1609 int pval;
1610 nodemask_t nodes;
1611
1612 if (nmask != NULL && maxnode < nr_node_ids)
1613 return -EINVAL;
1614
1615 addr = untagged_addr(addr);
1616
1617 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1618
1619 if (err)
1620 return err;
1621
1622 if (policy && put_user(pval, policy))
1623 return -EFAULT;
1624
1625 if (nmask)
1626 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1627
1628 return err;
1629}
1630
1631SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1632 unsigned long __user *, nmask, unsigned long, maxnode,
1633 unsigned long, addr, unsigned long, flags)
1634{
1635 return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags);
1636}
1637
1638#ifdef CONFIG_COMPAT
1639
1640COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1641 compat_ulong_t __user *, nmask,
1642 compat_ulong_t, maxnode,
1643 compat_ulong_t, addr, compat_ulong_t, flags)
1644{
1645 long err;
1646 unsigned long __user *nm = NULL;
1647 unsigned long nr_bits, alloc_size;
1648 DECLARE_BITMAP(bm, MAX_NUMNODES);
1649
1650 nr_bits = min_t(unsigned long, maxnode-1, nr_node_ids);
1651 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1652
1653 if (nmask)
1654 nm = compat_alloc_user_space(alloc_size);
1655
1656 err = kernel_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1657
1658 if (!err && nmask) {
1659 unsigned long copy_size;
1660 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1661 err = copy_from_user(bm, nm, copy_size);
1662 /* ensure entire bitmap is zeroed */
1663 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1664 err |= compat_put_bitmap(nmask, bm, nr_bits);
1665 }
1666
1667 return err;
1668}
1669
1670COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
1671 compat_ulong_t, maxnode)
1672{
1673 unsigned long __user *nm = NULL;
1674 unsigned long nr_bits, alloc_size;
1675 DECLARE_BITMAP(bm, MAX_NUMNODES);
1676
1677 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1678 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1679
1680 if (nmask) {
1681 if (compat_get_bitmap(bm, nmask, nr_bits))
1682 return -EFAULT;
1683 nm = compat_alloc_user_space(alloc_size);
1684 if (copy_to_user(nm, bm, alloc_size))
1685 return -EFAULT;
1686 }
1687
1688 return kernel_set_mempolicy(mode, nm, nr_bits+1);
1689}
1690
1691COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
1692 compat_ulong_t, mode, compat_ulong_t __user *, nmask,
1693 compat_ulong_t, maxnode, compat_ulong_t, flags)
1694{
1695 unsigned long __user *nm = NULL;
1696 unsigned long nr_bits, alloc_size;
1697 nodemask_t bm;
1698
1699 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1700 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1701
1702 if (nmask) {
1703 if (compat_get_bitmap(nodes_addr(bm), nmask, nr_bits))
1704 return -EFAULT;
1705 nm = compat_alloc_user_space(alloc_size);
1706 if (copy_to_user(nm, nodes_addr(bm), alloc_size))
1707 return -EFAULT;
1708 }
1709
1710 return kernel_mbind(start, len, mode, nm, nr_bits+1, flags);
1711}
1712
1713COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
1714 compat_ulong_t, maxnode,
1715 const compat_ulong_t __user *, old_nodes,
1716 const compat_ulong_t __user *, new_nodes)
1717{
1718 unsigned long __user *old = NULL;
1719 unsigned long __user *new = NULL;
1720 nodemask_t tmp_mask;
1721 unsigned long nr_bits;
1722 unsigned long size;
1723
1724 nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
1725 size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1726 if (old_nodes) {
1727 if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
1728 return -EFAULT;
1729 old = compat_alloc_user_space(new_nodes ? size * 2 : size);
1730 if (new_nodes)
1731 new = old + size / sizeof(unsigned long);
1732 if (copy_to_user(old, nodes_addr(tmp_mask), size))
1733 return -EFAULT;
1734 }
1735 if (new_nodes) {
1736 if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
1737 return -EFAULT;
1738 if (new == NULL)
1739 new = compat_alloc_user_space(size);
1740 if (copy_to_user(new, nodes_addr(tmp_mask), size))
1741 return -EFAULT;
1742 }
1743 return kernel_migrate_pages(pid, nr_bits + 1, old, new);
1744}
1745
1746#endif /* CONFIG_COMPAT */
1747
1748bool vma_migratable(struct vm_area_struct *vma)
1749{
1750 if (vma->vm_flags & (VM_IO | VM_PFNMAP))
1751 return false;
1752
1753 /*
1754 * DAX device mappings require predictable access latency, so avoid
1755 * incurring periodic faults.
1756 */
1757 if (vma_is_dax(vma))
1758 return false;
1759
1760 if (is_vm_hugetlb_page(vma) &&
1761 !hugepage_migration_supported(hstate_vma(vma)))
1762 return false;
1763
1764 /*
1765 * Migration allocates pages in the highest zone. If we cannot
1766 * do so then migration (at least from node to node) is not
1767 * possible.
1768 */
1769 if (vma->vm_file &&
1770 gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
1771 < policy_zone)
1772 return false;
1773 return true;
1774}
1775
1776struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
1777 unsigned long addr)
1778{
1779 struct mempolicy *pol = NULL;
1780
1781 if (vma) {
1782 if (vma->vm_ops && vma->vm_ops->get_policy) {
1783 pol = vma->vm_ops->get_policy(vma, addr);
1784 } else if (vma->vm_policy) {
1785 pol = vma->vm_policy;
1786
1787 /*
1788 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1789 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1790 * count on these policies which will be dropped by
1791 * mpol_cond_put() later
1792 */
1793 if (mpol_needs_cond_ref(pol))
1794 mpol_get(pol);
1795 }
1796 }
1797
1798 return pol;
1799}
1800
1801/*
1802 * get_vma_policy(@vma, @addr)
1803 * @vma: virtual memory area whose policy is sought
1804 * @addr: address in @vma for shared policy lookup
1805 *
1806 * Returns effective policy for a VMA at specified address.
1807 * Falls back to current->mempolicy or system default policy, as necessary.
1808 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1809 * count--added by the get_policy() vm_op, as appropriate--to protect against
1810 * freeing by another task. It is the caller's responsibility to free the
1811 * extra reference for shared policies.
1812 */
1813static struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
1814 unsigned long addr)
1815{
1816 struct mempolicy *pol = __get_vma_policy(vma, addr);
1817
1818 if (!pol)
1819 pol = get_task_policy(current);
1820
1821 return pol;
1822}
1823
1824bool vma_policy_mof(struct vm_area_struct *vma)
1825{
1826 struct mempolicy *pol;
1827
1828 if (vma->vm_ops && vma->vm_ops->get_policy) {
1829 bool ret = false;
1830
1831 pol = vma->vm_ops->get_policy(vma, vma->vm_start);
1832 if (pol && (pol->flags & MPOL_F_MOF))
1833 ret = true;
1834 mpol_cond_put(pol);
1835
1836 return ret;
1837 }
1838
1839 pol = vma->vm_policy;
1840 if (!pol)
1841 pol = get_task_policy(current);
1842
1843 return pol->flags & MPOL_F_MOF;
1844}
1845
1846static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1847{
1848 enum zone_type dynamic_policy_zone = policy_zone;
1849
1850 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1851
1852 /*
1853 * if policy->nodes has movable memory only,
1854 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1855 *
1856 * policy->nodes is intersect with node_states[N_MEMORY].
1857 * so if the following test fails, it implies
1858 * policy->nodes has movable memory only.
1859 */
1860 if (!nodes_intersects(policy->nodes, node_states[N_HIGH_MEMORY]))
1861 dynamic_policy_zone = ZONE_MOVABLE;
1862
1863 return zone >= dynamic_policy_zone;
1864}
1865
1866/*
1867 * Return a nodemask representing a mempolicy for filtering nodes for
1868 * page allocation
1869 */
1870nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1871{
1872 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1873 if (unlikely(policy->mode == MPOL_BIND) &&
1874 apply_policy_zone(policy, gfp_zone(gfp)) &&
1875 cpuset_nodemask_valid_mems_allowed(&policy->nodes))
1876 return &policy->nodes;
1877
1878 return NULL;
1879}
1880
1881/* Return the node id preferred by the given mempolicy, or the given id */
1882static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd)
1883{
1884 if (policy->mode == MPOL_PREFERRED) {
1885 nd = first_node(policy->nodes);
1886 } else {
1887 /*
1888 * __GFP_THISNODE shouldn't even be used with the bind policy
1889 * because we might easily break the expectation to stay on the
1890 * requested node and not break the policy.
1891 */
1892 WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE));
1893 }
1894
1895 return nd;
1896}
1897
1898/* Do dynamic interleaving for a process */
1899static unsigned interleave_nodes(struct mempolicy *policy)
1900{
1901 unsigned next;
1902 struct task_struct *me = current;
1903
1904 next = next_node_in(me->il_prev, policy->nodes);
1905 if (next < MAX_NUMNODES)
1906 me->il_prev = next;
1907 return next;
1908}
1909
1910/*
1911 * Depending on the memory policy provide a node from which to allocate the
1912 * next slab entry.
1913 */
1914unsigned int mempolicy_slab_node(void)
1915{
1916 struct mempolicy *policy;
1917 int node = numa_mem_id();
1918
1919 if (in_interrupt())
1920 return node;
1921
1922 policy = current->mempolicy;
1923 if (!policy)
1924 return node;
1925
1926 switch (policy->mode) {
1927 case MPOL_PREFERRED:
1928 return first_node(policy->nodes);
1929
1930 case MPOL_INTERLEAVE:
1931 return interleave_nodes(policy);
1932
1933 case MPOL_BIND: {
1934 struct zoneref *z;
1935
1936 /*
1937 * Follow bind policy behavior and start allocation at the
1938 * first node.
1939 */
1940 struct zonelist *zonelist;
1941 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1942 zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK];
1943 z = first_zones_zonelist(zonelist, highest_zoneidx,
1944 &policy->nodes);
1945 return z->zone ? zone_to_nid(z->zone) : node;
1946 }
1947 case MPOL_LOCAL:
1948 return node;
1949
1950 default:
1951 BUG();
1952 }
1953}
1954
1955/*
1956 * Do static interleaving for a VMA with known offset @n. Returns the n'th
1957 * node in pol->nodes (starting from n=0), wrapping around if n exceeds the
1958 * number of present nodes.
1959 */
1960static unsigned offset_il_node(struct mempolicy *pol, unsigned long n)
1961{
1962 nodemask_t nodemask = pol->nodes;
1963 unsigned int target, nnodes;
1964 int i;
1965 int nid;
1966 /*
1967 * The barrier will stabilize the nodemask in a register or on
1968 * the stack so that it will stop changing under the code.
1969 *
1970 * Between first_node() and next_node(), pol->nodes could be changed
1971 * by other threads. So we put pol->nodes in a local stack.
1972 */
1973 barrier();
1974
1975 nnodes = nodes_weight(nodemask);
1976 if (!nnodes)
1977 return numa_node_id();
1978 target = (unsigned int)n % nnodes;
1979 nid = first_node(nodemask);
1980 for (i = 0; i < target; i++)
1981 nid = next_node(nid, nodemask);
1982 return nid;
1983}
1984
1985/* Determine a node number for interleave */
1986static inline unsigned interleave_nid(struct mempolicy *pol,
1987 struct vm_area_struct *vma, unsigned long addr, int shift)
1988{
1989 if (vma) {
1990 unsigned long off;
1991
1992 /*
1993 * for small pages, there is no difference between
1994 * shift and PAGE_SHIFT, so the bit-shift is safe.
1995 * for huge pages, since vm_pgoff is in units of small
1996 * pages, we need to shift off the always 0 bits to get
1997 * a useful offset.
1998 */
1999 BUG_ON(shift < PAGE_SHIFT);
2000 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
2001 off += (addr - vma->vm_start) >> shift;
2002 return offset_il_node(pol, off);
2003 } else
2004 return interleave_nodes(pol);
2005}
2006
2007#ifdef CONFIG_HUGETLBFS
2008/*
2009 * huge_node(@vma, @addr, @gfp_flags, @mpol)
2010 * @vma: virtual memory area whose policy is sought
2011 * @addr: address in @vma for shared policy lookup and interleave policy
2012 * @gfp_flags: for requested zone
2013 * @mpol: pointer to mempolicy pointer for reference counted mempolicy
2014 * @nodemask: pointer to nodemask pointer for MPOL_BIND nodemask
2015 *
2016 * Returns a nid suitable for a huge page allocation and a pointer
2017 * to the struct mempolicy for conditional unref after allocation.
2018 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
2019 * @nodemask for filtering the zonelist.
2020 *
2021 * Must be protected by read_mems_allowed_begin()
2022 */
2023int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags,
2024 struct mempolicy **mpol, nodemask_t **nodemask)
2025{
2026 int nid;
2027
2028 *mpol = get_vma_policy(vma, addr);
2029 *nodemask = NULL; /* assume !MPOL_BIND */
2030
2031 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
2032 nid = interleave_nid(*mpol, vma, addr,
2033 huge_page_shift(hstate_vma(vma)));
2034 } else {
2035 nid = policy_node(gfp_flags, *mpol, numa_node_id());
2036 if ((*mpol)->mode == MPOL_BIND)
2037 *nodemask = &(*mpol)->nodes;
2038 }
2039 return nid;
2040}
2041
2042/*
2043 * init_nodemask_of_mempolicy
2044 *
2045 * If the current task's mempolicy is "default" [NULL], return 'false'
2046 * to indicate default policy. Otherwise, extract the policy nodemask
2047 * for 'bind' or 'interleave' policy into the argument nodemask, or
2048 * initialize the argument nodemask to contain the single node for
2049 * 'preferred' or 'local' policy and return 'true' to indicate presence
2050 * of non-default mempolicy.
2051 *
2052 * We don't bother with reference counting the mempolicy [mpol_get/put]
2053 * because the current task is examining it's own mempolicy and a task's
2054 * mempolicy is only ever changed by the task itself.
2055 *
2056 * N.B., it is the caller's responsibility to free a returned nodemask.
2057 */
2058bool init_nodemask_of_mempolicy(nodemask_t *mask)
2059{
2060 struct mempolicy *mempolicy;
2061
2062 if (!(mask && current->mempolicy))
2063 return false;
2064
2065 task_lock(current);
2066 mempolicy = current->mempolicy;
2067 switch (mempolicy->mode) {
2068 case MPOL_PREFERRED:
2069 case MPOL_BIND:
2070 case MPOL_INTERLEAVE:
2071 *mask = mempolicy->nodes;
2072 break;
2073
2074 case MPOL_LOCAL:
2075 init_nodemask_of_node(mask, numa_node_id());
2076 break;
2077
2078 default:
2079 BUG();
2080 }
2081 task_unlock(current);
2082
2083 return true;
2084}
2085#endif
2086
2087/*
2088 * mempolicy_in_oom_domain
2089 *
2090 * If tsk's mempolicy is "bind", check for intersection between mask and
2091 * the policy nodemask. Otherwise, return true for all other policies
2092 * including "interleave", as a tsk with "interleave" policy may have
2093 * memory allocated from all nodes in system.
2094 *
2095 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
2096 */
2097bool mempolicy_in_oom_domain(struct task_struct *tsk,
2098 const nodemask_t *mask)
2099{
2100 struct mempolicy *mempolicy;
2101 bool ret = true;
2102
2103 if (!mask)
2104 return ret;
2105
2106 task_lock(tsk);
2107 mempolicy = tsk->mempolicy;
2108 if (mempolicy && mempolicy->mode == MPOL_BIND)
2109 ret = nodes_intersects(mempolicy->nodes, *mask);
2110 task_unlock(tsk);
2111
2112 return ret;
2113}
2114
2115/* Allocate a page in interleaved policy.
2116 Own path because it needs to do special accounting. */
2117static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
2118 unsigned nid)
2119{
2120 struct page *page;
2121
2122 page = __alloc_pages(gfp, order, nid, NULL);
2123 /* skip NUMA_INTERLEAVE_HIT counter update if numa stats is disabled */
2124 if (!static_branch_likely(&vm_numa_stat_key))
2125 return page;
2126 if (page && page_to_nid(page) == nid) {
2127 preempt_disable();
2128 __count_numa_event(page_zone(page), NUMA_INTERLEAVE_HIT);
2129 preempt_enable();
2130 }
2131 return page;
2132}
2133
2134/**
2135 * alloc_pages_vma - Allocate a page for a VMA.
2136 * @gfp: GFP flags.
2137 * @order: Order of the GFP allocation.
2138 * @vma: Pointer to VMA or NULL if not available.
2139 * @addr: Virtual address of the allocation. Must be inside @vma.
2140 * @node: Which node to prefer for allocation (modulo policy).
2141 * @hugepage: For hugepages try only the preferred node if possible.
2142 *
2143 * Allocate a page for a specific address in @vma, using the appropriate
2144 * NUMA policy. When @vma is not NULL the caller must hold the mmap_lock
2145 * of the mm_struct of the VMA to prevent it from going away. Should be
2146 * used for all allocations for pages that will be mapped into user space.
2147 *
2148 * Return: The page on success or NULL if allocation fails.
2149 */
2150struct page *alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
2151 unsigned long addr, int node, bool hugepage)
2152{
2153 struct mempolicy *pol;
2154 struct page *page;
2155 int preferred_nid;
2156 nodemask_t *nmask;
2157
2158 pol = get_vma_policy(vma, addr);
2159
2160 if (pol->mode == MPOL_INTERLEAVE) {
2161 unsigned nid;
2162
2163 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2164 mpol_cond_put(pol);
2165 page = alloc_page_interleave(gfp, order, nid);
2166 goto out;
2167 }
2168
2169 if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
2170 int hpage_node = node;
2171
2172 /*
2173 * For hugepage allocation and non-interleave policy which
2174 * allows the current node (or other explicitly preferred
2175 * node) we only try to allocate from the current/preferred
2176 * node and don't fall back to other nodes, as the cost of
2177 * remote accesses would likely offset THP benefits.
2178 *
2179 * If the policy is interleave, or does not allow the current
2180 * node in its nodemask, we allocate the standard way.
2181 */
2182 if (pol->mode == MPOL_PREFERRED)
2183 hpage_node = first_node(pol->nodes);
2184
2185 nmask = policy_nodemask(gfp, pol);
2186 if (!nmask || node_isset(hpage_node, *nmask)) {
2187 mpol_cond_put(pol);
2188 /*
2189 * First, try to allocate THP only on local node, but
2190 * don't reclaim unnecessarily, just compact.
2191 */
2192 page = __alloc_pages_node(hpage_node,
2193 gfp | __GFP_THISNODE | __GFP_NORETRY, order);
2194
2195 /*
2196 * If hugepage allocations are configured to always
2197 * synchronous compact or the vma has been madvised
2198 * to prefer hugepage backing, retry allowing remote
2199 * memory with both reclaim and compact as well.
2200 */
2201 if (!page && (gfp & __GFP_DIRECT_RECLAIM))
2202 page = __alloc_pages_node(hpage_node,
2203 gfp, order);
2204
2205 goto out;
2206 }
2207 }
2208
2209 nmask = policy_nodemask(gfp, pol);
2210 preferred_nid = policy_node(gfp, pol, node);
2211 page = __alloc_pages(gfp, order, preferred_nid, nmask);
2212 mpol_cond_put(pol);
2213out:
2214 return page;
2215}
2216EXPORT_SYMBOL(alloc_pages_vma);
2217
2218/**
2219 * alloc_pages - Allocate pages.
2220 * @gfp: GFP flags.
2221 * @order: Power of two of number of pages to allocate.
2222 *
2223 * Allocate 1 << @order contiguous pages. The physical address of the
2224 * first page is naturally aligned (eg an order-3 allocation will be aligned
2225 * to a multiple of 8 * PAGE_SIZE bytes). The NUMA policy of the current
2226 * process is honoured when in process context.
2227 *
2228 * Context: Can be called from any context, providing the appropriate GFP
2229 * flags are used.
2230 * Return: The page on success or NULL if allocation fails.
2231 */
2232struct page *alloc_pages(gfp_t gfp, unsigned order)
2233{
2234 struct mempolicy *pol = &default_policy;
2235 struct page *page;
2236
2237 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2238 pol = get_task_policy(current);
2239
2240 /*
2241 * No reference counting needed for current->mempolicy
2242 * nor system default_policy
2243 */
2244 if (pol->mode == MPOL_INTERLEAVE)
2245 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
2246 else
2247 page = __alloc_pages(gfp, order,
2248 policy_node(gfp, pol, numa_node_id()),
2249 policy_nodemask(gfp, pol));
2250
2251 return page;
2252}
2253EXPORT_SYMBOL(alloc_pages);
2254
2255int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
2256{
2257 struct mempolicy *pol = mpol_dup(vma_policy(src));
2258
2259 if (IS_ERR(pol))
2260 return PTR_ERR(pol);
2261 dst->vm_policy = pol;
2262 return 0;
2263}
2264
2265/*
2266 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2267 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2268 * with the mems_allowed returned by cpuset_mems_allowed(). This
2269 * keeps mempolicies cpuset relative after its cpuset moves. See
2270 * further kernel/cpuset.c update_nodemask().
2271 *
2272 * current's mempolicy may be rebinded by the other task(the task that changes
2273 * cpuset's mems), so we needn't do rebind work for current task.
2274 */
2275
2276/* Slow path of a mempolicy duplicate */
2277struct mempolicy *__mpol_dup(struct mempolicy *old)
2278{
2279 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2280
2281 if (!new)
2282 return ERR_PTR(-ENOMEM);
2283
2284 /* task's mempolicy is protected by alloc_lock */
2285 if (old == current->mempolicy) {
2286 task_lock(current);
2287 *new = *old;
2288 task_unlock(current);
2289 } else
2290 *new = *old;
2291
2292 if (current_cpuset_is_being_rebound()) {
2293 nodemask_t mems = cpuset_mems_allowed(current);
2294 mpol_rebind_policy(new, &mems);
2295 }
2296 atomic_set(&new->refcnt, 1);
2297 return new;
2298}
2299
2300/* Slow path of a mempolicy comparison */
2301bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2302{
2303 if (!a || !b)
2304 return false;
2305 if (a->mode != b->mode)
2306 return false;
2307 if (a->flags != b->flags)
2308 return false;
2309 if (mpol_store_user_nodemask(a))
2310 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2311 return false;
2312
2313 switch (a->mode) {
2314 case MPOL_BIND:
2315 case MPOL_INTERLEAVE:
2316 case MPOL_PREFERRED:
2317 return !!nodes_equal(a->nodes, b->nodes);
2318 case MPOL_LOCAL:
2319 return true;
2320 default:
2321 BUG();
2322 return false;
2323 }
2324}
2325
2326/*
2327 * Shared memory backing store policy support.
2328 *
2329 * Remember policies even when nobody has shared memory mapped.
2330 * The policies are kept in Red-Black tree linked from the inode.
2331 * They are protected by the sp->lock rwlock, which should be held
2332 * for any accesses to the tree.
2333 */
2334
2335/*
2336 * lookup first element intersecting start-end. Caller holds sp->lock for
2337 * reading or for writing
2338 */
2339static struct sp_node *
2340sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2341{
2342 struct rb_node *n = sp->root.rb_node;
2343
2344 while (n) {
2345 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2346
2347 if (start >= p->end)
2348 n = n->rb_right;
2349 else if (end <= p->start)
2350 n = n->rb_left;
2351 else
2352 break;
2353 }
2354 if (!n)
2355 return NULL;
2356 for (;;) {
2357 struct sp_node *w = NULL;
2358 struct rb_node *prev = rb_prev(n);
2359 if (!prev)
2360 break;
2361 w = rb_entry(prev, struct sp_node, nd);
2362 if (w->end <= start)
2363 break;
2364 n = prev;
2365 }
2366 return rb_entry(n, struct sp_node, nd);
2367}
2368
2369/*
2370 * Insert a new shared policy into the list. Caller holds sp->lock for
2371 * writing.
2372 */
2373static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2374{
2375 struct rb_node **p = &sp->root.rb_node;
2376 struct rb_node *parent = NULL;
2377 struct sp_node *nd;
2378
2379 while (*p) {
2380 parent = *p;
2381 nd = rb_entry(parent, struct sp_node, nd);
2382 if (new->start < nd->start)
2383 p = &(*p)->rb_left;
2384 else if (new->end > nd->end)
2385 p = &(*p)->rb_right;
2386 else
2387 BUG();
2388 }
2389 rb_link_node(&new->nd, parent, p);
2390 rb_insert_color(&new->nd, &sp->root);
2391 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2392 new->policy ? new->policy->mode : 0);
2393}
2394
2395/* Find shared policy intersecting idx */
2396struct mempolicy *
2397mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2398{
2399 struct mempolicy *pol = NULL;
2400 struct sp_node *sn;
2401
2402 if (!sp->root.rb_node)
2403 return NULL;
2404 read_lock(&sp->lock);
2405 sn = sp_lookup(sp, idx, idx+1);
2406 if (sn) {
2407 mpol_get(sn->policy);
2408 pol = sn->policy;
2409 }
2410 read_unlock(&sp->lock);
2411 return pol;
2412}
2413
2414static void sp_free(struct sp_node *n)
2415{
2416 mpol_put(n->policy);
2417 kmem_cache_free(sn_cache, n);
2418}
2419
2420/**
2421 * mpol_misplaced - check whether current page node is valid in policy
2422 *
2423 * @page: page to be checked
2424 * @vma: vm area where page mapped
2425 * @addr: virtual address where page mapped
2426 *
2427 * Lookup current policy node id for vma,addr and "compare to" page's
2428 * node id. Policy determination "mimics" alloc_page_vma().
2429 * Called from fault path where we know the vma and faulting address.
2430 *
2431 * Return: -1 if the page is in a node that is valid for this policy, or a
2432 * suitable node ID to allocate a replacement page from.
2433 */
2434int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
2435{
2436 struct mempolicy *pol;
2437 struct zoneref *z;
2438 int curnid = page_to_nid(page);
2439 unsigned long pgoff;
2440 int thiscpu = raw_smp_processor_id();
2441 int thisnid = cpu_to_node(thiscpu);
2442 int polnid = NUMA_NO_NODE;
2443 int ret = -1;
2444
2445 pol = get_vma_policy(vma, addr);
2446 if (!(pol->flags & MPOL_F_MOF))
2447 goto out;
2448
2449 switch (pol->mode) {
2450 case MPOL_INTERLEAVE:
2451 pgoff = vma->vm_pgoff;
2452 pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
2453 polnid = offset_il_node(pol, pgoff);
2454 break;
2455
2456 case MPOL_PREFERRED:
2457 polnid = first_node(pol->nodes);
2458 break;
2459
2460 case MPOL_LOCAL:
2461 polnid = numa_node_id();
2462 break;
2463
2464 case MPOL_BIND:
2465 /* Optimize placement among multiple nodes via NUMA balancing */
2466 if (pol->flags & MPOL_F_MORON) {
2467 if (node_isset(thisnid, pol->nodes))
2468 break;
2469 goto out;
2470 }
2471
2472 /*
2473 * allows binding to multiple nodes.
2474 * use current page if in policy nodemask,
2475 * else select nearest allowed node, if any.
2476 * If no allowed nodes, use current [!misplaced].
2477 */
2478 if (node_isset(curnid, pol->nodes))
2479 goto out;
2480 z = first_zones_zonelist(
2481 node_zonelist(numa_node_id(), GFP_HIGHUSER),
2482 gfp_zone(GFP_HIGHUSER),
2483 &pol->nodes);
2484 polnid = zone_to_nid(z->zone);
2485 break;
2486
2487 default:
2488 BUG();
2489 }
2490
2491 /* Migrate the page towards the node whose CPU is referencing it */
2492 if (pol->flags & MPOL_F_MORON) {
2493 polnid = thisnid;
2494
2495 if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
2496 goto out;
2497 }
2498
2499 if (curnid != polnid)
2500 ret = polnid;
2501out:
2502 mpol_cond_put(pol);
2503
2504 return ret;
2505}
2506
2507/*
2508 * Drop the (possibly final) reference to task->mempolicy. It needs to be
2509 * dropped after task->mempolicy is set to NULL so that any allocation done as
2510 * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed
2511 * policy.
2512 */
2513void mpol_put_task_policy(struct task_struct *task)
2514{
2515 struct mempolicy *pol;
2516
2517 task_lock(task);
2518 pol = task->mempolicy;
2519 task->mempolicy = NULL;
2520 task_unlock(task);
2521 mpol_put(pol);
2522}
2523
2524static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2525{
2526 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2527 rb_erase(&n->nd, &sp->root);
2528 sp_free(n);
2529}
2530
2531static void sp_node_init(struct sp_node *node, unsigned long start,
2532 unsigned long end, struct mempolicy *pol)
2533{
2534 node->start = start;
2535 node->end = end;
2536 node->policy = pol;
2537}
2538
2539static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2540 struct mempolicy *pol)
2541{
2542 struct sp_node *n;
2543 struct mempolicy *newpol;
2544
2545 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2546 if (!n)
2547 return NULL;
2548
2549 newpol = mpol_dup(pol);
2550 if (IS_ERR(newpol)) {
2551 kmem_cache_free(sn_cache, n);
2552 return NULL;
2553 }
2554 newpol->flags |= MPOL_F_SHARED;
2555 sp_node_init(n, start, end, newpol);
2556
2557 return n;
2558}
2559
2560/* Replace a policy range. */
2561static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2562 unsigned long end, struct sp_node *new)
2563{
2564 struct sp_node *n;
2565 struct sp_node *n_new = NULL;
2566 struct mempolicy *mpol_new = NULL;
2567 int ret = 0;
2568
2569restart:
2570 write_lock(&sp->lock);
2571 n = sp_lookup(sp, start, end);
2572 /* Take care of old policies in the same range. */
2573 while (n && n->start < end) {
2574 struct rb_node *next = rb_next(&n->nd);
2575 if (n->start >= start) {
2576 if (n->end <= end)
2577 sp_delete(sp, n);
2578 else
2579 n->start = end;
2580 } else {
2581 /* Old policy spanning whole new range. */
2582 if (n->end > end) {
2583 if (!n_new)
2584 goto alloc_new;
2585
2586 *mpol_new = *n->policy;
2587 atomic_set(&mpol_new->refcnt, 1);
2588 sp_node_init(n_new, end, n->end, mpol_new);
2589 n->end = start;
2590 sp_insert(sp, n_new);
2591 n_new = NULL;
2592 mpol_new = NULL;
2593 break;
2594 } else
2595 n->end = start;
2596 }
2597 if (!next)
2598 break;
2599 n = rb_entry(next, struct sp_node, nd);
2600 }
2601 if (new)
2602 sp_insert(sp, new);
2603 write_unlock(&sp->lock);
2604 ret = 0;
2605
2606err_out:
2607 if (mpol_new)
2608 mpol_put(mpol_new);
2609 if (n_new)
2610 kmem_cache_free(sn_cache, n_new);
2611
2612 return ret;
2613
2614alloc_new:
2615 write_unlock(&sp->lock);
2616 ret = -ENOMEM;
2617 n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2618 if (!n_new)
2619 goto err_out;
2620 mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2621 if (!mpol_new)
2622 goto err_out;
2623 goto restart;
2624}
2625
2626/**
2627 * mpol_shared_policy_init - initialize shared policy for inode
2628 * @sp: pointer to inode shared policy
2629 * @mpol: struct mempolicy to install
2630 *
2631 * Install non-NULL @mpol in inode's shared policy rb-tree.
2632 * On entry, the current task has a reference on a non-NULL @mpol.
2633 * This must be released on exit.
2634 * This is called at get_inode() calls and we can use GFP_KERNEL.
2635 */
2636void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2637{
2638 int ret;
2639
2640 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2641 rwlock_init(&sp->lock);
2642
2643 if (mpol) {
2644 struct vm_area_struct pvma;
2645 struct mempolicy *new;
2646 NODEMASK_SCRATCH(scratch);
2647
2648 if (!scratch)
2649 goto put_mpol;
2650 /* contextualize the tmpfs mount point mempolicy */
2651 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2652 if (IS_ERR(new))
2653 goto free_scratch; /* no valid nodemask intersection */
2654
2655 task_lock(current);
2656 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2657 task_unlock(current);
2658 if (ret)
2659 goto put_new;
2660
2661 /* Create pseudo-vma that contains just the policy */
2662 vma_init(&pvma, NULL);
2663 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2664 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2665
2666put_new:
2667 mpol_put(new); /* drop initial ref */
2668free_scratch:
2669 NODEMASK_SCRATCH_FREE(scratch);
2670put_mpol:
2671 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2672 }
2673}
2674
2675int mpol_set_shared_policy(struct shared_policy *info,
2676 struct vm_area_struct *vma, struct mempolicy *npol)
2677{
2678 int err;
2679 struct sp_node *new = NULL;
2680 unsigned long sz = vma_pages(vma);
2681
2682 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2683 vma->vm_pgoff,
2684 sz, npol ? npol->mode : -1,
2685 npol ? npol->flags : -1,
2686 npol ? nodes_addr(npol->nodes)[0] : NUMA_NO_NODE);
2687
2688 if (npol) {
2689 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2690 if (!new)
2691 return -ENOMEM;
2692 }
2693 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2694 if (err && new)
2695 sp_free(new);
2696 return err;
2697}
2698
2699/* Free a backing policy store on inode delete. */
2700void mpol_free_shared_policy(struct shared_policy *p)
2701{
2702 struct sp_node *n;
2703 struct rb_node *next;
2704
2705 if (!p->root.rb_node)
2706 return;
2707 write_lock(&p->lock);
2708 next = rb_first(&p->root);
2709 while (next) {
2710 n = rb_entry(next, struct sp_node, nd);
2711 next = rb_next(&n->nd);
2712 sp_delete(p, n);
2713 }
2714 write_unlock(&p->lock);
2715}
2716
2717#ifdef CONFIG_NUMA_BALANCING
2718static int __initdata numabalancing_override;
2719
2720static void __init check_numabalancing_enable(void)
2721{
2722 bool numabalancing_default = false;
2723
2724 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2725 numabalancing_default = true;
2726
2727 /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
2728 if (numabalancing_override)
2729 set_numabalancing_state(numabalancing_override == 1);
2730
2731 if (num_online_nodes() > 1 && !numabalancing_override) {
2732 pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n",
2733 numabalancing_default ? "Enabling" : "Disabling");
2734 set_numabalancing_state(numabalancing_default);
2735 }
2736}
2737
2738static int __init setup_numabalancing(char *str)
2739{
2740 int ret = 0;
2741 if (!str)
2742 goto out;
2743
2744 if (!strcmp(str, "enable")) {
2745 numabalancing_override = 1;
2746 ret = 1;
2747 } else if (!strcmp(str, "disable")) {
2748 numabalancing_override = -1;
2749 ret = 1;
2750 }
2751out:
2752 if (!ret)
2753 pr_warn("Unable to parse numa_balancing=\n");
2754
2755 return ret;
2756}
2757__setup("numa_balancing=", setup_numabalancing);
2758#else
2759static inline void __init check_numabalancing_enable(void)
2760{
2761}
2762#endif /* CONFIG_NUMA_BALANCING */
2763
2764/* assumes fs == KERNEL_DS */
2765void __init numa_policy_init(void)
2766{
2767 nodemask_t interleave_nodes;
2768 unsigned long largest = 0;
2769 int nid, prefer = 0;
2770
2771 policy_cache = kmem_cache_create("numa_policy",
2772 sizeof(struct mempolicy),
2773 0, SLAB_PANIC, NULL);
2774
2775 sn_cache = kmem_cache_create("shared_policy_node",
2776 sizeof(struct sp_node),
2777 0, SLAB_PANIC, NULL);
2778
2779 for_each_node(nid) {
2780 preferred_node_policy[nid] = (struct mempolicy) {
2781 .refcnt = ATOMIC_INIT(1),
2782 .mode = MPOL_PREFERRED,
2783 .flags = MPOL_F_MOF | MPOL_F_MORON,
2784 .nodes = nodemask_of_node(nid),
2785 };
2786 }
2787
2788 /*
2789 * Set interleaving policy for system init. Interleaving is only
2790 * enabled across suitably sized nodes (default is >= 16MB), or
2791 * fall back to the largest node if they're all smaller.
2792 */
2793 nodes_clear(interleave_nodes);
2794 for_each_node_state(nid, N_MEMORY) {
2795 unsigned long total_pages = node_present_pages(nid);
2796
2797 /* Preserve the largest node */
2798 if (largest < total_pages) {
2799 largest = total_pages;
2800 prefer = nid;
2801 }
2802
2803 /* Interleave this node? */
2804 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2805 node_set(nid, interleave_nodes);
2806 }
2807
2808 /* All too small, use the largest */
2809 if (unlikely(nodes_empty(interleave_nodes)))
2810 node_set(prefer, interleave_nodes);
2811
2812 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2813 pr_err("%s: interleaving failed\n", __func__);
2814
2815 check_numabalancing_enable();
2816}
2817
2818/* Reset policy of current process to default */
2819void numa_default_policy(void)
2820{
2821 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2822}
2823
2824/*
2825 * Parse and format mempolicy from/to strings
2826 */
2827
2828static const char * const policy_modes[] =
2829{
2830 [MPOL_DEFAULT] = "default",
2831 [MPOL_PREFERRED] = "prefer",
2832 [MPOL_BIND] = "bind",
2833 [MPOL_INTERLEAVE] = "interleave",
2834 [MPOL_LOCAL] = "local",
2835};
2836
2837
2838#ifdef CONFIG_TMPFS
2839/**
2840 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2841 * @str: string containing mempolicy to parse
2842 * @mpol: pointer to struct mempolicy pointer, returned on success.
2843 *
2844 * Format of input:
2845 * <mode>[=<flags>][:<nodelist>]
2846 *
2847 * On success, returns 0, else 1
2848 */
2849int mpol_parse_str(char *str, struct mempolicy **mpol)
2850{
2851 struct mempolicy *new = NULL;
2852 unsigned short mode_flags;
2853 nodemask_t nodes;
2854 char *nodelist = strchr(str, ':');
2855 char *flags = strchr(str, '=');
2856 int err = 1, mode;
2857
2858 if (flags)
2859 *flags++ = '\0'; /* terminate mode string */
2860
2861 if (nodelist) {
2862 /* NUL-terminate mode or flags string */
2863 *nodelist++ = '\0';
2864 if (nodelist_parse(nodelist, nodes))
2865 goto out;
2866 if (!nodes_subset(nodes, node_states[N_MEMORY]))
2867 goto out;
2868 } else
2869 nodes_clear(nodes);
2870
2871 mode = match_string(policy_modes, MPOL_MAX, str);
2872 if (mode < 0)
2873 goto out;
2874
2875 switch (mode) {
2876 case MPOL_PREFERRED:
2877 /*
2878 * Insist on a nodelist of one node only, although later
2879 * we use first_node(nodes) to grab a single node, so here
2880 * nodelist (or nodes) cannot be empty.
2881 */
2882 if (nodelist) {
2883 char *rest = nodelist;
2884 while (isdigit(*rest))
2885 rest++;
2886 if (*rest)
2887 goto out;
2888 if (nodes_empty(nodes))
2889 goto out;
2890 }
2891 break;
2892 case MPOL_INTERLEAVE:
2893 /*
2894 * Default to online nodes with memory if no nodelist
2895 */
2896 if (!nodelist)
2897 nodes = node_states[N_MEMORY];
2898 break;
2899 case MPOL_LOCAL:
2900 /*
2901 * Don't allow a nodelist; mpol_new() checks flags
2902 */
2903 if (nodelist)
2904 goto out;
2905 break;
2906 case MPOL_DEFAULT:
2907 /*
2908 * Insist on a empty nodelist
2909 */
2910 if (!nodelist)
2911 err = 0;
2912 goto out;
2913 case MPOL_BIND:
2914 /*
2915 * Insist on a nodelist
2916 */
2917 if (!nodelist)
2918 goto out;
2919 }
2920
2921 mode_flags = 0;
2922 if (flags) {
2923 /*
2924 * Currently, we only support two mutually exclusive
2925 * mode flags.
2926 */
2927 if (!strcmp(flags, "static"))
2928 mode_flags |= MPOL_F_STATIC_NODES;
2929 else if (!strcmp(flags, "relative"))
2930 mode_flags |= MPOL_F_RELATIVE_NODES;
2931 else
2932 goto out;
2933 }
2934
2935 new = mpol_new(mode, mode_flags, &nodes);
2936 if (IS_ERR(new))
2937 goto out;
2938
2939 /*
2940 * Save nodes for mpol_to_str() to show the tmpfs mount options
2941 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
2942 */
2943 if (mode != MPOL_PREFERRED) {
2944 new->nodes = nodes;
2945 } else if (nodelist) {
2946 nodes_clear(new->nodes);
2947 node_set(first_node(nodes), new->nodes);
2948 } else {
2949 new->mode = MPOL_LOCAL;
2950 }
2951
2952 /*
2953 * Save nodes for contextualization: this will be used to "clone"
2954 * the mempolicy in a specific context [cpuset] at a later time.
2955 */
2956 new->w.user_nodemask = nodes;
2957
2958 err = 0;
2959
2960out:
2961 /* Restore string for error message */
2962 if (nodelist)
2963 *--nodelist = ':';
2964 if (flags)
2965 *--flags = '=';
2966 if (!err)
2967 *mpol = new;
2968 return err;
2969}
2970#endif /* CONFIG_TMPFS */
2971
2972/**
2973 * mpol_to_str - format a mempolicy structure for printing
2974 * @buffer: to contain formatted mempolicy string
2975 * @maxlen: length of @buffer
2976 * @pol: pointer to mempolicy to be formatted
2977 *
2978 * Convert @pol into a string. If @buffer is too short, truncate the string.
2979 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
2980 * longest flag, "relative", and to display at least a few node ids.
2981 */
2982void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
2983{
2984 char *p = buffer;
2985 nodemask_t nodes = NODE_MASK_NONE;
2986 unsigned short mode = MPOL_DEFAULT;
2987 unsigned short flags = 0;
2988
2989 if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
2990 mode = pol->mode;
2991 flags = pol->flags;
2992 }
2993
2994 switch (mode) {
2995 case MPOL_DEFAULT:
2996 case MPOL_LOCAL:
2997 break;
2998 case MPOL_PREFERRED:
2999 case MPOL_BIND:
3000 case MPOL_INTERLEAVE:
3001 nodes = pol->nodes;
3002 break;
3003 default:
3004 WARN_ON_ONCE(1);
3005 snprintf(p, maxlen, "unknown");
3006 return;
3007 }
3008
3009 p += snprintf(p, maxlen, "%s", policy_modes[mode]);
3010
3011 if (flags & MPOL_MODE_FLAGS) {
3012 p += snprintf(p, buffer + maxlen - p, "=");
3013
3014 /*
3015 * Currently, the only defined flags are mutually exclusive
3016 */
3017 if (flags & MPOL_F_STATIC_NODES)
3018 p += snprintf(p, buffer + maxlen - p, "static");
3019 else if (flags & MPOL_F_RELATIVE_NODES)
3020 p += snprintf(p, buffer + maxlen - p, "relative");
3021 }
3022
3023 if (!nodes_empty(nodes))
3024 p += scnprintf(p, buffer + maxlen - p, ":%*pbl",
3025 nodemask_pr_args(&nodes));
3026}
1/*
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 node -1 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#include <linux/mempolicy.h>
69#include <linux/mm.h>
70#include <linux/highmem.h>
71#include <linux/hugetlb.h>
72#include <linux/kernel.h>
73#include <linux/sched.h>
74#include <linux/nodemask.h>
75#include <linux/cpuset.h>
76#include <linux/slab.h>
77#include <linux/string.h>
78#include <linux/export.h>
79#include <linux/nsproxy.h>
80#include <linux/interrupt.h>
81#include <linux/init.h>
82#include <linux/compat.h>
83#include <linux/swap.h>
84#include <linux/seq_file.h>
85#include <linux/proc_fs.h>
86#include <linux/migrate.h>
87#include <linux/ksm.h>
88#include <linux/rmap.h>
89#include <linux/security.h>
90#include <linux/syscalls.h>
91#include <linux/ctype.h>
92#include <linux/mm_inline.h>
93
94#include <asm/tlbflush.h>
95#include <asm/uaccess.h>
96#include <linux/random.h>
97
98#include "internal.h"
99
100/* Internal flags */
101#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
102#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
103
104static struct kmem_cache *policy_cache;
105static struct kmem_cache *sn_cache;
106
107/* Highest zone. An specific allocation for a zone below that is not
108 policied. */
109enum zone_type policy_zone = 0;
110
111/*
112 * run-time system-wide default policy => local allocation
113 */
114static struct mempolicy default_policy = {
115 .refcnt = ATOMIC_INIT(1), /* never free it */
116 .mode = MPOL_PREFERRED,
117 .flags = MPOL_F_LOCAL,
118};
119
120static const struct mempolicy_operations {
121 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
122 /*
123 * If read-side task has no lock to protect task->mempolicy, write-side
124 * task will rebind the task->mempolicy by two step. The first step is
125 * setting all the newly nodes, and the second step is cleaning all the
126 * disallowed nodes. In this way, we can avoid finding no node to alloc
127 * page.
128 * If we have a lock to protect task->mempolicy in read-side, we do
129 * rebind directly.
130 *
131 * step:
132 * MPOL_REBIND_ONCE - do rebind work at once
133 * MPOL_REBIND_STEP1 - set all the newly nodes
134 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
135 */
136 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes,
137 enum mpol_rebind_step step);
138} mpol_ops[MPOL_MAX];
139
140/* Check that the nodemask contains at least one populated zone */
141static int is_valid_nodemask(const nodemask_t *nodemask)
142{
143 int nd, k;
144
145 for_each_node_mask(nd, *nodemask) {
146 struct zone *z;
147
148 for (k = 0; k <= policy_zone; k++) {
149 z = &NODE_DATA(nd)->node_zones[k];
150 if (z->present_pages > 0)
151 return 1;
152 }
153 }
154
155 return 0;
156}
157
158static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
159{
160 return pol->flags & MPOL_MODE_FLAGS;
161}
162
163static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
164 const nodemask_t *rel)
165{
166 nodemask_t tmp;
167 nodes_fold(tmp, *orig, nodes_weight(*rel));
168 nodes_onto(*ret, tmp, *rel);
169}
170
171static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
172{
173 if (nodes_empty(*nodes))
174 return -EINVAL;
175 pol->v.nodes = *nodes;
176 return 0;
177}
178
179static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
180{
181 if (!nodes)
182 pol->flags |= MPOL_F_LOCAL; /* local allocation */
183 else if (nodes_empty(*nodes))
184 return -EINVAL; /* no allowed nodes */
185 else
186 pol->v.preferred_node = first_node(*nodes);
187 return 0;
188}
189
190static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
191{
192 if (!is_valid_nodemask(nodes))
193 return -EINVAL;
194 pol->v.nodes = *nodes;
195 return 0;
196}
197
198/*
199 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
200 * any, for the new policy. mpol_new() has already validated the nodes
201 * parameter with respect to the policy mode and flags. But, we need to
202 * handle an empty nodemask with MPOL_PREFERRED here.
203 *
204 * Must be called holding task's alloc_lock to protect task's mems_allowed
205 * and mempolicy. May also be called holding the mmap_semaphore for write.
206 */
207static int mpol_set_nodemask(struct mempolicy *pol,
208 const nodemask_t *nodes, struct nodemask_scratch *nsc)
209{
210 int ret;
211
212 /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
213 if (pol == NULL)
214 return 0;
215 /* Check N_HIGH_MEMORY */
216 nodes_and(nsc->mask1,
217 cpuset_current_mems_allowed, node_states[N_HIGH_MEMORY]);
218
219 VM_BUG_ON(!nodes);
220 if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
221 nodes = NULL; /* explicit local allocation */
222 else {
223 if (pol->flags & MPOL_F_RELATIVE_NODES)
224 mpol_relative_nodemask(&nsc->mask2, nodes,&nsc->mask1);
225 else
226 nodes_and(nsc->mask2, *nodes, nsc->mask1);
227
228 if (mpol_store_user_nodemask(pol))
229 pol->w.user_nodemask = *nodes;
230 else
231 pol->w.cpuset_mems_allowed =
232 cpuset_current_mems_allowed;
233 }
234
235 if (nodes)
236 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
237 else
238 ret = mpol_ops[pol->mode].create(pol, NULL);
239 return ret;
240}
241
242/*
243 * This function just creates a new policy, does some check and simple
244 * initialization. You must invoke mpol_set_nodemask() to set nodes.
245 */
246static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
247 nodemask_t *nodes)
248{
249 struct mempolicy *policy;
250
251 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
252 mode, flags, nodes ? nodes_addr(*nodes)[0] : -1);
253
254 if (mode == MPOL_DEFAULT) {
255 if (nodes && !nodes_empty(*nodes))
256 return ERR_PTR(-EINVAL);
257 return NULL; /* simply delete any existing policy */
258 }
259 VM_BUG_ON(!nodes);
260
261 /*
262 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
263 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
264 * All other modes require a valid pointer to a non-empty nodemask.
265 */
266 if (mode == MPOL_PREFERRED) {
267 if (nodes_empty(*nodes)) {
268 if (((flags & MPOL_F_STATIC_NODES) ||
269 (flags & MPOL_F_RELATIVE_NODES)))
270 return ERR_PTR(-EINVAL);
271 }
272 } else if (nodes_empty(*nodes))
273 return ERR_PTR(-EINVAL);
274 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
275 if (!policy)
276 return ERR_PTR(-ENOMEM);
277 atomic_set(&policy->refcnt, 1);
278 policy->mode = mode;
279 policy->flags = flags;
280
281 return policy;
282}
283
284/* Slow path of a mpol destructor. */
285void __mpol_put(struct mempolicy *p)
286{
287 if (!atomic_dec_and_test(&p->refcnt))
288 return;
289 kmem_cache_free(policy_cache, p);
290}
291
292static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes,
293 enum mpol_rebind_step step)
294{
295}
296
297/*
298 * step:
299 * MPOL_REBIND_ONCE - do rebind work at once
300 * MPOL_REBIND_STEP1 - set all the newly nodes
301 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
302 */
303static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes,
304 enum mpol_rebind_step step)
305{
306 nodemask_t tmp;
307
308 if (pol->flags & MPOL_F_STATIC_NODES)
309 nodes_and(tmp, pol->w.user_nodemask, *nodes);
310 else if (pol->flags & MPOL_F_RELATIVE_NODES)
311 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
312 else {
313 /*
314 * if step == 1, we use ->w.cpuset_mems_allowed to cache the
315 * result
316 */
317 if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP1) {
318 nodes_remap(tmp, pol->v.nodes,
319 pol->w.cpuset_mems_allowed, *nodes);
320 pol->w.cpuset_mems_allowed = step ? tmp : *nodes;
321 } else if (step == MPOL_REBIND_STEP2) {
322 tmp = pol->w.cpuset_mems_allowed;
323 pol->w.cpuset_mems_allowed = *nodes;
324 } else
325 BUG();
326 }
327
328 if (nodes_empty(tmp))
329 tmp = *nodes;
330
331 if (step == MPOL_REBIND_STEP1)
332 nodes_or(pol->v.nodes, pol->v.nodes, tmp);
333 else if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP2)
334 pol->v.nodes = tmp;
335 else
336 BUG();
337
338 if (!node_isset(current->il_next, tmp)) {
339 current->il_next = next_node(current->il_next, tmp);
340 if (current->il_next >= MAX_NUMNODES)
341 current->il_next = first_node(tmp);
342 if (current->il_next >= MAX_NUMNODES)
343 current->il_next = numa_node_id();
344 }
345}
346
347static void mpol_rebind_preferred(struct mempolicy *pol,
348 const nodemask_t *nodes,
349 enum mpol_rebind_step step)
350{
351 nodemask_t tmp;
352
353 if (pol->flags & MPOL_F_STATIC_NODES) {
354 int node = first_node(pol->w.user_nodemask);
355
356 if (node_isset(node, *nodes)) {
357 pol->v.preferred_node = node;
358 pol->flags &= ~MPOL_F_LOCAL;
359 } else
360 pol->flags |= MPOL_F_LOCAL;
361 } else if (pol->flags & MPOL_F_RELATIVE_NODES) {
362 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
363 pol->v.preferred_node = first_node(tmp);
364 } else if (!(pol->flags & MPOL_F_LOCAL)) {
365 pol->v.preferred_node = node_remap(pol->v.preferred_node,
366 pol->w.cpuset_mems_allowed,
367 *nodes);
368 pol->w.cpuset_mems_allowed = *nodes;
369 }
370}
371
372/*
373 * mpol_rebind_policy - Migrate a policy to a different set of nodes
374 *
375 * If read-side task has no lock to protect task->mempolicy, write-side
376 * task will rebind the task->mempolicy by two step. The first step is
377 * setting all the newly nodes, and the second step is cleaning all the
378 * disallowed nodes. In this way, we can avoid finding no node to alloc
379 * page.
380 * If we have a lock to protect task->mempolicy in read-side, we do
381 * rebind directly.
382 *
383 * step:
384 * MPOL_REBIND_ONCE - do rebind work at once
385 * MPOL_REBIND_STEP1 - set all the newly nodes
386 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
387 */
388static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask,
389 enum mpol_rebind_step step)
390{
391 if (!pol)
392 return;
393 if (!mpol_store_user_nodemask(pol) && step == MPOL_REBIND_ONCE &&
394 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
395 return;
396
397 if (step == MPOL_REBIND_STEP1 && (pol->flags & MPOL_F_REBINDING))
398 return;
399
400 if (step == MPOL_REBIND_STEP2 && !(pol->flags & MPOL_F_REBINDING))
401 BUG();
402
403 if (step == MPOL_REBIND_STEP1)
404 pol->flags |= MPOL_F_REBINDING;
405 else if (step == MPOL_REBIND_STEP2)
406 pol->flags &= ~MPOL_F_REBINDING;
407 else if (step >= MPOL_REBIND_NSTEP)
408 BUG();
409
410 mpol_ops[pol->mode].rebind(pol, newmask, step);
411}
412
413/*
414 * Wrapper for mpol_rebind_policy() that just requires task
415 * pointer, and updates task mempolicy.
416 *
417 * Called with task's alloc_lock held.
418 */
419
420void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new,
421 enum mpol_rebind_step step)
422{
423 mpol_rebind_policy(tsk->mempolicy, new, step);
424}
425
426/*
427 * Rebind each vma in mm to new nodemask.
428 *
429 * Call holding a reference to mm. Takes mm->mmap_sem during call.
430 */
431
432void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
433{
434 struct vm_area_struct *vma;
435
436 down_write(&mm->mmap_sem);
437 for (vma = mm->mmap; vma; vma = vma->vm_next)
438 mpol_rebind_policy(vma->vm_policy, new, MPOL_REBIND_ONCE);
439 up_write(&mm->mmap_sem);
440}
441
442static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
443 [MPOL_DEFAULT] = {
444 .rebind = mpol_rebind_default,
445 },
446 [MPOL_INTERLEAVE] = {
447 .create = mpol_new_interleave,
448 .rebind = mpol_rebind_nodemask,
449 },
450 [MPOL_PREFERRED] = {
451 .create = mpol_new_preferred,
452 .rebind = mpol_rebind_preferred,
453 },
454 [MPOL_BIND] = {
455 .create = mpol_new_bind,
456 .rebind = mpol_rebind_nodemask,
457 },
458};
459
460static void migrate_page_add(struct page *page, struct list_head *pagelist,
461 unsigned long flags);
462
463/* Scan through pages checking if pages follow certain conditions. */
464static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
465 unsigned long addr, unsigned long end,
466 const nodemask_t *nodes, unsigned long flags,
467 void *private)
468{
469 pte_t *orig_pte;
470 pte_t *pte;
471 spinlock_t *ptl;
472
473 orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
474 do {
475 struct page *page;
476 int nid;
477
478 if (!pte_present(*pte))
479 continue;
480 page = vm_normal_page(vma, addr, *pte);
481 if (!page)
482 continue;
483 /*
484 * vm_normal_page() filters out zero pages, but there might
485 * still be PageReserved pages to skip, perhaps in a VDSO.
486 * And we cannot move PageKsm pages sensibly or safely yet.
487 */
488 if (PageReserved(page) || PageKsm(page))
489 continue;
490 nid = page_to_nid(page);
491 if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
492 continue;
493
494 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
495 migrate_page_add(page, private, flags);
496 else
497 break;
498 } while (pte++, addr += PAGE_SIZE, addr != end);
499 pte_unmap_unlock(orig_pte, ptl);
500 return addr != end;
501}
502
503static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
504 unsigned long addr, unsigned long end,
505 const nodemask_t *nodes, unsigned long flags,
506 void *private)
507{
508 pmd_t *pmd;
509 unsigned long next;
510
511 pmd = pmd_offset(pud, addr);
512 do {
513 next = pmd_addr_end(addr, end);
514 split_huge_page_pmd(vma->vm_mm, pmd);
515 if (pmd_none_or_trans_huge_or_clear_bad(pmd))
516 continue;
517 if (check_pte_range(vma, pmd, addr, next, nodes,
518 flags, private))
519 return -EIO;
520 } while (pmd++, addr = next, addr != end);
521 return 0;
522}
523
524static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
525 unsigned long addr, unsigned long end,
526 const nodemask_t *nodes, unsigned long flags,
527 void *private)
528{
529 pud_t *pud;
530 unsigned long next;
531
532 pud = pud_offset(pgd, addr);
533 do {
534 next = pud_addr_end(addr, end);
535 if (pud_none_or_clear_bad(pud))
536 continue;
537 if (check_pmd_range(vma, pud, addr, next, nodes,
538 flags, private))
539 return -EIO;
540 } while (pud++, addr = next, addr != end);
541 return 0;
542}
543
544static inline int check_pgd_range(struct vm_area_struct *vma,
545 unsigned long addr, unsigned long end,
546 const nodemask_t *nodes, unsigned long flags,
547 void *private)
548{
549 pgd_t *pgd;
550 unsigned long next;
551
552 pgd = pgd_offset(vma->vm_mm, addr);
553 do {
554 next = pgd_addr_end(addr, end);
555 if (pgd_none_or_clear_bad(pgd))
556 continue;
557 if (check_pud_range(vma, pgd, addr, next, nodes,
558 flags, private))
559 return -EIO;
560 } while (pgd++, addr = next, addr != end);
561 return 0;
562}
563
564/*
565 * Check if all pages in a range are on a set of nodes.
566 * If pagelist != NULL then isolate pages from the LRU and
567 * put them on the pagelist.
568 */
569static struct vm_area_struct *
570check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
571 const nodemask_t *nodes, unsigned long flags, void *private)
572{
573 int err;
574 struct vm_area_struct *first, *vma, *prev;
575
576
577 first = find_vma(mm, start);
578 if (!first)
579 return ERR_PTR(-EFAULT);
580 prev = NULL;
581 for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
582 if (!(flags & MPOL_MF_DISCONTIG_OK)) {
583 if (!vma->vm_next && vma->vm_end < end)
584 return ERR_PTR(-EFAULT);
585 if (prev && prev->vm_end < vma->vm_start)
586 return ERR_PTR(-EFAULT);
587 }
588 if (!is_vm_hugetlb_page(vma) &&
589 ((flags & MPOL_MF_STRICT) ||
590 ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
591 vma_migratable(vma)))) {
592 unsigned long endvma = vma->vm_end;
593
594 if (endvma > end)
595 endvma = end;
596 if (vma->vm_start > start)
597 start = vma->vm_start;
598 err = check_pgd_range(vma, start, endvma, nodes,
599 flags, private);
600 if (err) {
601 first = ERR_PTR(err);
602 break;
603 }
604 }
605 prev = vma;
606 }
607 return first;
608}
609
610/* Step 2: apply policy to a range and do splits. */
611static int mbind_range(struct mm_struct *mm, unsigned long start,
612 unsigned long end, struct mempolicy *new_pol)
613{
614 struct vm_area_struct *next;
615 struct vm_area_struct *prev;
616 struct vm_area_struct *vma;
617 int err = 0;
618 pgoff_t pgoff;
619 unsigned long vmstart;
620 unsigned long vmend;
621
622 vma = find_vma(mm, start);
623 if (!vma || vma->vm_start > start)
624 return -EFAULT;
625
626 prev = vma->vm_prev;
627 if (start > vma->vm_start)
628 prev = vma;
629
630 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
631 next = vma->vm_next;
632 vmstart = max(start, vma->vm_start);
633 vmend = min(end, vma->vm_end);
634
635 if (mpol_equal(vma_policy(vma), new_pol))
636 continue;
637
638 pgoff = vma->vm_pgoff +
639 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
640 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
641 vma->anon_vma, vma->vm_file, pgoff,
642 new_pol);
643 if (prev) {
644 vma = prev;
645 next = vma->vm_next;
646 continue;
647 }
648 if (vma->vm_start != vmstart) {
649 err = split_vma(vma->vm_mm, vma, vmstart, 1);
650 if (err)
651 goto out;
652 }
653 if (vma->vm_end != vmend) {
654 err = split_vma(vma->vm_mm, vma, vmend, 0);
655 if (err)
656 goto out;
657 }
658
659 /*
660 * Apply policy to a single VMA. The reference counting of
661 * policy for vma_policy linkages has already been handled by
662 * vma_merge and split_vma as necessary. If this is a shared
663 * policy then ->set_policy will increment the reference count
664 * for an sp node.
665 */
666 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
667 vma->vm_start, vma->vm_end, vma->vm_pgoff,
668 vma->vm_ops, vma->vm_file,
669 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
670 if (vma->vm_ops && vma->vm_ops->set_policy) {
671 err = vma->vm_ops->set_policy(vma, new_pol);
672 if (err)
673 goto out;
674 }
675 }
676
677 out:
678 return err;
679}
680
681/*
682 * Update task->flags PF_MEMPOLICY bit: set iff non-default
683 * mempolicy. Allows more rapid checking of this (combined perhaps
684 * with other PF_* flag bits) on memory allocation hot code paths.
685 *
686 * If called from outside this file, the task 'p' should -only- be
687 * a newly forked child not yet visible on the task list, because
688 * manipulating the task flags of a visible task is not safe.
689 *
690 * The above limitation is why this routine has the funny name
691 * mpol_fix_fork_child_flag().
692 *
693 * It is also safe to call this with a task pointer of current,
694 * which the static wrapper mpol_set_task_struct_flag() does,
695 * for use within this file.
696 */
697
698void mpol_fix_fork_child_flag(struct task_struct *p)
699{
700 if (p->mempolicy)
701 p->flags |= PF_MEMPOLICY;
702 else
703 p->flags &= ~PF_MEMPOLICY;
704}
705
706static void mpol_set_task_struct_flag(void)
707{
708 mpol_fix_fork_child_flag(current);
709}
710
711/* Set the process memory policy */
712static long do_set_mempolicy(unsigned short mode, unsigned short flags,
713 nodemask_t *nodes)
714{
715 struct mempolicy *new, *old;
716 struct mm_struct *mm = current->mm;
717 NODEMASK_SCRATCH(scratch);
718 int ret;
719
720 if (!scratch)
721 return -ENOMEM;
722
723 new = mpol_new(mode, flags, nodes);
724 if (IS_ERR(new)) {
725 ret = PTR_ERR(new);
726 goto out;
727 }
728 /*
729 * prevent changing our mempolicy while show_numa_maps()
730 * is using it.
731 * Note: do_set_mempolicy() can be called at init time
732 * with no 'mm'.
733 */
734 if (mm)
735 down_write(&mm->mmap_sem);
736 task_lock(current);
737 ret = mpol_set_nodemask(new, nodes, scratch);
738 if (ret) {
739 task_unlock(current);
740 if (mm)
741 up_write(&mm->mmap_sem);
742 mpol_put(new);
743 goto out;
744 }
745 old = current->mempolicy;
746 current->mempolicy = new;
747 mpol_set_task_struct_flag();
748 if (new && new->mode == MPOL_INTERLEAVE &&
749 nodes_weight(new->v.nodes))
750 current->il_next = first_node(new->v.nodes);
751 task_unlock(current);
752 if (mm)
753 up_write(&mm->mmap_sem);
754
755 mpol_put(old);
756 ret = 0;
757out:
758 NODEMASK_SCRATCH_FREE(scratch);
759 return ret;
760}
761
762/*
763 * Return nodemask for policy for get_mempolicy() query
764 *
765 * Called with task's alloc_lock held
766 */
767static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
768{
769 nodes_clear(*nodes);
770 if (p == &default_policy)
771 return;
772
773 switch (p->mode) {
774 case MPOL_BIND:
775 /* Fall through */
776 case MPOL_INTERLEAVE:
777 *nodes = p->v.nodes;
778 break;
779 case MPOL_PREFERRED:
780 if (!(p->flags & MPOL_F_LOCAL))
781 node_set(p->v.preferred_node, *nodes);
782 /* else return empty node mask for local allocation */
783 break;
784 default:
785 BUG();
786 }
787}
788
789static int lookup_node(struct mm_struct *mm, unsigned long addr)
790{
791 struct page *p;
792 int err;
793
794 err = get_user_pages(current, mm, addr & PAGE_MASK, 1, 0, 0, &p, NULL);
795 if (err >= 0) {
796 err = page_to_nid(p);
797 put_page(p);
798 }
799 return err;
800}
801
802/* Retrieve NUMA policy */
803static long do_get_mempolicy(int *policy, nodemask_t *nmask,
804 unsigned long addr, unsigned long flags)
805{
806 int err;
807 struct mm_struct *mm = current->mm;
808 struct vm_area_struct *vma = NULL;
809 struct mempolicy *pol = current->mempolicy;
810
811 if (flags &
812 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
813 return -EINVAL;
814
815 if (flags & MPOL_F_MEMS_ALLOWED) {
816 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
817 return -EINVAL;
818 *policy = 0; /* just so it's initialized */
819 task_lock(current);
820 *nmask = cpuset_current_mems_allowed;
821 task_unlock(current);
822 return 0;
823 }
824
825 if (flags & MPOL_F_ADDR) {
826 /*
827 * Do NOT fall back to task policy if the
828 * vma/shared policy at addr is NULL. We
829 * want to return MPOL_DEFAULT in this case.
830 */
831 down_read(&mm->mmap_sem);
832 vma = find_vma_intersection(mm, addr, addr+1);
833 if (!vma) {
834 up_read(&mm->mmap_sem);
835 return -EFAULT;
836 }
837 if (vma->vm_ops && vma->vm_ops->get_policy)
838 pol = vma->vm_ops->get_policy(vma, addr);
839 else
840 pol = vma->vm_policy;
841 } else if (addr)
842 return -EINVAL;
843
844 if (!pol)
845 pol = &default_policy; /* indicates default behavior */
846
847 if (flags & MPOL_F_NODE) {
848 if (flags & MPOL_F_ADDR) {
849 err = lookup_node(mm, addr);
850 if (err < 0)
851 goto out;
852 *policy = err;
853 } else if (pol == current->mempolicy &&
854 pol->mode == MPOL_INTERLEAVE) {
855 *policy = current->il_next;
856 } else {
857 err = -EINVAL;
858 goto out;
859 }
860 } else {
861 *policy = pol == &default_policy ? MPOL_DEFAULT :
862 pol->mode;
863 /*
864 * Internal mempolicy flags must be masked off before exposing
865 * the policy to userspace.
866 */
867 *policy |= (pol->flags & MPOL_MODE_FLAGS);
868 }
869
870 if (vma) {
871 up_read(¤t->mm->mmap_sem);
872 vma = NULL;
873 }
874
875 err = 0;
876 if (nmask) {
877 if (mpol_store_user_nodemask(pol)) {
878 *nmask = pol->w.user_nodemask;
879 } else {
880 task_lock(current);
881 get_policy_nodemask(pol, nmask);
882 task_unlock(current);
883 }
884 }
885
886 out:
887 mpol_cond_put(pol);
888 if (vma)
889 up_read(¤t->mm->mmap_sem);
890 return err;
891}
892
893#ifdef CONFIG_MIGRATION
894/*
895 * page migration
896 */
897static void migrate_page_add(struct page *page, struct list_head *pagelist,
898 unsigned long flags)
899{
900 /*
901 * Avoid migrating a page that is shared with others.
902 */
903 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
904 if (!isolate_lru_page(page)) {
905 list_add_tail(&page->lru, pagelist);
906 inc_zone_page_state(page, NR_ISOLATED_ANON +
907 page_is_file_cache(page));
908 }
909 }
910}
911
912static struct page *new_node_page(struct page *page, unsigned long node, int **x)
913{
914 return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
915}
916
917/*
918 * Migrate pages from one node to a target node.
919 * Returns error or the number of pages not migrated.
920 */
921static int migrate_to_node(struct mm_struct *mm, int source, int dest,
922 int flags)
923{
924 nodemask_t nmask;
925 LIST_HEAD(pagelist);
926 int err = 0;
927 struct vm_area_struct *vma;
928
929 nodes_clear(nmask);
930 node_set(source, nmask);
931
932 vma = check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
933 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
934 if (IS_ERR(vma))
935 return PTR_ERR(vma);
936
937 if (!list_empty(&pagelist)) {
938 err = migrate_pages(&pagelist, new_node_page, dest,
939 false, MIGRATE_SYNC);
940 if (err)
941 putback_lru_pages(&pagelist);
942 }
943
944 return err;
945}
946
947/*
948 * Move pages between the two nodesets so as to preserve the physical
949 * layout as much as possible.
950 *
951 * Returns the number of page that could not be moved.
952 */
953int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
954 const nodemask_t *to, int flags)
955{
956 int busy = 0;
957 int err;
958 nodemask_t tmp;
959
960 err = migrate_prep();
961 if (err)
962 return err;
963
964 down_read(&mm->mmap_sem);
965
966 err = migrate_vmas(mm, from, to, flags);
967 if (err)
968 goto out;
969
970 /*
971 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
972 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
973 * bit in 'tmp', and return that <source, dest> pair for migration.
974 * The pair of nodemasks 'to' and 'from' define the map.
975 *
976 * If no pair of bits is found that way, fallback to picking some
977 * pair of 'source' and 'dest' bits that are not the same. If the
978 * 'source' and 'dest' bits are the same, this represents a node
979 * that will be migrating to itself, so no pages need move.
980 *
981 * If no bits are left in 'tmp', or if all remaining bits left
982 * in 'tmp' correspond to the same bit in 'to', return false
983 * (nothing left to migrate).
984 *
985 * This lets us pick a pair of nodes to migrate between, such that
986 * if possible the dest node is not already occupied by some other
987 * source node, minimizing the risk of overloading the memory on a
988 * node that would happen if we migrated incoming memory to a node
989 * before migrating outgoing memory source that same node.
990 *
991 * A single scan of tmp is sufficient. As we go, we remember the
992 * most recent <s, d> pair that moved (s != d). If we find a pair
993 * that not only moved, but what's better, moved to an empty slot
994 * (d is not set in tmp), then we break out then, with that pair.
995 * Otherwise when we finish scanning from_tmp, we at least have the
996 * most recent <s, d> pair that moved. If we get all the way through
997 * the scan of tmp without finding any node that moved, much less
998 * moved to an empty node, then there is nothing left worth migrating.
999 */
1000
1001 tmp = *from;
1002 while (!nodes_empty(tmp)) {
1003 int s,d;
1004 int source = -1;
1005 int dest = 0;
1006
1007 for_each_node_mask(s, tmp) {
1008
1009 /*
1010 * do_migrate_pages() tries to maintain the relative
1011 * node relationship of the pages established between
1012 * threads and memory areas.
1013 *
1014 * However if the number of source nodes is not equal to
1015 * the number of destination nodes we can not preserve
1016 * this node relative relationship. In that case, skip
1017 * copying memory from a node that is in the destination
1018 * mask.
1019 *
1020 * Example: [2,3,4] -> [3,4,5] moves everything.
1021 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1022 */
1023
1024 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1025 (node_isset(s, *to)))
1026 continue;
1027
1028 d = node_remap(s, *from, *to);
1029 if (s == d)
1030 continue;
1031
1032 source = s; /* Node moved. Memorize */
1033 dest = d;
1034
1035 /* dest not in remaining from nodes? */
1036 if (!node_isset(dest, tmp))
1037 break;
1038 }
1039 if (source == -1)
1040 break;
1041
1042 node_clear(source, tmp);
1043 err = migrate_to_node(mm, source, dest, flags);
1044 if (err > 0)
1045 busy += err;
1046 if (err < 0)
1047 break;
1048 }
1049out:
1050 up_read(&mm->mmap_sem);
1051 if (err < 0)
1052 return err;
1053 return busy;
1054
1055}
1056
1057/*
1058 * Allocate a new page for page migration based on vma policy.
1059 * Start assuming that page is mapped by vma pointed to by @private.
1060 * Search forward from there, if not. N.B., this assumes that the
1061 * list of pages handed to migrate_pages()--which is how we get here--
1062 * is in virtual address order.
1063 */
1064static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1065{
1066 struct vm_area_struct *vma = (struct vm_area_struct *)private;
1067 unsigned long uninitialized_var(address);
1068
1069 while (vma) {
1070 address = page_address_in_vma(page, vma);
1071 if (address != -EFAULT)
1072 break;
1073 vma = vma->vm_next;
1074 }
1075
1076 /*
1077 * if !vma, alloc_page_vma() will use task or system default policy
1078 */
1079 return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1080}
1081#else
1082
1083static void migrate_page_add(struct page *page, struct list_head *pagelist,
1084 unsigned long flags)
1085{
1086}
1087
1088int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1089 const nodemask_t *to, int flags)
1090{
1091 return -ENOSYS;
1092}
1093
1094static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1095{
1096 return NULL;
1097}
1098#endif
1099
1100static long do_mbind(unsigned long start, unsigned long len,
1101 unsigned short mode, unsigned short mode_flags,
1102 nodemask_t *nmask, unsigned long flags)
1103{
1104 struct vm_area_struct *vma;
1105 struct mm_struct *mm = current->mm;
1106 struct mempolicy *new;
1107 unsigned long end;
1108 int err;
1109 LIST_HEAD(pagelist);
1110
1111 if (flags & ~(unsigned long)(MPOL_MF_STRICT |
1112 MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1113 return -EINVAL;
1114 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1115 return -EPERM;
1116
1117 if (start & ~PAGE_MASK)
1118 return -EINVAL;
1119
1120 if (mode == MPOL_DEFAULT)
1121 flags &= ~MPOL_MF_STRICT;
1122
1123 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1124 end = start + len;
1125
1126 if (end < start)
1127 return -EINVAL;
1128 if (end == start)
1129 return 0;
1130
1131 new = mpol_new(mode, mode_flags, nmask);
1132 if (IS_ERR(new))
1133 return PTR_ERR(new);
1134
1135 /*
1136 * If we are using the default policy then operation
1137 * on discontinuous address spaces is okay after all
1138 */
1139 if (!new)
1140 flags |= MPOL_MF_DISCONTIG_OK;
1141
1142 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1143 start, start + len, mode, mode_flags,
1144 nmask ? nodes_addr(*nmask)[0] : -1);
1145
1146 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1147
1148 err = migrate_prep();
1149 if (err)
1150 goto mpol_out;
1151 }
1152 {
1153 NODEMASK_SCRATCH(scratch);
1154 if (scratch) {
1155 down_write(&mm->mmap_sem);
1156 task_lock(current);
1157 err = mpol_set_nodemask(new, nmask, scratch);
1158 task_unlock(current);
1159 if (err)
1160 up_write(&mm->mmap_sem);
1161 } else
1162 err = -ENOMEM;
1163 NODEMASK_SCRATCH_FREE(scratch);
1164 }
1165 if (err)
1166 goto mpol_out;
1167
1168 vma = check_range(mm, start, end, nmask,
1169 flags | MPOL_MF_INVERT, &pagelist);
1170
1171 err = PTR_ERR(vma);
1172 if (!IS_ERR(vma)) {
1173 int nr_failed = 0;
1174
1175 err = mbind_range(mm, start, end, new);
1176
1177 if (!list_empty(&pagelist)) {
1178 nr_failed = migrate_pages(&pagelist, new_vma_page,
1179 (unsigned long)vma,
1180 false, MIGRATE_SYNC);
1181 if (nr_failed)
1182 putback_lru_pages(&pagelist);
1183 }
1184
1185 if (!err && nr_failed && (flags & MPOL_MF_STRICT))
1186 err = -EIO;
1187 } else
1188 putback_lru_pages(&pagelist);
1189
1190 up_write(&mm->mmap_sem);
1191 mpol_out:
1192 mpol_put(new);
1193 return err;
1194}
1195
1196/*
1197 * User space interface with variable sized bitmaps for nodelists.
1198 */
1199
1200/* Copy a node mask from user space. */
1201static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1202 unsigned long maxnode)
1203{
1204 unsigned long k;
1205 unsigned long nlongs;
1206 unsigned long endmask;
1207
1208 --maxnode;
1209 nodes_clear(*nodes);
1210 if (maxnode == 0 || !nmask)
1211 return 0;
1212 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1213 return -EINVAL;
1214
1215 nlongs = BITS_TO_LONGS(maxnode);
1216 if ((maxnode % BITS_PER_LONG) == 0)
1217 endmask = ~0UL;
1218 else
1219 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1220
1221 /* When the user specified more nodes than supported just check
1222 if the non supported part is all zero. */
1223 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1224 if (nlongs > PAGE_SIZE/sizeof(long))
1225 return -EINVAL;
1226 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1227 unsigned long t;
1228 if (get_user(t, nmask + k))
1229 return -EFAULT;
1230 if (k == nlongs - 1) {
1231 if (t & endmask)
1232 return -EINVAL;
1233 } else if (t)
1234 return -EINVAL;
1235 }
1236 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1237 endmask = ~0UL;
1238 }
1239
1240 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1241 return -EFAULT;
1242 nodes_addr(*nodes)[nlongs-1] &= endmask;
1243 return 0;
1244}
1245
1246/* Copy a kernel node mask to user space */
1247static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1248 nodemask_t *nodes)
1249{
1250 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1251 const int nbytes = BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long);
1252
1253 if (copy > nbytes) {
1254 if (copy > PAGE_SIZE)
1255 return -EINVAL;
1256 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1257 return -EFAULT;
1258 copy = nbytes;
1259 }
1260 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1261}
1262
1263SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1264 unsigned long, mode, unsigned long __user *, nmask,
1265 unsigned long, maxnode, unsigned, flags)
1266{
1267 nodemask_t nodes;
1268 int err;
1269 unsigned short mode_flags;
1270
1271 mode_flags = mode & MPOL_MODE_FLAGS;
1272 mode &= ~MPOL_MODE_FLAGS;
1273 if (mode >= MPOL_MAX)
1274 return -EINVAL;
1275 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1276 (mode_flags & MPOL_F_RELATIVE_NODES))
1277 return -EINVAL;
1278 err = get_nodes(&nodes, nmask, maxnode);
1279 if (err)
1280 return err;
1281 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1282}
1283
1284/* Set the process memory policy */
1285SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
1286 unsigned long, maxnode)
1287{
1288 int err;
1289 nodemask_t nodes;
1290 unsigned short flags;
1291
1292 flags = mode & MPOL_MODE_FLAGS;
1293 mode &= ~MPOL_MODE_FLAGS;
1294 if ((unsigned int)mode >= MPOL_MAX)
1295 return -EINVAL;
1296 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1297 return -EINVAL;
1298 err = get_nodes(&nodes, nmask, maxnode);
1299 if (err)
1300 return err;
1301 return do_set_mempolicy(mode, flags, &nodes);
1302}
1303
1304SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1305 const unsigned long __user *, old_nodes,
1306 const unsigned long __user *, new_nodes)
1307{
1308 const struct cred *cred = current_cred(), *tcred;
1309 struct mm_struct *mm = NULL;
1310 struct task_struct *task;
1311 nodemask_t task_nodes;
1312 int err;
1313 nodemask_t *old;
1314 nodemask_t *new;
1315 NODEMASK_SCRATCH(scratch);
1316
1317 if (!scratch)
1318 return -ENOMEM;
1319
1320 old = &scratch->mask1;
1321 new = &scratch->mask2;
1322
1323 err = get_nodes(old, old_nodes, maxnode);
1324 if (err)
1325 goto out;
1326
1327 err = get_nodes(new, new_nodes, maxnode);
1328 if (err)
1329 goto out;
1330
1331 /* Find the mm_struct */
1332 rcu_read_lock();
1333 task = pid ? find_task_by_vpid(pid) : current;
1334 if (!task) {
1335 rcu_read_unlock();
1336 err = -ESRCH;
1337 goto out;
1338 }
1339 get_task_struct(task);
1340
1341 err = -EINVAL;
1342
1343 /*
1344 * Check if this process has the right to modify the specified
1345 * process. The right exists if the process has administrative
1346 * capabilities, superuser privileges or the same
1347 * userid as the target process.
1348 */
1349 tcred = __task_cred(task);
1350 if (!uid_eq(cred->euid, tcred->suid) && !uid_eq(cred->euid, tcred->uid) &&
1351 !uid_eq(cred->uid, tcred->suid) && !uid_eq(cred->uid, tcred->uid) &&
1352 !capable(CAP_SYS_NICE)) {
1353 rcu_read_unlock();
1354 err = -EPERM;
1355 goto out_put;
1356 }
1357 rcu_read_unlock();
1358
1359 task_nodes = cpuset_mems_allowed(task);
1360 /* Is the user allowed to access the target nodes? */
1361 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1362 err = -EPERM;
1363 goto out_put;
1364 }
1365
1366 if (!nodes_subset(*new, node_states[N_HIGH_MEMORY])) {
1367 err = -EINVAL;
1368 goto out_put;
1369 }
1370
1371 err = security_task_movememory(task);
1372 if (err)
1373 goto out_put;
1374
1375 mm = get_task_mm(task);
1376 put_task_struct(task);
1377
1378 if (!mm) {
1379 err = -EINVAL;
1380 goto out;
1381 }
1382
1383 err = do_migrate_pages(mm, old, new,
1384 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1385
1386 mmput(mm);
1387out:
1388 NODEMASK_SCRATCH_FREE(scratch);
1389
1390 return err;
1391
1392out_put:
1393 put_task_struct(task);
1394 goto out;
1395
1396}
1397
1398
1399/* Retrieve NUMA policy */
1400SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1401 unsigned long __user *, nmask, unsigned long, maxnode,
1402 unsigned long, addr, unsigned long, flags)
1403{
1404 int err;
1405 int uninitialized_var(pval);
1406 nodemask_t nodes;
1407
1408 if (nmask != NULL && maxnode < MAX_NUMNODES)
1409 return -EINVAL;
1410
1411 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1412
1413 if (err)
1414 return err;
1415
1416 if (policy && put_user(pval, policy))
1417 return -EFAULT;
1418
1419 if (nmask)
1420 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1421
1422 return err;
1423}
1424
1425#ifdef CONFIG_COMPAT
1426
1427asmlinkage long compat_sys_get_mempolicy(int __user *policy,
1428 compat_ulong_t __user *nmask,
1429 compat_ulong_t maxnode,
1430 compat_ulong_t addr, compat_ulong_t flags)
1431{
1432 long err;
1433 unsigned long __user *nm = NULL;
1434 unsigned long nr_bits, alloc_size;
1435 DECLARE_BITMAP(bm, MAX_NUMNODES);
1436
1437 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1438 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1439
1440 if (nmask)
1441 nm = compat_alloc_user_space(alloc_size);
1442
1443 err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1444
1445 if (!err && nmask) {
1446 unsigned long copy_size;
1447 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1448 err = copy_from_user(bm, nm, copy_size);
1449 /* ensure entire bitmap is zeroed */
1450 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1451 err |= compat_put_bitmap(nmask, bm, nr_bits);
1452 }
1453
1454 return err;
1455}
1456
1457asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
1458 compat_ulong_t maxnode)
1459{
1460 long err = 0;
1461 unsigned long __user *nm = NULL;
1462 unsigned long nr_bits, alloc_size;
1463 DECLARE_BITMAP(bm, MAX_NUMNODES);
1464
1465 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1466 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1467
1468 if (nmask) {
1469 err = compat_get_bitmap(bm, nmask, nr_bits);
1470 nm = compat_alloc_user_space(alloc_size);
1471 err |= copy_to_user(nm, bm, alloc_size);
1472 }
1473
1474 if (err)
1475 return -EFAULT;
1476
1477 return sys_set_mempolicy(mode, nm, nr_bits+1);
1478}
1479
1480asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
1481 compat_ulong_t mode, compat_ulong_t __user *nmask,
1482 compat_ulong_t maxnode, compat_ulong_t flags)
1483{
1484 long err = 0;
1485 unsigned long __user *nm = NULL;
1486 unsigned long nr_bits, alloc_size;
1487 nodemask_t bm;
1488
1489 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1490 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1491
1492 if (nmask) {
1493 err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
1494 nm = compat_alloc_user_space(alloc_size);
1495 err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
1496 }
1497
1498 if (err)
1499 return -EFAULT;
1500
1501 return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
1502}
1503
1504#endif
1505
1506/*
1507 * get_vma_policy(@task, @vma, @addr)
1508 * @task - task for fallback if vma policy == default
1509 * @vma - virtual memory area whose policy is sought
1510 * @addr - address in @vma for shared policy lookup
1511 *
1512 * Returns effective policy for a VMA at specified address.
1513 * Falls back to @task or system default policy, as necessary.
1514 * Current or other task's task mempolicy and non-shared vma policies
1515 * are protected by the task's mmap_sem, which must be held for read by
1516 * the caller.
1517 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1518 * count--added by the get_policy() vm_op, as appropriate--to protect against
1519 * freeing by another task. It is the caller's responsibility to free the
1520 * extra reference for shared policies.
1521 */
1522struct mempolicy *get_vma_policy(struct task_struct *task,
1523 struct vm_area_struct *vma, unsigned long addr)
1524{
1525 struct mempolicy *pol = task->mempolicy;
1526
1527 if (vma) {
1528 if (vma->vm_ops && vma->vm_ops->get_policy) {
1529 struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
1530 addr);
1531 if (vpol)
1532 pol = vpol;
1533 } else if (vma->vm_policy)
1534 pol = vma->vm_policy;
1535 }
1536 if (!pol)
1537 pol = &default_policy;
1538 return pol;
1539}
1540
1541/*
1542 * Return a nodemask representing a mempolicy for filtering nodes for
1543 * page allocation
1544 */
1545static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1546{
1547 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1548 if (unlikely(policy->mode == MPOL_BIND) &&
1549 gfp_zone(gfp) >= policy_zone &&
1550 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1551 return &policy->v.nodes;
1552
1553 return NULL;
1554}
1555
1556/* Return a zonelist indicated by gfp for node representing a mempolicy */
1557static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
1558 int nd)
1559{
1560 switch (policy->mode) {
1561 case MPOL_PREFERRED:
1562 if (!(policy->flags & MPOL_F_LOCAL))
1563 nd = policy->v.preferred_node;
1564 break;
1565 case MPOL_BIND:
1566 /*
1567 * Normally, MPOL_BIND allocations are node-local within the
1568 * allowed nodemask. However, if __GFP_THISNODE is set and the
1569 * current node isn't part of the mask, we use the zonelist for
1570 * the first node in the mask instead.
1571 */
1572 if (unlikely(gfp & __GFP_THISNODE) &&
1573 unlikely(!node_isset(nd, policy->v.nodes)))
1574 nd = first_node(policy->v.nodes);
1575 break;
1576 default:
1577 BUG();
1578 }
1579 return node_zonelist(nd, gfp);
1580}
1581
1582/* Do dynamic interleaving for a process */
1583static unsigned interleave_nodes(struct mempolicy *policy)
1584{
1585 unsigned nid, next;
1586 struct task_struct *me = current;
1587
1588 nid = me->il_next;
1589 next = next_node(nid, policy->v.nodes);
1590 if (next >= MAX_NUMNODES)
1591 next = first_node(policy->v.nodes);
1592 if (next < MAX_NUMNODES)
1593 me->il_next = next;
1594 return nid;
1595}
1596
1597/*
1598 * Depending on the memory policy provide a node from which to allocate the
1599 * next slab entry.
1600 * @policy must be protected by freeing by the caller. If @policy is
1601 * the current task's mempolicy, this protection is implicit, as only the
1602 * task can change it's policy. The system default policy requires no
1603 * such protection.
1604 */
1605unsigned slab_node(struct mempolicy *policy)
1606{
1607 if (!policy || policy->flags & MPOL_F_LOCAL)
1608 return numa_node_id();
1609
1610 switch (policy->mode) {
1611 case MPOL_PREFERRED:
1612 /*
1613 * handled MPOL_F_LOCAL above
1614 */
1615 return policy->v.preferred_node;
1616
1617 case MPOL_INTERLEAVE:
1618 return interleave_nodes(policy);
1619
1620 case MPOL_BIND: {
1621 /*
1622 * Follow bind policy behavior and start allocation at the
1623 * first node.
1624 */
1625 struct zonelist *zonelist;
1626 struct zone *zone;
1627 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1628 zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
1629 (void)first_zones_zonelist(zonelist, highest_zoneidx,
1630 &policy->v.nodes,
1631 &zone);
1632 return zone ? zone->node : numa_node_id();
1633 }
1634
1635 default:
1636 BUG();
1637 }
1638}
1639
1640/* Do static interleaving for a VMA with known offset. */
1641static unsigned offset_il_node(struct mempolicy *pol,
1642 struct vm_area_struct *vma, unsigned long off)
1643{
1644 unsigned nnodes = nodes_weight(pol->v.nodes);
1645 unsigned target;
1646 int c;
1647 int nid = -1;
1648
1649 if (!nnodes)
1650 return numa_node_id();
1651 target = (unsigned int)off % nnodes;
1652 c = 0;
1653 do {
1654 nid = next_node(nid, pol->v.nodes);
1655 c++;
1656 } while (c <= target);
1657 return nid;
1658}
1659
1660/* Determine a node number for interleave */
1661static inline unsigned interleave_nid(struct mempolicy *pol,
1662 struct vm_area_struct *vma, unsigned long addr, int shift)
1663{
1664 if (vma) {
1665 unsigned long off;
1666
1667 /*
1668 * for small pages, there is no difference between
1669 * shift and PAGE_SHIFT, so the bit-shift is safe.
1670 * for huge pages, since vm_pgoff is in units of small
1671 * pages, we need to shift off the always 0 bits to get
1672 * a useful offset.
1673 */
1674 BUG_ON(shift < PAGE_SHIFT);
1675 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1676 off += (addr - vma->vm_start) >> shift;
1677 return offset_il_node(pol, vma, off);
1678 } else
1679 return interleave_nodes(pol);
1680}
1681
1682/*
1683 * Return the bit number of a random bit set in the nodemask.
1684 * (returns -1 if nodemask is empty)
1685 */
1686int node_random(const nodemask_t *maskp)
1687{
1688 int w, bit = -1;
1689
1690 w = nodes_weight(*maskp);
1691 if (w)
1692 bit = bitmap_ord_to_pos(maskp->bits,
1693 get_random_int() % w, MAX_NUMNODES);
1694 return bit;
1695}
1696
1697#ifdef CONFIG_HUGETLBFS
1698/*
1699 * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
1700 * @vma = virtual memory area whose policy is sought
1701 * @addr = address in @vma for shared policy lookup and interleave policy
1702 * @gfp_flags = for requested zone
1703 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
1704 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1705 *
1706 * Returns a zonelist suitable for a huge page allocation and a pointer
1707 * to the struct mempolicy for conditional unref after allocation.
1708 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1709 * @nodemask for filtering the zonelist.
1710 *
1711 * Must be protected by get_mems_allowed()
1712 */
1713struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1714 gfp_t gfp_flags, struct mempolicy **mpol,
1715 nodemask_t **nodemask)
1716{
1717 struct zonelist *zl;
1718
1719 *mpol = get_vma_policy(current, vma, addr);
1720 *nodemask = NULL; /* assume !MPOL_BIND */
1721
1722 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1723 zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1724 huge_page_shift(hstate_vma(vma))), gfp_flags);
1725 } else {
1726 zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1727 if ((*mpol)->mode == MPOL_BIND)
1728 *nodemask = &(*mpol)->v.nodes;
1729 }
1730 return zl;
1731}
1732
1733/*
1734 * init_nodemask_of_mempolicy
1735 *
1736 * If the current task's mempolicy is "default" [NULL], return 'false'
1737 * to indicate default policy. Otherwise, extract the policy nodemask
1738 * for 'bind' or 'interleave' policy into the argument nodemask, or
1739 * initialize the argument nodemask to contain the single node for
1740 * 'preferred' or 'local' policy and return 'true' to indicate presence
1741 * of non-default mempolicy.
1742 *
1743 * We don't bother with reference counting the mempolicy [mpol_get/put]
1744 * because the current task is examining it's own mempolicy and a task's
1745 * mempolicy is only ever changed by the task itself.
1746 *
1747 * N.B., it is the caller's responsibility to free a returned nodemask.
1748 */
1749bool init_nodemask_of_mempolicy(nodemask_t *mask)
1750{
1751 struct mempolicy *mempolicy;
1752 int nid;
1753
1754 if (!(mask && current->mempolicy))
1755 return false;
1756
1757 task_lock(current);
1758 mempolicy = current->mempolicy;
1759 switch (mempolicy->mode) {
1760 case MPOL_PREFERRED:
1761 if (mempolicy->flags & MPOL_F_LOCAL)
1762 nid = numa_node_id();
1763 else
1764 nid = mempolicy->v.preferred_node;
1765 init_nodemask_of_node(mask, nid);
1766 break;
1767
1768 case MPOL_BIND:
1769 /* Fall through */
1770 case MPOL_INTERLEAVE:
1771 *mask = mempolicy->v.nodes;
1772 break;
1773
1774 default:
1775 BUG();
1776 }
1777 task_unlock(current);
1778
1779 return true;
1780}
1781#endif
1782
1783/*
1784 * mempolicy_nodemask_intersects
1785 *
1786 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
1787 * policy. Otherwise, check for intersection between mask and the policy
1788 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
1789 * policy, always return true since it may allocate elsewhere on fallback.
1790 *
1791 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
1792 */
1793bool mempolicy_nodemask_intersects(struct task_struct *tsk,
1794 const nodemask_t *mask)
1795{
1796 struct mempolicy *mempolicy;
1797 bool ret = true;
1798
1799 if (!mask)
1800 return ret;
1801 task_lock(tsk);
1802 mempolicy = tsk->mempolicy;
1803 if (!mempolicy)
1804 goto out;
1805
1806 switch (mempolicy->mode) {
1807 case MPOL_PREFERRED:
1808 /*
1809 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
1810 * allocate from, they may fallback to other nodes when oom.
1811 * Thus, it's possible for tsk to have allocated memory from
1812 * nodes in mask.
1813 */
1814 break;
1815 case MPOL_BIND:
1816 case MPOL_INTERLEAVE:
1817 ret = nodes_intersects(mempolicy->v.nodes, *mask);
1818 break;
1819 default:
1820 BUG();
1821 }
1822out:
1823 task_unlock(tsk);
1824 return ret;
1825}
1826
1827/* Allocate a page in interleaved policy.
1828 Own path because it needs to do special accounting. */
1829static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
1830 unsigned nid)
1831{
1832 struct zonelist *zl;
1833 struct page *page;
1834
1835 zl = node_zonelist(nid, gfp);
1836 page = __alloc_pages(gfp, order, zl);
1837 if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1838 inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
1839 return page;
1840}
1841
1842/**
1843 * alloc_pages_vma - Allocate a page for a VMA.
1844 *
1845 * @gfp:
1846 * %GFP_USER user allocation.
1847 * %GFP_KERNEL kernel allocations,
1848 * %GFP_HIGHMEM highmem/user allocations,
1849 * %GFP_FS allocation should not call back into a file system.
1850 * %GFP_ATOMIC don't sleep.
1851 *
1852 * @order:Order of the GFP allocation.
1853 * @vma: Pointer to VMA or NULL if not available.
1854 * @addr: Virtual Address of the allocation. Must be inside the VMA.
1855 *
1856 * This function allocates a page from the kernel page pool and applies
1857 * a NUMA policy associated with the VMA or the current process.
1858 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
1859 * mm_struct of the VMA to prevent it from going away. Should be used for
1860 * all allocations for pages that will be mapped into
1861 * user space. Returns NULL when no page can be allocated.
1862 *
1863 * Should be called with the mm_sem of the vma hold.
1864 */
1865struct page *
1866alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
1867 unsigned long addr, int node)
1868{
1869 struct mempolicy *pol;
1870 struct zonelist *zl;
1871 struct page *page;
1872 unsigned int cpuset_mems_cookie;
1873
1874retry_cpuset:
1875 pol = get_vma_policy(current, vma, addr);
1876 cpuset_mems_cookie = get_mems_allowed();
1877
1878 if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
1879 unsigned nid;
1880
1881 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
1882 mpol_cond_put(pol);
1883 page = alloc_page_interleave(gfp, order, nid);
1884 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1885 goto retry_cpuset;
1886
1887 return page;
1888 }
1889 zl = policy_zonelist(gfp, pol, node);
1890 if (unlikely(mpol_needs_cond_ref(pol))) {
1891 /*
1892 * slow path: ref counted shared policy
1893 */
1894 struct page *page = __alloc_pages_nodemask(gfp, order,
1895 zl, policy_nodemask(gfp, pol));
1896 __mpol_put(pol);
1897 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1898 goto retry_cpuset;
1899 return page;
1900 }
1901 /*
1902 * fast path: default or task policy
1903 */
1904 page = __alloc_pages_nodemask(gfp, order, zl,
1905 policy_nodemask(gfp, pol));
1906 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1907 goto retry_cpuset;
1908 return page;
1909}
1910
1911/**
1912 * alloc_pages_current - Allocate pages.
1913 *
1914 * @gfp:
1915 * %GFP_USER user allocation,
1916 * %GFP_KERNEL kernel allocation,
1917 * %GFP_HIGHMEM highmem allocation,
1918 * %GFP_FS don't call back into a file system.
1919 * %GFP_ATOMIC don't sleep.
1920 * @order: Power of two of allocation size in pages. 0 is a single page.
1921 *
1922 * Allocate a page from the kernel page pool. When not in
1923 * interrupt context and apply the current process NUMA policy.
1924 * Returns NULL when no page can be allocated.
1925 *
1926 * Don't call cpuset_update_task_memory_state() unless
1927 * 1) it's ok to take cpuset_sem (can WAIT), and
1928 * 2) allocating for current task (not interrupt).
1929 */
1930struct page *alloc_pages_current(gfp_t gfp, unsigned order)
1931{
1932 struct mempolicy *pol = current->mempolicy;
1933 struct page *page;
1934 unsigned int cpuset_mems_cookie;
1935
1936 if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
1937 pol = &default_policy;
1938
1939retry_cpuset:
1940 cpuset_mems_cookie = get_mems_allowed();
1941
1942 /*
1943 * No reference counting needed for current->mempolicy
1944 * nor system default_policy
1945 */
1946 if (pol->mode == MPOL_INTERLEAVE)
1947 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
1948 else
1949 page = __alloc_pages_nodemask(gfp, order,
1950 policy_zonelist(gfp, pol, numa_node_id()),
1951 policy_nodemask(gfp, pol));
1952
1953 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1954 goto retry_cpuset;
1955
1956 return page;
1957}
1958EXPORT_SYMBOL(alloc_pages_current);
1959
1960/*
1961 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
1962 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
1963 * with the mems_allowed returned by cpuset_mems_allowed(). This
1964 * keeps mempolicies cpuset relative after its cpuset moves. See
1965 * further kernel/cpuset.c update_nodemask().
1966 *
1967 * current's mempolicy may be rebinded by the other task(the task that changes
1968 * cpuset's mems), so we needn't do rebind work for current task.
1969 */
1970
1971/* Slow path of a mempolicy duplicate */
1972struct mempolicy *__mpol_dup(struct mempolicy *old)
1973{
1974 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
1975
1976 if (!new)
1977 return ERR_PTR(-ENOMEM);
1978
1979 /* task's mempolicy is protected by alloc_lock */
1980 if (old == current->mempolicy) {
1981 task_lock(current);
1982 *new = *old;
1983 task_unlock(current);
1984 } else
1985 *new = *old;
1986
1987 rcu_read_lock();
1988 if (current_cpuset_is_being_rebound()) {
1989 nodemask_t mems = cpuset_mems_allowed(current);
1990 if (new->flags & MPOL_F_REBINDING)
1991 mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
1992 else
1993 mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
1994 }
1995 rcu_read_unlock();
1996 atomic_set(&new->refcnt, 1);
1997 return new;
1998}
1999
2000/*
2001 * If *frompol needs [has] an extra ref, copy *frompol to *tompol ,
2002 * eliminate the * MPOL_F_* flags that require conditional ref and
2003 * [NOTE!!!] drop the extra ref. Not safe to reference *frompol directly
2004 * after return. Use the returned value.
2005 *
2006 * Allows use of a mempolicy for, e.g., multiple allocations with a single
2007 * policy lookup, even if the policy needs/has extra ref on lookup.
2008 * shmem_readahead needs this.
2009 */
2010struct mempolicy *__mpol_cond_copy(struct mempolicy *tompol,
2011 struct mempolicy *frompol)
2012{
2013 if (!mpol_needs_cond_ref(frompol))
2014 return frompol;
2015
2016 *tompol = *frompol;
2017 tompol->flags &= ~MPOL_F_SHARED; /* copy doesn't need unref */
2018 __mpol_put(frompol);
2019 return tompol;
2020}
2021
2022/* Slow path of a mempolicy comparison */
2023bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2024{
2025 if (!a || !b)
2026 return false;
2027 if (a->mode != b->mode)
2028 return false;
2029 if (a->flags != b->flags)
2030 return false;
2031 if (mpol_store_user_nodemask(a))
2032 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2033 return false;
2034
2035 switch (a->mode) {
2036 case MPOL_BIND:
2037 /* Fall through */
2038 case MPOL_INTERLEAVE:
2039 return !!nodes_equal(a->v.nodes, b->v.nodes);
2040 case MPOL_PREFERRED:
2041 return a->v.preferred_node == b->v.preferred_node;
2042 default:
2043 BUG();
2044 return false;
2045 }
2046}
2047
2048/*
2049 * Shared memory backing store policy support.
2050 *
2051 * Remember policies even when nobody has shared memory mapped.
2052 * The policies are kept in Red-Black tree linked from the inode.
2053 * They are protected by the sp->lock spinlock, which should be held
2054 * for any accesses to the tree.
2055 */
2056
2057/* lookup first element intersecting start-end */
2058/* Caller holds sp->lock */
2059static struct sp_node *
2060sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2061{
2062 struct rb_node *n = sp->root.rb_node;
2063
2064 while (n) {
2065 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2066
2067 if (start >= p->end)
2068 n = n->rb_right;
2069 else if (end <= p->start)
2070 n = n->rb_left;
2071 else
2072 break;
2073 }
2074 if (!n)
2075 return NULL;
2076 for (;;) {
2077 struct sp_node *w = NULL;
2078 struct rb_node *prev = rb_prev(n);
2079 if (!prev)
2080 break;
2081 w = rb_entry(prev, struct sp_node, nd);
2082 if (w->end <= start)
2083 break;
2084 n = prev;
2085 }
2086 return rb_entry(n, struct sp_node, nd);
2087}
2088
2089/* Insert a new shared policy into the list. */
2090/* Caller holds sp->lock */
2091static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2092{
2093 struct rb_node **p = &sp->root.rb_node;
2094 struct rb_node *parent = NULL;
2095 struct sp_node *nd;
2096
2097 while (*p) {
2098 parent = *p;
2099 nd = rb_entry(parent, struct sp_node, nd);
2100 if (new->start < nd->start)
2101 p = &(*p)->rb_left;
2102 else if (new->end > nd->end)
2103 p = &(*p)->rb_right;
2104 else
2105 BUG();
2106 }
2107 rb_link_node(&new->nd, parent, p);
2108 rb_insert_color(&new->nd, &sp->root);
2109 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2110 new->policy ? new->policy->mode : 0);
2111}
2112
2113/* Find shared policy intersecting idx */
2114struct mempolicy *
2115mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2116{
2117 struct mempolicy *pol = NULL;
2118 struct sp_node *sn;
2119
2120 if (!sp->root.rb_node)
2121 return NULL;
2122 spin_lock(&sp->lock);
2123 sn = sp_lookup(sp, idx, idx+1);
2124 if (sn) {
2125 mpol_get(sn->policy);
2126 pol = sn->policy;
2127 }
2128 spin_unlock(&sp->lock);
2129 return pol;
2130}
2131
2132static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2133{
2134 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2135 rb_erase(&n->nd, &sp->root);
2136 mpol_put(n->policy);
2137 kmem_cache_free(sn_cache, n);
2138}
2139
2140static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2141 struct mempolicy *pol)
2142{
2143 struct sp_node *n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2144
2145 if (!n)
2146 return NULL;
2147 n->start = start;
2148 n->end = end;
2149 mpol_get(pol);
2150 pol->flags |= MPOL_F_SHARED; /* for unref */
2151 n->policy = pol;
2152 return n;
2153}
2154
2155/* Replace a policy range. */
2156static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2157 unsigned long end, struct sp_node *new)
2158{
2159 struct sp_node *n, *new2 = NULL;
2160
2161restart:
2162 spin_lock(&sp->lock);
2163 n = sp_lookup(sp, start, end);
2164 /* Take care of old policies in the same range. */
2165 while (n && n->start < end) {
2166 struct rb_node *next = rb_next(&n->nd);
2167 if (n->start >= start) {
2168 if (n->end <= end)
2169 sp_delete(sp, n);
2170 else
2171 n->start = end;
2172 } else {
2173 /* Old policy spanning whole new range. */
2174 if (n->end > end) {
2175 if (!new2) {
2176 spin_unlock(&sp->lock);
2177 new2 = sp_alloc(end, n->end, n->policy);
2178 if (!new2)
2179 return -ENOMEM;
2180 goto restart;
2181 }
2182 n->end = start;
2183 sp_insert(sp, new2);
2184 new2 = NULL;
2185 break;
2186 } else
2187 n->end = start;
2188 }
2189 if (!next)
2190 break;
2191 n = rb_entry(next, struct sp_node, nd);
2192 }
2193 if (new)
2194 sp_insert(sp, new);
2195 spin_unlock(&sp->lock);
2196 if (new2) {
2197 mpol_put(new2->policy);
2198 kmem_cache_free(sn_cache, new2);
2199 }
2200 return 0;
2201}
2202
2203/**
2204 * mpol_shared_policy_init - initialize shared policy for inode
2205 * @sp: pointer to inode shared policy
2206 * @mpol: struct mempolicy to install
2207 *
2208 * Install non-NULL @mpol in inode's shared policy rb-tree.
2209 * On entry, the current task has a reference on a non-NULL @mpol.
2210 * This must be released on exit.
2211 * This is called at get_inode() calls and we can use GFP_KERNEL.
2212 */
2213void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2214{
2215 int ret;
2216
2217 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2218 spin_lock_init(&sp->lock);
2219
2220 if (mpol) {
2221 struct vm_area_struct pvma;
2222 struct mempolicy *new;
2223 NODEMASK_SCRATCH(scratch);
2224
2225 if (!scratch)
2226 goto put_mpol;
2227 /* contextualize the tmpfs mount point mempolicy */
2228 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2229 if (IS_ERR(new))
2230 goto free_scratch; /* no valid nodemask intersection */
2231
2232 task_lock(current);
2233 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2234 task_unlock(current);
2235 if (ret)
2236 goto put_new;
2237
2238 /* Create pseudo-vma that contains just the policy */
2239 memset(&pvma, 0, sizeof(struct vm_area_struct));
2240 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2241 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2242
2243put_new:
2244 mpol_put(new); /* drop initial ref */
2245free_scratch:
2246 NODEMASK_SCRATCH_FREE(scratch);
2247put_mpol:
2248 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2249 }
2250}
2251
2252int mpol_set_shared_policy(struct shared_policy *info,
2253 struct vm_area_struct *vma, struct mempolicy *npol)
2254{
2255 int err;
2256 struct sp_node *new = NULL;
2257 unsigned long sz = vma_pages(vma);
2258
2259 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2260 vma->vm_pgoff,
2261 sz, npol ? npol->mode : -1,
2262 npol ? npol->flags : -1,
2263 npol ? nodes_addr(npol->v.nodes)[0] : -1);
2264
2265 if (npol) {
2266 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2267 if (!new)
2268 return -ENOMEM;
2269 }
2270 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2271 if (err && new)
2272 kmem_cache_free(sn_cache, new);
2273 return err;
2274}
2275
2276/* Free a backing policy store on inode delete. */
2277void mpol_free_shared_policy(struct shared_policy *p)
2278{
2279 struct sp_node *n;
2280 struct rb_node *next;
2281
2282 if (!p->root.rb_node)
2283 return;
2284 spin_lock(&p->lock);
2285 next = rb_first(&p->root);
2286 while (next) {
2287 n = rb_entry(next, struct sp_node, nd);
2288 next = rb_next(&n->nd);
2289 rb_erase(&n->nd, &p->root);
2290 mpol_put(n->policy);
2291 kmem_cache_free(sn_cache, n);
2292 }
2293 spin_unlock(&p->lock);
2294}
2295
2296/* assumes fs == KERNEL_DS */
2297void __init numa_policy_init(void)
2298{
2299 nodemask_t interleave_nodes;
2300 unsigned long largest = 0;
2301 int nid, prefer = 0;
2302
2303 policy_cache = kmem_cache_create("numa_policy",
2304 sizeof(struct mempolicy),
2305 0, SLAB_PANIC, NULL);
2306
2307 sn_cache = kmem_cache_create("shared_policy_node",
2308 sizeof(struct sp_node),
2309 0, SLAB_PANIC, NULL);
2310
2311 /*
2312 * Set interleaving policy for system init. Interleaving is only
2313 * enabled across suitably sized nodes (default is >= 16MB), or
2314 * fall back to the largest node if they're all smaller.
2315 */
2316 nodes_clear(interleave_nodes);
2317 for_each_node_state(nid, N_HIGH_MEMORY) {
2318 unsigned long total_pages = node_present_pages(nid);
2319
2320 /* Preserve the largest node */
2321 if (largest < total_pages) {
2322 largest = total_pages;
2323 prefer = nid;
2324 }
2325
2326 /* Interleave this node? */
2327 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2328 node_set(nid, interleave_nodes);
2329 }
2330
2331 /* All too small, use the largest */
2332 if (unlikely(nodes_empty(interleave_nodes)))
2333 node_set(prefer, interleave_nodes);
2334
2335 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2336 printk("numa_policy_init: interleaving failed\n");
2337}
2338
2339/* Reset policy of current process to default */
2340void numa_default_policy(void)
2341{
2342 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2343}
2344
2345/*
2346 * Parse and format mempolicy from/to strings
2347 */
2348
2349/*
2350 * "local" is pseudo-policy: MPOL_PREFERRED with MPOL_F_LOCAL flag
2351 * Used only for mpol_parse_str() and mpol_to_str()
2352 */
2353#define MPOL_LOCAL MPOL_MAX
2354static const char * const policy_modes[] =
2355{
2356 [MPOL_DEFAULT] = "default",
2357 [MPOL_PREFERRED] = "prefer",
2358 [MPOL_BIND] = "bind",
2359 [MPOL_INTERLEAVE] = "interleave",
2360 [MPOL_LOCAL] = "local"
2361};
2362
2363
2364#ifdef CONFIG_TMPFS
2365/**
2366 * mpol_parse_str - parse string to mempolicy
2367 * @str: string containing mempolicy to parse
2368 * @mpol: pointer to struct mempolicy pointer, returned on success.
2369 * @no_context: flag whether to "contextualize" the mempolicy
2370 *
2371 * Format of input:
2372 * <mode>[=<flags>][:<nodelist>]
2373 *
2374 * if @no_context is true, save the input nodemask in w.user_nodemask in
2375 * the returned mempolicy. This will be used to "clone" the mempolicy in
2376 * a specific context [cpuset] at a later time. Used to parse tmpfs mpol
2377 * mount option. Note that if 'static' or 'relative' mode flags were
2378 * specified, the input nodemask will already have been saved. Saving
2379 * it again is redundant, but safe.
2380 *
2381 * On success, returns 0, else 1
2382 */
2383int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context)
2384{
2385 struct mempolicy *new = NULL;
2386 unsigned short mode;
2387 unsigned short uninitialized_var(mode_flags);
2388 nodemask_t nodes;
2389 char *nodelist = strchr(str, ':');
2390 char *flags = strchr(str, '=');
2391 int err = 1;
2392
2393 if (nodelist) {
2394 /* NUL-terminate mode or flags string */
2395 *nodelist++ = '\0';
2396 if (nodelist_parse(nodelist, nodes))
2397 goto out;
2398 if (!nodes_subset(nodes, node_states[N_HIGH_MEMORY]))
2399 goto out;
2400 } else
2401 nodes_clear(nodes);
2402
2403 if (flags)
2404 *flags++ = '\0'; /* terminate mode string */
2405
2406 for (mode = 0; mode <= MPOL_LOCAL; mode++) {
2407 if (!strcmp(str, policy_modes[mode])) {
2408 break;
2409 }
2410 }
2411 if (mode > MPOL_LOCAL)
2412 goto out;
2413
2414 switch (mode) {
2415 case MPOL_PREFERRED:
2416 /*
2417 * Insist on a nodelist of one node only
2418 */
2419 if (nodelist) {
2420 char *rest = nodelist;
2421 while (isdigit(*rest))
2422 rest++;
2423 if (*rest)
2424 goto out;
2425 }
2426 break;
2427 case MPOL_INTERLEAVE:
2428 /*
2429 * Default to online nodes with memory if no nodelist
2430 */
2431 if (!nodelist)
2432 nodes = node_states[N_HIGH_MEMORY];
2433 break;
2434 case MPOL_LOCAL:
2435 /*
2436 * Don't allow a nodelist; mpol_new() checks flags
2437 */
2438 if (nodelist)
2439 goto out;
2440 mode = MPOL_PREFERRED;
2441 break;
2442 case MPOL_DEFAULT:
2443 /*
2444 * Insist on a empty nodelist
2445 */
2446 if (!nodelist)
2447 err = 0;
2448 goto out;
2449 case MPOL_BIND:
2450 /*
2451 * Insist on a nodelist
2452 */
2453 if (!nodelist)
2454 goto out;
2455 }
2456
2457 mode_flags = 0;
2458 if (flags) {
2459 /*
2460 * Currently, we only support two mutually exclusive
2461 * mode flags.
2462 */
2463 if (!strcmp(flags, "static"))
2464 mode_flags |= MPOL_F_STATIC_NODES;
2465 else if (!strcmp(flags, "relative"))
2466 mode_flags |= MPOL_F_RELATIVE_NODES;
2467 else
2468 goto out;
2469 }
2470
2471 new = mpol_new(mode, mode_flags, &nodes);
2472 if (IS_ERR(new))
2473 goto out;
2474
2475 if (no_context) {
2476 /* save for contextualization */
2477 new->w.user_nodemask = nodes;
2478 } else {
2479 int ret;
2480 NODEMASK_SCRATCH(scratch);
2481 if (scratch) {
2482 task_lock(current);
2483 ret = mpol_set_nodemask(new, &nodes, scratch);
2484 task_unlock(current);
2485 } else
2486 ret = -ENOMEM;
2487 NODEMASK_SCRATCH_FREE(scratch);
2488 if (ret) {
2489 mpol_put(new);
2490 goto out;
2491 }
2492 }
2493 err = 0;
2494
2495out:
2496 /* Restore string for error message */
2497 if (nodelist)
2498 *--nodelist = ':';
2499 if (flags)
2500 *--flags = '=';
2501 if (!err)
2502 *mpol = new;
2503 return err;
2504}
2505#endif /* CONFIG_TMPFS */
2506
2507/**
2508 * mpol_to_str - format a mempolicy structure for printing
2509 * @buffer: to contain formatted mempolicy string
2510 * @maxlen: length of @buffer
2511 * @pol: pointer to mempolicy to be formatted
2512 * @no_context: "context free" mempolicy - use nodemask in w.user_nodemask
2513 *
2514 * Convert a mempolicy into a string.
2515 * Returns the number of characters in buffer (if positive)
2516 * or an error (negative)
2517 */
2518int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol, int no_context)
2519{
2520 char *p = buffer;
2521 int l;
2522 nodemask_t nodes;
2523 unsigned short mode;
2524 unsigned short flags = pol ? pol->flags : 0;
2525
2526 /*
2527 * Sanity check: room for longest mode, flag and some nodes
2528 */
2529 VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
2530
2531 if (!pol || pol == &default_policy)
2532 mode = MPOL_DEFAULT;
2533 else
2534 mode = pol->mode;
2535
2536 switch (mode) {
2537 case MPOL_DEFAULT:
2538 nodes_clear(nodes);
2539 break;
2540
2541 case MPOL_PREFERRED:
2542 nodes_clear(nodes);
2543 if (flags & MPOL_F_LOCAL)
2544 mode = MPOL_LOCAL; /* pseudo-policy */
2545 else
2546 node_set(pol->v.preferred_node, nodes);
2547 break;
2548
2549 case MPOL_BIND:
2550 /* Fall through */
2551 case MPOL_INTERLEAVE:
2552 if (no_context)
2553 nodes = pol->w.user_nodemask;
2554 else
2555 nodes = pol->v.nodes;
2556 break;
2557
2558 default:
2559 return -EINVAL;
2560 }
2561
2562 l = strlen(policy_modes[mode]);
2563 if (buffer + maxlen < p + l + 1)
2564 return -ENOSPC;
2565
2566 strcpy(p, policy_modes[mode]);
2567 p += l;
2568
2569 if (flags & MPOL_MODE_FLAGS) {
2570 if (buffer + maxlen < p + 2)
2571 return -ENOSPC;
2572 *p++ = '=';
2573
2574 /*
2575 * Currently, the only defined flags are mutually exclusive
2576 */
2577 if (flags & MPOL_F_STATIC_NODES)
2578 p += snprintf(p, buffer + maxlen - p, "static");
2579 else if (flags & MPOL_F_RELATIVE_NODES)
2580 p += snprintf(p, buffer + maxlen - p, "relative");
2581 }
2582
2583 if (!nodes_empty(nodes)) {
2584 if (buffer + maxlen < p + 2)
2585 return -ENOSPC;
2586 *p++ = ':';
2587 p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);
2588 }
2589 return p - buffer;
2590}