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