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) && !(pol->flags & MPOL_F_LOCAL) &&
354 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
355 return;
356
357 mpol_ops[pol->mode].rebind(pol, newmask);
358}
359
360/*
361 * Wrapper for mpol_rebind_policy() that just requires task
362 * pointer, and updates task mempolicy.
363 *
364 * Called with task's alloc_lock held.
365 */
366
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(struct mm_struct *mm, unsigned long addr)
801{
802 struct page *p;
803 int err;
804
805 int locked = 1;
806 err = get_user_pages_locked(addr & PAGE_MASK, 1, 0, &p, &locked);
807 if (err >= 0) {
808 err = page_to_nid(p);
809 put_page(p);
810 }
811 if (locked)
812 up_read(&mm->mmap_sem);
813 return err;
814}
815
816/* Retrieve NUMA policy */
817static long do_get_mempolicy(int *policy, nodemask_t *nmask,
818 unsigned long addr, unsigned long flags)
819{
820 int err;
821 struct mm_struct *mm = current->mm;
822 struct vm_area_struct *vma = NULL;
823 struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL;
824
825 if (flags &
826 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
827 return -EINVAL;
828
829 if (flags & MPOL_F_MEMS_ALLOWED) {
830 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
831 return -EINVAL;
832 *policy = 0; /* just so it's initialized */
833 task_lock(current);
834 *nmask = cpuset_current_mems_allowed;
835 task_unlock(current);
836 return 0;
837 }
838
839 if (flags & MPOL_F_ADDR) {
840 /*
841 * Do NOT fall back to task policy if the
842 * vma/shared policy at addr is NULL. We
843 * want to return MPOL_DEFAULT in this case.
844 */
845 down_read(&mm->mmap_sem);
846 vma = find_vma_intersection(mm, addr, addr+1);
847 if (!vma) {
848 up_read(&mm->mmap_sem);
849 return -EFAULT;
850 }
851 if (vma->vm_ops && vma->vm_ops->get_policy)
852 pol = vma->vm_ops->get_policy(vma, addr);
853 else
854 pol = vma->vm_policy;
855 } else if (addr)
856 return -EINVAL;
857
858 if (!pol)
859 pol = &default_policy; /* indicates default behavior */
860
861 if (flags & MPOL_F_NODE) {
862 if (flags & MPOL_F_ADDR) {
863 /*
864 * Take a refcount on the mpol, lookup_node()
865 * wil drop the mmap_sem, so after calling
866 * lookup_node() only "pol" remains valid, "vma"
867 * is stale.
868 */
869 pol_refcount = pol;
870 vma = NULL;
871 mpol_get(pol);
872 err = lookup_node(mm, addr);
873 if (err < 0)
874 goto out;
875 *policy = err;
876 } else if (pol == current->mempolicy &&
877 pol->mode == MPOL_INTERLEAVE) {
878 *policy = next_node_in(current->il_prev, pol->v.nodes);
879 } else {
880 err = -EINVAL;
881 goto out;
882 }
883 } else {
884 *policy = pol == &default_policy ? MPOL_DEFAULT :
885 pol->mode;
886 /*
887 * Internal mempolicy flags must be masked off before exposing
888 * the policy to userspace.
889 */
890 *policy |= (pol->flags & MPOL_MODE_FLAGS);
891 }
892
893 err = 0;
894 if (nmask) {
895 if (mpol_store_user_nodemask(pol)) {
896 *nmask = pol->w.user_nodemask;
897 } else {
898 task_lock(current);
899 get_policy_nodemask(pol, nmask);
900 task_unlock(current);
901 }
902 }
903
904 out:
905 mpol_cond_put(pol);
906 if (vma)
907 up_read(&mm->mmap_sem);
908 if (pol_refcount)
909 mpol_put(pol_refcount);
910 return err;
911}
912
913#ifdef CONFIG_MIGRATION
914/*
915 * page migration, thp tail pages can be passed.
916 */
917static void migrate_page_add(struct page *page, struct list_head *pagelist,
918 unsigned long flags)
919{
920 struct page *head = compound_head(page);
921 /*
922 * Avoid migrating a page that is shared with others.
923 */
924 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(head) == 1) {
925 if (!isolate_lru_page(head)) {
926 list_add_tail(&head->lru, pagelist);
927 mod_node_page_state(page_pgdat(head),
928 NR_ISOLATED_ANON + page_is_file_cache(head),
929 hpage_nr_pages(head));
930 }
931 }
932}
933
934/* page allocation callback for NUMA node migration */
935struct page *alloc_new_node_page(struct page *page, unsigned long node)
936{
937 if (PageHuge(page))
938 return alloc_huge_page_node(page_hstate(compound_head(page)),
939 node);
940 else if (PageTransHuge(page)) {
941 struct page *thp;
942
943 thp = alloc_pages_node(node,
944 (GFP_TRANSHUGE | __GFP_THISNODE),
945 HPAGE_PMD_ORDER);
946 if (!thp)
947 return NULL;
948 prep_transhuge_page(thp);
949 return thp;
950 } else
951 return __alloc_pages_node(node, GFP_HIGHUSER_MOVABLE |
952 __GFP_THISNODE, 0);
953}
954
955/*
956 * Migrate pages from one node to a target node.
957 * Returns error or the number of pages not migrated.
958 */
959static int migrate_to_node(struct mm_struct *mm, int source, int dest,
960 int flags)
961{
962 nodemask_t nmask;
963 LIST_HEAD(pagelist);
964 int err = 0;
965
966 nodes_clear(nmask);
967 node_set(source, nmask);
968
969 /*
970 * This does not "check" the range but isolates all pages that
971 * need migration. Between passing in the full user address
972 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
973 */
974 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
975 queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
976 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
977
978 if (!list_empty(&pagelist)) {
979 err = migrate_pages(&pagelist, alloc_new_node_page, NULL, dest,
980 MIGRATE_SYNC, MR_SYSCALL);
981 if (err)
982 putback_movable_pages(&pagelist);
983 }
984
985 return err;
986}
987
988/*
989 * Move pages between the two nodesets so as to preserve the physical
990 * layout as much as possible.
991 *
992 * Returns the number of page that could not be moved.
993 */
994int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
995 const nodemask_t *to, int flags)
996{
997 int busy = 0;
998 int err;
999 nodemask_t tmp;
1000
1001 err = migrate_prep();
1002 if (err)
1003 return err;
1004
1005 down_read(&mm->mmap_sem);
1006
1007 /*
1008 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1009 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1010 * bit in 'tmp', and return that <source, dest> pair for migration.
1011 * The pair of nodemasks 'to' and 'from' define the map.
1012 *
1013 * If no pair of bits is found that way, fallback to picking some
1014 * pair of 'source' and 'dest' bits that are not the same. If the
1015 * 'source' and 'dest' bits are the same, this represents a node
1016 * that will be migrating to itself, so no pages need move.
1017 *
1018 * If no bits are left in 'tmp', or if all remaining bits left
1019 * in 'tmp' correspond to the same bit in 'to', return false
1020 * (nothing left to migrate).
1021 *
1022 * This lets us pick a pair of nodes to migrate between, such that
1023 * if possible the dest node is not already occupied by some other
1024 * source node, minimizing the risk of overloading the memory on a
1025 * node that would happen if we migrated incoming memory to a node
1026 * before migrating outgoing memory source that same node.
1027 *
1028 * A single scan of tmp is sufficient. As we go, we remember the
1029 * most recent <s, d> pair that moved (s != d). If we find a pair
1030 * that not only moved, but what's better, moved to an empty slot
1031 * (d is not set in tmp), then we break out then, with that pair.
1032 * Otherwise when we finish scanning from_tmp, we at least have the
1033 * most recent <s, d> pair that moved. If we get all the way through
1034 * the scan of tmp without finding any node that moved, much less
1035 * moved to an empty node, then there is nothing left worth migrating.
1036 */
1037
1038 tmp = *from;
1039 while (!nodes_empty(tmp)) {
1040 int s,d;
1041 int source = NUMA_NO_NODE;
1042 int dest = 0;
1043
1044 for_each_node_mask(s, tmp) {
1045
1046 /*
1047 * do_migrate_pages() tries to maintain the relative
1048 * node relationship of the pages established between
1049 * threads and memory areas.
1050 *
1051 * However if the number of source nodes is not equal to
1052 * the number of destination nodes we can not preserve
1053 * this node relative relationship. In that case, skip
1054 * copying memory from a node that is in the destination
1055 * mask.
1056 *
1057 * Example: [2,3,4] -> [3,4,5] moves everything.
1058 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1059 */
1060
1061 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1062 (node_isset(s, *to)))
1063 continue;
1064
1065 d = node_remap(s, *from, *to);
1066 if (s == d)
1067 continue;
1068
1069 source = s; /* Node moved. Memorize */
1070 dest = d;
1071
1072 /* dest not in remaining from nodes? */
1073 if (!node_isset(dest, tmp))
1074 break;
1075 }
1076 if (source == NUMA_NO_NODE)
1077 break;
1078
1079 node_clear(source, tmp);
1080 err = migrate_to_node(mm, source, dest, flags);
1081 if (err > 0)
1082 busy += err;
1083 if (err < 0)
1084 break;
1085 }
1086 up_read(&mm->mmap_sem);
1087 if (err < 0)
1088 return err;
1089 return busy;
1090
1091}
1092
1093/*
1094 * Allocate a new page for page migration based on vma policy.
1095 * Start by assuming the page is mapped by the same vma as contains @start.
1096 * Search forward from there, if not. N.B., this assumes that the
1097 * list of pages handed to migrate_pages()--which is how we get here--
1098 * is in virtual address order.
1099 */
1100static struct page *new_page(struct page *page, unsigned long start)
1101{
1102 struct vm_area_struct *vma;
1103 unsigned long uninitialized_var(address);
1104
1105 vma = find_vma(current->mm, start);
1106 while (vma) {
1107 address = page_address_in_vma(page, vma);
1108 if (address != -EFAULT)
1109 break;
1110 vma = vma->vm_next;
1111 }
1112
1113 if (PageHuge(page)) {
1114 return alloc_huge_page_vma(page_hstate(compound_head(page)),
1115 vma, address);
1116 } else if (PageTransHuge(page)) {
1117 struct page *thp;
1118
1119 thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
1120 HPAGE_PMD_ORDER);
1121 if (!thp)
1122 return NULL;
1123 prep_transhuge_page(thp);
1124 return thp;
1125 }
1126 /*
1127 * if !vma, alloc_page_vma() will use task or system default policy
1128 */
1129 return alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL,
1130 vma, address);
1131}
1132#else
1133
1134static void migrate_page_add(struct page *page, struct list_head *pagelist,
1135 unsigned long flags)
1136{
1137}
1138
1139int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1140 const nodemask_t *to, int flags)
1141{
1142 return -ENOSYS;
1143}
1144
1145static struct page *new_page(struct page *page, unsigned long start)
1146{
1147 return NULL;
1148}
1149#endif
1150
1151static long do_mbind(unsigned long start, unsigned long len,
1152 unsigned short mode, unsigned short mode_flags,
1153 nodemask_t *nmask, unsigned long flags)
1154{
1155 struct mm_struct *mm = current->mm;
1156 struct mempolicy *new;
1157 unsigned long end;
1158 int err;
1159 LIST_HEAD(pagelist);
1160
1161 if (flags & ~(unsigned long)MPOL_MF_VALID)
1162 return -EINVAL;
1163 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1164 return -EPERM;
1165
1166 if (start & ~PAGE_MASK)
1167 return -EINVAL;
1168
1169 if (mode == MPOL_DEFAULT)
1170 flags &= ~MPOL_MF_STRICT;
1171
1172 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1173 end = start + len;
1174
1175 if (end < start)
1176 return -EINVAL;
1177 if (end == start)
1178 return 0;
1179
1180 new = mpol_new(mode, mode_flags, nmask);
1181 if (IS_ERR(new))
1182 return PTR_ERR(new);
1183
1184 if (flags & MPOL_MF_LAZY)
1185 new->flags |= MPOL_F_MOF;
1186
1187 /*
1188 * If we are using the default policy then operation
1189 * on discontinuous address spaces is okay after all
1190 */
1191 if (!new)
1192 flags |= MPOL_MF_DISCONTIG_OK;
1193
1194 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1195 start, start + len, mode, mode_flags,
1196 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1197
1198 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1199
1200 err = migrate_prep();
1201 if (err)
1202 goto mpol_out;
1203 }
1204 {
1205 NODEMASK_SCRATCH(scratch);
1206 if (scratch) {
1207 down_write(&mm->mmap_sem);
1208 task_lock(current);
1209 err = mpol_set_nodemask(new, nmask, scratch);
1210 task_unlock(current);
1211 if (err)
1212 up_write(&mm->mmap_sem);
1213 } else
1214 err = -ENOMEM;
1215 NODEMASK_SCRATCH_FREE(scratch);
1216 }
1217 if (err)
1218 goto mpol_out;
1219
1220 err = queue_pages_range(mm, start, end, nmask,
1221 flags | MPOL_MF_INVERT, &pagelist);
1222 if (!err)
1223 err = mbind_range(mm, start, end, new);
1224
1225 if (!err) {
1226 int nr_failed = 0;
1227
1228 if (!list_empty(&pagelist)) {
1229 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1230 nr_failed = migrate_pages(&pagelist, new_page, NULL,
1231 start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
1232 if (nr_failed)
1233 putback_movable_pages(&pagelist);
1234 }
1235
1236 if (nr_failed && (flags & MPOL_MF_STRICT))
1237 err = -EIO;
1238 } else
1239 putback_movable_pages(&pagelist);
1240
1241 up_write(&mm->mmap_sem);
1242 mpol_out:
1243 mpol_put(new);
1244 return err;
1245}
1246
1247/*
1248 * User space interface with variable sized bitmaps for nodelists.
1249 */
1250
1251/* Copy a node mask from user space. */
1252static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1253 unsigned long maxnode)
1254{
1255 unsigned long k;
1256 unsigned long t;
1257 unsigned long nlongs;
1258 unsigned long endmask;
1259
1260 --maxnode;
1261 nodes_clear(*nodes);
1262 if (maxnode == 0 || !nmask)
1263 return 0;
1264 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1265 return -EINVAL;
1266
1267 nlongs = BITS_TO_LONGS(maxnode);
1268 if ((maxnode % BITS_PER_LONG) == 0)
1269 endmask = ~0UL;
1270 else
1271 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1272
1273 /*
1274 * When the user specified more nodes than supported just check
1275 * if the non supported part is all zero.
1276 *
1277 * If maxnode have more longs than MAX_NUMNODES, check
1278 * the bits in that area first. And then go through to
1279 * check the rest bits which equal or bigger than MAX_NUMNODES.
1280 * Otherwise, just check bits [MAX_NUMNODES, maxnode).
1281 */
1282 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1283 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1284 if (get_user(t, nmask + k))
1285 return -EFAULT;
1286 if (k == nlongs - 1) {
1287 if (t & endmask)
1288 return -EINVAL;
1289 } else if (t)
1290 return -EINVAL;
1291 }
1292 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1293 endmask = ~0UL;
1294 }
1295
1296 if (maxnode > MAX_NUMNODES && MAX_NUMNODES % BITS_PER_LONG != 0) {
1297 unsigned long valid_mask = endmask;
1298
1299 valid_mask &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
1300 if (get_user(t, nmask + nlongs - 1))
1301 return -EFAULT;
1302 if (t & valid_mask)
1303 return -EINVAL;
1304 }
1305
1306 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1307 return -EFAULT;
1308 nodes_addr(*nodes)[nlongs-1] &= endmask;
1309 return 0;
1310}
1311
1312/* Copy a kernel node mask to user space */
1313static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1314 nodemask_t *nodes)
1315{
1316 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1317 unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long);
1318
1319 if (copy > nbytes) {
1320 if (copy > PAGE_SIZE)
1321 return -EINVAL;
1322 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1323 return -EFAULT;
1324 copy = nbytes;
1325 }
1326 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1327}
1328
1329static long kernel_mbind(unsigned long start, unsigned long len,
1330 unsigned long mode, const unsigned long __user *nmask,
1331 unsigned long maxnode, unsigned int flags)
1332{
1333 nodemask_t nodes;
1334 int err;
1335 unsigned short mode_flags;
1336
1337 mode_flags = mode & MPOL_MODE_FLAGS;
1338 mode &= ~MPOL_MODE_FLAGS;
1339 if (mode >= MPOL_MAX)
1340 return -EINVAL;
1341 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1342 (mode_flags & MPOL_F_RELATIVE_NODES))
1343 return -EINVAL;
1344 err = get_nodes(&nodes, nmask, maxnode);
1345 if (err)
1346 return err;
1347 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1348}
1349
1350SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1351 unsigned long, mode, const unsigned long __user *, nmask,
1352 unsigned long, maxnode, unsigned int, flags)
1353{
1354 return kernel_mbind(start, len, mode, nmask, maxnode, flags);
1355}
1356
1357/* Set the process memory policy */
1358static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
1359 unsigned long maxnode)
1360{
1361 int err;
1362 nodemask_t nodes;
1363 unsigned short flags;
1364
1365 flags = mode & MPOL_MODE_FLAGS;
1366 mode &= ~MPOL_MODE_FLAGS;
1367 if ((unsigned int)mode >= MPOL_MAX)
1368 return -EINVAL;
1369 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1370 return -EINVAL;
1371 err = get_nodes(&nodes, nmask, maxnode);
1372 if (err)
1373 return err;
1374 return do_set_mempolicy(mode, flags, &nodes);
1375}
1376
1377SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
1378 unsigned long, maxnode)
1379{
1380 return kernel_set_mempolicy(mode, nmask, maxnode);
1381}
1382
1383static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
1384 const unsigned long __user *old_nodes,
1385 const unsigned long __user *new_nodes)
1386{
1387 struct mm_struct *mm = NULL;
1388 struct task_struct *task;
1389 nodemask_t task_nodes;
1390 int err;
1391 nodemask_t *old;
1392 nodemask_t *new;
1393 NODEMASK_SCRATCH(scratch);
1394
1395 if (!scratch)
1396 return -ENOMEM;
1397
1398 old = &scratch->mask1;
1399 new = &scratch->mask2;
1400
1401 err = get_nodes(old, old_nodes, maxnode);
1402 if (err)
1403 goto out;
1404
1405 err = get_nodes(new, new_nodes, maxnode);
1406 if (err)
1407 goto out;
1408
1409 /* Find the mm_struct */
1410 rcu_read_lock();
1411 task = pid ? find_task_by_vpid(pid) : current;
1412 if (!task) {
1413 rcu_read_unlock();
1414 err = -ESRCH;
1415 goto out;
1416 }
1417 get_task_struct(task);
1418
1419 err = -EINVAL;
1420
1421 /*
1422 * Check if this process has the right to modify the specified process.
1423 * Use the regular "ptrace_may_access()" checks.
1424 */
1425 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
1426 rcu_read_unlock();
1427 err = -EPERM;
1428 goto out_put;
1429 }
1430 rcu_read_unlock();
1431
1432 task_nodes = cpuset_mems_allowed(task);
1433 /* Is the user allowed to access the target nodes? */
1434 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1435 err = -EPERM;
1436 goto out_put;
1437 }
1438
1439 task_nodes = cpuset_mems_allowed(current);
1440 nodes_and(*new, *new, task_nodes);
1441 if (nodes_empty(*new))
1442 goto out_put;
1443
1444 nodes_and(*new, *new, node_states[N_MEMORY]);
1445 if (nodes_empty(*new))
1446 goto out_put;
1447
1448 err = security_task_movememory(task);
1449 if (err)
1450 goto out_put;
1451
1452 mm = get_task_mm(task);
1453 put_task_struct(task);
1454
1455 if (!mm) {
1456 err = -EINVAL;
1457 goto out;
1458 }
1459
1460 err = do_migrate_pages(mm, old, new,
1461 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1462
1463 mmput(mm);
1464out:
1465 NODEMASK_SCRATCH_FREE(scratch);
1466
1467 return err;
1468
1469out_put:
1470 put_task_struct(task);
1471 goto out;
1472
1473}
1474
1475SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1476 const unsigned long __user *, old_nodes,
1477 const unsigned long __user *, new_nodes)
1478{
1479 return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes);
1480}
1481
1482
1483/* Retrieve NUMA policy */
1484static int kernel_get_mempolicy(int __user *policy,
1485 unsigned long __user *nmask,
1486 unsigned long maxnode,
1487 unsigned long addr,
1488 unsigned long flags)
1489{
1490 int err;
1491 int uninitialized_var(pval);
1492 nodemask_t nodes;
1493
1494 if (nmask != NULL && maxnode < nr_node_ids)
1495 return -EINVAL;
1496
1497 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1498
1499 if (err)
1500 return err;
1501
1502 if (policy && put_user(pval, policy))
1503 return -EFAULT;
1504
1505 if (nmask)
1506 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1507
1508 return err;
1509}
1510
1511SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1512 unsigned long __user *, nmask, unsigned long, maxnode,
1513 unsigned long, addr, unsigned long, flags)
1514{
1515 return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags);
1516}
1517
1518#ifdef CONFIG_COMPAT
1519
1520COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1521 compat_ulong_t __user *, nmask,
1522 compat_ulong_t, maxnode,
1523 compat_ulong_t, addr, compat_ulong_t, flags)
1524{
1525 long err;
1526 unsigned long __user *nm = NULL;
1527 unsigned long nr_bits, alloc_size;
1528 DECLARE_BITMAP(bm, MAX_NUMNODES);
1529
1530 nr_bits = min_t(unsigned long, maxnode-1, nr_node_ids);
1531 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1532
1533 if (nmask)
1534 nm = compat_alloc_user_space(alloc_size);
1535
1536 err = kernel_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1537
1538 if (!err && nmask) {
1539 unsigned long copy_size;
1540 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1541 err = copy_from_user(bm, nm, copy_size);
1542 /* ensure entire bitmap is zeroed */
1543 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1544 err |= compat_put_bitmap(nmask, bm, nr_bits);
1545 }
1546
1547 return err;
1548}
1549
1550COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
1551 compat_ulong_t, maxnode)
1552{
1553 unsigned long __user *nm = NULL;
1554 unsigned long nr_bits, alloc_size;
1555 DECLARE_BITMAP(bm, MAX_NUMNODES);
1556
1557 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1558 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1559
1560 if (nmask) {
1561 if (compat_get_bitmap(bm, nmask, nr_bits))
1562 return -EFAULT;
1563 nm = compat_alloc_user_space(alloc_size);
1564 if (copy_to_user(nm, bm, alloc_size))
1565 return -EFAULT;
1566 }
1567
1568 return kernel_set_mempolicy(mode, nm, nr_bits+1);
1569}
1570
1571COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
1572 compat_ulong_t, mode, compat_ulong_t __user *, nmask,
1573 compat_ulong_t, maxnode, compat_ulong_t, flags)
1574{
1575 unsigned long __user *nm = NULL;
1576 unsigned long nr_bits, alloc_size;
1577 nodemask_t bm;
1578
1579 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1580 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1581
1582 if (nmask) {
1583 if (compat_get_bitmap(nodes_addr(bm), nmask, nr_bits))
1584 return -EFAULT;
1585 nm = compat_alloc_user_space(alloc_size);
1586 if (copy_to_user(nm, nodes_addr(bm), alloc_size))
1587 return -EFAULT;
1588 }
1589
1590 return kernel_mbind(start, len, mode, nm, nr_bits+1, flags);
1591}
1592
1593COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
1594 compat_ulong_t, maxnode,
1595 const compat_ulong_t __user *, old_nodes,
1596 const compat_ulong_t __user *, new_nodes)
1597{
1598 unsigned long __user *old = NULL;
1599 unsigned long __user *new = NULL;
1600 nodemask_t tmp_mask;
1601 unsigned long nr_bits;
1602 unsigned long size;
1603
1604 nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
1605 size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1606 if (old_nodes) {
1607 if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
1608 return -EFAULT;
1609 old = compat_alloc_user_space(new_nodes ? size * 2 : size);
1610 if (new_nodes)
1611 new = old + size / sizeof(unsigned long);
1612 if (copy_to_user(old, nodes_addr(tmp_mask), size))
1613 return -EFAULT;
1614 }
1615 if (new_nodes) {
1616 if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
1617 return -EFAULT;
1618 if (new == NULL)
1619 new = compat_alloc_user_space(size);
1620 if (copy_to_user(new, nodes_addr(tmp_mask), size))
1621 return -EFAULT;
1622 }
1623 return kernel_migrate_pages(pid, nr_bits + 1, old, new);
1624}
1625
1626#endif /* CONFIG_COMPAT */
1627
1628struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
1629 unsigned long addr)
1630{
1631 struct mempolicy *pol = NULL;
1632
1633 if (vma) {
1634 if (vma->vm_ops && vma->vm_ops->get_policy) {
1635 pol = vma->vm_ops->get_policy(vma, addr);
1636 } else if (vma->vm_policy) {
1637 pol = vma->vm_policy;
1638
1639 /*
1640 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1641 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1642 * count on these policies which will be dropped by
1643 * mpol_cond_put() later
1644 */
1645 if (mpol_needs_cond_ref(pol))
1646 mpol_get(pol);
1647 }
1648 }
1649
1650 return pol;
1651}
1652
1653/*
1654 * get_vma_policy(@vma, @addr)
1655 * @vma: virtual memory area whose policy is sought
1656 * @addr: address in @vma for shared policy lookup
1657 *
1658 * Returns effective policy for a VMA at specified address.
1659 * Falls back to current->mempolicy or system default policy, as necessary.
1660 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1661 * count--added by the get_policy() vm_op, as appropriate--to protect against
1662 * freeing by another task. It is the caller's responsibility to free the
1663 * extra reference for shared policies.
1664 */
1665static struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
1666 unsigned long addr)
1667{
1668 struct mempolicy *pol = __get_vma_policy(vma, addr);
1669
1670 if (!pol)
1671 pol = get_task_policy(current);
1672
1673 return pol;
1674}
1675
1676bool vma_policy_mof(struct vm_area_struct *vma)
1677{
1678 struct mempolicy *pol;
1679
1680 if (vma->vm_ops && vma->vm_ops->get_policy) {
1681 bool ret = false;
1682
1683 pol = vma->vm_ops->get_policy(vma, vma->vm_start);
1684 if (pol && (pol->flags & MPOL_F_MOF))
1685 ret = true;
1686 mpol_cond_put(pol);
1687
1688 return ret;
1689 }
1690
1691 pol = vma->vm_policy;
1692 if (!pol)
1693 pol = get_task_policy(current);
1694
1695 return pol->flags & MPOL_F_MOF;
1696}
1697
1698static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1699{
1700 enum zone_type dynamic_policy_zone = policy_zone;
1701
1702 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1703
1704 /*
1705 * if policy->v.nodes has movable memory only,
1706 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1707 *
1708 * policy->v.nodes is intersect with node_states[N_MEMORY].
1709 * so if the following test faile, it implies
1710 * policy->v.nodes has movable memory only.
1711 */
1712 if (!nodes_intersects(policy->v.nodes, node_states[N_HIGH_MEMORY]))
1713 dynamic_policy_zone = ZONE_MOVABLE;
1714
1715 return zone >= dynamic_policy_zone;
1716}
1717
1718/*
1719 * Return a nodemask representing a mempolicy for filtering nodes for
1720 * page allocation
1721 */
1722static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1723{
1724 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1725 if (unlikely(policy->mode == MPOL_BIND) &&
1726 apply_policy_zone(policy, gfp_zone(gfp)) &&
1727 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1728 return &policy->v.nodes;
1729
1730 return NULL;
1731}
1732
1733/* Return the node id preferred by the given mempolicy, or the given id */
1734static int policy_node(gfp_t gfp, struct mempolicy *policy,
1735 int nd)
1736{
1737 if (policy->mode == MPOL_PREFERRED && !(policy->flags & MPOL_F_LOCAL))
1738 nd = policy->v.preferred_node;
1739 else {
1740 /*
1741 * __GFP_THISNODE shouldn't even be used with the bind policy
1742 * because we might easily break the expectation to stay on the
1743 * requested node and not break the policy.
1744 */
1745 WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE));
1746 }
1747
1748 return nd;
1749}
1750
1751/* Do dynamic interleaving for a process */
1752static unsigned interleave_nodes(struct mempolicy *policy)
1753{
1754 unsigned next;
1755 struct task_struct *me = current;
1756
1757 next = next_node_in(me->il_prev, policy->v.nodes);
1758 if (next < MAX_NUMNODES)
1759 me->il_prev = next;
1760 return next;
1761}
1762
1763/*
1764 * Depending on the memory policy provide a node from which to allocate the
1765 * next slab entry.
1766 */
1767unsigned int mempolicy_slab_node(void)
1768{
1769 struct mempolicy *policy;
1770 int node = numa_mem_id();
1771
1772 if (in_interrupt())
1773 return node;
1774
1775 policy = current->mempolicy;
1776 if (!policy || policy->flags & MPOL_F_LOCAL)
1777 return node;
1778
1779 switch (policy->mode) {
1780 case MPOL_PREFERRED:
1781 /*
1782 * handled MPOL_F_LOCAL above
1783 */
1784 return policy->v.preferred_node;
1785
1786 case MPOL_INTERLEAVE:
1787 return interleave_nodes(policy);
1788
1789 case MPOL_BIND: {
1790 struct zoneref *z;
1791
1792 /*
1793 * Follow bind policy behavior and start allocation at the
1794 * first node.
1795 */
1796 struct zonelist *zonelist;
1797 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1798 zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK];
1799 z = first_zones_zonelist(zonelist, highest_zoneidx,
1800 &policy->v.nodes);
1801 return z->zone ? zone_to_nid(z->zone) : node;
1802 }
1803
1804 default:
1805 BUG();
1806 }
1807}
1808
1809/*
1810 * Do static interleaving for a VMA with known offset @n. Returns the n'th
1811 * node in pol->v.nodes (starting from n=0), wrapping around if n exceeds the
1812 * number of present nodes.
1813 */
1814static unsigned offset_il_node(struct mempolicy *pol, unsigned long n)
1815{
1816 unsigned nnodes = nodes_weight(pol->v.nodes);
1817 unsigned target;
1818 int i;
1819 int nid;
1820
1821 if (!nnodes)
1822 return numa_node_id();
1823 target = (unsigned int)n % nnodes;
1824 nid = first_node(pol->v.nodes);
1825 for (i = 0; i < target; i++)
1826 nid = next_node(nid, pol->v.nodes);
1827 return nid;
1828}
1829
1830/* Determine a node number for interleave */
1831static inline unsigned interleave_nid(struct mempolicy *pol,
1832 struct vm_area_struct *vma, unsigned long addr, int shift)
1833{
1834 if (vma) {
1835 unsigned long off;
1836
1837 /*
1838 * for small pages, there is no difference between
1839 * shift and PAGE_SHIFT, so the bit-shift is safe.
1840 * for huge pages, since vm_pgoff is in units of small
1841 * pages, we need to shift off the always 0 bits to get
1842 * a useful offset.
1843 */
1844 BUG_ON(shift < PAGE_SHIFT);
1845 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1846 off += (addr - vma->vm_start) >> shift;
1847 return offset_il_node(pol, off);
1848 } else
1849 return interleave_nodes(pol);
1850}
1851
1852#ifdef CONFIG_HUGETLBFS
1853/*
1854 * huge_node(@vma, @addr, @gfp_flags, @mpol)
1855 * @vma: virtual memory area whose policy is sought
1856 * @addr: address in @vma for shared policy lookup and interleave policy
1857 * @gfp_flags: for requested zone
1858 * @mpol: pointer to mempolicy pointer for reference counted mempolicy
1859 * @nodemask: pointer to nodemask pointer for MPOL_BIND nodemask
1860 *
1861 * Returns a nid suitable for a huge page allocation and a pointer
1862 * to the struct mempolicy for conditional unref after allocation.
1863 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1864 * @nodemask for filtering the zonelist.
1865 *
1866 * Must be protected by read_mems_allowed_begin()
1867 */
1868int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags,
1869 struct mempolicy **mpol, nodemask_t **nodemask)
1870{
1871 int nid;
1872
1873 *mpol = get_vma_policy(vma, addr);
1874 *nodemask = NULL; /* assume !MPOL_BIND */
1875
1876 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1877 nid = interleave_nid(*mpol, vma, addr,
1878 huge_page_shift(hstate_vma(vma)));
1879 } else {
1880 nid = policy_node(gfp_flags, *mpol, numa_node_id());
1881 if ((*mpol)->mode == MPOL_BIND)
1882 *nodemask = &(*mpol)->v.nodes;
1883 }
1884 return nid;
1885}
1886
1887/*
1888 * init_nodemask_of_mempolicy
1889 *
1890 * If the current task's mempolicy is "default" [NULL], return 'false'
1891 * to indicate default policy. Otherwise, extract the policy nodemask
1892 * for 'bind' or 'interleave' policy into the argument nodemask, or
1893 * initialize the argument nodemask to contain the single node for
1894 * 'preferred' or 'local' policy and return 'true' to indicate presence
1895 * of non-default mempolicy.
1896 *
1897 * We don't bother with reference counting the mempolicy [mpol_get/put]
1898 * because the current task is examining it's own mempolicy and a task's
1899 * mempolicy is only ever changed by the task itself.
1900 *
1901 * N.B., it is the caller's responsibility to free a returned nodemask.
1902 */
1903bool init_nodemask_of_mempolicy(nodemask_t *mask)
1904{
1905 struct mempolicy *mempolicy;
1906 int nid;
1907
1908 if (!(mask && current->mempolicy))
1909 return false;
1910
1911 task_lock(current);
1912 mempolicy = current->mempolicy;
1913 switch (mempolicy->mode) {
1914 case MPOL_PREFERRED:
1915 if (mempolicy->flags & MPOL_F_LOCAL)
1916 nid = numa_node_id();
1917 else
1918 nid = mempolicy->v.preferred_node;
1919 init_nodemask_of_node(mask, nid);
1920 break;
1921
1922 case MPOL_BIND:
1923 /* Fall through */
1924 case MPOL_INTERLEAVE:
1925 *mask = mempolicy->v.nodes;
1926 break;
1927
1928 default:
1929 BUG();
1930 }
1931 task_unlock(current);
1932
1933 return true;
1934}
1935#endif
1936
1937/*
1938 * mempolicy_nodemask_intersects
1939 *
1940 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
1941 * policy. Otherwise, check for intersection between mask and the policy
1942 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
1943 * policy, always return true since it may allocate elsewhere on fallback.
1944 *
1945 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
1946 */
1947bool mempolicy_nodemask_intersects(struct task_struct *tsk,
1948 const nodemask_t *mask)
1949{
1950 struct mempolicy *mempolicy;
1951 bool ret = true;
1952
1953 if (!mask)
1954 return ret;
1955 task_lock(tsk);
1956 mempolicy = tsk->mempolicy;
1957 if (!mempolicy)
1958 goto out;
1959
1960 switch (mempolicy->mode) {
1961 case MPOL_PREFERRED:
1962 /*
1963 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
1964 * allocate from, they may fallback to other nodes when oom.
1965 * Thus, it's possible for tsk to have allocated memory from
1966 * nodes in mask.
1967 */
1968 break;
1969 case MPOL_BIND:
1970 case MPOL_INTERLEAVE:
1971 ret = nodes_intersects(mempolicy->v.nodes, *mask);
1972 break;
1973 default:
1974 BUG();
1975 }
1976out:
1977 task_unlock(tsk);
1978 return ret;
1979}
1980
1981/* Allocate a page in interleaved policy.
1982 Own path because it needs to do special accounting. */
1983static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
1984 unsigned nid)
1985{
1986 struct page *page;
1987
1988 page = __alloc_pages(gfp, order, nid);
1989 /* skip NUMA_INTERLEAVE_HIT counter update if numa stats is disabled */
1990 if (!static_branch_likely(&vm_numa_stat_key))
1991 return page;
1992 if (page && page_to_nid(page) == nid) {
1993 preempt_disable();
1994 __inc_numa_state(page_zone(page), NUMA_INTERLEAVE_HIT);
1995 preempt_enable();
1996 }
1997 return page;
1998}
1999
2000/**
2001 * alloc_pages_vma - Allocate a page for a VMA.
2002 *
2003 * @gfp:
2004 * %GFP_USER user allocation.
2005 * %GFP_KERNEL kernel allocations,
2006 * %GFP_HIGHMEM highmem/user allocations,
2007 * %GFP_FS allocation should not call back into a file system.
2008 * %GFP_ATOMIC don't sleep.
2009 *
2010 * @order:Order of the GFP allocation.
2011 * @vma: Pointer to VMA or NULL if not available.
2012 * @addr: Virtual Address of the allocation. Must be inside the VMA.
2013 * @node: Which node to prefer for allocation (modulo policy).
2014 * @hugepage: for hugepages try only the preferred node if possible
2015 *
2016 * This function allocates a page from the kernel page pool and applies
2017 * a NUMA policy associated with the VMA or the current process.
2018 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
2019 * mm_struct of the VMA to prevent it from going away. Should be used for
2020 * all allocations for pages that will be mapped into user space. Returns
2021 * NULL when no page can be allocated.
2022 */
2023struct page *
2024alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
2025 unsigned long addr, int node, bool hugepage)
2026{
2027 struct mempolicy *pol;
2028 struct page *page;
2029 int preferred_nid;
2030 nodemask_t *nmask;
2031
2032 pol = get_vma_policy(vma, addr);
2033
2034 if (pol->mode == MPOL_INTERLEAVE) {
2035 unsigned nid;
2036
2037 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2038 mpol_cond_put(pol);
2039 page = alloc_page_interleave(gfp, order, nid);
2040 goto out;
2041 }
2042
2043 if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
2044 int hpage_node = node;
2045
2046 /*
2047 * For hugepage allocation and non-interleave policy which
2048 * allows the current node (or other explicitly preferred
2049 * node) we only try to allocate from the current/preferred
2050 * node and don't fall back to other nodes, as the cost of
2051 * remote accesses would likely offset THP benefits.
2052 *
2053 * If the policy is interleave, or does not allow the current
2054 * node in its nodemask, we allocate the standard way.
2055 */
2056 if (pol->mode == MPOL_PREFERRED && !(pol->flags & MPOL_F_LOCAL))
2057 hpage_node = pol->v.preferred_node;
2058
2059 nmask = policy_nodemask(gfp, pol);
2060 if (!nmask || node_isset(hpage_node, *nmask)) {
2061 mpol_cond_put(pol);
2062 page = __alloc_pages_node(hpage_node,
2063 gfp | __GFP_THISNODE, order);
2064 goto out;
2065 }
2066 }
2067
2068 nmask = policy_nodemask(gfp, pol);
2069 preferred_nid = policy_node(gfp, pol, node);
2070 page = __alloc_pages_nodemask(gfp, order, preferred_nid, nmask);
2071 mpol_cond_put(pol);
2072out:
2073 return page;
2074}
2075
2076/**
2077 * alloc_pages_current - Allocate pages.
2078 *
2079 * @gfp:
2080 * %GFP_USER user allocation,
2081 * %GFP_KERNEL kernel allocation,
2082 * %GFP_HIGHMEM highmem allocation,
2083 * %GFP_FS don't call back into a file system.
2084 * %GFP_ATOMIC don't sleep.
2085 * @order: Power of two of allocation size in pages. 0 is a single page.
2086 *
2087 * Allocate a page from the kernel page pool. When not in
2088 * interrupt context and apply the current process NUMA policy.
2089 * Returns NULL when no page can be allocated.
2090 */
2091struct page *alloc_pages_current(gfp_t gfp, unsigned order)
2092{
2093 struct mempolicy *pol = &default_policy;
2094 struct page *page;
2095
2096 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2097 pol = get_task_policy(current);
2098
2099 /*
2100 * No reference counting needed for current->mempolicy
2101 * nor system default_policy
2102 */
2103 if (pol->mode == MPOL_INTERLEAVE)
2104 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
2105 else
2106 page = __alloc_pages_nodemask(gfp, order,
2107 policy_node(gfp, pol, numa_node_id()),
2108 policy_nodemask(gfp, pol));
2109
2110 return page;
2111}
2112EXPORT_SYMBOL(alloc_pages_current);
2113
2114int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
2115{
2116 struct mempolicy *pol = mpol_dup(vma_policy(src));
2117
2118 if (IS_ERR(pol))
2119 return PTR_ERR(pol);
2120 dst->vm_policy = pol;
2121 return 0;
2122}
2123
2124/*
2125 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2126 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2127 * with the mems_allowed returned by cpuset_mems_allowed(). This
2128 * keeps mempolicies cpuset relative after its cpuset moves. See
2129 * further kernel/cpuset.c update_nodemask().
2130 *
2131 * current's mempolicy may be rebinded by the other task(the task that changes
2132 * cpuset's mems), so we needn't do rebind work for current task.
2133 */
2134
2135/* Slow path of a mempolicy duplicate */
2136struct mempolicy *__mpol_dup(struct mempolicy *old)
2137{
2138 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2139
2140 if (!new)
2141 return ERR_PTR(-ENOMEM);
2142
2143 /* task's mempolicy is protected by alloc_lock */
2144 if (old == current->mempolicy) {
2145 task_lock(current);
2146 *new = *old;
2147 task_unlock(current);
2148 } else
2149 *new = *old;
2150
2151 if (current_cpuset_is_being_rebound()) {
2152 nodemask_t mems = cpuset_mems_allowed(current);
2153 mpol_rebind_policy(new, &mems);
2154 }
2155 atomic_set(&new->refcnt, 1);
2156 return new;
2157}
2158
2159/* Slow path of a mempolicy comparison */
2160bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2161{
2162 if (!a || !b)
2163 return false;
2164 if (a->mode != b->mode)
2165 return false;
2166 if (a->flags != b->flags)
2167 return false;
2168 if (mpol_store_user_nodemask(a))
2169 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2170 return false;
2171
2172 switch (a->mode) {
2173 case MPOL_BIND:
2174 /* Fall through */
2175 case MPOL_INTERLEAVE:
2176 return !!nodes_equal(a->v.nodes, b->v.nodes);
2177 case MPOL_PREFERRED:
2178 /* a's ->flags is the same as b's */
2179 if (a->flags & MPOL_F_LOCAL)
2180 return true;
2181 return a->v.preferred_node == b->v.preferred_node;
2182 default:
2183 BUG();
2184 return false;
2185 }
2186}
2187
2188/*
2189 * Shared memory backing store policy support.
2190 *
2191 * Remember policies even when nobody has shared memory mapped.
2192 * The policies are kept in Red-Black tree linked from the inode.
2193 * They are protected by the sp->lock rwlock, which should be held
2194 * for any accesses to the tree.
2195 */
2196
2197/*
2198 * lookup first element intersecting start-end. Caller holds sp->lock for
2199 * reading or for writing
2200 */
2201static struct sp_node *
2202sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2203{
2204 struct rb_node *n = sp->root.rb_node;
2205
2206 while (n) {
2207 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2208
2209 if (start >= p->end)
2210 n = n->rb_right;
2211 else if (end <= p->start)
2212 n = n->rb_left;
2213 else
2214 break;
2215 }
2216 if (!n)
2217 return NULL;
2218 for (;;) {
2219 struct sp_node *w = NULL;
2220 struct rb_node *prev = rb_prev(n);
2221 if (!prev)
2222 break;
2223 w = rb_entry(prev, struct sp_node, nd);
2224 if (w->end <= start)
2225 break;
2226 n = prev;
2227 }
2228 return rb_entry(n, struct sp_node, nd);
2229}
2230
2231/*
2232 * Insert a new shared policy into the list. Caller holds sp->lock for
2233 * writing.
2234 */
2235static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2236{
2237 struct rb_node **p = &sp->root.rb_node;
2238 struct rb_node *parent = NULL;
2239 struct sp_node *nd;
2240
2241 while (*p) {
2242 parent = *p;
2243 nd = rb_entry(parent, struct sp_node, nd);
2244 if (new->start < nd->start)
2245 p = &(*p)->rb_left;
2246 else if (new->end > nd->end)
2247 p = &(*p)->rb_right;
2248 else
2249 BUG();
2250 }
2251 rb_link_node(&new->nd, parent, p);
2252 rb_insert_color(&new->nd, &sp->root);
2253 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2254 new->policy ? new->policy->mode : 0);
2255}
2256
2257/* Find shared policy intersecting idx */
2258struct mempolicy *
2259mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2260{
2261 struct mempolicy *pol = NULL;
2262 struct sp_node *sn;
2263
2264 if (!sp->root.rb_node)
2265 return NULL;
2266 read_lock(&sp->lock);
2267 sn = sp_lookup(sp, idx, idx+1);
2268 if (sn) {
2269 mpol_get(sn->policy);
2270 pol = sn->policy;
2271 }
2272 read_unlock(&sp->lock);
2273 return pol;
2274}
2275
2276static void sp_free(struct sp_node *n)
2277{
2278 mpol_put(n->policy);
2279 kmem_cache_free(sn_cache, n);
2280}
2281
2282/**
2283 * mpol_misplaced - check whether current page node is valid in policy
2284 *
2285 * @page: page to be checked
2286 * @vma: vm area where page mapped
2287 * @addr: virtual address where page mapped
2288 *
2289 * Lookup current policy node id for vma,addr and "compare to" page's
2290 * node id.
2291 *
2292 * Returns:
2293 * -1 - not misplaced, page is in the right node
2294 * node - node id where the page should be
2295 *
2296 * Policy determination "mimics" alloc_page_vma().
2297 * Called from fault path where we know the vma and faulting address.
2298 */
2299int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
2300{
2301 struct mempolicy *pol;
2302 struct zoneref *z;
2303 int curnid = page_to_nid(page);
2304 unsigned long pgoff;
2305 int thiscpu = raw_smp_processor_id();
2306 int thisnid = cpu_to_node(thiscpu);
2307 int polnid = NUMA_NO_NODE;
2308 int ret = -1;
2309
2310 pol = get_vma_policy(vma, addr);
2311 if (!(pol->flags & MPOL_F_MOF))
2312 goto out;
2313
2314 switch (pol->mode) {
2315 case MPOL_INTERLEAVE:
2316 pgoff = vma->vm_pgoff;
2317 pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
2318 polnid = offset_il_node(pol, pgoff);
2319 break;
2320
2321 case MPOL_PREFERRED:
2322 if (pol->flags & MPOL_F_LOCAL)
2323 polnid = numa_node_id();
2324 else
2325 polnid = pol->v.preferred_node;
2326 break;
2327
2328 case MPOL_BIND:
2329
2330 /*
2331 * allows binding to multiple nodes.
2332 * use current page if in policy nodemask,
2333 * else select nearest allowed node, if any.
2334 * If no allowed nodes, use current [!misplaced].
2335 */
2336 if (node_isset(curnid, pol->v.nodes))
2337 goto out;
2338 z = first_zones_zonelist(
2339 node_zonelist(numa_node_id(), GFP_HIGHUSER),
2340 gfp_zone(GFP_HIGHUSER),
2341 &pol->v.nodes);
2342 polnid = zone_to_nid(z->zone);
2343 break;
2344
2345 default:
2346 BUG();
2347 }
2348
2349 /* Migrate the page towards the node whose CPU is referencing it */
2350 if (pol->flags & MPOL_F_MORON) {
2351 polnid = thisnid;
2352
2353 if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
2354 goto out;
2355 }
2356
2357 if (curnid != polnid)
2358 ret = polnid;
2359out:
2360 mpol_cond_put(pol);
2361
2362 return ret;
2363}
2364
2365/*
2366 * Drop the (possibly final) reference to task->mempolicy. It needs to be
2367 * dropped after task->mempolicy is set to NULL so that any allocation done as
2368 * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed
2369 * policy.
2370 */
2371void mpol_put_task_policy(struct task_struct *task)
2372{
2373 struct mempolicy *pol;
2374
2375 task_lock(task);
2376 pol = task->mempolicy;
2377 task->mempolicy = NULL;
2378 task_unlock(task);
2379 mpol_put(pol);
2380}
2381
2382static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2383{
2384 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2385 rb_erase(&n->nd, &sp->root);
2386 sp_free(n);
2387}
2388
2389static void sp_node_init(struct sp_node *node, unsigned long start,
2390 unsigned long end, struct mempolicy *pol)
2391{
2392 node->start = start;
2393 node->end = end;
2394 node->policy = pol;
2395}
2396
2397static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2398 struct mempolicy *pol)
2399{
2400 struct sp_node *n;
2401 struct mempolicy *newpol;
2402
2403 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2404 if (!n)
2405 return NULL;
2406
2407 newpol = mpol_dup(pol);
2408 if (IS_ERR(newpol)) {
2409 kmem_cache_free(sn_cache, n);
2410 return NULL;
2411 }
2412 newpol->flags |= MPOL_F_SHARED;
2413 sp_node_init(n, start, end, newpol);
2414
2415 return n;
2416}
2417
2418/* Replace a policy range. */
2419static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2420 unsigned long end, struct sp_node *new)
2421{
2422 struct sp_node *n;
2423 struct sp_node *n_new = NULL;
2424 struct mempolicy *mpol_new = NULL;
2425 int ret = 0;
2426
2427restart:
2428 write_lock(&sp->lock);
2429 n = sp_lookup(sp, start, end);
2430 /* Take care of old policies in the same range. */
2431 while (n && n->start < end) {
2432 struct rb_node *next = rb_next(&n->nd);
2433 if (n->start >= start) {
2434 if (n->end <= end)
2435 sp_delete(sp, n);
2436 else
2437 n->start = end;
2438 } else {
2439 /* Old policy spanning whole new range. */
2440 if (n->end > end) {
2441 if (!n_new)
2442 goto alloc_new;
2443
2444 *mpol_new = *n->policy;
2445 atomic_set(&mpol_new->refcnt, 1);
2446 sp_node_init(n_new, end, n->end, mpol_new);
2447 n->end = start;
2448 sp_insert(sp, n_new);
2449 n_new = NULL;
2450 mpol_new = NULL;
2451 break;
2452 } else
2453 n->end = start;
2454 }
2455 if (!next)
2456 break;
2457 n = rb_entry(next, struct sp_node, nd);
2458 }
2459 if (new)
2460 sp_insert(sp, new);
2461 write_unlock(&sp->lock);
2462 ret = 0;
2463
2464err_out:
2465 if (mpol_new)
2466 mpol_put(mpol_new);
2467 if (n_new)
2468 kmem_cache_free(sn_cache, n_new);
2469
2470 return ret;
2471
2472alloc_new:
2473 write_unlock(&sp->lock);
2474 ret = -ENOMEM;
2475 n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2476 if (!n_new)
2477 goto err_out;
2478 mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2479 if (!mpol_new)
2480 goto err_out;
2481 goto restart;
2482}
2483
2484/**
2485 * mpol_shared_policy_init - initialize shared policy for inode
2486 * @sp: pointer to inode shared policy
2487 * @mpol: struct mempolicy to install
2488 *
2489 * Install non-NULL @mpol in inode's shared policy rb-tree.
2490 * On entry, the current task has a reference on a non-NULL @mpol.
2491 * This must be released on exit.
2492 * This is called at get_inode() calls and we can use GFP_KERNEL.
2493 */
2494void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2495{
2496 int ret;
2497
2498 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2499 rwlock_init(&sp->lock);
2500
2501 if (mpol) {
2502 struct vm_area_struct pvma;
2503 struct mempolicy *new;
2504 NODEMASK_SCRATCH(scratch);
2505
2506 if (!scratch)
2507 goto put_mpol;
2508 /* contextualize the tmpfs mount point mempolicy */
2509 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2510 if (IS_ERR(new))
2511 goto free_scratch; /* no valid nodemask intersection */
2512
2513 task_lock(current);
2514 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2515 task_unlock(current);
2516 if (ret)
2517 goto put_new;
2518
2519 /* Create pseudo-vma that contains just the policy */
2520 vma_init(&pvma, NULL);
2521 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2522 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2523
2524put_new:
2525 mpol_put(new); /* drop initial ref */
2526free_scratch:
2527 NODEMASK_SCRATCH_FREE(scratch);
2528put_mpol:
2529 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2530 }
2531}
2532
2533int mpol_set_shared_policy(struct shared_policy *info,
2534 struct vm_area_struct *vma, struct mempolicy *npol)
2535{
2536 int err;
2537 struct sp_node *new = NULL;
2538 unsigned long sz = vma_pages(vma);
2539
2540 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2541 vma->vm_pgoff,
2542 sz, npol ? npol->mode : -1,
2543 npol ? npol->flags : -1,
2544 npol ? nodes_addr(npol->v.nodes)[0] : NUMA_NO_NODE);
2545
2546 if (npol) {
2547 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2548 if (!new)
2549 return -ENOMEM;
2550 }
2551 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2552 if (err && new)
2553 sp_free(new);
2554 return err;
2555}
2556
2557/* Free a backing policy store on inode delete. */
2558void mpol_free_shared_policy(struct shared_policy *p)
2559{
2560 struct sp_node *n;
2561 struct rb_node *next;
2562
2563 if (!p->root.rb_node)
2564 return;
2565 write_lock(&p->lock);
2566 next = rb_first(&p->root);
2567 while (next) {
2568 n = rb_entry(next, struct sp_node, nd);
2569 next = rb_next(&n->nd);
2570 sp_delete(p, n);
2571 }
2572 write_unlock(&p->lock);
2573}
2574
2575#ifdef CONFIG_NUMA_BALANCING
2576static int __initdata numabalancing_override;
2577
2578static void __init check_numabalancing_enable(void)
2579{
2580 bool numabalancing_default = false;
2581
2582 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2583 numabalancing_default = true;
2584
2585 /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
2586 if (numabalancing_override)
2587 set_numabalancing_state(numabalancing_override == 1);
2588
2589 if (num_online_nodes() > 1 && !numabalancing_override) {
2590 pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n",
2591 numabalancing_default ? "Enabling" : "Disabling");
2592 set_numabalancing_state(numabalancing_default);
2593 }
2594}
2595
2596static int __init setup_numabalancing(char *str)
2597{
2598 int ret = 0;
2599 if (!str)
2600 goto out;
2601
2602 if (!strcmp(str, "enable")) {
2603 numabalancing_override = 1;
2604 ret = 1;
2605 } else if (!strcmp(str, "disable")) {
2606 numabalancing_override = -1;
2607 ret = 1;
2608 }
2609out:
2610 if (!ret)
2611 pr_warn("Unable to parse numa_balancing=\n");
2612
2613 return ret;
2614}
2615__setup("numa_balancing=", setup_numabalancing);
2616#else
2617static inline void __init check_numabalancing_enable(void)
2618{
2619}
2620#endif /* CONFIG_NUMA_BALANCING */
2621
2622/* assumes fs == KERNEL_DS */
2623void __init numa_policy_init(void)
2624{
2625 nodemask_t interleave_nodes;
2626 unsigned long largest = 0;
2627 int nid, prefer = 0;
2628
2629 policy_cache = kmem_cache_create("numa_policy",
2630 sizeof(struct mempolicy),
2631 0, SLAB_PANIC, NULL);
2632
2633 sn_cache = kmem_cache_create("shared_policy_node",
2634 sizeof(struct sp_node),
2635 0, SLAB_PANIC, NULL);
2636
2637 for_each_node(nid) {
2638 preferred_node_policy[nid] = (struct mempolicy) {
2639 .refcnt = ATOMIC_INIT(1),
2640 .mode = MPOL_PREFERRED,
2641 .flags = MPOL_F_MOF | MPOL_F_MORON,
2642 .v = { .preferred_node = nid, },
2643 };
2644 }
2645
2646 /*
2647 * Set interleaving policy for system init. Interleaving is only
2648 * enabled across suitably sized nodes (default is >= 16MB), or
2649 * fall back to the largest node if they're all smaller.
2650 */
2651 nodes_clear(interleave_nodes);
2652 for_each_node_state(nid, N_MEMORY) {
2653 unsigned long total_pages = node_present_pages(nid);
2654
2655 /* Preserve the largest node */
2656 if (largest < total_pages) {
2657 largest = total_pages;
2658 prefer = nid;
2659 }
2660
2661 /* Interleave this node? */
2662 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2663 node_set(nid, interleave_nodes);
2664 }
2665
2666 /* All too small, use the largest */
2667 if (unlikely(nodes_empty(interleave_nodes)))
2668 node_set(prefer, interleave_nodes);
2669
2670 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2671 pr_err("%s: interleaving failed\n", __func__);
2672
2673 check_numabalancing_enable();
2674}
2675
2676/* Reset policy of current process to default */
2677void numa_default_policy(void)
2678{
2679 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2680}
2681
2682/*
2683 * Parse and format mempolicy from/to strings
2684 */
2685
2686/*
2687 * "local" is implemented internally by MPOL_PREFERRED with MPOL_F_LOCAL flag.
2688 */
2689static const char * const policy_modes[] =
2690{
2691 [MPOL_DEFAULT] = "default",
2692 [MPOL_PREFERRED] = "prefer",
2693 [MPOL_BIND] = "bind",
2694 [MPOL_INTERLEAVE] = "interleave",
2695 [MPOL_LOCAL] = "local",
2696};
2697
2698
2699#ifdef CONFIG_TMPFS
2700/**
2701 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2702 * @str: string containing mempolicy to parse
2703 * @mpol: pointer to struct mempolicy pointer, returned on success.
2704 *
2705 * Format of input:
2706 * <mode>[=<flags>][:<nodelist>]
2707 *
2708 * On success, returns 0, else 1
2709 */
2710int mpol_parse_str(char *str, struct mempolicy **mpol)
2711{
2712 struct mempolicy *new = NULL;
2713 unsigned short mode_flags;
2714 nodemask_t nodes;
2715 char *nodelist = strchr(str, ':');
2716 char *flags = strchr(str, '=');
2717 int err = 1, mode;
2718
2719 if (nodelist) {
2720 /* NUL-terminate mode or flags string */
2721 *nodelist++ = '\0';
2722 if (nodelist_parse(nodelist, nodes))
2723 goto out;
2724 if (!nodes_subset(nodes, node_states[N_MEMORY]))
2725 goto out;
2726 } else
2727 nodes_clear(nodes);
2728
2729 if (flags)
2730 *flags++ = '\0'; /* terminate mode string */
2731
2732 mode = match_string(policy_modes, MPOL_MAX, str);
2733 if (mode < 0)
2734 goto out;
2735
2736 switch (mode) {
2737 case MPOL_PREFERRED:
2738 /*
2739 * Insist on a nodelist of one node only
2740 */
2741 if (nodelist) {
2742 char *rest = nodelist;
2743 while (isdigit(*rest))
2744 rest++;
2745 if (*rest)
2746 goto out;
2747 }
2748 break;
2749 case MPOL_INTERLEAVE:
2750 /*
2751 * Default to online nodes with memory if no nodelist
2752 */
2753 if (!nodelist)
2754 nodes = node_states[N_MEMORY];
2755 break;
2756 case MPOL_LOCAL:
2757 /*
2758 * Don't allow a nodelist; mpol_new() checks flags
2759 */
2760 if (nodelist)
2761 goto out;
2762 mode = MPOL_PREFERRED;
2763 break;
2764 case MPOL_DEFAULT:
2765 /*
2766 * Insist on a empty nodelist
2767 */
2768 if (!nodelist)
2769 err = 0;
2770 goto out;
2771 case MPOL_BIND:
2772 /*
2773 * Insist on a nodelist
2774 */
2775 if (!nodelist)
2776 goto out;
2777 }
2778
2779 mode_flags = 0;
2780 if (flags) {
2781 /*
2782 * Currently, we only support two mutually exclusive
2783 * mode flags.
2784 */
2785 if (!strcmp(flags, "static"))
2786 mode_flags |= MPOL_F_STATIC_NODES;
2787 else if (!strcmp(flags, "relative"))
2788 mode_flags |= MPOL_F_RELATIVE_NODES;
2789 else
2790 goto out;
2791 }
2792
2793 new = mpol_new(mode, mode_flags, &nodes);
2794 if (IS_ERR(new))
2795 goto out;
2796
2797 /*
2798 * Save nodes for mpol_to_str() to show the tmpfs mount options
2799 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
2800 */
2801 if (mode != MPOL_PREFERRED)
2802 new->v.nodes = nodes;
2803 else if (nodelist)
2804 new->v.preferred_node = first_node(nodes);
2805 else
2806 new->flags |= MPOL_F_LOCAL;
2807
2808 /*
2809 * Save nodes for contextualization: this will be used to "clone"
2810 * the mempolicy in a specific context [cpuset] at a later time.
2811 */
2812 new->w.user_nodemask = nodes;
2813
2814 err = 0;
2815
2816out:
2817 /* Restore string for error message */
2818 if (nodelist)
2819 *--nodelist = ':';
2820 if (flags)
2821 *--flags = '=';
2822 if (!err)
2823 *mpol = new;
2824 return err;
2825}
2826#endif /* CONFIG_TMPFS */
2827
2828/**
2829 * mpol_to_str - format a mempolicy structure for printing
2830 * @buffer: to contain formatted mempolicy string
2831 * @maxlen: length of @buffer
2832 * @pol: pointer to mempolicy to be formatted
2833 *
2834 * Convert @pol into a string. If @buffer is too short, truncate the string.
2835 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
2836 * longest flag, "relative", and to display at least a few node ids.
2837 */
2838void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
2839{
2840 char *p = buffer;
2841 nodemask_t nodes = NODE_MASK_NONE;
2842 unsigned short mode = MPOL_DEFAULT;
2843 unsigned short flags = 0;
2844
2845 if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
2846 mode = pol->mode;
2847 flags = pol->flags;
2848 }
2849
2850 switch (mode) {
2851 case MPOL_DEFAULT:
2852 break;
2853 case MPOL_PREFERRED:
2854 if (flags & MPOL_F_LOCAL)
2855 mode = MPOL_LOCAL;
2856 else
2857 node_set(pol->v.preferred_node, nodes);
2858 break;
2859 case MPOL_BIND:
2860 case MPOL_INTERLEAVE:
2861 nodes = pol->v.nodes;
2862 break;
2863 default:
2864 WARN_ON_ONCE(1);
2865 snprintf(p, maxlen, "unknown");
2866 return;
2867 }
2868
2869 p += snprintf(p, maxlen, "%s", policy_modes[mode]);
2870
2871 if (flags & MPOL_MODE_FLAGS) {
2872 p += snprintf(p, buffer + maxlen - p, "=");
2873
2874 /*
2875 * Currently, the only defined flags are mutually exclusive
2876 */
2877 if (flags & MPOL_F_STATIC_NODES)
2878 p += snprintf(p, buffer + maxlen - p, "static");
2879 else if (flags & MPOL_F_RELATIVE_NODES)
2880 p += snprintf(p, buffer + maxlen - p, "relative");
2881 }
2882
2883 if (!nodes_empty(nodes))
2884 p += scnprintf(p, buffer + maxlen - p, ":%*pbl",
2885 nodemask_pr_args(&nodes));
2886}
2887