1 // SPDX-License-Identifier: GPL-2.0-only
3 * Simple NUMA memory policy for the Linux kernel.
5 * Copyright 2003,2004 Andi Kleen, SuSE Labs.
6 * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc.
8 * NUMA policy allows the user to give hints in which node(s) memory should
11 * Support four policies per VMA and per process:
13 * The VMA policy has priority over the process policy for a page fault.
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
22 * bind Only allocate memory on a specific set of nodes,
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
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
34 * preferred many Try a set of nodes first before normal fallback. This is
35 * similar to preferred without the special case.
37 * default Allocate on the local node first, or when on a VMA
38 * use the process policy. This is what Linux always did
39 * in a NUMA aware kernel and still does by, ahem, default.
41 * The process policy is applied for most non interrupt memory allocations
42 * in that process' context. Interrupts ignore the policies and always
43 * try to allocate on the local CPU. The VMA policy is only applied for memory
44 * allocations for a VMA in the VM.
46 * Currently there are a few corner cases in swapping where the policy
47 * is not applied, but the majority should be handled. When process policy
48 * is used it is not remembered over swap outs/swap ins.
50 * Only the highest zone in the zone hierarchy gets policied. Allocations
51 * requesting a lower zone just use default policy. This implies that
52 * on systems with highmem kernel lowmem allocation don't get policied.
53 * Same with GFP_DMA allocations.
55 * For shmfs/tmpfs/hugetlbfs shared memory the policy is shared between
56 * all users and remembered even when nobody has memory mapped.
60 fix mmap readahead to honour policy and enable policy for any page cache
62 statistics for bigpages
63 global policy for page cache? currently it uses process policy. Requires
65 handle mremap for shared memory (currently ignored for the policy)
67 make bind policy root only? It can trigger oom much faster and the
68 kernel is not always grateful with that.
71 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
73 #include <linux/mempolicy.h>
74 #include <linux/pagewalk.h>
75 #include <linux/highmem.h>
76 #include <linux/hugetlb.h>
77 #include <linux/kernel.h>
78 #include <linux/sched.h>
79 #include <linux/sched/mm.h>
80 #include <linux/sched/numa_balancing.h>
81 #include <linux/sched/task.h>
82 #include <linux/nodemask.h>
83 #include <linux/cpuset.h>
84 #include <linux/slab.h>
85 #include <linux/string.h>
86 #include <linux/export.h>
87 #include <linux/nsproxy.h>
88 #include <linux/interrupt.h>
89 #include <linux/init.h>
90 #include <linux/compat.h>
91 #include <linux/ptrace.h>
92 #include <linux/swap.h>
93 #include <linux/seq_file.h>
94 #include <linux/proc_fs.h>
95 #include <linux/migrate.h>
96 #include <linux/ksm.h>
97 #include <linux/rmap.h>
98 #include <linux/security.h>
99 #include <linux/syscalls.h>
100 #include <linux/ctype.h>
101 #include <linux/mm_inline.h>
102 #include <linux/mmu_notifier.h>
103 #include <linux/printk.h>
104 #include <linux/swapops.h>
106 #include <asm/tlbflush.h>
107 #include <linux/uaccess.h>
109 #include "internal.h"
112 #define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
113 #define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
115 static struct kmem_cache *policy_cache;
116 static struct kmem_cache *sn_cache;
118 /* Highest zone. An specific allocation for a zone below that is not
120 enum zone_type policy_zone = 0;
123 * run-time system-wide default policy => local allocation
125 static struct mempolicy default_policy = {
126 .refcnt = ATOMIC_INIT(1), /* never free it */
130 static struct mempolicy preferred_node_policy[MAX_NUMNODES];
133 * numa_map_to_online_node - Find closest online node
134 * @node: Node id to start the search
136 * Lookup the next closest node by distance if @nid is not online.
138 * Return: this @node if it is online, otherwise the closest node by distance
140 int numa_map_to_online_node(int node)
142 int min_dist = INT_MAX, dist, n, min_node;
144 if (node == NUMA_NO_NODE || node_online(node))
148 for_each_online_node(n) {
149 dist = node_distance(node, n);
150 if (dist < min_dist) {
158 EXPORT_SYMBOL_GPL(numa_map_to_online_node);
160 struct mempolicy *get_task_policy(struct task_struct *p)
162 struct mempolicy *pol = p->mempolicy;
168 node = numa_node_id();
169 if (node != NUMA_NO_NODE) {
170 pol = &preferred_node_policy[node];
171 /* preferred_node_policy is not initialised early in boot */
176 return &default_policy;
179 static const struct mempolicy_operations {
180 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
181 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes);
182 } mpol_ops[MPOL_MAX];
184 static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
186 return pol->flags & MPOL_MODE_FLAGS;
189 static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
190 const nodemask_t *rel)
193 nodes_fold(tmp, *orig, nodes_weight(*rel));
194 nodes_onto(*ret, tmp, *rel);
197 static int mpol_new_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
199 if (nodes_empty(*nodes))
205 static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
207 if (nodes_empty(*nodes))
210 nodes_clear(pol->nodes);
211 node_set(first_node(*nodes), pol->nodes);
216 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
217 * any, for the new policy. mpol_new() has already validated the nodes
218 * parameter with respect to the policy mode and flags.
220 * Must be called holding task's alloc_lock to protect task's mems_allowed
221 * and mempolicy. May also be called holding the mmap_lock for write.
223 static int mpol_set_nodemask(struct mempolicy *pol,
224 const nodemask_t *nodes, struct nodemask_scratch *nsc)
229 * Default (pol==NULL) resp. local memory policies are not a
230 * subject of any remapping. They also do not need any special
233 if (!pol || pol->mode == MPOL_LOCAL)
237 nodes_and(nsc->mask1,
238 cpuset_current_mems_allowed, node_states[N_MEMORY]);
242 if (pol->flags & MPOL_F_RELATIVE_NODES)
243 mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1);
245 nodes_and(nsc->mask2, *nodes, nsc->mask1);
247 if (mpol_store_user_nodemask(pol))
248 pol->w.user_nodemask = *nodes;
250 pol->w.cpuset_mems_allowed = cpuset_current_mems_allowed;
252 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
257 * This function just creates a new policy, does some check and simple
258 * initialization. You must invoke mpol_set_nodemask() to set nodes.
260 static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
263 struct mempolicy *policy;
265 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
266 mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE);
268 if (mode == MPOL_DEFAULT) {
269 if (nodes && !nodes_empty(*nodes))
270 return ERR_PTR(-EINVAL);
276 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
277 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
278 * All other modes require a valid pointer to a non-empty nodemask.
280 if (mode == MPOL_PREFERRED) {
281 if (nodes_empty(*nodes)) {
282 if (((flags & MPOL_F_STATIC_NODES) ||
283 (flags & MPOL_F_RELATIVE_NODES)))
284 return ERR_PTR(-EINVAL);
288 } else if (mode == MPOL_LOCAL) {
289 if (!nodes_empty(*nodes) ||
290 (flags & MPOL_F_STATIC_NODES) ||
291 (flags & MPOL_F_RELATIVE_NODES))
292 return ERR_PTR(-EINVAL);
293 } else if (nodes_empty(*nodes))
294 return ERR_PTR(-EINVAL);
295 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
297 return ERR_PTR(-ENOMEM);
298 atomic_set(&policy->refcnt, 1);
300 policy->flags = flags;
301 policy->home_node = NUMA_NO_NODE;
306 /* Slow path of a mpol destructor. */
307 void __mpol_put(struct mempolicy *p)
309 if (!atomic_dec_and_test(&p->refcnt))
311 kmem_cache_free(policy_cache, p);
314 static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes)
318 static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
322 if (pol->flags & MPOL_F_STATIC_NODES)
323 nodes_and(tmp, pol->w.user_nodemask, *nodes);
324 else if (pol->flags & MPOL_F_RELATIVE_NODES)
325 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
327 nodes_remap(tmp, pol->nodes, pol->w.cpuset_mems_allowed,
329 pol->w.cpuset_mems_allowed = *nodes;
332 if (nodes_empty(tmp))
338 static void mpol_rebind_preferred(struct mempolicy *pol,
339 const nodemask_t *nodes)
341 pol->w.cpuset_mems_allowed = *nodes;
345 * mpol_rebind_policy - Migrate a policy to a different set of nodes
347 * Per-vma policies are protected by mmap_lock. Allocations using per-task
348 * policies are protected by task->mems_allowed_seq to prevent a premature
349 * OOM/allocation failure due to parallel nodemask modification.
351 static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask)
355 if (!mpol_store_user_nodemask(pol) &&
356 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
359 mpol_ops[pol->mode].rebind(pol, newmask);
363 * Wrapper for mpol_rebind_policy() that just requires task
364 * pointer, and updates task mempolicy.
366 * Called with task's alloc_lock held.
369 void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new)
371 mpol_rebind_policy(tsk->mempolicy, new);
375 * Rebind each vma in mm to new nodemask.
377 * Call holding a reference to mm. Takes mm->mmap_lock during call.
380 void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
382 struct vm_area_struct *vma;
385 for (vma = mm->mmap; vma; vma = vma->vm_next)
386 mpol_rebind_policy(vma->vm_policy, new);
387 mmap_write_unlock(mm);
390 static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
392 .rebind = mpol_rebind_default,
394 [MPOL_INTERLEAVE] = {
395 .create = mpol_new_nodemask,
396 .rebind = mpol_rebind_nodemask,
399 .create = mpol_new_preferred,
400 .rebind = mpol_rebind_preferred,
403 .create = mpol_new_nodemask,
404 .rebind = mpol_rebind_nodemask,
407 .rebind = mpol_rebind_default,
409 [MPOL_PREFERRED_MANY] = {
410 .create = mpol_new_nodemask,
411 .rebind = mpol_rebind_preferred,
415 static int migrate_page_add(struct page *page, struct list_head *pagelist,
416 unsigned long flags);
419 struct list_head *pagelist;
424 struct vm_area_struct *first;
428 * Check if the page's nid is in qp->nmask.
430 * If MPOL_MF_INVERT is set in qp->flags, check if the nid is
431 * in the invert of qp->nmask.
433 static inline bool queue_pages_required(struct page *page,
434 struct queue_pages *qp)
436 int nid = page_to_nid(page);
437 unsigned long flags = qp->flags;
439 return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT);
443 * queue_pages_pmd() has four possible return values:
444 * 0 - pages are placed on the right node or queued successfully, or
445 * special page is met, i.e. huge zero page.
446 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
449 * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an
450 * existing page was already on a node that does not follow the
453 static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
454 unsigned long end, struct mm_walk *walk)
459 struct queue_pages *qp = walk->private;
462 if (unlikely(is_pmd_migration_entry(*pmd))) {
466 page = pmd_page(*pmd);
467 if (is_huge_zero_page(page)) {
469 walk->action = ACTION_CONTINUE;
472 if (!queue_pages_required(page, qp))
476 /* go to thp migration */
477 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
478 if (!vma_migratable(walk->vma) ||
479 migrate_page_add(page, qp->pagelist, flags)) {
492 * Scan through pages checking if pages follow certain conditions,
493 * and move them to the pagelist if they do.
495 * queue_pages_pte_range() has three possible return values:
496 * 0 - pages are placed on the right node or queued successfully, or
497 * special page is met, i.e. zero page.
498 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
500 * -EIO - only MPOL_MF_STRICT was specified and an existing page was already
501 * on a node that does not follow the policy.
503 static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
504 unsigned long end, struct mm_walk *walk)
506 struct vm_area_struct *vma = walk->vma;
508 struct queue_pages *qp = walk->private;
509 unsigned long flags = qp->flags;
511 bool has_unmovable = false;
512 pte_t *pte, *mapped_pte;
515 ptl = pmd_trans_huge_lock(pmd, vma);
517 ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
521 /* THP was split, fall through to pte walk */
523 if (pmd_trans_unstable(pmd))
526 mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
527 for (; addr != end; pte++, addr += PAGE_SIZE) {
528 if (!pte_present(*pte))
530 page = vm_normal_page(vma, addr, *pte);
534 * vm_normal_page() filters out zero pages, but there might
535 * still be PageReserved pages to skip, perhaps in a VDSO.
537 if (PageReserved(page))
539 if (!queue_pages_required(page, qp))
541 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
542 /* MPOL_MF_STRICT must be specified if we get here */
543 if (!vma_migratable(vma)) {
544 has_unmovable = true;
549 * Do not abort immediately since there may be
550 * temporary off LRU pages in the range. Still
551 * need migrate other LRU pages.
553 if (migrate_page_add(page, qp->pagelist, flags))
554 has_unmovable = true;
558 pte_unmap_unlock(mapped_pte, ptl);
564 return addr != end ? -EIO : 0;
567 static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
568 unsigned long addr, unsigned long end,
569 struct mm_walk *walk)
572 #ifdef CONFIG_HUGETLB_PAGE
573 struct queue_pages *qp = walk->private;
574 unsigned long flags = (qp->flags & MPOL_MF_VALID);
579 ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
580 entry = huge_ptep_get(pte);
581 if (!pte_present(entry))
583 page = pte_page(entry);
584 if (!queue_pages_required(page, qp))
587 if (flags == MPOL_MF_STRICT) {
589 * STRICT alone means only detecting misplaced page and no
590 * need to further check other vma.
596 if (!vma_migratable(walk->vma)) {
598 * Must be STRICT with MOVE*, otherwise .test_walk() have
599 * stopped walking current vma.
600 * Detecting misplaced page but allow migrating pages which
607 /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
608 if (flags & (MPOL_MF_MOVE_ALL) ||
609 (flags & MPOL_MF_MOVE && page_mapcount(page) == 1)) {
610 if (!isolate_huge_page(page, qp->pagelist) &&
611 (flags & MPOL_MF_STRICT))
613 * Failed to isolate page but allow migrating pages
614 * which have been queued.
626 #ifdef CONFIG_NUMA_BALANCING
628 * This is used to mark a range of virtual addresses to be inaccessible.
629 * These are later cleared by a NUMA hinting fault. Depending on these
630 * faults, pages may be migrated for better NUMA placement.
632 * This is assuming that NUMA faults are handled using PROT_NONE. If
633 * an architecture makes a different choice, it will need further
634 * changes to the core.
636 unsigned long change_prot_numa(struct vm_area_struct *vma,
637 unsigned long addr, unsigned long end)
641 nr_updated = change_protection(vma, addr, end, PAGE_NONE, MM_CP_PROT_NUMA);
643 count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
648 static unsigned long change_prot_numa(struct vm_area_struct *vma,
649 unsigned long addr, unsigned long end)
653 #endif /* CONFIG_NUMA_BALANCING */
655 static int queue_pages_test_walk(unsigned long start, unsigned long end,
656 struct mm_walk *walk)
658 struct vm_area_struct *vma = walk->vma;
659 struct queue_pages *qp = walk->private;
660 unsigned long endvma = vma->vm_end;
661 unsigned long flags = qp->flags;
663 /* range check first */
664 VM_BUG_ON_VMA(!range_in_vma(vma, start, end), vma);
668 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
669 (qp->start < vma->vm_start))
670 /* hole at head side of range */
673 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
674 ((vma->vm_end < qp->end) &&
675 (!vma->vm_next || vma->vm_end < vma->vm_next->vm_start)))
676 /* hole at middle or tail of range */
680 * Need check MPOL_MF_STRICT to return -EIO if possible
681 * regardless of vma_migratable
683 if (!vma_migratable(vma) &&
684 !(flags & MPOL_MF_STRICT))
690 if (flags & MPOL_MF_LAZY) {
691 /* Similar to task_numa_work, skip inaccessible VMAs */
692 if (!is_vm_hugetlb_page(vma) && vma_is_accessible(vma) &&
693 !(vma->vm_flags & VM_MIXEDMAP))
694 change_prot_numa(vma, start, endvma);
698 /* queue pages from current vma */
699 if (flags & MPOL_MF_VALID)
704 static const struct mm_walk_ops queue_pages_walk_ops = {
705 .hugetlb_entry = queue_pages_hugetlb,
706 .pmd_entry = queue_pages_pte_range,
707 .test_walk = queue_pages_test_walk,
711 * Walk through page tables and collect pages to be migrated.
713 * If pages found in a given range are on a set of nodes (determined by
714 * @nodes and @flags,) it's isolated and queued to the pagelist which is
715 * passed via @private.
717 * queue_pages_range() has three possible return values:
718 * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
720 * 0 - queue pages successfully or no misplaced page.
721 * errno - i.e. misplaced pages with MPOL_MF_STRICT specified (-EIO) or
722 * memory range specified by nodemask and maxnode points outside
723 * your accessible address space (-EFAULT)
726 queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
727 nodemask_t *nodes, unsigned long flags,
728 struct list_head *pagelist)
731 struct queue_pages qp = {
732 .pagelist = pagelist,
740 err = walk_page_range(mm, start, end, &queue_pages_walk_ops, &qp);
743 /* whole range in hole */
750 * Apply policy to a single VMA
751 * This must be called with the mmap_lock held for writing.
753 static int vma_replace_policy(struct vm_area_struct *vma,
754 struct mempolicy *pol)
757 struct mempolicy *old;
758 struct mempolicy *new;
760 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
761 vma->vm_start, vma->vm_end, vma->vm_pgoff,
762 vma->vm_ops, vma->vm_file,
763 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
769 if (vma->vm_ops && vma->vm_ops->set_policy) {
770 err = vma->vm_ops->set_policy(vma, new);
775 old = vma->vm_policy;
776 vma->vm_policy = new; /* protected by mmap_lock */
785 /* Step 2: apply policy to a range and do splits. */
786 static int mbind_range(struct mm_struct *mm, unsigned long start,
787 unsigned long end, struct mempolicy *new_pol)
789 struct vm_area_struct *next;
790 struct vm_area_struct *prev;
791 struct vm_area_struct *vma;
794 unsigned long vmstart;
797 vma = find_vma(mm, start);
801 if (start > vma->vm_start)
804 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
806 vmstart = max(start, vma->vm_start);
807 vmend = min(end, vma->vm_end);
809 if (mpol_equal(vma_policy(vma), new_pol))
812 pgoff = vma->vm_pgoff +
813 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
814 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
815 vma->anon_vma, vma->vm_file, pgoff,
816 new_pol, vma->vm_userfaultfd_ctx,
821 if (mpol_equal(vma_policy(vma), new_pol))
823 /* vma_merge() joined vma && vma->next, case 8 */
826 if (vma->vm_start != vmstart) {
827 err = split_vma(vma->vm_mm, vma, vmstart, 1);
831 if (vma->vm_end != vmend) {
832 err = split_vma(vma->vm_mm, vma, vmend, 0);
837 err = vma_replace_policy(vma, new_pol);
846 /* Set the process memory policy */
847 static long do_set_mempolicy(unsigned short mode, unsigned short flags,
850 struct mempolicy *new, *old;
851 NODEMASK_SCRATCH(scratch);
857 new = mpol_new(mode, flags, nodes);
863 ret = mpol_set_nodemask(new, nodes, scratch);
869 old = current->mempolicy;
870 current->mempolicy = new;
871 if (new && new->mode == MPOL_INTERLEAVE)
872 current->il_prev = MAX_NUMNODES-1;
873 task_unlock(current);
877 NODEMASK_SCRATCH_FREE(scratch);
882 * Return nodemask for policy for get_mempolicy() query
884 * Called with task's alloc_lock held
886 static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
889 if (p == &default_policy)
894 case MPOL_INTERLEAVE:
896 case MPOL_PREFERRED_MANY:
900 /* return empty node mask for local allocation */
907 static int lookup_node(struct mm_struct *mm, unsigned long addr)
909 struct page *p = NULL;
912 ret = get_user_pages_fast(addr & PAGE_MASK, 1, 0, &p);
914 ret = page_to_nid(p);
920 /* Retrieve NUMA policy */
921 static long do_get_mempolicy(int *policy, nodemask_t *nmask,
922 unsigned long addr, unsigned long flags)
925 struct mm_struct *mm = current->mm;
926 struct vm_area_struct *vma = NULL;
927 struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL;
930 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
933 if (flags & MPOL_F_MEMS_ALLOWED) {
934 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
936 *policy = 0; /* just so it's initialized */
938 *nmask = cpuset_current_mems_allowed;
939 task_unlock(current);
943 if (flags & MPOL_F_ADDR) {
945 * Do NOT fall back to task policy if the
946 * vma/shared policy at addr is NULL. We
947 * want to return MPOL_DEFAULT in this case.
950 vma = vma_lookup(mm, addr);
952 mmap_read_unlock(mm);
955 if (vma->vm_ops && vma->vm_ops->get_policy)
956 pol = vma->vm_ops->get_policy(vma, addr);
958 pol = vma->vm_policy;
963 pol = &default_policy; /* indicates default behavior */
965 if (flags & MPOL_F_NODE) {
966 if (flags & MPOL_F_ADDR) {
968 * Take a refcount on the mpol, because we are about to
969 * drop the mmap_lock, after which only "pol" remains
970 * valid, "vma" is stale.
975 mmap_read_unlock(mm);
976 err = lookup_node(mm, addr);
980 } else if (pol == current->mempolicy &&
981 pol->mode == MPOL_INTERLEAVE) {
982 *policy = next_node_in(current->il_prev, pol->nodes);
988 *policy = pol == &default_policy ? MPOL_DEFAULT :
991 * Internal mempolicy flags must be masked off before exposing
992 * the policy to userspace.
994 *policy |= (pol->flags & MPOL_MODE_FLAGS);
999 if (mpol_store_user_nodemask(pol)) {
1000 *nmask = pol->w.user_nodemask;
1003 get_policy_nodemask(pol, nmask);
1004 task_unlock(current);
1011 mmap_read_unlock(mm);
1013 mpol_put(pol_refcount);
1017 #ifdef CONFIG_MIGRATION
1019 * page migration, thp tail pages can be passed.
1021 static int migrate_page_add(struct page *page, struct list_head *pagelist,
1022 unsigned long flags)
1024 struct page *head = compound_head(page);
1026 * Avoid migrating a page that is shared with others.
1028 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(head) == 1) {
1029 if (!isolate_lru_page(head)) {
1030 list_add_tail(&head->lru, pagelist);
1031 mod_node_page_state(page_pgdat(head),
1032 NR_ISOLATED_ANON + page_is_file_lru(head),
1033 thp_nr_pages(head));
1034 } else if (flags & MPOL_MF_STRICT) {
1036 * Non-movable page may reach here. And, there may be
1037 * temporary off LRU pages or non-LRU movable pages.
1038 * Treat them as unmovable pages since they can't be
1039 * isolated, so they can't be moved at the moment. It
1040 * should return -EIO for this case too.
1050 * Migrate pages from one node to a target node.
1051 * Returns error or the number of pages not migrated.
1053 static int migrate_to_node(struct mm_struct *mm, int source, int dest,
1057 LIST_HEAD(pagelist);
1059 struct migration_target_control mtc = {
1061 .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE,
1065 node_set(source, nmask);
1068 * This does not "check" the range but isolates all pages that
1069 * need migration. Between passing in the full user address
1070 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
1072 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
1073 queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1074 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
1076 if (!list_empty(&pagelist)) {
1077 err = migrate_pages(&pagelist, alloc_migration_target, NULL,
1078 (unsigned long)&mtc, MIGRATE_SYNC, MR_SYSCALL, NULL);
1080 putback_movable_pages(&pagelist);
1087 * Move pages between the two nodesets so as to preserve the physical
1088 * layout as much as possible.
1090 * Returns the number of page that could not be moved.
1092 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1093 const nodemask_t *to, int flags)
1099 lru_cache_disable();
1104 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1105 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1106 * bit in 'tmp', and return that <source, dest> pair for migration.
1107 * The pair of nodemasks 'to' and 'from' define the map.
1109 * If no pair of bits is found that way, fallback to picking some
1110 * pair of 'source' and 'dest' bits that are not the same. If the
1111 * 'source' and 'dest' bits are the same, this represents a node
1112 * that will be migrating to itself, so no pages need move.
1114 * If no bits are left in 'tmp', or if all remaining bits left
1115 * in 'tmp' correspond to the same bit in 'to', return false
1116 * (nothing left to migrate).
1118 * This lets us pick a pair of nodes to migrate between, such that
1119 * if possible the dest node is not already occupied by some other
1120 * source node, minimizing the risk of overloading the memory on a
1121 * node that would happen if we migrated incoming memory to a node
1122 * before migrating outgoing memory source that same node.
1124 * A single scan of tmp is sufficient. As we go, we remember the
1125 * most recent <s, d> pair that moved (s != d). If we find a pair
1126 * that not only moved, but what's better, moved to an empty slot
1127 * (d is not set in tmp), then we break out then, with that pair.
1128 * Otherwise when we finish scanning from_tmp, we at least have the
1129 * most recent <s, d> pair that moved. If we get all the way through
1130 * the scan of tmp without finding any node that moved, much less
1131 * moved to an empty node, then there is nothing left worth migrating.
1135 while (!nodes_empty(tmp)) {
1137 int source = NUMA_NO_NODE;
1140 for_each_node_mask(s, tmp) {
1143 * do_migrate_pages() tries to maintain the relative
1144 * node relationship of the pages established between
1145 * threads and memory areas.
1147 * However if the number of source nodes is not equal to
1148 * the number of destination nodes we can not preserve
1149 * this node relative relationship. In that case, skip
1150 * copying memory from a node that is in the destination
1153 * Example: [2,3,4] -> [3,4,5] moves everything.
1154 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1157 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1158 (node_isset(s, *to)))
1161 d = node_remap(s, *from, *to);
1165 source = s; /* Node moved. Memorize */
1168 /* dest not in remaining from nodes? */
1169 if (!node_isset(dest, tmp))
1172 if (source == NUMA_NO_NODE)
1175 node_clear(source, tmp);
1176 err = migrate_to_node(mm, source, dest, flags);
1182 mmap_read_unlock(mm);
1192 * Allocate a new page for page migration based on vma policy.
1193 * Start by assuming the page is mapped by the same vma as contains @start.
1194 * Search forward from there, if not. N.B., this assumes that the
1195 * list of pages handed to migrate_pages()--which is how we get here--
1196 * is in virtual address order.
1198 static struct page *new_page(struct page *page, unsigned long start)
1200 struct vm_area_struct *vma;
1201 unsigned long address;
1203 vma = find_vma(current->mm, start);
1205 address = page_address_in_vma(page, vma);
1206 if (address != -EFAULT)
1211 if (PageHuge(page)) {
1212 return alloc_huge_page_vma(page_hstate(compound_head(page)),
1214 } else if (PageTransHuge(page)) {
1217 thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
1221 prep_transhuge_page(thp);
1225 * if !vma, alloc_page_vma() will use task or system default policy
1227 return alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL,
1232 static int migrate_page_add(struct page *page, struct list_head *pagelist,
1233 unsigned long flags)
1238 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1239 const nodemask_t *to, int flags)
1244 static struct page *new_page(struct page *page, unsigned long start)
1250 static long do_mbind(unsigned long start, unsigned long len,
1251 unsigned short mode, unsigned short mode_flags,
1252 nodemask_t *nmask, unsigned long flags)
1254 struct mm_struct *mm = current->mm;
1255 struct mempolicy *new;
1259 LIST_HEAD(pagelist);
1261 if (flags & ~(unsigned long)MPOL_MF_VALID)
1263 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1266 if (start & ~PAGE_MASK)
1269 if (mode == MPOL_DEFAULT)
1270 flags &= ~MPOL_MF_STRICT;
1272 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1280 new = mpol_new(mode, mode_flags, nmask);
1282 return PTR_ERR(new);
1284 if (flags & MPOL_MF_LAZY)
1285 new->flags |= MPOL_F_MOF;
1288 * If we are using the default policy then operation
1289 * on discontinuous address spaces is okay after all
1292 flags |= MPOL_MF_DISCONTIG_OK;
1294 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1295 start, start + len, mode, mode_flags,
1296 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1298 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1300 lru_cache_disable();
1303 NODEMASK_SCRATCH(scratch);
1305 mmap_write_lock(mm);
1306 err = mpol_set_nodemask(new, nmask, scratch);
1308 mmap_write_unlock(mm);
1311 NODEMASK_SCRATCH_FREE(scratch);
1316 ret = queue_pages_range(mm, start, end, nmask,
1317 flags | MPOL_MF_INVERT, &pagelist);
1324 err = mbind_range(mm, start, end, new);
1329 if (!list_empty(&pagelist)) {
1330 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1331 nr_failed = migrate_pages(&pagelist, new_page, NULL,
1332 start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND, NULL);
1334 putback_movable_pages(&pagelist);
1337 if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
1341 if (!list_empty(&pagelist))
1342 putback_movable_pages(&pagelist);
1345 mmap_write_unlock(mm);
1348 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1354 * User space interface with variable sized bitmaps for nodelists.
1356 static int get_bitmap(unsigned long *mask, const unsigned long __user *nmask,
1357 unsigned long maxnode)
1359 unsigned long nlongs = BITS_TO_LONGS(maxnode);
1362 if (in_compat_syscall())
1363 ret = compat_get_bitmap(mask,
1364 (const compat_ulong_t __user *)nmask,
1367 ret = copy_from_user(mask, nmask,
1368 nlongs * sizeof(unsigned long));
1373 if (maxnode % BITS_PER_LONG)
1374 mask[nlongs - 1] &= (1UL << (maxnode % BITS_PER_LONG)) - 1;
1379 /* Copy a node mask from user space. */
1380 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1381 unsigned long maxnode)
1384 nodes_clear(*nodes);
1385 if (maxnode == 0 || !nmask)
1387 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1391 * When the user specified more nodes than supported just check
1392 * if the non supported part is all zero, one word at a time,
1393 * starting at the end.
1395 while (maxnode > MAX_NUMNODES) {
1396 unsigned long bits = min_t(unsigned long, maxnode, BITS_PER_LONG);
1399 if (get_bitmap(&t, &nmask[maxnode / BITS_PER_LONG], bits))
1402 if (maxnode - bits >= MAX_NUMNODES) {
1405 maxnode = MAX_NUMNODES;
1406 t &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
1412 return get_bitmap(nodes_addr(*nodes), nmask, maxnode);
1415 /* Copy a kernel node mask to user space */
1416 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1419 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1420 unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long);
1421 bool compat = in_compat_syscall();
1424 nbytes = BITS_TO_COMPAT_LONGS(nr_node_ids) * sizeof(compat_long_t);
1426 if (copy > nbytes) {
1427 if (copy > PAGE_SIZE)
1429 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1432 maxnode = nr_node_ids;
1436 return compat_put_bitmap((compat_ulong_t __user *)mask,
1437 nodes_addr(*nodes), maxnode);
1439 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1442 /* Basic parameter sanity check used by both mbind() and set_mempolicy() */
1443 static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)
1445 *flags = *mode & MPOL_MODE_FLAGS;
1446 *mode &= ~MPOL_MODE_FLAGS;
1448 if ((unsigned int)(*mode) >= MPOL_MAX)
1450 if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))
1452 if (*flags & MPOL_F_NUMA_BALANCING) {
1453 if (*mode != MPOL_BIND)
1455 *flags |= (MPOL_F_MOF | MPOL_F_MORON);
1460 static long kernel_mbind(unsigned long start, unsigned long len,
1461 unsigned long mode, const unsigned long __user *nmask,
1462 unsigned long maxnode, unsigned int flags)
1464 unsigned short mode_flags;
1469 start = untagged_addr(start);
1470 err = sanitize_mpol_flags(&lmode, &mode_flags);
1474 err = get_nodes(&nodes, nmask, maxnode);
1478 return do_mbind(start, len, lmode, mode_flags, &nodes, flags);
1481 SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, len,
1482 unsigned long, home_node, unsigned long, flags)
1484 struct mm_struct *mm = current->mm;
1485 struct vm_area_struct *vma;
1486 struct mempolicy *new;
1487 unsigned long vmstart;
1488 unsigned long vmend;
1492 start = untagged_addr(start);
1493 if (start & ~PAGE_MASK)
1496 * flags is used for future extension if any.
1502 * Check home_node is online to avoid accessing uninitialized
1505 if (home_node >= MAX_NUMNODES || !node_online(home_node))
1508 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1515 mmap_write_lock(mm);
1516 vma = find_vma(mm, start);
1517 for (; vma && vma->vm_start < end; vma = vma->vm_next) {
1519 vmstart = max(start, vma->vm_start);
1520 vmend = min(end, vma->vm_end);
1521 new = mpol_dup(vma_policy(vma));
1527 * Only update home node if there is an existing vma policy
1533 * If any vma in the range got policy other than MPOL_BIND
1534 * or MPOL_PREFERRED_MANY we return error. We don't reset
1535 * the home node for vmas we already updated before.
1537 if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
1542 new->home_node = home_node;
1543 err = mbind_range(mm, vmstart, vmend, new);
1548 mmap_write_unlock(mm);
1552 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1553 unsigned long, mode, const unsigned long __user *, nmask,
1554 unsigned long, maxnode, unsigned int, flags)
1556 return kernel_mbind(start, len, mode, nmask, maxnode, flags);
1559 /* Set the process memory policy */
1560 static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
1561 unsigned long maxnode)
1563 unsigned short mode_flags;
1568 err = sanitize_mpol_flags(&lmode, &mode_flags);
1572 err = get_nodes(&nodes, nmask, maxnode);
1576 return do_set_mempolicy(lmode, mode_flags, &nodes);
1579 SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
1580 unsigned long, maxnode)
1582 return kernel_set_mempolicy(mode, nmask, maxnode);
1585 static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
1586 const unsigned long __user *old_nodes,
1587 const unsigned long __user *new_nodes)
1589 struct mm_struct *mm = NULL;
1590 struct task_struct *task;
1591 nodemask_t task_nodes;
1595 NODEMASK_SCRATCH(scratch);
1600 old = &scratch->mask1;
1601 new = &scratch->mask2;
1603 err = get_nodes(old, old_nodes, maxnode);
1607 err = get_nodes(new, new_nodes, maxnode);
1611 /* Find the mm_struct */
1613 task = pid ? find_task_by_vpid(pid) : current;
1619 get_task_struct(task);
1624 * Check if this process has the right to modify the specified process.
1625 * Use the regular "ptrace_may_access()" checks.
1627 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
1634 task_nodes = cpuset_mems_allowed(task);
1635 /* Is the user allowed to access the target nodes? */
1636 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1641 task_nodes = cpuset_mems_allowed(current);
1642 nodes_and(*new, *new, task_nodes);
1643 if (nodes_empty(*new))
1646 err = security_task_movememory(task);
1650 mm = get_task_mm(task);
1651 put_task_struct(task);
1658 err = do_migrate_pages(mm, old, new,
1659 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1663 NODEMASK_SCRATCH_FREE(scratch);
1668 put_task_struct(task);
1673 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1674 const unsigned long __user *, old_nodes,
1675 const unsigned long __user *, new_nodes)
1677 return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes);
1681 /* Retrieve NUMA policy */
1682 static int kernel_get_mempolicy(int __user *policy,
1683 unsigned long __user *nmask,
1684 unsigned long maxnode,
1686 unsigned long flags)
1692 if (nmask != NULL && maxnode < nr_node_ids)
1695 addr = untagged_addr(addr);
1697 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1702 if (policy && put_user(pval, policy))
1706 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1711 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1712 unsigned long __user *, nmask, unsigned long, maxnode,
1713 unsigned long, addr, unsigned long, flags)
1715 return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags);
1718 bool vma_migratable(struct vm_area_struct *vma)
1720 if (vma->vm_flags & (VM_IO | VM_PFNMAP))
1724 * DAX device mappings require predictable access latency, so avoid
1725 * incurring periodic faults.
1727 if (vma_is_dax(vma))
1730 if (is_vm_hugetlb_page(vma) &&
1731 !hugepage_migration_supported(hstate_vma(vma)))
1735 * Migration allocates pages in the highest zone. If we cannot
1736 * do so then migration (at least from node to node) is not
1740 gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
1746 struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
1749 struct mempolicy *pol = NULL;
1752 if (vma->vm_ops && vma->vm_ops->get_policy) {
1753 pol = vma->vm_ops->get_policy(vma, addr);
1754 } else if (vma->vm_policy) {
1755 pol = vma->vm_policy;
1758 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1759 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1760 * count on these policies which will be dropped by
1761 * mpol_cond_put() later
1763 if (mpol_needs_cond_ref(pol))
1772 * get_vma_policy(@vma, @addr)
1773 * @vma: virtual memory area whose policy is sought
1774 * @addr: address in @vma for shared policy lookup
1776 * Returns effective policy for a VMA at specified address.
1777 * Falls back to current->mempolicy or system default policy, as necessary.
1778 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1779 * count--added by the get_policy() vm_op, as appropriate--to protect against
1780 * freeing by another task. It is the caller's responsibility to free the
1781 * extra reference for shared policies.
1783 static struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
1786 struct mempolicy *pol = __get_vma_policy(vma, addr);
1789 pol = get_task_policy(current);
1794 bool vma_policy_mof(struct vm_area_struct *vma)
1796 struct mempolicy *pol;
1798 if (vma->vm_ops && vma->vm_ops->get_policy) {
1801 pol = vma->vm_ops->get_policy(vma, vma->vm_start);
1802 if (pol && (pol->flags & MPOL_F_MOF))
1809 pol = vma->vm_policy;
1811 pol = get_task_policy(current);
1813 return pol->flags & MPOL_F_MOF;
1816 static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1818 enum zone_type dynamic_policy_zone = policy_zone;
1820 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1823 * if policy->nodes has movable memory only,
1824 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1826 * policy->nodes is intersect with node_states[N_MEMORY].
1827 * so if the following test fails, it implies
1828 * policy->nodes has movable memory only.
1830 if (!nodes_intersects(policy->nodes, node_states[N_HIGH_MEMORY]))
1831 dynamic_policy_zone = ZONE_MOVABLE;
1833 return zone >= dynamic_policy_zone;
1837 * Return a nodemask representing a mempolicy for filtering nodes for
1840 nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1842 int mode = policy->mode;
1844 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1845 if (unlikely(mode == MPOL_BIND) &&
1846 apply_policy_zone(policy, gfp_zone(gfp)) &&
1847 cpuset_nodemask_valid_mems_allowed(&policy->nodes))
1848 return &policy->nodes;
1850 if (mode == MPOL_PREFERRED_MANY)
1851 return &policy->nodes;
1857 * Return the preferred node id for 'prefer' mempolicy, and return
1858 * the given id for all other policies.
1860 * policy_node() is always coupled with policy_nodemask(), which
1861 * secures the nodemask limit for 'bind' and 'prefer-many' policy.
1863 static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd)
1865 if (policy->mode == MPOL_PREFERRED) {
1866 nd = first_node(policy->nodes);
1869 * __GFP_THISNODE shouldn't even be used with the bind policy
1870 * because we might easily break the expectation to stay on the
1871 * requested node and not break the policy.
1873 WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE));
1876 if ((policy->mode == MPOL_BIND ||
1877 policy->mode == MPOL_PREFERRED_MANY) &&
1878 policy->home_node != NUMA_NO_NODE)
1879 return policy->home_node;
1884 /* Do dynamic interleaving for a process */
1885 static unsigned interleave_nodes(struct mempolicy *policy)
1888 struct task_struct *me = current;
1890 next = next_node_in(me->il_prev, policy->nodes);
1891 if (next < MAX_NUMNODES)
1897 * Depending on the memory policy provide a node from which to allocate the
1900 unsigned int mempolicy_slab_node(void)
1902 struct mempolicy *policy;
1903 int node = numa_mem_id();
1908 policy = current->mempolicy;
1912 switch (policy->mode) {
1913 case MPOL_PREFERRED:
1914 return first_node(policy->nodes);
1916 case MPOL_INTERLEAVE:
1917 return interleave_nodes(policy);
1920 case MPOL_PREFERRED_MANY:
1925 * Follow bind policy behavior and start allocation at the
1928 struct zonelist *zonelist;
1929 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1930 zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK];
1931 z = first_zones_zonelist(zonelist, highest_zoneidx,
1933 return z->zone ? zone_to_nid(z->zone) : node;
1944 * Do static interleaving for a VMA with known offset @n. Returns the n'th
1945 * node in pol->nodes (starting from n=0), wrapping around if n exceeds the
1946 * number of present nodes.
1948 static unsigned offset_il_node(struct mempolicy *pol, unsigned long n)
1950 nodemask_t nodemask = pol->nodes;
1951 unsigned int target, nnodes;
1955 * The barrier will stabilize the nodemask in a register or on
1956 * the stack so that it will stop changing under the code.
1958 * Between first_node() and next_node(), pol->nodes could be changed
1959 * by other threads. So we put pol->nodes in a local stack.
1963 nnodes = nodes_weight(nodemask);
1965 return numa_node_id();
1966 target = (unsigned int)n % nnodes;
1967 nid = first_node(nodemask);
1968 for (i = 0; i < target; i++)
1969 nid = next_node(nid, nodemask);
1973 /* Determine a node number for interleave */
1974 static inline unsigned interleave_nid(struct mempolicy *pol,
1975 struct vm_area_struct *vma, unsigned long addr, int shift)
1981 * for small pages, there is no difference between
1982 * shift and PAGE_SHIFT, so the bit-shift is safe.
1983 * for huge pages, since vm_pgoff is in units of small
1984 * pages, we need to shift off the always 0 bits to get
1987 BUG_ON(shift < PAGE_SHIFT);
1988 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1989 off += (addr - vma->vm_start) >> shift;
1990 return offset_il_node(pol, off);
1992 return interleave_nodes(pol);
1995 #ifdef CONFIG_HUGETLBFS
1997 * huge_node(@vma, @addr, @gfp_flags, @mpol)
1998 * @vma: virtual memory area whose policy is sought
1999 * @addr: address in @vma for shared policy lookup and interleave policy
2000 * @gfp_flags: for requested zone
2001 * @mpol: pointer to mempolicy pointer for reference counted mempolicy
2002 * @nodemask: pointer to nodemask pointer for 'bind' and 'prefer-many' policy
2004 * Returns a nid suitable for a huge page allocation and a pointer
2005 * to the struct mempolicy for conditional unref after allocation.
2006 * If the effective policy is 'bind' or 'prefer-many', returns a pointer
2007 * to the mempolicy's @nodemask for filtering the zonelist.
2009 * Must be protected by read_mems_allowed_begin()
2011 int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags,
2012 struct mempolicy **mpol, nodemask_t **nodemask)
2017 *mpol = get_vma_policy(vma, addr);
2019 mode = (*mpol)->mode;
2021 if (unlikely(mode == MPOL_INTERLEAVE)) {
2022 nid = interleave_nid(*mpol, vma, addr,
2023 huge_page_shift(hstate_vma(vma)));
2025 nid = policy_node(gfp_flags, *mpol, numa_node_id());
2026 if (mode == MPOL_BIND || mode == MPOL_PREFERRED_MANY)
2027 *nodemask = &(*mpol)->nodes;
2033 * init_nodemask_of_mempolicy
2035 * If the current task's mempolicy is "default" [NULL], return 'false'
2036 * to indicate default policy. Otherwise, extract the policy nodemask
2037 * for 'bind' or 'interleave' policy into the argument nodemask, or
2038 * initialize the argument nodemask to contain the single node for
2039 * 'preferred' or 'local' policy and return 'true' to indicate presence
2040 * of non-default mempolicy.
2042 * We don't bother with reference counting the mempolicy [mpol_get/put]
2043 * because the current task is examining it's own mempolicy and a task's
2044 * mempolicy is only ever changed by the task itself.
2046 * N.B., it is the caller's responsibility to free a returned nodemask.
2048 bool init_nodemask_of_mempolicy(nodemask_t *mask)
2050 struct mempolicy *mempolicy;
2052 if (!(mask && current->mempolicy))
2056 mempolicy = current->mempolicy;
2057 switch (mempolicy->mode) {
2058 case MPOL_PREFERRED:
2059 case MPOL_PREFERRED_MANY:
2061 case MPOL_INTERLEAVE:
2062 *mask = mempolicy->nodes;
2066 init_nodemask_of_node(mask, numa_node_id());
2072 task_unlock(current);
2079 * mempolicy_in_oom_domain
2081 * If tsk's mempolicy is "bind", check for intersection between mask and
2082 * the policy nodemask. Otherwise, return true for all other policies
2083 * including "interleave", as a tsk with "interleave" policy may have
2084 * memory allocated from all nodes in system.
2086 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
2088 bool mempolicy_in_oom_domain(struct task_struct *tsk,
2089 const nodemask_t *mask)
2091 struct mempolicy *mempolicy;
2098 mempolicy = tsk->mempolicy;
2099 if (mempolicy && mempolicy->mode == MPOL_BIND)
2100 ret = nodes_intersects(mempolicy->nodes, *mask);
2106 /* Allocate a page in interleaved policy.
2107 Own path because it needs to do special accounting. */
2108 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
2113 page = __alloc_pages(gfp, order, nid, NULL);
2114 /* skip NUMA_INTERLEAVE_HIT counter update if numa stats is disabled */
2115 if (!static_branch_likely(&vm_numa_stat_key))
2117 if (page && page_to_nid(page) == nid) {
2119 __count_numa_event(page_zone(page), NUMA_INTERLEAVE_HIT);
2125 static struct page *alloc_pages_preferred_many(gfp_t gfp, unsigned int order,
2126 int nid, struct mempolicy *pol)
2129 gfp_t preferred_gfp;
2132 * This is a two pass approach. The first pass will only try the
2133 * preferred nodes but skip the direct reclaim and allow the
2134 * allocation to fail, while the second pass will try all the
2137 preferred_gfp = gfp | __GFP_NOWARN;
2138 preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
2139 page = __alloc_pages(preferred_gfp, order, nid, &pol->nodes);
2141 page = __alloc_pages(gfp, order, nid, NULL);
2147 * alloc_pages_vma - Allocate a page for a VMA.
2149 * @order: Order of the GFP allocation.
2150 * @vma: Pointer to VMA or NULL if not available.
2151 * @addr: Virtual address of the allocation. Must be inside @vma.
2152 * @hugepage: For hugepages try only the preferred node if possible.
2154 * Allocate a page for a specific address in @vma, using the appropriate
2155 * NUMA policy. When @vma is not NULL the caller must hold the mmap_lock
2156 * of the mm_struct of the VMA to prevent it from going away. Should be
2157 * used for all allocations for pages that will be mapped into user space.
2159 * Return: The page on success or NULL if allocation fails.
2161 struct page *alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
2162 unsigned long addr, bool hugepage)
2164 struct mempolicy *pol;
2165 int node = numa_node_id();
2170 pol = get_vma_policy(vma, addr);
2172 if (pol->mode == MPOL_INTERLEAVE) {
2175 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2177 page = alloc_page_interleave(gfp, order, nid);
2181 if (pol->mode == MPOL_PREFERRED_MANY) {
2182 node = policy_node(gfp, pol, node);
2183 page = alloc_pages_preferred_many(gfp, order, node, pol);
2188 if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
2189 int hpage_node = node;
2192 * For hugepage allocation and non-interleave policy which
2193 * allows the current node (or other explicitly preferred
2194 * node) we only try to allocate from the current/preferred
2195 * node and don't fall back to other nodes, as the cost of
2196 * remote accesses would likely offset THP benefits.
2198 * If the policy is interleave or does not allow the current
2199 * node in its nodemask, we allocate the standard way.
2201 if (pol->mode == MPOL_PREFERRED)
2202 hpage_node = first_node(pol->nodes);
2204 nmask = policy_nodemask(gfp, pol);
2205 if (!nmask || node_isset(hpage_node, *nmask)) {
2208 * First, try to allocate THP only on local node, but
2209 * don't reclaim unnecessarily, just compact.
2211 page = __alloc_pages_node(hpage_node,
2212 gfp | __GFP_THISNODE | __GFP_NORETRY, order);
2215 * If hugepage allocations are configured to always
2216 * synchronous compact or the vma has been madvised
2217 * to prefer hugepage backing, retry allowing remote
2218 * memory with both reclaim and compact as well.
2220 if (!page && (gfp & __GFP_DIRECT_RECLAIM))
2221 page = __alloc_pages(gfp, order, hpage_node, nmask);
2227 nmask = policy_nodemask(gfp, pol);
2228 preferred_nid = policy_node(gfp, pol, node);
2229 page = __alloc_pages(gfp, order, preferred_nid, nmask);
2234 EXPORT_SYMBOL(alloc_pages_vma);
2237 * alloc_pages - Allocate pages.
2239 * @order: Power of two of number of pages to allocate.
2241 * Allocate 1 << @order contiguous pages. The physical address of the
2242 * first page is naturally aligned (eg an order-3 allocation will be aligned
2243 * to a multiple of 8 * PAGE_SIZE bytes). The NUMA policy of the current
2244 * process is honoured when in process context.
2246 * Context: Can be called from any context, providing the appropriate GFP
2248 * Return: The page on success or NULL if allocation fails.
2250 struct page *alloc_pages(gfp_t gfp, unsigned order)
2252 struct mempolicy *pol = &default_policy;
2255 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2256 pol = get_task_policy(current);
2259 * No reference counting needed for current->mempolicy
2260 * nor system default_policy
2262 if (pol->mode == MPOL_INTERLEAVE)
2263 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
2264 else if (pol->mode == MPOL_PREFERRED_MANY)
2265 page = alloc_pages_preferred_many(gfp, order,
2266 policy_node(gfp, pol, numa_node_id()), pol);
2268 page = __alloc_pages(gfp, order,
2269 policy_node(gfp, pol, numa_node_id()),
2270 policy_nodemask(gfp, pol));
2274 EXPORT_SYMBOL(alloc_pages);
2276 struct folio *folio_alloc(gfp_t gfp, unsigned order)
2278 struct page *page = alloc_pages(gfp | __GFP_COMP, order);
2280 if (page && order > 1)
2281 prep_transhuge_page(page);
2282 return (struct folio *)page;
2284 EXPORT_SYMBOL(folio_alloc);
2286 static unsigned long alloc_pages_bulk_array_interleave(gfp_t gfp,
2287 struct mempolicy *pol, unsigned long nr_pages,
2288 struct page **page_array)
2291 unsigned long nr_pages_per_node;
2294 unsigned long nr_allocated;
2295 unsigned long total_allocated = 0;
2297 nodes = nodes_weight(pol->nodes);
2298 nr_pages_per_node = nr_pages / nodes;
2299 delta = nr_pages - nodes * nr_pages_per_node;
2301 for (i = 0; i < nodes; i++) {
2303 nr_allocated = __alloc_pages_bulk(gfp,
2304 interleave_nodes(pol), NULL,
2305 nr_pages_per_node + 1, NULL,
2309 nr_allocated = __alloc_pages_bulk(gfp,
2310 interleave_nodes(pol), NULL,
2311 nr_pages_per_node, NULL, page_array);
2314 page_array += nr_allocated;
2315 total_allocated += nr_allocated;
2318 return total_allocated;
2321 static unsigned long alloc_pages_bulk_array_preferred_many(gfp_t gfp, int nid,
2322 struct mempolicy *pol, unsigned long nr_pages,
2323 struct page **page_array)
2325 gfp_t preferred_gfp;
2326 unsigned long nr_allocated = 0;
2328 preferred_gfp = gfp | __GFP_NOWARN;
2329 preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
2331 nr_allocated = __alloc_pages_bulk(preferred_gfp, nid, &pol->nodes,
2332 nr_pages, NULL, page_array);
2334 if (nr_allocated < nr_pages)
2335 nr_allocated += __alloc_pages_bulk(gfp, numa_node_id(), NULL,
2336 nr_pages - nr_allocated, NULL,
2337 page_array + nr_allocated);
2338 return nr_allocated;
2341 /* alloc pages bulk and mempolicy should be considered at the
2342 * same time in some situation such as vmalloc.
2344 * It can accelerate memory allocation especially interleaving
2347 unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp,
2348 unsigned long nr_pages, struct page **page_array)
2350 struct mempolicy *pol = &default_policy;
2352 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2353 pol = get_task_policy(current);
2355 if (pol->mode == MPOL_INTERLEAVE)
2356 return alloc_pages_bulk_array_interleave(gfp, pol,
2357 nr_pages, page_array);
2359 if (pol->mode == MPOL_PREFERRED_MANY)
2360 return alloc_pages_bulk_array_preferred_many(gfp,
2361 numa_node_id(), pol, nr_pages, page_array);
2363 return __alloc_pages_bulk(gfp, policy_node(gfp, pol, numa_node_id()),
2364 policy_nodemask(gfp, pol), nr_pages, NULL,
2368 int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
2370 struct mempolicy *pol = mpol_dup(vma_policy(src));
2373 return PTR_ERR(pol);
2374 dst->vm_policy = pol;
2379 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2380 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2381 * with the mems_allowed returned by cpuset_mems_allowed(). This
2382 * keeps mempolicies cpuset relative after its cpuset moves. See
2383 * further kernel/cpuset.c update_nodemask().
2385 * current's mempolicy may be rebinded by the other task(the task that changes
2386 * cpuset's mems), so we needn't do rebind work for current task.
2389 /* Slow path of a mempolicy duplicate */
2390 struct mempolicy *__mpol_dup(struct mempolicy *old)
2392 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2395 return ERR_PTR(-ENOMEM);
2397 /* task's mempolicy is protected by alloc_lock */
2398 if (old == current->mempolicy) {
2401 task_unlock(current);
2405 if (current_cpuset_is_being_rebound()) {
2406 nodemask_t mems = cpuset_mems_allowed(current);
2407 mpol_rebind_policy(new, &mems);
2409 atomic_set(&new->refcnt, 1);
2413 /* Slow path of a mempolicy comparison */
2414 bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2418 if (a->mode != b->mode)
2420 if (a->flags != b->flags)
2422 if (a->home_node != b->home_node)
2424 if (mpol_store_user_nodemask(a))
2425 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2430 case MPOL_INTERLEAVE:
2431 case MPOL_PREFERRED:
2432 case MPOL_PREFERRED_MANY:
2433 return !!nodes_equal(a->nodes, b->nodes);
2443 * Shared memory backing store policy support.
2445 * Remember policies even when nobody has shared memory mapped.
2446 * The policies are kept in Red-Black tree linked from the inode.
2447 * They are protected by the sp->lock rwlock, which should be held
2448 * for any accesses to the tree.
2452 * lookup first element intersecting start-end. Caller holds sp->lock for
2453 * reading or for writing
2455 static struct sp_node *
2456 sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2458 struct rb_node *n = sp->root.rb_node;
2461 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2463 if (start >= p->end)
2465 else if (end <= p->start)
2473 struct sp_node *w = NULL;
2474 struct rb_node *prev = rb_prev(n);
2477 w = rb_entry(prev, struct sp_node, nd);
2478 if (w->end <= start)
2482 return rb_entry(n, struct sp_node, nd);
2486 * Insert a new shared policy into the list. Caller holds sp->lock for
2489 static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2491 struct rb_node **p = &sp->root.rb_node;
2492 struct rb_node *parent = NULL;
2497 nd = rb_entry(parent, struct sp_node, nd);
2498 if (new->start < nd->start)
2500 else if (new->end > nd->end)
2501 p = &(*p)->rb_right;
2505 rb_link_node(&new->nd, parent, p);
2506 rb_insert_color(&new->nd, &sp->root);
2507 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2508 new->policy ? new->policy->mode : 0);
2511 /* Find shared policy intersecting idx */
2513 mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2515 struct mempolicy *pol = NULL;
2518 if (!sp->root.rb_node)
2520 read_lock(&sp->lock);
2521 sn = sp_lookup(sp, idx, idx+1);
2523 mpol_get(sn->policy);
2526 read_unlock(&sp->lock);
2530 static void sp_free(struct sp_node *n)
2532 mpol_put(n->policy);
2533 kmem_cache_free(sn_cache, n);
2537 * mpol_misplaced - check whether current page node is valid in policy
2539 * @page: page to be checked
2540 * @vma: vm area where page mapped
2541 * @addr: virtual address where page mapped
2543 * Lookup current policy node id for vma,addr and "compare to" page's
2544 * node id. Policy determination "mimics" alloc_page_vma().
2545 * Called from fault path where we know the vma and faulting address.
2547 * Return: NUMA_NO_NODE if the page is in a node that is valid for this
2548 * policy, or a suitable node ID to allocate a replacement page from.
2550 int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
2552 struct mempolicy *pol;
2554 int curnid = page_to_nid(page);
2555 unsigned long pgoff;
2556 int thiscpu = raw_smp_processor_id();
2557 int thisnid = cpu_to_node(thiscpu);
2558 int polnid = NUMA_NO_NODE;
2559 int ret = NUMA_NO_NODE;
2561 pol = get_vma_policy(vma, addr);
2562 if (!(pol->flags & MPOL_F_MOF))
2565 switch (pol->mode) {
2566 case MPOL_INTERLEAVE:
2567 pgoff = vma->vm_pgoff;
2568 pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
2569 polnid = offset_il_node(pol, pgoff);
2572 case MPOL_PREFERRED:
2573 if (node_isset(curnid, pol->nodes))
2575 polnid = first_node(pol->nodes);
2579 polnid = numa_node_id();
2583 /* Optimize placement among multiple nodes via NUMA balancing */
2584 if (pol->flags & MPOL_F_MORON) {
2585 if (node_isset(thisnid, pol->nodes))
2591 case MPOL_PREFERRED_MANY:
2593 * use current page if in policy nodemask,
2594 * else select nearest allowed node, if any.
2595 * If no allowed nodes, use current [!misplaced].
2597 if (node_isset(curnid, pol->nodes))
2599 z = first_zones_zonelist(
2600 node_zonelist(numa_node_id(), GFP_HIGHUSER),
2601 gfp_zone(GFP_HIGHUSER),
2603 polnid = zone_to_nid(z->zone);
2610 /* Migrate the page towards the node whose CPU is referencing it */
2611 if (pol->flags & MPOL_F_MORON) {
2614 if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
2618 if (curnid != polnid)
2627 * Drop the (possibly final) reference to task->mempolicy. It needs to be
2628 * dropped after task->mempolicy is set to NULL so that any allocation done as
2629 * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed
2632 void mpol_put_task_policy(struct task_struct *task)
2634 struct mempolicy *pol;
2637 pol = task->mempolicy;
2638 task->mempolicy = NULL;
2643 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2645 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2646 rb_erase(&n->nd, &sp->root);
2650 static void sp_node_init(struct sp_node *node, unsigned long start,
2651 unsigned long end, struct mempolicy *pol)
2653 node->start = start;
2658 static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2659 struct mempolicy *pol)
2662 struct mempolicy *newpol;
2664 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2668 newpol = mpol_dup(pol);
2669 if (IS_ERR(newpol)) {
2670 kmem_cache_free(sn_cache, n);
2673 newpol->flags |= MPOL_F_SHARED;
2674 sp_node_init(n, start, end, newpol);
2679 /* Replace a policy range. */
2680 static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2681 unsigned long end, struct sp_node *new)
2684 struct sp_node *n_new = NULL;
2685 struct mempolicy *mpol_new = NULL;
2689 write_lock(&sp->lock);
2690 n = sp_lookup(sp, start, end);
2691 /* Take care of old policies in the same range. */
2692 while (n && n->start < end) {
2693 struct rb_node *next = rb_next(&n->nd);
2694 if (n->start >= start) {
2700 /* Old policy spanning whole new range. */
2705 *mpol_new = *n->policy;
2706 atomic_set(&mpol_new->refcnt, 1);
2707 sp_node_init(n_new, end, n->end, mpol_new);
2709 sp_insert(sp, n_new);
2718 n = rb_entry(next, struct sp_node, nd);
2722 write_unlock(&sp->lock);
2729 kmem_cache_free(sn_cache, n_new);
2734 write_unlock(&sp->lock);
2736 n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2739 mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2746 * mpol_shared_policy_init - initialize shared policy for inode
2747 * @sp: pointer to inode shared policy
2748 * @mpol: struct mempolicy to install
2750 * Install non-NULL @mpol in inode's shared policy rb-tree.
2751 * On entry, the current task has a reference on a non-NULL @mpol.
2752 * This must be released on exit.
2753 * This is called at get_inode() calls and we can use GFP_KERNEL.
2755 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2759 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2760 rwlock_init(&sp->lock);
2763 struct vm_area_struct pvma;
2764 struct mempolicy *new;
2765 NODEMASK_SCRATCH(scratch);
2769 /* contextualize the tmpfs mount point mempolicy */
2770 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2772 goto free_scratch; /* no valid nodemask intersection */
2775 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2776 task_unlock(current);
2780 /* Create pseudo-vma that contains just the policy */
2781 vma_init(&pvma, NULL);
2782 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2783 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2786 mpol_put(new); /* drop initial ref */
2788 NODEMASK_SCRATCH_FREE(scratch);
2790 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2794 int mpol_set_shared_policy(struct shared_policy *info,
2795 struct vm_area_struct *vma, struct mempolicy *npol)
2798 struct sp_node *new = NULL;
2799 unsigned long sz = vma_pages(vma);
2801 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2803 sz, npol ? npol->mode : -1,
2804 npol ? npol->flags : -1,
2805 npol ? nodes_addr(npol->nodes)[0] : NUMA_NO_NODE);
2808 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2812 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2818 /* Free a backing policy store on inode delete. */
2819 void mpol_free_shared_policy(struct shared_policy *p)
2822 struct rb_node *next;
2824 if (!p->root.rb_node)
2826 write_lock(&p->lock);
2827 next = rb_first(&p->root);
2829 n = rb_entry(next, struct sp_node, nd);
2830 next = rb_next(&n->nd);
2833 write_unlock(&p->lock);
2836 #ifdef CONFIG_NUMA_BALANCING
2837 static int __initdata numabalancing_override;
2839 static void __init check_numabalancing_enable(void)
2841 bool numabalancing_default = false;
2843 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2844 numabalancing_default = true;
2846 /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
2847 if (numabalancing_override)
2848 set_numabalancing_state(numabalancing_override == 1);
2850 if (num_online_nodes() > 1 && !numabalancing_override) {
2851 pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n",
2852 numabalancing_default ? "Enabling" : "Disabling");
2853 set_numabalancing_state(numabalancing_default);
2857 static int __init setup_numabalancing(char *str)
2863 if (!strcmp(str, "enable")) {
2864 numabalancing_override = 1;
2866 } else if (!strcmp(str, "disable")) {
2867 numabalancing_override = -1;
2872 pr_warn("Unable to parse numa_balancing=\n");
2876 __setup("numa_balancing=", setup_numabalancing);
2878 static inline void __init check_numabalancing_enable(void)
2881 #endif /* CONFIG_NUMA_BALANCING */
2883 /* assumes fs == KERNEL_DS */
2884 void __init numa_policy_init(void)
2886 nodemask_t interleave_nodes;
2887 unsigned long largest = 0;
2888 int nid, prefer = 0;
2890 policy_cache = kmem_cache_create("numa_policy",
2891 sizeof(struct mempolicy),
2892 0, SLAB_PANIC, NULL);
2894 sn_cache = kmem_cache_create("shared_policy_node",
2895 sizeof(struct sp_node),
2896 0, SLAB_PANIC, NULL);
2898 for_each_node(nid) {
2899 preferred_node_policy[nid] = (struct mempolicy) {
2900 .refcnt = ATOMIC_INIT(1),
2901 .mode = MPOL_PREFERRED,
2902 .flags = MPOL_F_MOF | MPOL_F_MORON,
2903 .nodes = nodemask_of_node(nid),
2908 * Set interleaving policy for system init. Interleaving is only
2909 * enabled across suitably sized nodes (default is >= 16MB), or
2910 * fall back to the largest node if they're all smaller.
2912 nodes_clear(interleave_nodes);
2913 for_each_node_state(nid, N_MEMORY) {
2914 unsigned long total_pages = node_present_pages(nid);
2916 /* Preserve the largest node */
2917 if (largest < total_pages) {
2918 largest = total_pages;
2922 /* Interleave this node? */
2923 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2924 node_set(nid, interleave_nodes);
2927 /* All too small, use the largest */
2928 if (unlikely(nodes_empty(interleave_nodes)))
2929 node_set(prefer, interleave_nodes);
2931 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2932 pr_err("%s: interleaving failed\n", __func__);
2934 check_numabalancing_enable();
2937 /* Reset policy of current process to default */
2938 void numa_default_policy(void)
2940 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2944 * Parse and format mempolicy from/to strings
2947 static const char * const policy_modes[] =
2949 [MPOL_DEFAULT] = "default",
2950 [MPOL_PREFERRED] = "prefer",
2951 [MPOL_BIND] = "bind",
2952 [MPOL_INTERLEAVE] = "interleave",
2953 [MPOL_LOCAL] = "local",
2954 [MPOL_PREFERRED_MANY] = "prefer (many)",
2960 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2961 * @str: string containing mempolicy to parse
2962 * @mpol: pointer to struct mempolicy pointer, returned on success.
2965 * <mode>[=<flags>][:<nodelist>]
2967 * Return: %0 on success, else %1
2969 int mpol_parse_str(char *str, struct mempolicy **mpol)
2971 struct mempolicy *new = NULL;
2972 unsigned short mode_flags;
2974 char *nodelist = strchr(str, ':');
2975 char *flags = strchr(str, '=');
2979 *flags++ = '\0'; /* terminate mode string */
2982 /* NUL-terminate mode or flags string */
2984 if (nodelist_parse(nodelist, nodes))
2986 if (!nodes_subset(nodes, node_states[N_MEMORY]))
2991 mode = match_string(policy_modes, MPOL_MAX, str);
2996 case MPOL_PREFERRED:
2998 * Insist on a nodelist of one node only, although later
2999 * we use first_node(nodes) to grab a single node, so here
3000 * nodelist (or nodes) cannot be empty.
3003 char *rest = nodelist;
3004 while (isdigit(*rest))
3008 if (nodes_empty(nodes))
3012 case MPOL_INTERLEAVE:
3014 * Default to online nodes with memory if no nodelist
3017 nodes = node_states[N_MEMORY];
3021 * Don't allow a nodelist; mpol_new() checks flags
3028 * Insist on a empty nodelist
3033 case MPOL_PREFERRED_MANY:
3036 * Insist on a nodelist
3045 * Currently, we only support two mutually exclusive
3048 if (!strcmp(flags, "static"))
3049 mode_flags |= MPOL_F_STATIC_NODES;
3050 else if (!strcmp(flags, "relative"))
3051 mode_flags |= MPOL_F_RELATIVE_NODES;
3056 new = mpol_new(mode, mode_flags, &nodes);
3061 * Save nodes for mpol_to_str() to show the tmpfs mount options
3062 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
3064 if (mode != MPOL_PREFERRED) {
3066 } else if (nodelist) {
3067 nodes_clear(new->nodes);
3068 node_set(first_node(nodes), new->nodes);
3070 new->mode = MPOL_LOCAL;
3074 * Save nodes for contextualization: this will be used to "clone"
3075 * the mempolicy in a specific context [cpuset] at a later time.
3077 new->w.user_nodemask = nodes;
3082 /* Restore string for error message */
3091 #endif /* CONFIG_TMPFS */
3094 * mpol_to_str - format a mempolicy structure for printing
3095 * @buffer: to contain formatted mempolicy string
3096 * @maxlen: length of @buffer
3097 * @pol: pointer to mempolicy to be formatted
3099 * Convert @pol into a string. If @buffer is too short, truncate the string.
3100 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
3101 * longest flag, "relative", and to display at least a few node ids.
3103 void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
3106 nodemask_t nodes = NODE_MASK_NONE;
3107 unsigned short mode = MPOL_DEFAULT;
3108 unsigned short flags = 0;
3110 if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
3119 case MPOL_PREFERRED:
3120 case MPOL_PREFERRED_MANY:
3122 case MPOL_INTERLEAVE:
3127 snprintf(p, maxlen, "unknown");
3131 p += snprintf(p, maxlen, "%s", policy_modes[mode]);
3133 if (flags & MPOL_MODE_FLAGS) {
3134 p += snprintf(p, buffer + maxlen - p, "=");
3137 * Currently, the only defined flags are mutually exclusive
3139 if (flags & MPOL_F_STATIC_NODES)
3140 p += snprintf(p, buffer + maxlen - p, "static");
3141 else if (flags & MPOL_F_RELATIVE_NODES)
3142 p += snprintf(p, buffer + maxlen - p, "relative");
3145 if (!nodes_empty(nodes))
3146 p += scnprintf(p, buffer + maxlen - p, ":%*pbl",
3147 nodemask_pr_args(&nodes));