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 * 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.
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.
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.
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.
52 * For shmfs/tmpfs/hugetlbfs shared memory the policy is shared between
53 * all users and remembered even when nobody has memory mapped.
57 fix mmap readahead to honour policy and enable policy for any page cache
59 statistics for bigpages
60 global policy for page cache? currently it uses process policy. Requires
62 handle mremap for shared memory (currently ignored for the policy)
64 make bind policy root only? It can trigger oom much faster and the
65 kernel is not always grateful with that.
68 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
70 #include <linux/mempolicy.h>
71 #include <linux/pagewalk.h>
72 #include <linux/highmem.h>
73 #include <linux/hugetlb.h>
74 #include <linux/kernel.h>
75 #include <linux/sched.h>
76 #include <linux/sched/mm.h>
77 #include <linux/sched/numa_balancing.h>
78 #include <linux/sched/task.h>
79 #include <linux/nodemask.h>
80 #include <linux/cpuset.h>
81 #include <linux/slab.h>
82 #include <linux/string.h>
83 #include <linux/export.h>
84 #include <linux/nsproxy.h>
85 #include <linux/interrupt.h>
86 #include <linux/init.h>
87 #include <linux/compat.h>
88 #include <linux/ptrace.h>
89 #include <linux/swap.h>
90 #include <linux/seq_file.h>
91 #include <linux/proc_fs.h>
92 #include <linux/migrate.h>
93 #include <linux/ksm.h>
94 #include <linux/rmap.h>
95 #include <linux/security.h>
96 #include <linux/syscalls.h>
97 #include <linux/ctype.h>
98 #include <linux/mm_inline.h>
99 #include <linux/mmu_notifier.h>
100 #include <linux/printk.h>
101 #include <linux/swapops.h>
103 #include <asm/tlbflush.h>
104 #include <linux/uaccess.h>
106 #include "internal.h"
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 */
112 static struct kmem_cache *policy_cache;
113 static struct kmem_cache *sn_cache;
115 /* Highest zone. An specific allocation for a zone below that is not
117 enum zone_type policy_zone = 0;
120 * run-time system-wide default policy => local allocation
122 static struct mempolicy default_policy = {
123 .refcnt = ATOMIC_INIT(1), /* never free it */
124 .mode = MPOL_PREFERRED,
125 .flags = MPOL_F_LOCAL,
128 static struct mempolicy preferred_node_policy[MAX_NUMNODES];
131 * numa_map_to_online_node - Find closest online node
132 * @node: Node id to start the search
134 * Lookup the next closest node by distance if @nid is not online.
136 int numa_map_to_online_node(int node)
138 int min_dist = INT_MAX, dist, n, min_node;
140 if (node == NUMA_NO_NODE || node_online(node))
144 for_each_online_node(n) {
145 dist = node_distance(node, n);
146 if (dist < min_dist) {
154 EXPORT_SYMBOL_GPL(numa_map_to_online_node);
156 struct mempolicy *get_task_policy(struct task_struct *p)
158 struct mempolicy *pol = p->mempolicy;
164 node = numa_node_id();
165 if (node != NUMA_NO_NODE) {
166 pol = &preferred_node_policy[node];
167 /* preferred_node_policy is not initialised early in boot */
172 return &default_policy;
175 static const struct mempolicy_operations {
176 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
177 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes);
178 } mpol_ops[MPOL_MAX];
180 static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
182 return pol->flags & MPOL_MODE_FLAGS;
185 static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
186 const nodemask_t *rel)
189 nodes_fold(tmp, *orig, nodes_weight(*rel));
190 nodes_onto(*ret, tmp, *rel);
193 static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
195 if (nodes_empty(*nodes))
197 pol->v.nodes = *nodes;
201 static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
204 pol->flags |= MPOL_F_LOCAL; /* local allocation */
205 else if (nodes_empty(*nodes))
206 return -EINVAL; /* no allowed nodes */
208 pol->v.preferred_node = first_node(*nodes);
212 static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
214 if (nodes_empty(*nodes))
216 pol->v.nodes = *nodes;
221 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
222 * any, for the new policy. mpol_new() has already validated the nodes
223 * parameter with respect to the policy mode and flags. But, we need to
224 * handle an empty nodemask with MPOL_PREFERRED here.
226 * Must be called holding task's alloc_lock to protect task's mems_allowed
227 * and mempolicy. May also be called holding the mmap_lock for write.
229 static int mpol_set_nodemask(struct mempolicy *pol,
230 const nodemask_t *nodes, struct nodemask_scratch *nsc)
234 /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
238 nodes_and(nsc->mask1,
239 cpuset_current_mems_allowed, node_states[N_MEMORY]);
242 if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
243 nodes = NULL; /* explicit local allocation */
245 if (pol->flags & MPOL_F_RELATIVE_NODES)
246 mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1);
248 nodes_and(nsc->mask2, *nodes, nsc->mask1);
250 if (mpol_store_user_nodemask(pol))
251 pol->w.user_nodemask = *nodes;
253 pol->w.cpuset_mems_allowed =
254 cpuset_current_mems_allowed;
258 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
260 ret = mpol_ops[pol->mode].create(pol, NULL);
265 * This function just creates a new policy, does some check and simple
266 * initialization. You must invoke mpol_set_nodemask() to set nodes.
268 static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
271 struct mempolicy *policy;
273 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
274 mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE);
276 if (mode == MPOL_DEFAULT) {
277 if (nodes && !nodes_empty(*nodes))
278 return ERR_PTR(-EINVAL);
284 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
285 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
286 * All other modes require a valid pointer to a non-empty nodemask.
288 if (mode == MPOL_PREFERRED) {
289 if (nodes_empty(*nodes)) {
290 if (((flags & MPOL_F_STATIC_NODES) ||
291 (flags & MPOL_F_RELATIVE_NODES)))
292 return ERR_PTR(-EINVAL);
294 } else if (mode == MPOL_LOCAL) {
295 if (!nodes_empty(*nodes) ||
296 (flags & MPOL_F_STATIC_NODES) ||
297 (flags & MPOL_F_RELATIVE_NODES))
298 return ERR_PTR(-EINVAL);
299 mode = MPOL_PREFERRED;
300 } else if (nodes_empty(*nodes))
301 return ERR_PTR(-EINVAL);
302 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
304 return ERR_PTR(-ENOMEM);
305 atomic_set(&policy->refcnt, 1);
307 policy->flags = flags;
312 /* Slow path of a mpol destructor. */
313 void __mpol_put(struct mempolicy *p)
315 if (!atomic_dec_and_test(&p->refcnt))
317 kmem_cache_free(policy_cache, p);
320 static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes)
324 static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
328 if (pol->flags & MPOL_F_STATIC_NODES)
329 nodes_and(tmp, pol->w.user_nodemask, *nodes);
330 else if (pol->flags & MPOL_F_RELATIVE_NODES)
331 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
333 nodes_remap(tmp, pol->v.nodes,pol->w.cpuset_mems_allowed,
335 pol->w.cpuset_mems_allowed = *nodes;
338 if (nodes_empty(tmp))
344 static void mpol_rebind_preferred(struct mempolicy *pol,
345 const nodemask_t *nodes)
349 if (pol->flags & MPOL_F_STATIC_NODES) {
350 int node = first_node(pol->w.user_nodemask);
352 if (node_isset(node, *nodes)) {
353 pol->v.preferred_node = node;
354 pol->flags &= ~MPOL_F_LOCAL;
356 pol->flags |= MPOL_F_LOCAL;
357 } else if (pol->flags & MPOL_F_RELATIVE_NODES) {
358 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
359 pol->v.preferred_node = first_node(tmp);
360 } else if (!(pol->flags & MPOL_F_LOCAL)) {
361 pol->v.preferred_node = node_remap(pol->v.preferred_node,
362 pol->w.cpuset_mems_allowed,
364 pol->w.cpuset_mems_allowed = *nodes;
369 * mpol_rebind_policy - Migrate a policy to a different set of nodes
371 * Per-vma policies are protected by mmap_lock. Allocations using per-task
372 * policies are protected by task->mems_allowed_seq to prevent a premature
373 * OOM/allocation failure due to parallel nodemask modification.
375 static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask)
377 if (!pol || pol->mode == MPOL_LOCAL)
379 if (!mpol_store_user_nodemask(pol) && !(pol->flags & MPOL_F_LOCAL) &&
380 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
383 mpol_ops[pol->mode].rebind(pol, newmask);
387 * Wrapper for mpol_rebind_policy() that just requires task
388 * pointer, and updates task mempolicy.
390 * Called with task's alloc_lock held.
393 void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new)
395 mpol_rebind_policy(tsk->mempolicy, new);
399 * Rebind each vma in mm to new nodemask.
401 * Call holding a reference to mm. Takes mm->mmap_lock during call.
404 void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
406 struct vm_area_struct *vma;
409 for (vma = mm->mmap; vma; vma = vma->vm_next)
410 mpol_rebind_policy(vma->vm_policy, new);
411 mmap_write_unlock(mm);
414 static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
416 .rebind = mpol_rebind_default,
418 [MPOL_INTERLEAVE] = {
419 .create = mpol_new_interleave,
420 .rebind = mpol_rebind_nodemask,
423 .create = mpol_new_preferred,
424 .rebind = mpol_rebind_preferred,
427 .create = mpol_new_bind,
428 .rebind = mpol_rebind_nodemask,
432 static int migrate_page_add(struct page *page, struct list_head *pagelist,
433 unsigned long flags);
436 struct list_head *pagelist;
441 struct vm_area_struct *first;
445 * Check if the page's nid is in qp->nmask.
447 * If MPOL_MF_INVERT is set in qp->flags, check if the nid is
448 * in the invert of qp->nmask.
450 static inline bool queue_pages_required(struct page *page,
451 struct queue_pages *qp)
453 int nid = page_to_nid(page);
454 unsigned long flags = qp->flags;
456 return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT);
460 * queue_pages_pmd() has four possible return values:
461 * 0 - pages are placed on the right node or queued successfully.
462 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
465 * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an
466 * existing page was already on a node that does not follow the
469 static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
470 unsigned long end, struct mm_walk *walk)
475 struct queue_pages *qp = walk->private;
478 if (unlikely(is_pmd_migration_entry(*pmd))) {
482 page = pmd_page(*pmd);
483 if (is_huge_zero_page(page)) {
485 __split_huge_pmd(walk->vma, pmd, addr, false, NULL);
489 if (!queue_pages_required(page, qp))
493 /* go to thp migration */
494 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
495 if (!vma_migratable(walk->vma) ||
496 migrate_page_add(page, qp->pagelist, flags)) {
509 * Scan through pages checking if pages follow certain conditions,
510 * and move them to the pagelist if they do.
512 * queue_pages_pte_range() has three possible return values:
513 * 0 - pages are placed on the right node or queued successfully.
514 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
516 * -EIO - only MPOL_MF_STRICT was specified and an existing page was already
517 * on a node that does not follow the policy.
519 static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
520 unsigned long end, struct mm_walk *walk)
522 struct vm_area_struct *vma = walk->vma;
524 struct queue_pages *qp = walk->private;
525 unsigned long flags = qp->flags;
527 bool has_unmovable = false;
528 pte_t *pte, *mapped_pte;
531 ptl = pmd_trans_huge_lock(pmd, vma);
533 ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
537 /* THP was split, fall through to pte walk */
539 if (pmd_trans_unstable(pmd))
542 mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
543 for (; addr != end; pte++, addr += PAGE_SIZE) {
544 if (!pte_present(*pte))
546 page = vm_normal_page(vma, addr, *pte);
550 * vm_normal_page() filters out zero pages, but there might
551 * still be PageReserved pages to skip, perhaps in a VDSO.
553 if (PageReserved(page))
555 if (!queue_pages_required(page, qp))
557 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
558 /* MPOL_MF_STRICT must be specified if we get here */
559 if (!vma_migratable(vma)) {
560 has_unmovable = true;
565 * Do not abort immediately since there may be
566 * temporary off LRU pages in the range. Still
567 * need migrate other LRU pages.
569 if (migrate_page_add(page, qp->pagelist, flags))
570 has_unmovable = true;
574 pte_unmap_unlock(mapped_pte, ptl);
580 return addr != end ? -EIO : 0;
583 static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
584 unsigned long addr, unsigned long end,
585 struct mm_walk *walk)
588 #ifdef CONFIG_HUGETLB_PAGE
589 struct queue_pages *qp = walk->private;
590 unsigned long flags = (qp->flags & MPOL_MF_VALID);
595 ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
596 entry = huge_ptep_get(pte);
597 if (!pte_present(entry))
599 page = pte_page(entry);
600 if (!queue_pages_required(page, qp))
603 if (flags == MPOL_MF_STRICT) {
605 * STRICT alone means only detecting misplaced page and no
606 * need to further check other vma.
612 if (!vma_migratable(walk->vma)) {
614 * Must be STRICT with MOVE*, otherwise .test_walk() have
615 * stopped walking current vma.
616 * Detecting misplaced page but allow migrating pages which
623 /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
624 if (flags & (MPOL_MF_MOVE_ALL) ||
625 (flags & MPOL_MF_MOVE && page_mapcount(page) == 1 &&
626 !hugetlb_pmd_shared(pte))) {
627 if (isolate_hugetlb(page, qp->pagelist) &&
628 (flags & MPOL_MF_STRICT))
630 * Failed to isolate page but allow migrating pages
631 * which have been queued.
643 #ifdef CONFIG_NUMA_BALANCING
645 * This is used to mark a range of virtual addresses to be inaccessible.
646 * These are later cleared by a NUMA hinting fault. Depending on these
647 * faults, pages may be migrated for better NUMA placement.
649 * This is assuming that NUMA faults are handled using PROT_NONE. If
650 * an architecture makes a different choice, it will need further
651 * changes to the core.
653 unsigned long change_prot_numa(struct vm_area_struct *vma,
654 unsigned long addr, unsigned long end)
658 nr_updated = change_protection(vma, addr, end, PAGE_NONE, MM_CP_PROT_NUMA);
660 count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
665 static unsigned long change_prot_numa(struct vm_area_struct *vma,
666 unsigned long addr, unsigned long end)
670 #endif /* CONFIG_NUMA_BALANCING */
672 static int queue_pages_test_walk(unsigned long start, unsigned long end,
673 struct mm_walk *walk)
675 struct vm_area_struct *vma = walk->vma;
676 struct queue_pages *qp = walk->private;
677 unsigned long endvma = vma->vm_end;
678 unsigned long flags = qp->flags;
680 /* range check first */
681 VM_BUG_ON_VMA((vma->vm_start > start) || (vma->vm_end < end), vma);
685 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
686 (qp->start < vma->vm_start))
687 /* hole at head side of range */
690 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
691 ((vma->vm_end < qp->end) &&
692 (!vma->vm_next || vma->vm_end < vma->vm_next->vm_start)))
693 /* hole at middle or tail of range */
697 * Need check MPOL_MF_STRICT to return -EIO if possible
698 * regardless of vma_migratable
700 if (!vma_migratable(vma) &&
701 !(flags & MPOL_MF_STRICT))
707 if (flags & MPOL_MF_LAZY) {
708 /* Similar to task_numa_work, skip inaccessible VMAs */
709 if (!is_vm_hugetlb_page(vma) && vma_is_accessible(vma) &&
710 !(vma->vm_flags & VM_MIXEDMAP))
711 change_prot_numa(vma, start, endvma);
715 /* queue pages from current vma */
716 if (flags & MPOL_MF_VALID)
721 static const struct mm_walk_ops queue_pages_walk_ops = {
722 .hugetlb_entry = queue_pages_hugetlb,
723 .pmd_entry = queue_pages_pte_range,
724 .test_walk = queue_pages_test_walk,
728 * Walk through page tables and collect pages to be migrated.
730 * If pages found in a given range are on a set of nodes (determined by
731 * @nodes and @flags,) it's isolated and queued to the pagelist which is
732 * passed via @private.
734 * queue_pages_range() has three possible return values:
735 * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
737 * 0 - queue pages successfully or no misplaced page.
738 * errno - i.e. misplaced pages with MPOL_MF_STRICT specified (-EIO) or
739 * memory range specified by nodemask and maxnode points outside
740 * your accessible address space (-EFAULT)
743 queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
744 nodemask_t *nodes, unsigned long flags,
745 struct list_head *pagelist)
748 struct queue_pages qp = {
749 .pagelist = pagelist,
757 err = walk_page_range(mm, start, end, &queue_pages_walk_ops, &qp);
760 /* whole range in hole */
767 * Apply policy to a single VMA
768 * This must be called with the mmap_lock held for writing.
770 static int vma_replace_policy(struct vm_area_struct *vma,
771 struct mempolicy *pol)
774 struct mempolicy *old;
775 struct mempolicy *new;
777 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
778 vma->vm_start, vma->vm_end, vma->vm_pgoff,
779 vma->vm_ops, vma->vm_file,
780 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
786 if (vma->vm_ops && vma->vm_ops->set_policy) {
787 err = vma->vm_ops->set_policy(vma, new);
792 old = vma->vm_policy;
793 vma->vm_policy = new; /* protected by mmap_lock */
802 /* Step 2: apply policy to a range and do splits. */
803 static int mbind_range(struct mm_struct *mm, unsigned long start,
804 unsigned long end, struct mempolicy *new_pol)
806 struct vm_area_struct *prev;
807 struct vm_area_struct *vma;
810 unsigned long vmstart;
813 vma = find_vma(mm, start);
817 if (start > vma->vm_start)
820 for (; vma && vma->vm_start < end; prev = vma, vma = vma->vm_next) {
821 vmstart = max(start, vma->vm_start);
822 vmend = min(end, vma->vm_end);
824 if (mpol_equal(vma_policy(vma), new_pol))
827 pgoff = vma->vm_pgoff +
828 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
829 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
830 vma->anon_vma, vma->vm_file, pgoff,
831 new_pol, vma->vm_userfaultfd_ctx);
836 if (vma->vm_start != vmstart) {
837 err = split_vma(vma->vm_mm, vma, vmstart, 1);
841 if (vma->vm_end != vmend) {
842 err = split_vma(vma->vm_mm, vma, vmend, 0);
847 err = vma_replace_policy(vma, new_pol);
856 /* Set the process memory policy */
857 static long do_set_mempolicy(unsigned short mode, unsigned short flags,
860 struct mempolicy *new, *old;
861 NODEMASK_SCRATCH(scratch);
867 new = mpol_new(mode, flags, nodes);
873 ret = mpol_set_nodemask(new, nodes, scratch);
879 old = current->mempolicy;
880 current->mempolicy = new;
881 if (new && new->mode == MPOL_INTERLEAVE)
882 current->il_prev = MAX_NUMNODES-1;
883 task_unlock(current);
887 NODEMASK_SCRATCH_FREE(scratch);
892 * Return nodemask for policy for get_mempolicy() query
894 * Called with task's alloc_lock held
896 static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
899 if (p == &default_policy)
904 case MPOL_INTERLEAVE:
908 if (!(p->flags & MPOL_F_LOCAL))
909 node_set(p->v.preferred_node, *nodes);
910 /* else return empty node mask for local allocation */
917 static int lookup_node(struct mm_struct *mm, unsigned long addr)
919 struct page *p = NULL;
923 err = get_user_pages_locked(addr & PAGE_MASK, 1, 0, &p, &locked);
925 err = page_to_nid(p);
929 mmap_read_unlock(mm);
933 /* Retrieve NUMA policy */
934 static long do_get_mempolicy(int *policy, nodemask_t *nmask,
935 unsigned long addr, unsigned long flags)
938 struct mm_struct *mm = current->mm;
939 struct vm_area_struct *vma = NULL;
940 struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL;
943 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
946 if (flags & MPOL_F_MEMS_ALLOWED) {
947 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
949 *policy = 0; /* just so it's initialized */
951 *nmask = cpuset_current_mems_allowed;
952 task_unlock(current);
956 if (flags & MPOL_F_ADDR) {
958 * Do NOT fall back to task policy if the
959 * vma/shared policy at addr is NULL. We
960 * want to return MPOL_DEFAULT in this case.
963 vma = find_vma_intersection(mm, addr, addr+1);
965 mmap_read_unlock(mm);
968 if (vma->vm_ops && vma->vm_ops->get_policy)
969 pol = vma->vm_ops->get_policy(vma, addr);
971 pol = vma->vm_policy;
976 pol = &default_policy; /* indicates default behavior */
978 if (flags & MPOL_F_NODE) {
979 if (flags & MPOL_F_ADDR) {
981 * Take a refcount on the mpol, lookup_node()
982 * wil drop the mmap_lock, so after calling
983 * lookup_node() only "pol" remains valid, "vma"
989 err = lookup_node(mm, addr);
993 } else if (pol == current->mempolicy &&
994 pol->mode == MPOL_INTERLEAVE) {
995 *policy = next_node_in(current->il_prev, pol->v.nodes);
1001 *policy = pol == &default_policy ? MPOL_DEFAULT :
1004 * Internal mempolicy flags must be masked off before exposing
1005 * the policy to userspace.
1007 *policy |= (pol->flags & MPOL_MODE_FLAGS);
1012 if (mpol_store_user_nodemask(pol)) {
1013 *nmask = pol->w.user_nodemask;
1016 get_policy_nodemask(pol, nmask);
1017 task_unlock(current);
1024 mmap_read_unlock(mm);
1026 mpol_put(pol_refcount);
1030 #ifdef CONFIG_MIGRATION
1032 * page migration, thp tail pages can be passed.
1034 static int migrate_page_add(struct page *page, struct list_head *pagelist,
1035 unsigned long flags)
1037 struct page *head = compound_head(page);
1039 * Avoid migrating a page that is shared with others.
1041 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(head) == 1) {
1042 if (!isolate_lru_page(head)) {
1043 list_add_tail(&head->lru, pagelist);
1044 mod_node_page_state(page_pgdat(head),
1045 NR_ISOLATED_ANON + page_is_file_lru(head),
1046 thp_nr_pages(head));
1047 } else if (flags & MPOL_MF_STRICT) {
1049 * Non-movable page may reach here. And, there may be
1050 * temporary off LRU pages or non-LRU movable pages.
1051 * Treat them as unmovable pages since they can't be
1052 * isolated, so they can't be moved at the moment. It
1053 * should return -EIO for this case too.
1063 * Migrate pages from one node to a target node.
1064 * Returns error or the number of pages not migrated.
1066 static int migrate_to_node(struct mm_struct *mm, int source, int dest,
1070 LIST_HEAD(pagelist);
1072 struct migration_target_control mtc = {
1074 .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE,
1078 node_set(source, nmask);
1081 * This does not "check" the range but isolates all pages that
1082 * need migration. Between passing in the full user address
1083 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
1085 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
1086 queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1087 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
1089 if (!list_empty(&pagelist)) {
1090 err = migrate_pages(&pagelist, alloc_migration_target, NULL,
1091 (unsigned long)&mtc, MIGRATE_SYNC, MR_SYSCALL);
1093 putback_movable_pages(&pagelist);
1100 * Move pages between the two nodesets so as to preserve the physical
1101 * layout as much as possible.
1103 * Returns the number of page that could not be moved.
1105 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1106 const nodemask_t *to, int flags)
1112 err = migrate_prep();
1119 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1120 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1121 * bit in 'tmp', and return that <source, dest> pair for migration.
1122 * The pair of nodemasks 'to' and 'from' define the map.
1124 * If no pair of bits is found that way, fallback to picking some
1125 * pair of 'source' and 'dest' bits that are not the same. If the
1126 * 'source' and 'dest' bits are the same, this represents a node
1127 * that will be migrating to itself, so no pages need move.
1129 * If no bits are left in 'tmp', or if all remaining bits left
1130 * in 'tmp' correspond to the same bit in 'to', return false
1131 * (nothing left to migrate).
1133 * This lets us pick a pair of nodes to migrate between, such that
1134 * if possible the dest node is not already occupied by some other
1135 * source node, minimizing the risk of overloading the memory on a
1136 * node that would happen if we migrated incoming memory to a node
1137 * before migrating outgoing memory source that same node.
1139 * A single scan of tmp is sufficient. As we go, we remember the
1140 * most recent <s, d> pair that moved (s != d). If we find a pair
1141 * that not only moved, but what's better, moved to an empty slot
1142 * (d is not set in tmp), then we break out then, with that pair.
1143 * Otherwise when we finish scanning from_tmp, we at least have the
1144 * most recent <s, d> pair that moved. If we get all the way through
1145 * the scan of tmp without finding any node that moved, much less
1146 * moved to an empty node, then there is nothing left worth migrating.
1150 while (!nodes_empty(tmp)) {
1152 int source = NUMA_NO_NODE;
1155 for_each_node_mask(s, tmp) {
1158 * do_migrate_pages() tries to maintain the relative
1159 * node relationship of the pages established between
1160 * threads and memory areas.
1162 * However if the number of source nodes is not equal to
1163 * the number of destination nodes we can not preserve
1164 * this node relative relationship. In that case, skip
1165 * copying memory from a node that is in the destination
1168 * Example: [2,3,4] -> [3,4,5] moves everything.
1169 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1172 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1173 (node_isset(s, *to)))
1176 d = node_remap(s, *from, *to);
1180 source = s; /* Node moved. Memorize */
1183 /* dest not in remaining from nodes? */
1184 if (!node_isset(dest, tmp))
1187 if (source == NUMA_NO_NODE)
1190 node_clear(source, tmp);
1191 err = migrate_to_node(mm, source, dest, flags);
1197 mmap_read_unlock(mm);
1205 * Allocate a new page for page migration based on vma policy.
1206 * Start by assuming the page is mapped by the same vma as contains @start.
1207 * Search forward from there, if not. N.B., this assumes that the
1208 * list of pages handed to migrate_pages()--which is how we get here--
1209 * is in virtual address order.
1211 static struct page *new_page(struct page *page, unsigned long start)
1213 struct vm_area_struct *vma;
1214 unsigned long address;
1216 vma = find_vma(current->mm, start);
1218 address = page_address_in_vma(page, vma);
1219 if (address != -EFAULT)
1224 if (PageHuge(page)) {
1225 return alloc_huge_page_vma(page_hstate(compound_head(page)),
1227 } else if (PageTransHuge(page)) {
1230 thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
1234 prep_transhuge_page(thp);
1238 * if !vma, alloc_page_vma() will use task or system default policy
1240 return alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL,
1245 static int migrate_page_add(struct page *page, struct list_head *pagelist,
1246 unsigned long flags)
1251 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1252 const nodemask_t *to, int flags)
1257 static struct page *new_page(struct page *page, unsigned long start)
1263 static long do_mbind(unsigned long start, unsigned long len,
1264 unsigned short mode, unsigned short mode_flags,
1265 nodemask_t *nmask, unsigned long flags)
1267 struct mm_struct *mm = current->mm;
1268 struct mempolicy *new;
1272 LIST_HEAD(pagelist);
1274 if (flags & ~(unsigned long)MPOL_MF_VALID)
1276 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1279 if (start & ~PAGE_MASK)
1282 if (mode == MPOL_DEFAULT)
1283 flags &= ~MPOL_MF_STRICT;
1285 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1293 new = mpol_new(mode, mode_flags, nmask);
1295 return PTR_ERR(new);
1297 if (flags & MPOL_MF_LAZY)
1298 new->flags |= MPOL_F_MOF;
1301 * If we are using the default policy then operation
1302 * on discontinuous address spaces is okay after all
1305 flags |= MPOL_MF_DISCONTIG_OK;
1307 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1308 start, start + len, mode, mode_flags,
1309 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1311 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1313 err = migrate_prep();
1318 NODEMASK_SCRATCH(scratch);
1320 mmap_write_lock(mm);
1321 err = mpol_set_nodemask(new, nmask, scratch);
1323 mmap_write_unlock(mm);
1326 NODEMASK_SCRATCH_FREE(scratch);
1331 ret = queue_pages_range(mm, start, end, nmask,
1332 flags | MPOL_MF_INVERT, &pagelist);
1339 err = mbind_range(mm, start, end, new);
1344 if (!list_empty(&pagelist)) {
1345 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1346 nr_failed = migrate_pages(&pagelist, new_page, NULL,
1347 start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
1349 putback_movable_pages(&pagelist);
1352 if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
1356 if (!list_empty(&pagelist))
1357 putback_movable_pages(&pagelist);
1360 mmap_write_unlock(mm);
1367 * User space interface with variable sized bitmaps for nodelists.
1370 /* Copy a node mask from user space. */
1371 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1372 unsigned long maxnode)
1376 unsigned long nlongs;
1377 unsigned long endmask;
1380 nodes_clear(*nodes);
1381 if (maxnode == 0 || !nmask)
1383 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1386 nlongs = BITS_TO_LONGS(maxnode);
1387 if ((maxnode % BITS_PER_LONG) == 0)
1390 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1393 * When the user specified more nodes than supported just check
1394 * if the non supported part is all zero.
1396 * If maxnode have more longs than MAX_NUMNODES, check
1397 * the bits in that area first. And then go through to
1398 * check the rest bits which equal or bigger than MAX_NUMNODES.
1399 * Otherwise, just check bits [MAX_NUMNODES, maxnode).
1401 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1402 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1403 if (get_user(t, nmask + k))
1405 if (k == nlongs - 1) {
1411 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1415 if (maxnode > MAX_NUMNODES && MAX_NUMNODES % BITS_PER_LONG != 0) {
1416 unsigned long valid_mask = endmask;
1418 valid_mask &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
1419 if (get_user(t, nmask + nlongs - 1))
1425 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1427 nodes_addr(*nodes)[nlongs-1] &= endmask;
1431 /* Copy a kernel node mask to user space */
1432 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1435 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1436 unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long);
1438 if (copy > nbytes) {
1439 if (copy > PAGE_SIZE)
1441 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1445 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1448 static long kernel_mbind(unsigned long start, unsigned long len,
1449 unsigned long mode, const unsigned long __user *nmask,
1450 unsigned long maxnode, unsigned int flags)
1454 unsigned short mode_flags;
1456 start = untagged_addr(start);
1457 mode_flags = mode & MPOL_MODE_FLAGS;
1458 mode &= ~MPOL_MODE_FLAGS;
1459 if (mode >= MPOL_MAX)
1461 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1462 (mode_flags & MPOL_F_RELATIVE_NODES))
1464 err = get_nodes(&nodes, nmask, maxnode);
1467 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1470 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1471 unsigned long, mode, const unsigned long __user *, nmask,
1472 unsigned long, maxnode, unsigned int, flags)
1474 return kernel_mbind(start, len, mode, nmask, maxnode, flags);
1477 /* Set the process memory policy */
1478 static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
1479 unsigned long maxnode)
1483 unsigned short flags;
1485 flags = mode & MPOL_MODE_FLAGS;
1486 mode &= ~MPOL_MODE_FLAGS;
1487 if ((unsigned int)mode >= MPOL_MAX)
1489 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1491 err = get_nodes(&nodes, nmask, maxnode);
1494 return do_set_mempolicy(mode, flags, &nodes);
1497 SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
1498 unsigned long, maxnode)
1500 return kernel_set_mempolicy(mode, nmask, maxnode);
1503 static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
1504 const unsigned long __user *old_nodes,
1505 const unsigned long __user *new_nodes)
1507 struct mm_struct *mm = NULL;
1508 struct task_struct *task;
1509 nodemask_t task_nodes;
1513 NODEMASK_SCRATCH(scratch);
1518 old = &scratch->mask1;
1519 new = &scratch->mask2;
1521 err = get_nodes(old, old_nodes, maxnode);
1525 err = get_nodes(new, new_nodes, maxnode);
1529 /* Find the mm_struct */
1531 task = pid ? find_task_by_vpid(pid) : current;
1537 get_task_struct(task);
1542 * Check if this process has the right to modify the specified process.
1543 * Use the regular "ptrace_may_access()" checks.
1545 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
1552 task_nodes = cpuset_mems_allowed(task);
1553 /* Is the user allowed to access the target nodes? */
1554 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1559 task_nodes = cpuset_mems_allowed(current);
1560 nodes_and(*new, *new, task_nodes);
1561 if (nodes_empty(*new))
1564 err = security_task_movememory(task);
1568 mm = get_task_mm(task);
1569 put_task_struct(task);
1576 err = do_migrate_pages(mm, old, new,
1577 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1581 NODEMASK_SCRATCH_FREE(scratch);
1586 put_task_struct(task);
1591 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1592 const unsigned long __user *, old_nodes,
1593 const unsigned long __user *, new_nodes)
1595 return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes);
1599 /* Retrieve NUMA policy */
1600 static int kernel_get_mempolicy(int __user *policy,
1601 unsigned long __user *nmask,
1602 unsigned long maxnode,
1604 unsigned long flags)
1610 if (nmask != NULL && maxnode < nr_node_ids)
1613 addr = untagged_addr(addr);
1615 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1620 if (policy && put_user(pval, policy))
1624 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1629 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1630 unsigned long __user *, nmask, unsigned long, maxnode,
1631 unsigned long, addr, unsigned long, flags)
1633 return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags);
1636 #ifdef CONFIG_COMPAT
1638 COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1639 compat_ulong_t __user *, nmask,
1640 compat_ulong_t, maxnode,
1641 compat_ulong_t, addr, compat_ulong_t, flags)
1644 unsigned long __user *nm = NULL;
1645 unsigned long nr_bits, alloc_size;
1646 DECLARE_BITMAP(bm, MAX_NUMNODES);
1648 nr_bits = min_t(unsigned long, maxnode-1, nr_node_ids);
1649 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1652 nm = compat_alloc_user_space(alloc_size);
1654 err = kernel_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1656 if (!err && nmask) {
1657 unsigned long copy_size;
1658 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1659 err = copy_from_user(bm, nm, copy_size);
1660 /* ensure entire bitmap is zeroed */
1661 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1662 err |= compat_put_bitmap(nmask, bm, nr_bits);
1668 COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
1669 compat_ulong_t, maxnode)
1671 unsigned long __user *nm = NULL;
1672 unsigned long nr_bits, alloc_size;
1673 DECLARE_BITMAP(bm, MAX_NUMNODES);
1675 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1676 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1679 if (compat_get_bitmap(bm, nmask, nr_bits))
1681 nm = compat_alloc_user_space(alloc_size);
1682 if (copy_to_user(nm, bm, alloc_size))
1686 return kernel_set_mempolicy(mode, nm, nr_bits+1);
1689 COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
1690 compat_ulong_t, mode, compat_ulong_t __user *, nmask,
1691 compat_ulong_t, maxnode, compat_ulong_t, flags)
1693 unsigned long __user *nm = NULL;
1694 unsigned long nr_bits, alloc_size;
1697 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1698 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1701 if (compat_get_bitmap(nodes_addr(bm), nmask, nr_bits))
1703 nm = compat_alloc_user_space(alloc_size);
1704 if (copy_to_user(nm, nodes_addr(bm), alloc_size))
1708 return kernel_mbind(start, len, mode, nm, nr_bits+1, flags);
1711 COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
1712 compat_ulong_t, maxnode,
1713 const compat_ulong_t __user *, old_nodes,
1714 const compat_ulong_t __user *, new_nodes)
1716 unsigned long __user *old = NULL;
1717 unsigned long __user *new = NULL;
1718 nodemask_t tmp_mask;
1719 unsigned long nr_bits;
1722 nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
1723 size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1725 if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
1727 old = compat_alloc_user_space(new_nodes ? size * 2 : size);
1729 new = old + size / sizeof(unsigned long);
1730 if (copy_to_user(old, nodes_addr(tmp_mask), size))
1734 if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
1737 new = compat_alloc_user_space(size);
1738 if (copy_to_user(new, nodes_addr(tmp_mask), size))
1741 return kernel_migrate_pages(pid, nr_bits + 1, old, new);
1744 #endif /* CONFIG_COMPAT */
1746 bool vma_migratable(struct vm_area_struct *vma)
1748 if (vma->vm_flags & (VM_IO | VM_PFNMAP))
1752 * DAX device mappings require predictable access latency, so avoid
1753 * incurring periodic faults.
1755 if (vma_is_dax(vma))
1758 if (is_vm_hugetlb_page(vma) &&
1759 !hugepage_migration_supported(hstate_vma(vma)))
1763 * Migration allocates pages in the highest zone. If we cannot
1764 * do so then migration (at least from node to node) is not
1768 gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
1774 struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
1777 struct mempolicy *pol = NULL;
1780 if (vma->vm_ops && vma->vm_ops->get_policy) {
1781 pol = vma->vm_ops->get_policy(vma, addr);
1782 } else if (vma->vm_policy) {
1783 pol = vma->vm_policy;
1786 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1787 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1788 * count on these policies which will be dropped by
1789 * mpol_cond_put() later
1791 if (mpol_needs_cond_ref(pol))
1800 * get_vma_policy(@vma, @addr)
1801 * @vma: virtual memory area whose policy is sought
1802 * @addr: address in @vma for shared policy lookup
1804 * Returns effective policy for a VMA at specified address.
1805 * Falls back to current->mempolicy or system default policy, as necessary.
1806 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1807 * count--added by the get_policy() vm_op, as appropriate--to protect against
1808 * freeing by another task. It is the caller's responsibility to free the
1809 * extra reference for shared policies.
1811 static struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
1814 struct mempolicy *pol = __get_vma_policy(vma, addr);
1817 pol = get_task_policy(current);
1822 bool vma_policy_mof(struct vm_area_struct *vma)
1824 struct mempolicy *pol;
1826 if (vma->vm_ops && vma->vm_ops->get_policy) {
1829 pol = vma->vm_ops->get_policy(vma, vma->vm_start);
1830 if (pol && (pol->flags & MPOL_F_MOF))
1837 pol = vma->vm_policy;
1839 pol = get_task_policy(current);
1841 return pol->flags & MPOL_F_MOF;
1844 static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1846 enum zone_type dynamic_policy_zone = policy_zone;
1848 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1851 * if policy->v.nodes has movable memory only,
1852 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1854 * policy->v.nodes is intersect with node_states[N_MEMORY].
1855 * so if the following test faile, it implies
1856 * policy->v.nodes has movable memory only.
1858 if (!nodes_intersects(policy->v.nodes, node_states[N_HIGH_MEMORY]))
1859 dynamic_policy_zone = ZONE_MOVABLE;
1861 return zone >= dynamic_policy_zone;
1865 * Return a nodemask representing a mempolicy for filtering nodes for
1868 nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1870 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1871 if (unlikely(policy->mode == MPOL_BIND) &&
1872 apply_policy_zone(policy, gfp_zone(gfp)) &&
1873 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1874 return &policy->v.nodes;
1879 /* Return the node id preferred by the given mempolicy, or the given id */
1880 static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd)
1882 if (policy->mode == MPOL_PREFERRED && !(policy->flags & MPOL_F_LOCAL))
1883 nd = policy->v.preferred_node;
1886 * __GFP_THISNODE shouldn't even be used with the bind policy
1887 * because we might easily break the expectation to stay on the
1888 * requested node and not break the policy.
1890 WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE));
1896 /* Do dynamic interleaving for a process */
1897 static unsigned interleave_nodes(struct mempolicy *policy)
1900 struct task_struct *me = current;
1902 next = next_node_in(me->il_prev, policy->v.nodes);
1903 if (next < MAX_NUMNODES)
1909 * Depending on the memory policy provide a node from which to allocate the
1912 unsigned int mempolicy_slab_node(void)
1914 struct mempolicy *policy;
1915 int node = numa_mem_id();
1920 policy = current->mempolicy;
1921 if (!policy || policy->flags & MPOL_F_LOCAL)
1924 switch (policy->mode) {
1925 case MPOL_PREFERRED:
1927 * handled MPOL_F_LOCAL above
1929 return policy->v.preferred_node;
1931 case MPOL_INTERLEAVE:
1932 return interleave_nodes(policy);
1938 * Follow bind policy behavior and start allocation at the
1941 struct zonelist *zonelist;
1942 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1943 zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK];
1944 z = first_zones_zonelist(zonelist, highest_zoneidx,
1946 return z->zone ? zone_to_nid(z->zone) : node;
1955 * Do static interleaving for a VMA with known offset @n. Returns the n'th
1956 * node in pol->v.nodes (starting from n=0), wrapping around if n exceeds the
1957 * number of present nodes.
1959 static unsigned offset_il_node(struct mempolicy *pol, unsigned long n)
1961 unsigned nnodes = nodes_weight(pol->v.nodes);
1967 return numa_node_id();
1968 target = (unsigned int)n % nnodes;
1969 nid = first_node(pol->v.nodes);
1970 for (i = 0; i < target; i++)
1971 nid = next_node(nid, pol->v.nodes);
1975 /* Determine a node number for interleave */
1976 static inline unsigned interleave_nid(struct mempolicy *pol,
1977 struct vm_area_struct *vma, unsigned long addr, int shift)
1983 * for small pages, there is no difference between
1984 * shift and PAGE_SHIFT, so the bit-shift is safe.
1985 * for huge pages, since vm_pgoff is in units of small
1986 * pages, we need to shift off the always 0 bits to get
1989 BUG_ON(shift < PAGE_SHIFT);
1990 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1991 off += (addr - vma->vm_start) >> shift;
1992 return offset_il_node(pol, off);
1994 return interleave_nodes(pol);
1997 #ifdef CONFIG_HUGETLBFS
1999 * huge_node(@vma, @addr, @gfp_flags, @mpol)
2000 * @vma: virtual memory area whose policy is sought
2001 * @addr: address in @vma for shared policy lookup and interleave policy
2002 * @gfp_flags: for requested zone
2003 * @mpol: pointer to mempolicy pointer for reference counted mempolicy
2004 * @nodemask: pointer to nodemask pointer for MPOL_BIND nodemask
2006 * Returns a nid suitable for a huge page allocation and a pointer
2007 * to the struct mempolicy for conditional unref after allocation.
2008 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
2009 * @nodemask for filtering the zonelist.
2011 * Must be protected by read_mems_allowed_begin()
2013 int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags,
2014 struct mempolicy **mpol, nodemask_t **nodemask)
2018 *mpol = get_vma_policy(vma, addr);
2019 *nodemask = NULL; /* assume !MPOL_BIND */
2021 if (unlikely((*mpol)->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 ((*mpol)->mode == MPOL_BIND)
2027 *nodemask = &(*mpol)->v.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;
2053 if (!(mask && current->mempolicy))
2057 mempolicy = current->mempolicy;
2058 switch (mempolicy->mode) {
2059 case MPOL_PREFERRED:
2060 if (mempolicy->flags & MPOL_F_LOCAL)
2061 nid = numa_node_id();
2063 nid = mempolicy->v.preferred_node;
2064 init_nodemask_of_node(mask, nid);
2068 case MPOL_INTERLEAVE:
2069 *mask = mempolicy->v.nodes;
2075 task_unlock(current);
2082 * mempolicy_nodemask_intersects
2084 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
2085 * policy. Otherwise, check for intersection between mask and the policy
2086 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
2087 * policy, always return true since it may allocate elsewhere on fallback.
2089 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
2091 bool mempolicy_nodemask_intersects(struct task_struct *tsk,
2092 const nodemask_t *mask)
2094 struct mempolicy *mempolicy;
2100 mempolicy = tsk->mempolicy;
2104 switch (mempolicy->mode) {
2105 case MPOL_PREFERRED:
2107 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
2108 * allocate from, they may fallback to other nodes when oom.
2109 * Thus, it's possible for tsk to have allocated memory from
2114 case MPOL_INTERLEAVE:
2115 ret = nodes_intersects(mempolicy->v.nodes, *mask);
2125 /* Allocate a page in interleaved policy.
2126 Own path because it needs to do special accounting. */
2127 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
2132 page = __alloc_pages(gfp, order, nid);
2133 /* skip NUMA_INTERLEAVE_HIT counter update if numa stats is disabled */
2134 if (!static_branch_likely(&vm_numa_stat_key))
2136 if (page && page_to_nid(page) == nid) {
2138 __inc_numa_state(page_zone(page), NUMA_INTERLEAVE_HIT);
2145 * alloc_pages_vma - Allocate a page for a VMA.
2148 * %GFP_USER user allocation.
2149 * %GFP_KERNEL kernel allocations,
2150 * %GFP_HIGHMEM highmem/user allocations,
2151 * %GFP_FS allocation should not call back into a file system.
2152 * %GFP_ATOMIC don't sleep.
2154 * @order:Order of the GFP allocation.
2155 * @vma: Pointer to VMA or NULL if not available.
2156 * @addr: Virtual Address of the allocation. Must be inside the VMA.
2157 * @node: Which node to prefer for allocation (modulo policy).
2158 * @hugepage: for hugepages try only the preferred node if possible
2160 * This function allocates a page from the kernel page pool and applies
2161 * a NUMA policy associated with the VMA or the current process.
2162 * When VMA is not NULL caller must read-lock the mmap_lock of the
2163 * mm_struct of the VMA to prevent it from going away. Should be used for
2164 * all allocations for pages that will be mapped into user space. Returns
2165 * NULL when no page can be allocated.
2168 alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
2169 unsigned long addr, int node, bool hugepage)
2171 struct mempolicy *pol;
2176 pol = get_vma_policy(vma, addr);
2178 if (pol->mode == MPOL_INTERLEAVE) {
2181 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2183 page = alloc_page_interleave(gfp, order, nid);
2187 if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
2188 int hpage_node = node;
2191 * For hugepage allocation and non-interleave policy which
2192 * allows the current node (or other explicitly preferred
2193 * node) we only try to allocate from the current/preferred
2194 * node and don't fall back to other nodes, as the cost of
2195 * remote accesses would likely offset THP benefits.
2197 * If the policy is interleave, or does not allow the current
2198 * node in its nodemask, we allocate the standard way.
2200 if (pol->mode == MPOL_PREFERRED && !(pol->flags & MPOL_F_LOCAL))
2201 hpage_node = pol->v.preferred_node;
2203 nmask = policy_nodemask(gfp, pol);
2204 if (!nmask || node_isset(hpage_node, *nmask)) {
2207 * First, try to allocate THP only on local node, but
2208 * don't reclaim unnecessarily, just compact.
2210 page = __alloc_pages_node(hpage_node,
2211 gfp | __GFP_THISNODE | __GFP_NORETRY, order);
2214 * If hugepage allocations are configured to always
2215 * synchronous compact or the vma has been madvised
2216 * to prefer hugepage backing, retry allowing remote
2217 * memory with both reclaim and compact as well.
2219 if (!page && (gfp & __GFP_DIRECT_RECLAIM))
2220 page = __alloc_pages_nodemask(gfp, order,
2227 nmask = policy_nodemask(gfp, pol);
2228 preferred_nid = policy_node(gfp, pol, node);
2229 page = __alloc_pages_nodemask(gfp, order, preferred_nid, nmask);
2234 EXPORT_SYMBOL(alloc_pages_vma);
2237 * alloc_pages_current - Allocate pages.
2240 * %GFP_USER user allocation,
2241 * %GFP_KERNEL kernel allocation,
2242 * %GFP_HIGHMEM highmem allocation,
2243 * %GFP_FS don't call back into a file system.
2244 * %GFP_ATOMIC don't sleep.
2245 * @order: Power of two of allocation size in pages. 0 is a single page.
2247 * Allocate a page from the kernel page pool. When not in
2248 * interrupt context and apply the current process NUMA policy.
2249 * Returns NULL when no page can be allocated.
2251 struct page *alloc_pages_current(gfp_t gfp, unsigned order)
2253 struct mempolicy *pol = &default_policy;
2256 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2257 pol = get_task_policy(current);
2260 * No reference counting needed for current->mempolicy
2261 * nor system default_policy
2263 if (pol->mode == MPOL_INTERLEAVE)
2264 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
2266 page = __alloc_pages_nodemask(gfp, order,
2267 policy_node(gfp, pol, numa_node_id()),
2268 policy_nodemask(gfp, pol));
2272 EXPORT_SYMBOL(alloc_pages_current);
2274 int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
2276 struct mempolicy *pol = mpol_dup(vma_policy(src));
2279 return PTR_ERR(pol);
2280 dst->vm_policy = pol;
2285 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2286 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2287 * with the mems_allowed returned by cpuset_mems_allowed(). This
2288 * keeps mempolicies cpuset relative after its cpuset moves. See
2289 * further kernel/cpuset.c update_nodemask().
2291 * current's mempolicy may be rebinded by the other task(the task that changes
2292 * cpuset's mems), so we needn't do rebind work for current task.
2295 /* Slow path of a mempolicy duplicate */
2296 struct mempolicy *__mpol_dup(struct mempolicy *old)
2298 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2301 return ERR_PTR(-ENOMEM);
2303 /* task's mempolicy is protected by alloc_lock */
2304 if (old == current->mempolicy) {
2307 task_unlock(current);
2311 if (current_cpuset_is_being_rebound()) {
2312 nodemask_t mems = cpuset_mems_allowed(current);
2313 mpol_rebind_policy(new, &mems);
2315 atomic_set(&new->refcnt, 1);
2319 /* Slow path of a mempolicy comparison */
2320 bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2324 if (a->mode != b->mode)
2326 if (a->flags != b->flags)
2328 if (mpol_store_user_nodemask(a))
2329 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2334 case MPOL_INTERLEAVE:
2335 return !!nodes_equal(a->v.nodes, b->v.nodes);
2336 case MPOL_PREFERRED:
2337 /* a's ->flags is the same as b's */
2338 if (a->flags & MPOL_F_LOCAL)
2340 return a->v.preferred_node == b->v.preferred_node;
2348 * Shared memory backing store policy support.
2350 * Remember policies even when nobody has shared memory mapped.
2351 * The policies are kept in Red-Black tree linked from the inode.
2352 * They are protected by the sp->lock rwlock, which should be held
2353 * for any accesses to the tree.
2357 * lookup first element intersecting start-end. Caller holds sp->lock for
2358 * reading or for writing
2360 static struct sp_node *
2361 sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2363 struct rb_node *n = sp->root.rb_node;
2366 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2368 if (start >= p->end)
2370 else if (end <= p->start)
2378 struct sp_node *w = NULL;
2379 struct rb_node *prev = rb_prev(n);
2382 w = rb_entry(prev, struct sp_node, nd);
2383 if (w->end <= start)
2387 return rb_entry(n, struct sp_node, nd);
2391 * Insert a new shared policy into the list. Caller holds sp->lock for
2394 static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2396 struct rb_node **p = &sp->root.rb_node;
2397 struct rb_node *parent = NULL;
2402 nd = rb_entry(parent, struct sp_node, nd);
2403 if (new->start < nd->start)
2405 else if (new->end > nd->end)
2406 p = &(*p)->rb_right;
2410 rb_link_node(&new->nd, parent, p);
2411 rb_insert_color(&new->nd, &sp->root);
2412 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2413 new->policy ? new->policy->mode : 0);
2416 /* Find shared policy intersecting idx */
2418 mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2420 struct mempolicy *pol = NULL;
2423 if (!sp->root.rb_node)
2425 read_lock(&sp->lock);
2426 sn = sp_lookup(sp, idx, idx+1);
2428 mpol_get(sn->policy);
2431 read_unlock(&sp->lock);
2435 static void sp_free(struct sp_node *n)
2437 mpol_put(n->policy);
2438 kmem_cache_free(sn_cache, n);
2442 * mpol_misplaced - check whether current page node is valid in policy
2444 * @page: page to be checked
2445 * @vma: vm area where page mapped
2446 * @addr: virtual address where page mapped
2448 * Lookup current policy node id for vma,addr and "compare to" page's
2452 * -1 - not misplaced, page is in the right node
2453 * node - node id where the page should be
2455 * Policy determination "mimics" alloc_page_vma().
2456 * Called from fault path where we know the vma and faulting address.
2458 int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
2460 struct mempolicy *pol;
2462 int curnid = page_to_nid(page);
2463 unsigned long pgoff;
2464 int thiscpu = raw_smp_processor_id();
2465 int thisnid = cpu_to_node(thiscpu);
2466 int polnid = NUMA_NO_NODE;
2469 pol = get_vma_policy(vma, addr);
2470 if (!(pol->flags & MPOL_F_MOF))
2473 switch (pol->mode) {
2474 case MPOL_INTERLEAVE:
2475 pgoff = vma->vm_pgoff;
2476 pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
2477 polnid = offset_il_node(pol, pgoff);
2480 case MPOL_PREFERRED:
2481 if (pol->flags & MPOL_F_LOCAL)
2482 polnid = numa_node_id();
2484 polnid = pol->v.preferred_node;
2490 * allows binding to multiple nodes.
2491 * use current page if in policy nodemask,
2492 * else select nearest allowed node, if any.
2493 * If no allowed nodes, use current [!misplaced].
2495 if (node_isset(curnid, pol->v.nodes))
2497 z = first_zones_zonelist(
2498 node_zonelist(numa_node_id(), GFP_HIGHUSER),
2499 gfp_zone(GFP_HIGHUSER),
2501 polnid = zone_to_nid(z->zone);
2508 /* Migrate the page towards the node whose CPU is referencing it */
2509 if (pol->flags & MPOL_F_MORON) {
2512 if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
2516 if (curnid != polnid)
2525 * Drop the (possibly final) reference to task->mempolicy. It needs to be
2526 * dropped after task->mempolicy is set to NULL so that any allocation done as
2527 * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed
2530 void mpol_put_task_policy(struct task_struct *task)
2532 struct mempolicy *pol;
2535 pol = task->mempolicy;
2536 task->mempolicy = NULL;
2541 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2543 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2544 rb_erase(&n->nd, &sp->root);
2548 static void sp_node_init(struct sp_node *node, unsigned long start,
2549 unsigned long end, struct mempolicy *pol)
2551 node->start = start;
2556 static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2557 struct mempolicy *pol)
2560 struct mempolicy *newpol;
2562 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2566 newpol = mpol_dup(pol);
2567 if (IS_ERR(newpol)) {
2568 kmem_cache_free(sn_cache, n);
2571 newpol->flags |= MPOL_F_SHARED;
2572 sp_node_init(n, start, end, newpol);
2577 /* Replace a policy range. */
2578 static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2579 unsigned long end, struct sp_node *new)
2582 struct sp_node *n_new = NULL;
2583 struct mempolicy *mpol_new = NULL;
2587 write_lock(&sp->lock);
2588 n = sp_lookup(sp, start, end);
2589 /* Take care of old policies in the same range. */
2590 while (n && n->start < end) {
2591 struct rb_node *next = rb_next(&n->nd);
2592 if (n->start >= start) {
2598 /* Old policy spanning whole new range. */
2603 *mpol_new = *n->policy;
2604 atomic_set(&mpol_new->refcnt, 1);
2605 sp_node_init(n_new, end, n->end, mpol_new);
2607 sp_insert(sp, n_new);
2616 n = rb_entry(next, struct sp_node, nd);
2620 write_unlock(&sp->lock);
2627 kmem_cache_free(sn_cache, n_new);
2632 write_unlock(&sp->lock);
2634 n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2637 mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2640 atomic_set(&mpol_new->refcnt, 1);
2645 * mpol_shared_policy_init - initialize shared policy for inode
2646 * @sp: pointer to inode shared policy
2647 * @mpol: struct mempolicy to install
2649 * Install non-NULL @mpol in inode's shared policy rb-tree.
2650 * On entry, the current task has a reference on a non-NULL @mpol.
2651 * This must be released on exit.
2652 * This is called at get_inode() calls and we can use GFP_KERNEL.
2654 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2658 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2659 rwlock_init(&sp->lock);
2662 struct vm_area_struct pvma;
2663 struct mempolicy *new;
2664 NODEMASK_SCRATCH(scratch);
2668 /* contextualize the tmpfs mount point mempolicy */
2669 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2671 goto free_scratch; /* no valid nodemask intersection */
2674 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2675 task_unlock(current);
2679 /* Create pseudo-vma that contains just the policy */
2680 vma_init(&pvma, NULL);
2681 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2682 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2685 mpol_put(new); /* drop initial ref */
2687 NODEMASK_SCRATCH_FREE(scratch);
2689 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2693 int mpol_set_shared_policy(struct shared_policy *info,
2694 struct vm_area_struct *vma, struct mempolicy *npol)
2697 struct sp_node *new = NULL;
2698 unsigned long sz = vma_pages(vma);
2700 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2702 sz, npol ? npol->mode : -1,
2703 npol ? npol->flags : -1,
2704 npol ? nodes_addr(npol->v.nodes)[0] : NUMA_NO_NODE);
2707 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2711 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2717 /* Free a backing policy store on inode delete. */
2718 void mpol_free_shared_policy(struct shared_policy *p)
2721 struct rb_node *next;
2723 if (!p->root.rb_node)
2725 write_lock(&p->lock);
2726 next = rb_first(&p->root);
2728 n = rb_entry(next, struct sp_node, nd);
2729 next = rb_next(&n->nd);
2732 write_unlock(&p->lock);
2735 #ifdef CONFIG_NUMA_BALANCING
2736 static int __initdata numabalancing_override;
2738 static void __init check_numabalancing_enable(void)
2740 bool numabalancing_default = false;
2742 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2743 numabalancing_default = true;
2745 /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
2746 if (numabalancing_override)
2747 set_numabalancing_state(numabalancing_override == 1);
2749 if (num_online_nodes() > 1 && !numabalancing_override) {
2750 pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n",
2751 numabalancing_default ? "Enabling" : "Disabling");
2752 set_numabalancing_state(numabalancing_default);
2756 static int __init setup_numabalancing(char *str)
2762 if (!strcmp(str, "enable")) {
2763 numabalancing_override = 1;
2765 } else if (!strcmp(str, "disable")) {
2766 numabalancing_override = -1;
2771 pr_warn("Unable to parse numa_balancing=\n");
2775 __setup("numa_balancing=", setup_numabalancing);
2777 static inline void __init check_numabalancing_enable(void)
2780 #endif /* CONFIG_NUMA_BALANCING */
2782 /* assumes fs == KERNEL_DS */
2783 void __init numa_policy_init(void)
2785 nodemask_t interleave_nodes;
2786 unsigned long largest = 0;
2787 int nid, prefer = 0;
2789 policy_cache = kmem_cache_create("numa_policy",
2790 sizeof(struct mempolicy),
2791 0, SLAB_PANIC, NULL);
2793 sn_cache = kmem_cache_create("shared_policy_node",
2794 sizeof(struct sp_node),
2795 0, SLAB_PANIC, NULL);
2797 for_each_node(nid) {
2798 preferred_node_policy[nid] = (struct mempolicy) {
2799 .refcnt = ATOMIC_INIT(1),
2800 .mode = MPOL_PREFERRED,
2801 .flags = MPOL_F_MOF | MPOL_F_MORON,
2802 .v = { .preferred_node = nid, },
2807 * Set interleaving policy for system init. Interleaving is only
2808 * enabled across suitably sized nodes (default is >= 16MB), or
2809 * fall back to the largest node if they're all smaller.
2811 nodes_clear(interleave_nodes);
2812 for_each_node_state(nid, N_MEMORY) {
2813 unsigned long total_pages = node_present_pages(nid);
2815 /* Preserve the largest node */
2816 if (largest < total_pages) {
2817 largest = total_pages;
2821 /* Interleave this node? */
2822 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2823 node_set(nid, interleave_nodes);
2826 /* All too small, use the largest */
2827 if (unlikely(nodes_empty(interleave_nodes)))
2828 node_set(prefer, interleave_nodes);
2830 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2831 pr_err("%s: interleaving failed\n", __func__);
2833 check_numabalancing_enable();
2836 /* Reset policy of current process to default */
2837 void numa_default_policy(void)
2839 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2843 * Parse and format mempolicy from/to strings
2847 * "local" is implemented internally by MPOL_PREFERRED with MPOL_F_LOCAL flag.
2849 static const char * const policy_modes[] =
2851 [MPOL_DEFAULT] = "default",
2852 [MPOL_PREFERRED] = "prefer",
2853 [MPOL_BIND] = "bind",
2854 [MPOL_INTERLEAVE] = "interleave",
2855 [MPOL_LOCAL] = "local",
2861 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2862 * @str: string containing mempolicy to parse
2863 * @mpol: pointer to struct mempolicy pointer, returned on success.
2866 * <mode>[=<flags>][:<nodelist>]
2868 * On success, returns 0, else 1
2870 int mpol_parse_str(char *str, struct mempolicy **mpol)
2872 struct mempolicy *new = NULL;
2873 unsigned short mode_flags;
2875 char *nodelist = strchr(str, ':');
2876 char *flags = strchr(str, '=');
2880 *flags++ = '\0'; /* terminate mode string */
2883 /* NUL-terminate mode or flags string */
2885 if (nodelist_parse(nodelist, nodes))
2887 if (!nodes_subset(nodes, node_states[N_MEMORY]))
2892 mode = match_string(policy_modes, MPOL_MAX, str);
2897 case MPOL_PREFERRED:
2899 * Insist on a nodelist of one node only, although later
2900 * we use first_node(nodes) to grab a single node, so here
2901 * nodelist (or nodes) cannot be empty.
2904 char *rest = nodelist;
2905 while (isdigit(*rest))
2909 if (nodes_empty(nodes))
2913 case MPOL_INTERLEAVE:
2915 * Default to online nodes with memory if no nodelist
2918 nodes = node_states[N_MEMORY];
2922 * Don't allow a nodelist; mpol_new() checks flags
2926 mode = MPOL_PREFERRED;
2930 * Insist on a empty nodelist
2937 * Insist on a nodelist
2946 * Currently, we only support two mutually exclusive
2949 if (!strcmp(flags, "static"))
2950 mode_flags |= MPOL_F_STATIC_NODES;
2951 else if (!strcmp(flags, "relative"))
2952 mode_flags |= MPOL_F_RELATIVE_NODES;
2957 new = mpol_new(mode, mode_flags, &nodes);
2962 * Save nodes for mpol_to_str() to show the tmpfs mount options
2963 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
2965 if (mode != MPOL_PREFERRED)
2966 new->v.nodes = nodes;
2968 new->v.preferred_node = first_node(nodes);
2970 new->flags |= MPOL_F_LOCAL;
2973 * Save nodes for contextualization: this will be used to "clone"
2974 * the mempolicy in a specific context [cpuset] at a later time.
2976 new->w.user_nodemask = nodes;
2981 /* Restore string for error message */
2990 #endif /* CONFIG_TMPFS */
2993 * mpol_to_str - format a mempolicy structure for printing
2994 * @buffer: to contain formatted mempolicy string
2995 * @maxlen: length of @buffer
2996 * @pol: pointer to mempolicy to be formatted
2998 * Convert @pol into a string. If @buffer is too short, truncate the string.
2999 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
3000 * longest flag, "relative", and to display at least a few node ids.
3002 void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
3005 nodemask_t nodes = NODE_MASK_NONE;
3006 unsigned short mode = MPOL_DEFAULT;
3007 unsigned short flags = 0;
3009 if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
3017 case MPOL_PREFERRED:
3018 if (flags & MPOL_F_LOCAL)
3021 node_set(pol->v.preferred_node, nodes);
3024 case MPOL_INTERLEAVE:
3025 nodes = pol->v.nodes;
3029 snprintf(p, maxlen, "unknown");
3033 p += snprintf(p, maxlen, "%s", policy_modes[mode]);
3035 if (flags & MPOL_MODE_FLAGS) {
3036 p += snprintf(p, buffer + maxlen - p, "=");
3039 * Currently, the only defined flags are mutually exclusive
3041 if (flags & MPOL_F_STATIC_NODES)
3042 p += snprintf(p, buffer + maxlen - p, "static");
3043 else if (flags & MPOL_F_RELATIVE_NODES)
3044 p += snprintf(p, buffer + maxlen - p, "relative");
3047 if (!nodes_empty(nodes))
3048 p += scnprintf(p, buffer + maxlen - p, ":%*pbl",
3049 nodemask_pr_args(&nodes));