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];
130 struct mempolicy *get_task_policy(struct task_struct *p)
132 struct mempolicy *pol = p->mempolicy;
138 node = numa_node_id();
139 if (node != NUMA_NO_NODE) {
140 pol = &preferred_node_policy[node];
141 /* preferred_node_policy is not initialised early in boot */
146 return &default_policy;
149 static const struct mempolicy_operations {
150 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
151 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes);
152 } mpol_ops[MPOL_MAX];
154 static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
156 return pol->flags & MPOL_MODE_FLAGS;
159 static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
160 const nodemask_t *rel)
163 nodes_fold(tmp, *orig, nodes_weight(*rel));
164 nodes_onto(*ret, tmp, *rel);
167 static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
169 if (nodes_empty(*nodes))
171 pol->v.nodes = *nodes;
175 static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
178 pol->flags |= MPOL_F_LOCAL; /* local allocation */
179 else if (nodes_empty(*nodes))
180 return -EINVAL; /* no allowed nodes */
182 pol->v.preferred_node = first_node(*nodes);
186 static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
188 if (nodes_empty(*nodes))
190 pol->v.nodes = *nodes;
195 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
196 * any, for the new policy. mpol_new() has already validated the nodes
197 * parameter with respect to the policy mode and flags. But, we need to
198 * handle an empty nodemask with MPOL_PREFERRED here.
200 * Must be called holding task's alloc_lock to protect task's mems_allowed
201 * and mempolicy. May also be called holding the mmap_semaphore for write.
203 static int mpol_set_nodemask(struct mempolicy *pol,
204 const nodemask_t *nodes, struct nodemask_scratch *nsc)
208 /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
212 nodes_and(nsc->mask1,
213 cpuset_current_mems_allowed, node_states[N_MEMORY]);
216 if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
217 nodes = NULL; /* explicit local allocation */
219 if (pol->flags & MPOL_F_RELATIVE_NODES)
220 mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1);
222 nodes_and(nsc->mask2, *nodes, nsc->mask1);
224 if (mpol_store_user_nodemask(pol))
225 pol->w.user_nodemask = *nodes;
227 pol->w.cpuset_mems_allowed =
228 cpuset_current_mems_allowed;
232 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
234 ret = mpol_ops[pol->mode].create(pol, NULL);
239 * This function just creates a new policy, does some check and simple
240 * initialization. You must invoke mpol_set_nodemask() to set nodes.
242 static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
245 struct mempolicy *policy;
247 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
248 mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE);
250 if (mode == MPOL_DEFAULT) {
251 if (nodes && !nodes_empty(*nodes))
252 return ERR_PTR(-EINVAL);
258 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
259 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
260 * All other modes require a valid pointer to a non-empty nodemask.
262 if (mode == MPOL_PREFERRED) {
263 if (nodes_empty(*nodes)) {
264 if (((flags & MPOL_F_STATIC_NODES) ||
265 (flags & MPOL_F_RELATIVE_NODES)))
266 return ERR_PTR(-EINVAL);
268 } else if (mode == MPOL_LOCAL) {
269 if (!nodes_empty(*nodes) ||
270 (flags & MPOL_F_STATIC_NODES) ||
271 (flags & MPOL_F_RELATIVE_NODES))
272 return ERR_PTR(-EINVAL);
273 mode = MPOL_PREFERRED;
274 } else if (nodes_empty(*nodes))
275 return ERR_PTR(-EINVAL);
276 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
278 return ERR_PTR(-ENOMEM);
279 atomic_set(&policy->refcnt, 1);
281 policy->flags = flags;
286 /* Slow path of a mpol destructor. */
287 void __mpol_put(struct mempolicy *p)
289 if (!atomic_dec_and_test(&p->refcnt))
291 kmem_cache_free(policy_cache, p);
294 static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes)
298 static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
302 if (pol->flags & MPOL_F_STATIC_NODES)
303 nodes_and(tmp, pol->w.user_nodemask, *nodes);
304 else if (pol->flags & MPOL_F_RELATIVE_NODES)
305 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
307 nodes_remap(tmp, pol->v.nodes,pol->w.cpuset_mems_allowed,
309 pol->w.cpuset_mems_allowed = *nodes;
312 if (nodes_empty(tmp))
318 static void mpol_rebind_preferred(struct mempolicy *pol,
319 const nodemask_t *nodes)
323 if (pol->flags & MPOL_F_STATIC_NODES) {
324 int node = first_node(pol->w.user_nodemask);
326 if (node_isset(node, *nodes)) {
327 pol->v.preferred_node = node;
328 pol->flags &= ~MPOL_F_LOCAL;
330 pol->flags |= MPOL_F_LOCAL;
331 } else if (pol->flags & MPOL_F_RELATIVE_NODES) {
332 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
333 pol->v.preferred_node = first_node(tmp);
334 } else if (!(pol->flags & MPOL_F_LOCAL)) {
335 pol->v.preferred_node = node_remap(pol->v.preferred_node,
336 pol->w.cpuset_mems_allowed,
338 pol->w.cpuset_mems_allowed = *nodes;
343 * mpol_rebind_policy - Migrate a policy to a different set of nodes
345 * Per-vma policies are protected by mmap_sem. Allocations using per-task
346 * policies are protected by task->mems_allowed_seq to prevent a premature
347 * OOM/allocation failure due to parallel nodemask modification.
349 static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask)
353 if (!mpol_store_user_nodemask(pol) && !(pol->flags & MPOL_F_LOCAL) &&
354 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
357 mpol_ops[pol->mode].rebind(pol, newmask);
361 * Wrapper for mpol_rebind_policy() that just requires task
362 * pointer, and updates task mempolicy.
364 * Called with task's alloc_lock held.
367 void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new)
369 mpol_rebind_policy(tsk->mempolicy, new);
373 * Rebind each vma in mm to new nodemask.
375 * Call holding a reference to mm. Takes mm->mmap_sem during call.
378 void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
380 struct vm_area_struct *vma;
382 down_write(&mm->mmap_sem);
383 for (vma = mm->mmap; vma; vma = vma->vm_next)
384 mpol_rebind_policy(vma->vm_policy, new);
385 up_write(&mm->mmap_sem);
388 static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
390 .rebind = mpol_rebind_default,
392 [MPOL_INTERLEAVE] = {
393 .create = mpol_new_interleave,
394 .rebind = mpol_rebind_nodemask,
397 .create = mpol_new_preferred,
398 .rebind = mpol_rebind_preferred,
401 .create = mpol_new_bind,
402 .rebind = mpol_rebind_nodemask,
406 static int migrate_page_add(struct page *page, struct list_head *pagelist,
407 unsigned long flags);
410 struct list_head *pagelist;
415 struct vm_area_struct *first;
419 * Check if the page's nid is in qp->nmask.
421 * If MPOL_MF_INVERT is set in qp->flags, check if the nid is
422 * in the invert of qp->nmask.
424 static inline bool queue_pages_required(struct page *page,
425 struct queue_pages *qp)
427 int nid = page_to_nid(page);
428 unsigned long flags = qp->flags;
430 return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT);
434 * queue_pages_pmd() has four possible return values:
435 * 0 - pages are placed on the right node or queued successfully.
436 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
439 * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an
440 * existing page was already on a node that does not follow the
443 static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
444 unsigned long end, struct mm_walk *walk)
449 struct queue_pages *qp = walk->private;
452 if (unlikely(is_pmd_migration_entry(*pmd))) {
456 page = pmd_page(*pmd);
457 if (is_huge_zero_page(page)) {
459 __split_huge_pmd(walk->vma, pmd, addr, false, NULL);
463 if (!queue_pages_required(page, qp))
467 /* go to thp migration */
468 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
469 if (!vma_migratable(walk->vma) ||
470 migrate_page_add(page, qp->pagelist, flags)) {
483 * Scan through pages checking if pages follow certain conditions,
484 * and move them to the pagelist if they do.
486 * queue_pages_pte_range() has three possible return values:
487 * 0 - pages are placed on the right node or queued successfully.
488 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
490 * -EIO - only MPOL_MF_STRICT was specified and an existing page was already
491 * on a node that does not follow the policy.
493 static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
494 unsigned long end, struct mm_walk *walk)
496 struct vm_area_struct *vma = walk->vma;
498 struct queue_pages *qp = walk->private;
499 unsigned long flags = qp->flags;
501 bool has_unmovable = false;
505 ptl = pmd_trans_huge_lock(pmd, vma);
507 ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
511 /* THP was split, fall through to pte walk */
513 if (pmd_trans_unstable(pmd))
516 pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
517 for (; addr != end; pte++, addr += PAGE_SIZE) {
518 if (!pte_present(*pte))
520 page = vm_normal_page(vma, addr, *pte);
524 * vm_normal_page() filters out zero pages, but there might
525 * still be PageReserved pages to skip, perhaps in a VDSO.
527 if (PageReserved(page))
529 if (!queue_pages_required(page, qp))
531 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
532 /* MPOL_MF_STRICT must be specified if we get here */
533 if (!vma_migratable(vma)) {
534 has_unmovable = true;
539 * Do not abort immediately since there may be
540 * temporary off LRU pages in the range. Still
541 * need migrate other LRU pages.
543 if (migrate_page_add(page, qp->pagelist, flags))
544 has_unmovable = true;
548 pte_unmap_unlock(pte - 1, ptl);
554 return addr != end ? -EIO : 0;
557 static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
558 unsigned long addr, unsigned long end,
559 struct mm_walk *walk)
562 #ifdef CONFIG_HUGETLB_PAGE
563 struct queue_pages *qp = walk->private;
564 unsigned long flags = (qp->flags & MPOL_MF_VALID);
569 ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
570 entry = huge_ptep_get(pte);
571 if (!pte_present(entry))
573 page = pte_page(entry);
574 if (!queue_pages_required(page, qp))
577 if (flags == MPOL_MF_STRICT) {
579 * STRICT alone means only detecting misplaced page and no
580 * need to further check other vma.
586 if (!vma_migratable(walk->vma)) {
588 * Must be STRICT with MOVE*, otherwise .test_walk() have
589 * stopped walking current vma.
590 * Detecting misplaced page but allow migrating pages which
597 /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
598 if (flags & (MPOL_MF_MOVE_ALL) ||
599 (flags & MPOL_MF_MOVE && page_mapcount(page) == 1)) {
600 if (!isolate_huge_page(page, qp->pagelist) &&
601 (flags & MPOL_MF_STRICT))
603 * Failed to isolate page but allow migrating pages
604 * which have been queued.
616 #ifdef CONFIG_NUMA_BALANCING
618 * This is used to mark a range of virtual addresses to be inaccessible.
619 * These are later cleared by a NUMA hinting fault. Depending on these
620 * faults, pages may be migrated for better NUMA placement.
622 * This is assuming that NUMA faults are handled using PROT_NONE. If
623 * an architecture makes a different choice, it will need further
624 * changes to the core.
626 unsigned long change_prot_numa(struct vm_area_struct *vma,
627 unsigned long addr, unsigned long end)
631 nr_updated = change_protection(vma, addr, end, PAGE_NONE, MM_CP_PROT_NUMA);
633 count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
638 static unsigned long change_prot_numa(struct vm_area_struct *vma,
639 unsigned long addr, unsigned long end)
643 #endif /* CONFIG_NUMA_BALANCING */
645 static int queue_pages_test_walk(unsigned long start, unsigned long end,
646 struct mm_walk *walk)
648 struct vm_area_struct *vma = walk->vma;
649 struct queue_pages *qp = walk->private;
650 unsigned long endvma = vma->vm_end;
651 unsigned long flags = qp->flags;
653 /* range check first */
654 VM_BUG_ON_VMA((vma->vm_start > start) || (vma->vm_end < end), vma);
658 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
659 (qp->start < vma->vm_start))
660 /* hole at head side of range */
663 if (!(flags & MPOL_MF_DISCONTIG_OK) &&
664 ((vma->vm_end < qp->end) &&
665 (!vma->vm_next || vma->vm_end < vma->vm_next->vm_start)))
666 /* hole at middle or tail of range */
670 * Need check MPOL_MF_STRICT to return -EIO if possible
671 * regardless of vma_migratable
673 if (!vma_migratable(vma) &&
674 !(flags & MPOL_MF_STRICT))
680 if (flags & MPOL_MF_LAZY) {
681 /* Similar to task_numa_work, skip inaccessible VMAs */
682 if (!is_vm_hugetlb_page(vma) && vma_is_accessible(vma) &&
683 !(vma->vm_flags & VM_MIXEDMAP))
684 change_prot_numa(vma, start, endvma);
688 /* queue pages from current vma */
689 if (flags & MPOL_MF_VALID)
694 static const struct mm_walk_ops queue_pages_walk_ops = {
695 .hugetlb_entry = queue_pages_hugetlb,
696 .pmd_entry = queue_pages_pte_range,
697 .test_walk = queue_pages_test_walk,
701 * Walk through page tables and collect pages to be migrated.
703 * If pages found in a given range are on a set of nodes (determined by
704 * @nodes and @flags,) it's isolated and queued to the pagelist which is
705 * passed via @private.
707 * queue_pages_range() has three possible return values:
708 * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
710 * 0 - queue pages successfully or no misplaced page.
711 * errno - i.e. misplaced pages with MPOL_MF_STRICT specified (-EIO) or
712 * memory range specified by nodemask and maxnode points outside
713 * your accessible address space (-EFAULT)
716 queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
717 nodemask_t *nodes, unsigned long flags,
718 struct list_head *pagelist)
721 struct queue_pages qp = {
722 .pagelist = pagelist,
730 err = walk_page_range(mm, start, end, &queue_pages_walk_ops, &qp);
733 /* whole range in hole */
740 * Apply policy to a single VMA
741 * This must be called with the mmap_sem held for writing.
743 static int vma_replace_policy(struct vm_area_struct *vma,
744 struct mempolicy *pol)
747 struct mempolicy *old;
748 struct mempolicy *new;
750 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
751 vma->vm_start, vma->vm_end, vma->vm_pgoff,
752 vma->vm_ops, vma->vm_file,
753 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
759 if (vma->vm_ops && vma->vm_ops->set_policy) {
760 err = vma->vm_ops->set_policy(vma, new);
765 old = vma->vm_policy;
766 vma->vm_policy = new; /* protected by mmap_sem */
775 /* Step 2: apply policy to a range and do splits. */
776 static int mbind_range(struct mm_struct *mm, unsigned long start,
777 unsigned long end, struct mempolicy *new_pol)
779 struct vm_area_struct *next;
780 struct vm_area_struct *prev;
781 struct vm_area_struct *vma;
784 unsigned long vmstart;
787 vma = find_vma(mm, start);
791 if (start > vma->vm_start)
794 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
796 vmstart = max(start, vma->vm_start);
797 vmend = min(end, vma->vm_end);
799 if (mpol_equal(vma_policy(vma), new_pol))
802 pgoff = vma->vm_pgoff +
803 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
804 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
805 vma->anon_vma, vma->vm_file, pgoff,
806 new_pol, vma->vm_userfaultfd_ctx);
810 if (mpol_equal(vma_policy(vma), new_pol))
812 /* vma_merge() joined vma && vma->next, case 8 */
815 if (vma->vm_start != vmstart) {
816 err = split_vma(vma->vm_mm, vma, vmstart, 1);
820 if (vma->vm_end != vmend) {
821 err = split_vma(vma->vm_mm, vma, vmend, 0);
826 err = vma_replace_policy(vma, new_pol);
835 /* Set the process memory policy */
836 static long do_set_mempolicy(unsigned short mode, unsigned short flags,
839 struct mempolicy *new, *old;
840 NODEMASK_SCRATCH(scratch);
846 new = mpol_new(mode, flags, nodes);
853 ret = mpol_set_nodemask(new, nodes, scratch);
855 task_unlock(current);
859 old = current->mempolicy;
860 current->mempolicy = new;
861 if (new && new->mode == MPOL_INTERLEAVE)
862 current->il_prev = MAX_NUMNODES-1;
863 task_unlock(current);
867 NODEMASK_SCRATCH_FREE(scratch);
872 * Return nodemask for policy for get_mempolicy() query
874 * Called with task's alloc_lock held
876 static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
879 if (p == &default_policy)
884 case MPOL_INTERLEAVE:
888 if (!(p->flags & MPOL_F_LOCAL))
889 node_set(p->v.preferred_node, *nodes);
890 /* else return empty node mask for local allocation */
897 static int lookup_node(struct mm_struct *mm, unsigned long addr)
903 err = get_user_pages_locked(addr & PAGE_MASK, 1, 0, &p, &locked);
905 err = page_to_nid(p);
909 up_read(&mm->mmap_sem);
913 /* Retrieve NUMA policy */
914 static long do_get_mempolicy(int *policy, nodemask_t *nmask,
915 unsigned long addr, unsigned long flags)
918 struct mm_struct *mm = current->mm;
919 struct vm_area_struct *vma = NULL;
920 struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL;
923 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
926 if (flags & MPOL_F_MEMS_ALLOWED) {
927 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
929 *policy = 0; /* just so it's initialized */
931 *nmask = cpuset_current_mems_allowed;
932 task_unlock(current);
936 if (flags & MPOL_F_ADDR) {
938 * Do NOT fall back to task policy if the
939 * vma/shared policy at addr is NULL. We
940 * want to return MPOL_DEFAULT in this case.
942 down_read(&mm->mmap_sem);
943 vma = find_vma_intersection(mm, addr, addr+1);
945 up_read(&mm->mmap_sem);
948 if (vma->vm_ops && vma->vm_ops->get_policy)
949 pol = vma->vm_ops->get_policy(vma, addr);
951 pol = vma->vm_policy;
956 pol = &default_policy; /* indicates default behavior */
958 if (flags & MPOL_F_NODE) {
959 if (flags & MPOL_F_ADDR) {
961 * Take a refcount on the mpol, lookup_node()
962 * wil drop the mmap_sem, so after calling
963 * lookup_node() only "pol" remains valid, "vma"
969 err = lookup_node(mm, addr);
973 } else if (pol == current->mempolicy &&
974 pol->mode == MPOL_INTERLEAVE) {
975 *policy = next_node_in(current->il_prev, pol->v.nodes);
981 *policy = pol == &default_policy ? MPOL_DEFAULT :
984 * Internal mempolicy flags must be masked off before exposing
985 * the policy to userspace.
987 *policy |= (pol->flags & MPOL_MODE_FLAGS);
992 if (mpol_store_user_nodemask(pol)) {
993 *nmask = pol->w.user_nodemask;
996 get_policy_nodemask(pol, nmask);
997 task_unlock(current);
1004 up_read(&mm->mmap_sem);
1006 mpol_put(pol_refcount);
1010 #ifdef CONFIG_MIGRATION
1012 * page migration, thp tail pages can be passed.
1014 static int migrate_page_add(struct page *page, struct list_head *pagelist,
1015 unsigned long flags)
1017 struct page *head = compound_head(page);
1019 * Avoid migrating a page that is shared with others.
1021 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(head) == 1) {
1022 if (!isolate_lru_page(head)) {
1023 list_add_tail(&head->lru, pagelist);
1024 mod_node_page_state(page_pgdat(head),
1025 NR_ISOLATED_ANON + page_is_file_lru(head),
1026 hpage_nr_pages(head));
1027 } else if (flags & MPOL_MF_STRICT) {
1029 * Non-movable page may reach here. And, there may be
1030 * temporary off LRU pages or non-LRU movable pages.
1031 * Treat them as unmovable pages since they can't be
1032 * isolated, so they can't be moved at the moment. It
1033 * should return -EIO for this case too.
1042 /* page allocation callback for NUMA node migration */
1043 struct page *alloc_new_node_page(struct page *page, unsigned long node)
1046 return alloc_huge_page_node(page_hstate(compound_head(page)),
1048 else if (PageTransHuge(page)) {
1051 thp = alloc_pages_node(node,
1052 (GFP_TRANSHUGE | __GFP_THISNODE),
1056 prep_transhuge_page(thp);
1059 return __alloc_pages_node(node, GFP_HIGHUSER_MOVABLE |
1064 * Migrate pages from one node to a target node.
1065 * Returns error or the number of pages not migrated.
1067 static int migrate_to_node(struct mm_struct *mm, int source, int dest,
1071 LIST_HEAD(pagelist);
1075 node_set(source, nmask);
1078 * This does not "check" the range but isolates all pages that
1079 * need migration. Between passing in the full user address
1080 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
1082 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
1083 queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1084 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
1086 if (!list_empty(&pagelist)) {
1087 err = migrate_pages(&pagelist, alloc_new_node_page, NULL, dest,
1088 MIGRATE_SYNC, MR_SYSCALL);
1090 putback_movable_pages(&pagelist);
1097 * Move pages between the two nodesets so as to preserve the physical
1098 * layout as much as possible.
1100 * Returns the number of page that could not be moved.
1102 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1103 const nodemask_t *to, int flags)
1109 err = migrate_prep();
1113 down_read(&mm->mmap_sem);
1116 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1117 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1118 * bit in 'tmp', and return that <source, dest> pair for migration.
1119 * The pair of nodemasks 'to' and 'from' define the map.
1121 * If no pair of bits is found that way, fallback to picking some
1122 * pair of 'source' and 'dest' bits that are not the same. If the
1123 * 'source' and 'dest' bits are the same, this represents a node
1124 * that will be migrating to itself, so no pages need move.
1126 * If no bits are left in 'tmp', or if all remaining bits left
1127 * in 'tmp' correspond to the same bit in 'to', return false
1128 * (nothing left to migrate).
1130 * This lets us pick a pair of nodes to migrate between, such that
1131 * if possible the dest node is not already occupied by some other
1132 * source node, minimizing the risk of overloading the memory on a
1133 * node that would happen if we migrated incoming memory to a node
1134 * before migrating outgoing memory source that same node.
1136 * A single scan of tmp is sufficient. As we go, we remember the
1137 * most recent <s, d> pair that moved (s != d). If we find a pair
1138 * that not only moved, but what's better, moved to an empty slot
1139 * (d is not set in tmp), then we break out then, with that pair.
1140 * Otherwise when we finish scanning from_tmp, we at least have the
1141 * most recent <s, d> pair that moved. If we get all the way through
1142 * the scan of tmp without finding any node that moved, much less
1143 * moved to an empty node, then there is nothing left worth migrating.
1147 while (!nodes_empty(tmp)) {
1149 int source = NUMA_NO_NODE;
1152 for_each_node_mask(s, tmp) {
1155 * do_migrate_pages() tries to maintain the relative
1156 * node relationship of the pages established between
1157 * threads and memory areas.
1159 * However if the number of source nodes is not equal to
1160 * the number of destination nodes we can not preserve
1161 * this node relative relationship. In that case, skip
1162 * copying memory from a node that is in the destination
1165 * Example: [2,3,4] -> [3,4,5] moves everything.
1166 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1169 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1170 (node_isset(s, *to)))
1173 d = node_remap(s, *from, *to);
1177 source = s; /* Node moved. Memorize */
1180 /* dest not in remaining from nodes? */
1181 if (!node_isset(dest, tmp))
1184 if (source == NUMA_NO_NODE)
1187 node_clear(source, tmp);
1188 err = migrate_to_node(mm, source, dest, flags);
1194 up_read(&mm->mmap_sem);
1202 * Allocate a new page for page migration based on vma policy.
1203 * Start by assuming the page is mapped by the same vma as contains @start.
1204 * Search forward from there, if not. N.B., this assumes that the
1205 * list of pages handed to migrate_pages()--which is how we get here--
1206 * is in virtual address order.
1208 static struct page *new_page(struct page *page, unsigned long start)
1210 struct vm_area_struct *vma;
1211 unsigned long uninitialized_var(address);
1213 vma = find_vma(current->mm, start);
1215 address = page_address_in_vma(page, vma);
1216 if (address != -EFAULT)
1221 if (PageHuge(page)) {
1222 return alloc_huge_page_vma(page_hstate(compound_head(page)),
1224 } else if (PageTransHuge(page)) {
1227 thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
1231 prep_transhuge_page(thp);
1235 * if !vma, alloc_page_vma() will use task or system default policy
1237 return alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL,
1242 static int migrate_page_add(struct page *page, struct list_head *pagelist,
1243 unsigned long flags)
1248 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1249 const nodemask_t *to, int flags)
1254 static struct page *new_page(struct page *page, unsigned long start)
1260 static long do_mbind(unsigned long start, unsigned long len,
1261 unsigned short mode, unsigned short mode_flags,
1262 nodemask_t *nmask, unsigned long flags)
1264 struct mm_struct *mm = current->mm;
1265 struct mempolicy *new;
1269 LIST_HEAD(pagelist);
1271 if (flags & ~(unsigned long)MPOL_MF_VALID)
1273 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1276 if (start & ~PAGE_MASK)
1279 if (mode == MPOL_DEFAULT)
1280 flags &= ~MPOL_MF_STRICT;
1282 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1290 new = mpol_new(mode, mode_flags, nmask);
1292 return PTR_ERR(new);
1294 if (flags & MPOL_MF_LAZY)
1295 new->flags |= MPOL_F_MOF;
1298 * If we are using the default policy then operation
1299 * on discontinuous address spaces is okay after all
1302 flags |= MPOL_MF_DISCONTIG_OK;
1304 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1305 start, start + len, mode, mode_flags,
1306 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1308 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1310 err = migrate_prep();
1315 NODEMASK_SCRATCH(scratch);
1317 down_write(&mm->mmap_sem);
1319 err = mpol_set_nodemask(new, nmask, scratch);
1320 task_unlock(current);
1322 up_write(&mm->mmap_sem);
1325 NODEMASK_SCRATCH_FREE(scratch);
1330 ret = queue_pages_range(mm, start, end, nmask,
1331 flags | MPOL_MF_INVERT, &pagelist);
1338 err = mbind_range(mm, start, end, new);
1343 if (!list_empty(&pagelist)) {
1344 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1345 nr_failed = migrate_pages(&pagelist, new_page, NULL,
1346 start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
1348 putback_movable_pages(&pagelist);
1351 if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
1355 if (!list_empty(&pagelist))
1356 putback_movable_pages(&pagelist);
1359 up_write(&mm->mmap_sem);
1366 * User space interface with variable sized bitmaps for nodelists.
1369 /* Copy a node mask from user space. */
1370 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1371 unsigned long maxnode)
1375 unsigned long nlongs;
1376 unsigned long endmask;
1379 nodes_clear(*nodes);
1380 if (maxnode == 0 || !nmask)
1382 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1385 nlongs = BITS_TO_LONGS(maxnode);
1386 if ((maxnode % BITS_PER_LONG) == 0)
1389 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1392 * When the user specified more nodes than supported just check
1393 * if the non supported part is all zero.
1395 * If maxnode have more longs than MAX_NUMNODES, check
1396 * the bits in that area first. And then go through to
1397 * check the rest bits which equal or bigger than MAX_NUMNODES.
1398 * Otherwise, just check bits [MAX_NUMNODES, maxnode).
1400 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1401 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1402 if (get_user(t, nmask + k))
1404 if (k == nlongs - 1) {
1410 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1414 if (maxnode > MAX_NUMNODES && MAX_NUMNODES % BITS_PER_LONG != 0) {
1415 unsigned long valid_mask = endmask;
1417 valid_mask &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
1418 if (get_user(t, nmask + nlongs - 1))
1424 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1426 nodes_addr(*nodes)[nlongs-1] &= endmask;
1430 /* Copy a kernel node mask to user space */
1431 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1434 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1435 unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long);
1437 if (copy > nbytes) {
1438 if (copy > PAGE_SIZE)
1440 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1444 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1447 static long kernel_mbind(unsigned long start, unsigned long len,
1448 unsigned long mode, const unsigned long __user *nmask,
1449 unsigned long maxnode, unsigned int flags)
1453 unsigned short mode_flags;
1455 start = untagged_addr(start);
1456 mode_flags = mode & MPOL_MODE_FLAGS;
1457 mode &= ~MPOL_MODE_FLAGS;
1458 if (mode >= MPOL_MAX)
1460 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1461 (mode_flags & MPOL_F_RELATIVE_NODES))
1463 err = get_nodes(&nodes, nmask, maxnode);
1466 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1469 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1470 unsigned long, mode, const unsigned long __user *, nmask,
1471 unsigned long, maxnode, unsigned int, flags)
1473 return kernel_mbind(start, len, mode, nmask, maxnode, flags);
1476 /* Set the process memory policy */
1477 static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
1478 unsigned long maxnode)
1482 unsigned short flags;
1484 flags = mode & MPOL_MODE_FLAGS;
1485 mode &= ~MPOL_MODE_FLAGS;
1486 if ((unsigned int)mode >= MPOL_MAX)
1488 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1490 err = get_nodes(&nodes, nmask, maxnode);
1493 return do_set_mempolicy(mode, flags, &nodes);
1496 SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
1497 unsigned long, maxnode)
1499 return kernel_set_mempolicy(mode, nmask, maxnode);
1502 static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
1503 const unsigned long __user *old_nodes,
1504 const unsigned long __user *new_nodes)
1506 struct mm_struct *mm = NULL;
1507 struct task_struct *task;
1508 nodemask_t task_nodes;
1512 NODEMASK_SCRATCH(scratch);
1517 old = &scratch->mask1;
1518 new = &scratch->mask2;
1520 err = get_nodes(old, old_nodes, maxnode);
1524 err = get_nodes(new, new_nodes, maxnode);
1528 /* Find the mm_struct */
1530 task = pid ? find_task_by_vpid(pid) : current;
1536 get_task_struct(task);
1541 * Check if this process has the right to modify the specified process.
1542 * Use the regular "ptrace_may_access()" checks.
1544 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
1551 task_nodes = cpuset_mems_allowed(task);
1552 /* Is the user allowed to access the target nodes? */
1553 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1558 task_nodes = cpuset_mems_allowed(current);
1559 nodes_and(*new, *new, task_nodes);
1560 if (nodes_empty(*new))
1563 err = security_task_movememory(task);
1567 mm = get_task_mm(task);
1568 put_task_struct(task);
1575 err = do_migrate_pages(mm, old, new,
1576 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1580 NODEMASK_SCRATCH_FREE(scratch);
1585 put_task_struct(task);
1590 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1591 const unsigned long __user *, old_nodes,
1592 const unsigned long __user *, new_nodes)
1594 return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes);
1598 /* Retrieve NUMA policy */
1599 static int kernel_get_mempolicy(int __user *policy,
1600 unsigned long __user *nmask,
1601 unsigned long maxnode,
1603 unsigned long flags)
1606 int uninitialized_var(pval);
1609 addr = untagged_addr(addr);
1611 if (nmask != NULL && maxnode < nr_node_ids)
1614 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1619 if (policy && put_user(pval, policy))
1623 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1628 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1629 unsigned long __user *, nmask, unsigned long, maxnode,
1630 unsigned long, addr, unsigned long, flags)
1632 return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags);
1635 #ifdef CONFIG_COMPAT
1637 COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1638 compat_ulong_t __user *, nmask,
1639 compat_ulong_t, maxnode,
1640 compat_ulong_t, addr, compat_ulong_t, flags)
1643 unsigned long __user *nm = NULL;
1644 unsigned long nr_bits, alloc_size;
1645 DECLARE_BITMAP(bm, MAX_NUMNODES);
1647 nr_bits = min_t(unsigned long, maxnode-1, nr_node_ids);
1648 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1651 nm = compat_alloc_user_space(alloc_size);
1653 err = kernel_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1655 if (!err && nmask) {
1656 unsigned long copy_size;
1657 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1658 err = copy_from_user(bm, nm, copy_size);
1659 /* ensure entire bitmap is zeroed */
1660 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1661 err |= compat_put_bitmap(nmask, bm, nr_bits);
1667 COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
1668 compat_ulong_t, maxnode)
1670 unsigned long __user *nm = NULL;
1671 unsigned long nr_bits, alloc_size;
1672 DECLARE_BITMAP(bm, MAX_NUMNODES);
1674 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1675 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1678 if (compat_get_bitmap(bm, nmask, nr_bits))
1680 nm = compat_alloc_user_space(alloc_size);
1681 if (copy_to_user(nm, bm, alloc_size))
1685 return kernel_set_mempolicy(mode, nm, nr_bits+1);
1688 COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
1689 compat_ulong_t, mode, compat_ulong_t __user *, nmask,
1690 compat_ulong_t, maxnode, compat_ulong_t, flags)
1692 unsigned long __user *nm = NULL;
1693 unsigned long nr_bits, alloc_size;
1696 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1697 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1700 if (compat_get_bitmap(nodes_addr(bm), nmask, nr_bits))
1702 nm = compat_alloc_user_space(alloc_size);
1703 if (copy_to_user(nm, nodes_addr(bm), alloc_size))
1707 return kernel_mbind(start, len, mode, nm, nr_bits+1, flags);
1710 COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
1711 compat_ulong_t, maxnode,
1712 const compat_ulong_t __user *, old_nodes,
1713 const compat_ulong_t __user *, new_nodes)
1715 unsigned long __user *old = NULL;
1716 unsigned long __user *new = NULL;
1717 nodemask_t tmp_mask;
1718 unsigned long nr_bits;
1721 nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
1722 size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1724 if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
1726 old = compat_alloc_user_space(new_nodes ? size * 2 : size);
1728 new = old + size / sizeof(unsigned long);
1729 if (copy_to_user(old, nodes_addr(tmp_mask), size))
1733 if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
1736 new = compat_alloc_user_space(size);
1737 if (copy_to_user(new, nodes_addr(tmp_mask), size))
1740 return kernel_migrate_pages(pid, nr_bits + 1, old, new);
1743 #endif /* CONFIG_COMPAT */
1745 bool vma_migratable(struct vm_area_struct *vma)
1747 if (vma->vm_flags & (VM_IO | VM_PFNMAP))
1751 * DAX device mappings require predictable access latency, so avoid
1752 * incurring periodic faults.
1754 if (vma_is_dax(vma))
1757 if (is_vm_hugetlb_page(vma) &&
1758 !hugepage_migration_supported(hstate_vma(vma)))
1762 * Migration allocates pages in the highest zone. If we cannot
1763 * do so then migration (at least from node to node) is not
1767 gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
1773 struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
1776 struct mempolicy *pol = NULL;
1779 if (vma->vm_ops && vma->vm_ops->get_policy) {
1780 pol = vma->vm_ops->get_policy(vma, addr);
1781 } else if (vma->vm_policy) {
1782 pol = vma->vm_policy;
1785 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1786 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1787 * count on these policies which will be dropped by
1788 * mpol_cond_put() later
1790 if (mpol_needs_cond_ref(pol))
1799 * get_vma_policy(@vma, @addr)
1800 * @vma: virtual memory area whose policy is sought
1801 * @addr: address in @vma for shared policy lookup
1803 * Returns effective policy for a VMA at specified address.
1804 * Falls back to current->mempolicy or system default policy, as necessary.
1805 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1806 * count--added by the get_policy() vm_op, as appropriate--to protect against
1807 * freeing by another task. It is the caller's responsibility to free the
1808 * extra reference for shared policies.
1810 static struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
1813 struct mempolicy *pol = __get_vma_policy(vma, addr);
1816 pol = get_task_policy(current);
1821 bool vma_policy_mof(struct vm_area_struct *vma)
1823 struct mempolicy *pol;
1825 if (vma->vm_ops && vma->vm_ops->get_policy) {
1828 pol = vma->vm_ops->get_policy(vma, vma->vm_start);
1829 if (pol && (pol->flags & MPOL_F_MOF))
1836 pol = vma->vm_policy;
1838 pol = get_task_policy(current);
1840 return pol->flags & MPOL_F_MOF;
1843 static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1845 enum zone_type dynamic_policy_zone = policy_zone;
1847 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1850 * if policy->v.nodes has movable memory only,
1851 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1853 * policy->v.nodes is intersect with node_states[N_MEMORY].
1854 * so if the following test faile, it implies
1855 * policy->v.nodes has movable memory only.
1857 if (!nodes_intersects(policy->v.nodes, node_states[N_HIGH_MEMORY]))
1858 dynamic_policy_zone = ZONE_MOVABLE;
1860 return zone >= dynamic_policy_zone;
1864 * Return a nodemask representing a mempolicy for filtering nodes for
1867 static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1869 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1870 if (unlikely(policy->mode == MPOL_BIND) &&
1871 apply_policy_zone(policy, gfp_zone(gfp)) &&
1872 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1873 return &policy->v.nodes;
1878 /* Return the node id preferred by the given mempolicy, or the given id */
1879 static int policy_node(gfp_t gfp, struct mempolicy *policy,
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 hold down_read on the mmap_sem 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_node(hpage_node,
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);
2644 * mpol_shared_policy_init - initialize shared policy for inode
2645 * @sp: pointer to inode shared policy
2646 * @mpol: struct mempolicy to install
2648 * Install non-NULL @mpol in inode's shared policy rb-tree.
2649 * On entry, the current task has a reference on a non-NULL @mpol.
2650 * This must be released on exit.
2651 * This is called at get_inode() calls and we can use GFP_KERNEL.
2653 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2657 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2658 rwlock_init(&sp->lock);
2661 struct vm_area_struct pvma;
2662 struct mempolicy *new;
2663 NODEMASK_SCRATCH(scratch);
2667 /* contextualize the tmpfs mount point mempolicy */
2668 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2670 goto free_scratch; /* no valid nodemask intersection */
2673 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2674 task_unlock(current);
2678 /* Create pseudo-vma that contains just the policy */
2679 vma_init(&pvma, NULL);
2680 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2681 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2684 mpol_put(new); /* drop initial ref */
2686 NODEMASK_SCRATCH_FREE(scratch);
2688 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2692 int mpol_set_shared_policy(struct shared_policy *info,
2693 struct vm_area_struct *vma, struct mempolicy *npol)
2696 struct sp_node *new = NULL;
2697 unsigned long sz = vma_pages(vma);
2699 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2701 sz, npol ? npol->mode : -1,
2702 npol ? npol->flags : -1,
2703 npol ? nodes_addr(npol->v.nodes)[0] : NUMA_NO_NODE);
2706 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2710 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2716 /* Free a backing policy store on inode delete. */
2717 void mpol_free_shared_policy(struct shared_policy *p)
2720 struct rb_node *next;
2722 if (!p->root.rb_node)
2724 write_lock(&p->lock);
2725 next = rb_first(&p->root);
2727 n = rb_entry(next, struct sp_node, nd);
2728 next = rb_next(&n->nd);
2731 write_unlock(&p->lock);
2734 #ifdef CONFIG_NUMA_BALANCING
2735 static int __initdata numabalancing_override;
2737 static void __init check_numabalancing_enable(void)
2739 bool numabalancing_default = false;
2741 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2742 numabalancing_default = true;
2744 /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
2745 if (numabalancing_override)
2746 set_numabalancing_state(numabalancing_override == 1);
2748 if (num_online_nodes() > 1 && !numabalancing_override) {
2749 pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n",
2750 numabalancing_default ? "Enabling" : "Disabling");
2751 set_numabalancing_state(numabalancing_default);
2755 static int __init setup_numabalancing(char *str)
2761 if (!strcmp(str, "enable")) {
2762 numabalancing_override = 1;
2764 } else if (!strcmp(str, "disable")) {
2765 numabalancing_override = -1;
2770 pr_warn("Unable to parse numa_balancing=\n");
2774 __setup("numa_balancing=", setup_numabalancing);
2776 static inline void __init check_numabalancing_enable(void)
2779 #endif /* CONFIG_NUMA_BALANCING */
2781 /* assumes fs == KERNEL_DS */
2782 void __init numa_policy_init(void)
2784 nodemask_t interleave_nodes;
2785 unsigned long largest = 0;
2786 int nid, prefer = 0;
2788 policy_cache = kmem_cache_create("numa_policy",
2789 sizeof(struct mempolicy),
2790 0, SLAB_PANIC, NULL);
2792 sn_cache = kmem_cache_create("shared_policy_node",
2793 sizeof(struct sp_node),
2794 0, SLAB_PANIC, NULL);
2796 for_each_node(nid) {
2797 preferred_node_policy[nid] = (struct mempolicy) {
2798 .refcnt = ATOMIC_INIT(1),
2799 .mode = MPOL_PREFERRED,
2800 .flags = MPOL_F_MOF | MPOL_F_MORON,
2801 .v = { .preferred_node = nid, },
2806 * Set interleaving policy for system init. Interleaving is only
2807 * enabled across suitably sized nodes (default is >= 16MB), or
2808 * fall back to the largest node if they're all smaller.
2810 nodes_clear(interleave_nodes);
2811 for_each_node_state(nid, N_MEMORY) {
2812 unsigned long total_pages = node_present_pages(nid);
2814 /* Preserve the largest node */
2815 if (largest < total_pages) {
2816 largest = total_pages;
2820 /* Interleave this node? */
2821 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2822 node_set(nid, interleave_nodes);
2825 /* All too small, use the largest */
2826 if (unlikely(nodes_empty(interleave_nodes)))
2827 node_set(prefer, interleave_nodes);
2829 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2830 pr_err("%s: interleaving failed\n", __func__);
2832 check_numabalancing_enable();
2835 /* Reset policy of current process to default */
2836 void numa_default_policy(void)
2838 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2842 * Parse and format mempolicy from/to strings
2846 * "local" is implemented internally by MPOL_PREFERRED with MPOL_F_LOCAL flag.
2848 static const char * const policy_modes[] =
2850 [MPOL_DEFAULT] = "default",
2851 [MPOL_PREFERRED] = "prefer",
2852 [MPOL_BIND] = "bind",
2853 [MPOL_INTERLEAVE] = "interleave",
2854 [MPOL_LOCAL] = "local",
2860 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2861 * @str: string containing mempolicy to parse
2862 * @mpol: pointer to struct mempolicy pointer, returned on success.
2865 * <mode>[=<flags>][:<nodelist>]
2867 * On success, returns 0, else 1
2869 int mpol_parse_str(char *str, struct mempolicy **mpol)
2871 struct mempolicy *new = NULL;
2872 unsigned short mode_flags;
2874 char *nodelist = strchr(str, ':');
2875 char *flags = strchr(str, '=');
2879 *flags++ = '\0'; /* terminate mode string */
2882 /* NUL-terminate mode or flags string */
2884 if (nodelist_parse(nodelist, nodes))
2886 if (!nodes_subset(nodes, node_states[N_MEMORY]))
2891 mode = match_string(policy_modes, MPOL_MAX, str);
2896 case MPOL_PREFERRED:
2898 * Insist on a nodelist of one node only, although later
2899 * we use first_node(nodes) to grab a single node, so here
2900 * nodelist (or nodes) cannot be empty.
2903 char *rest = nodelist;
2904 while (isdigit(*rest))
2908 if (nodes_empty(nodes))
2912 case MPOL_INTERLEAVE:
2914 * Default to online nodes with memory if no nodelist
2917 nodes = node_states[N_MEMORY];
2921 * Don't allow a nodelist; mpol_new() checks flags
2925 mode = MPOL_PREFERRED;
2929 * Insist on a empty nodelist
2936 * Insist on a nodelist
2945 * Currently, we only support two mutually exclusive
2948 if (!strcmp(flags, "static"))
2949 mode_flags |= MPOL_F_STATIC_NODES;
2950 else if (!strcmp(flags, "relative"))
2951 mode_flags |= MPOL_F_RELATIVE_NODES;
2956 new = mpol_new(mode, mode_flags, &nodes);
2961 * Save nodes for mpol_to_str() to show the tmpfs mount options
2962 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
2964 if (mode != MPOL_PREFERRED)
2965 new->v.nodes = nodes;
2967 new->v.preferred_node = first_node(nodes);
2969 new->flags |= MPOL_F_LOCAL;
2972 * Save nodes for contextualization: this will be used to "clone"
2973 * the mempolicy in a specific context [cpuset] at a later time.
2975 new->w.user_nodemask = nodes;
2980 /* Restore string for error message */
2989 #endif /* CONFIG_TMPFS */
2992 * mpol_to_str - format a mempolicy structure for printing
2993 * @buffer: to contain formatted mempolicy string
2994 * @maxlen: length of @buffer
2995 * @pol: pointer to mempolicy to be formatted
2997 * Convert @pol into a string. If @buffer is too short, truncate the string.
2998 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
2999 * longest flag, "relative", and to display at least a few node ids.
3001 void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
3004 nodemask_t nodes = NODE_MASK_NONE;
3005 unsigned short mode = MPOL_DEFAULT;
3006 unsigned short flags = 0;
3008 if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
3016 case MPOL_PREFERRED:
3017 if (flags & MPOL_F_LOCAL)
3020 node_set(pol->v.preferred_node, nodes);
3023 case MPOL_INTERLEAVE:
3024 nodes = pol->v.nodes;
3028 snprintf(p, maxlen, "unknown");
3032 p += snprintf(p, maxlen, "%s", policy_modes[mode]);
3034 if (flags & MPOL_MODE_FLAGS) {
3035 p += snprintf(p, buffer + maxlen - p, "=");
3038 * Currently, the only defined flags are mutually exclusive
3040 if (flags & MPOL_F_STATIC_NODES)
3041 p += snprintf(p, buffer + maxlen - p, "static");
3042 else if (flags & MPOL_F_RELATIVE_NODES)
3043 p += snprintf(p, buffer + maxlen - p, "relative");
3046 if (!nodes_empty(nodes))
3047 p += scnprintf(p, buffer + maxlen - p, ":%*pbl",
3048 nodemask_pr_args(&nodes));