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;
413 struct vm_area_struct *prev;
417 * Check if the page's nid is in qp->nmask.
419 * If MPOL_MF_INVERT is set in qp->flags, check if the nid is
420 * in the invert of qp->nmask.
422 static inline bool queue_pages_required(struct page *page,
423 struct queue_pages *qp)
425 int nid = page_to_nid(page);
426 unsigned long flags = qp->flags;
428 return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT);
432 * queue_pages_pmd() has four possible return values:
433 * 0 - pages are placed on the right node or queued successfully.
434 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
437 * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an
438 * existing page was already on a node that does not follow the
441 static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
442 unsigned long end, struct mm_walk *walk)
446 struct queue_pages *qp = walk->private;
449 if (unlikely(is_pmd_migration_entry(*pmd))) {
453 page = pmd_page(*pmd);
454 if (is_huge_zero_page(page)) {
456 __split_huge_pmd(walk->vma, pmd, addr, false, NULL);
460 if (!queue_pages_required(page, qp))
464 /* go to thp migration */
465 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
466 if (!vma_migratable(walk->vma) ||
467 migrate_page_add(page, qp->pagelist, flags)) {
480 * Scan through pages checking if pages follow certain conditions,
481 * and move them to the pagelist if they do.
483 * queue_pages_pte_range() has three possible return values:
484 * 0 - pages are placed on the right node or queued successfully.
485 * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
487 * -EIO - only MPOL_MF_STRICT was specified and an existing page was already
488 * on a node that does not follow the policy.
490 static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
491 unsigned long end, struct mm_walk *walk)
493 struct vm_area_struct *vma = walk->vma;
495 struct queue_pages *qp = walk->private;
496 unsigned long flags = qp->flags;
498 bool has_unmovable = false;
502 ptl = pmd_trans_huge_lock(pmd, vma);
504 ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
508 /* THP was split, fall through to pte walk */
510 if (pmd_trans_unstable(pmd))
513 pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
514 for (; addr != end; pte++, addr += PAGE_SIZE) {
515 if (!pte_present(*pte))
517 page = vm_normal_page(vma, addr, *pte);
521 * vm_normal_page() filters out zero pages, but there might
522 * still be PageReserved pages to skip, perhaps in a VDSO.
524 if (PageReserved(page))
526 if (!queue_pages_required(page, qp))
528 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
529 /* MPOL_MF_STRICT must be specified if we get here */
530 if (!vma_migratable(vma)) {
531 has_unmovable = true;
536 * Do not abort immediately since there may be
537 * temporary off LRU pages in the range. Still
538 * need migrate other LRU pages.
540 if (migrate_page_add(page, qp->pagelist, flags))
541 has_unmovable = true;
545 pte_unmap_unlock(pte - 1, ptl);
551 return addr != end ? -EIO : 0;
554 static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
555 unsigned long addr, unsigned long end,
556 struct mm_walk *walk)
558 #ifdef CONFIG_HUGETLB_PAGE
559 struct queue_pages *qp = walk->private;
560 unsigned long flags = qp->flags;
565 ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
566 entry = huge_ptep_get(pte);
567 if (!pte_present(entry))
569 page = pte_page(entry);
570 if (!queue_pages_required(page, qp))
572 /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
573 if (flags & (MPOL_MF_MOVE_ALL) ||
574 (flags & MPOL_MF_MOVE && page_mapcount(page) == 1))
575 isolate_huge_page(page, qp->pagelist);
584 #ifdef CONFIG_NUMA_BALANCING
586 * This is used to mark a range of virtual addresses to be inaccessible.
587 * These are later cleared by a NUMA hinting fault. Depending on these
588 * faults, pages may be migrated for better NUMA placement.
590 * This is assuming that NUMA faults are handled using PROT_NONE. If
591 * an architecture makes a different choice, it will need further
592 * changes to the core.
594 unsigned long change_prot_numa(struct vm_area_struct *vma,
595 unsigned long addr, unsigned long end)
599 nr_updated = change_protection(vma, addr, end, PAGE_NONE, 0, 1);
601 count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
606 static unsigned long change_prot_numa(struct vm_area_struct *vma,
607 unsigned long addr, unsigned long end)
611 #endif /* CONFIG_NUMA_BALANCING */
613 static int queue_pages_test_walk(unsigned long start, unsigned long end,
614 struct mm_walk *walk)
616 struct vm_area_struct *vma = walk->vma;
617 struct queue_pages *qp = walk->private;
618 unsigned long endvma = vma->vm_end;
619 unsigned long flags = qp->flags;
622 * Need check MPOL_MF_STRICT to return -EIO if possible
623 * regardless of vma_migratable
625 if (!vma_migratable(vma) &&
626 !(flags & MPOL_MF_STRICT))
631 if (vma->vm_start > start)
632 start = vma->vm_start;
634 if (!(flags & MPOL_MF_DISCONTIG_OK)) {
635 if (!vma->vm_next && vma->vm_end < end)
637 if (qp->prev && qp->prev->vm_end < vma->vm_start)
643 if (flags & MPOL_MF_LAZY) {
644 /* Similar to task_numa_work, skip inaccessible VMAs */
645 if (!is_vm_hugetlb_page(vma) &&
646 (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) &&
647 !(vma->vm_flags & VM_MIXEDMAP))
648 change_prot_numa(vma, start, endvma);
652 /* queue pages from current vma */
653 if (flags & MPOL_MF_VALID)
658 static const struct mm_walk_ops queue_pages_walk_ops = {
659 .hugetlb_entry = queue_pages_hugetlb,
660 .pmd_entry = queue_pages_pte_range,
661 .test_walk = queue_pages_test_walk,
665 * Walk through page tables and collect pages to be migrated.
667 * If pages found in a given range are on a set of nodes (determined by
668 * @nodes and @flags,) it's isolated and queued to the pagelist which is
669 * passed via @private.
671 * queue_pages_range() has three possible return values:
672 * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
674 * 0 - queue pages successfully or no misplaced page.
675 * -EIO - there is misplaced page and only MPOL_MF_STRICT was specified.
678 queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
679 nodemask_t *nodes, unsigned long flags,
680 struct list_head *pagelist)
682 struct queue_pages qp = {
683 .pagelist = pagelist,
689 return walk_page_range(mm, start, end, &queue_pages_walk_ops, &qp);
693 * Apply policy to a single VMA
694 * This must be called with the mmap_sem held for writing.
696 static int vma_replace_policy(struct vm_area_struct *vma,
697 struct mempolicy *pol)
700 struct mempolicy *old;
701 struct mempolicy *new;
703 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
704 vma->vm_start, vma->vm_end, vma->vm_pgoff,
705 vma->vm_ops, vma->vm_file,
706 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
712 if (vma->vm_ops && vma->vm_ops->set_policy) {
713 err = vma->vm_ops->set_policy(vma, new);
718 old = vma->vm_policy;
719 vma->vm_policy = new; /* protected by mmap_sem */
728 /* Step 2: apply policy to a range and do splits. */
729 static int mbind_range(struct mm_struct *mm, unsigned long start,
730 unsigned long end, struct mempolicy *new_pol)
732 struct vm_area_struct *next;
733 struct vm_area_struct *prev;
734 struct vm_area_struct *vma;
737 unsigned long vmstart;
740 vma = find_vma(mm, start);
741 if (!vma || vma->vm_start > start)
745 if (start > vma->vm_start)
748 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
750 vmstart = max(start, vma->vm_start);
751 vmend = min(end, vma->vm_end);
753 if (mpol_equal(vma_policy(vma), new_pol))
756 pgoff = vma->vm_pgoff +
757 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
758 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
759 vma->anon_vma, vma->vm_file, pgoff,
760 new_pol, vma->vm_userfaultfd_ctx);
764 if (mpol_equal(vma_policy(vma), new_pol))
766 /* vma_merge() joined vma && vma->next, case 8 */
769 if (vma->vm_start != vmstart) {
770 err = split_vma(vma->vm_mm, vma, vmstart, 1);
774 if (vma->vm_end != vmend) {
775 err = split_vma(vma->vm_mm, vma, vmend, 0);
780 err = vma_replace_policy(vma, new_pol);
789 /* Set the process memory policy */
790 static long do_set_mempolicy(unsigned short mode, unsigned short flags,
793 struct mempolicy *new, *old;
794 NODEMASK_SCRATCH(scratch);
800 new = mpol_new(mode, flags, nodes);
807 ret = mpol_set_nodemask(new, nodes, scratch);
809 task_unlock(current);
813 old = current->mempolicy;
814 current->mempolicy = new;
815 if (new && new->mode == MPOL_INTERLEAVE)
816 current->il_prev = MAX_NUMNODES-1;
817 task_unlock(current);
821 NODEMASK_SCRATCH_FREE(scratch);
826 * Return nodemask for policy for get_mempolicy() query
828 * Called with task's alloc_lock held
830 static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
833 if (p == &default_policy)
839 case MPOL_INTERLEAVE:
843 if (!(p->flags & MPOL_F_LOCAL))
844 node_set(p->v.preferred_node, *nodes);
845 /* else return empty node mask for local allocation */
852 static int lookup_node(struct mm_struct *mm, unsigned long addr)
858 err = get_user_pages_locked(addr & PAGE_MASK, 1, 0, &p, &locked);
860 err = page_to_nid(p);
864 up_read(&mm->mmap_sem);
868 /* Retrieve NUMA policy */
869 static long do_get_mempolicy(int *policy, nodemask_t *nmask,
870 unsigned long addr, unsigned long flags)
873 struct mm_struct *mm = current->mm;
874 struct vm_area_struct *vma = NULL;
875 struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL;
878 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
881 if (flags & MPOL_F_MEMS_ALLOWED) {
882 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
884 *policy = 0; /* just so it's initialized */
886 *nmask = cpuset_current_mems_allowed;
887 task_unlock(current);
891 if (flags & MPOL_F_ADDR) {
893 * Do NOT fall back to task policy if the
894 * vma/shared policy at addr is NULL. We
895 * want to return MPOL_DEFAULT in this case.
897 down_read(&mm->mmap_sem);
898 vma = find_vma_intersection(mm, addr, addr+1);
900 up_read(&mm->mmap_sem);
903 if (vma->vm_ops && vma->vm_ops->get_policy)
904 pol = vma->vm_ops->get_policy(vma, addr);
906 pol = vma->vm_policy;
911 pol = &default_policy; /* indicates default behavior */
913 if (flags & MPOL_F_NODE) {
914 if (flags & MPOL_F_ADDR) {
916 * Take a refcount on the mpol, lookup_node()
917 * wil drop the mmap_sem, so after calling
918 * lookup_node() only "pol" remains valid, "vma"
924 err = lookup_node(mm, addr);
928 } else if (pol == current->mempolicy &&
929 pol->mode == MPOL_INTERLEAVE) {
930 *policy = next_node_in(current->il_prev, pol->v.nodes);
936 *policy = pol == &default_policy ? MPOL_DEFAULT :
939 * Internal mempolicy flags must be masked off before exposing
940 * the policy to userspace.
942 *policy |= (pol->flags & MPOL_MODE_FLAGS);
947 if (mpol_store_user_nodemask(pol)) {
948 *nmask = pol->w.user_nodemask;
951 get_policy_nodemask(pol, nmask);
952 task_unlock(current);
959 up_read(&mm->mmap_sem);
961 mpol_put(pol_refcount);
965 #ifdef CONFIG_MIGRATION
967 * page migration, thp tail pages can be passed.
969 static int migrate_page_add(struct page *page, struct list_head *pagelist,
972 struct page *head = compound_head(page);
974 * Avoid migrating a page that is shared with others.
976 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(head) == 1) {
977 if (!isolate_lru_page(head)) {
978 list_add_tail(&head->lru, pagelist);
979 mod_node_page_state(page_pgdat(head),
980 NR_ISOLATED_ANON + page_is_file_cache(head),
981 hpage_nr_pages(head));
982 } else if (flags & MPOL_MF_STRICT) {
984 * Non-movable page may reach here. And, there may be
985 * temporary off LRU pages or non-LRU movable pages.
986 * Treat them as unmovable pages since they can't be
987 * isolated, so they can't be moved at the moment. It
988 * should return -EIO for this case too.
997 /* page allocation callback for NUMA node migration */
998 struct page *alloc_new_node_page(struct page *page, unsigned long node)
1001 return alloc_huge_page_node(page_hstate(compound_head(page)),
1003 else if (PageTransHuge(page)) {
1006 thp = alloc_pages_node(node,
1007 (GFP_TRANSHUGE | __GFP_THISNODE),
1011 prep_transhuge_page(thp);
1014 return __alloc_pages_node(node, GFP_HIGHUSER_MOVABLE |
1019 * Migrate pages from one node to a target node.
1020 * Returns error or the number of pages not migrated.
1022 static int migrate_to_node(struct mm_struct *mm, int source, int dest,
1026 LIST_HEAD(pagelist);
1030 node_set(source, nmask);
1033 * This does not "check" the range but isolates all pages that
1034 * need migration. Between passing in the full user address
1035 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
1037 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
1038 queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1039 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
1041 if (!list_empty(&pagelist)) {
1042 err = migrate_pages(&pagelist, alloc_new_node_page, NULL, dest,
1043 MIGRATE_SYNC, MR_SYSCALL);
1045 putback_movable_pages(&pagelist);
1052 * Move pages between the two nodesets so as to preserve the physical
1053 * layout as much as possible.
1055 * Returns the number of page that could not be moved.
1057 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1058 const nodemask_t *to, int flags)
1064 err = migrate_prep();
1068 down_read(&mm->mmap_sem);
1071 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1072 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1073 * bit in 'tmp', and return that <source, dest> pair for migration.
1074 * The pair of nodemasks 'to' and 'from' define the map.
1076 * If no pair of bits is found that way, fallback to picking some
1077 * pair of 'source' and 'dest' bits that are not the same. If the
1078 * 'source' and 'dest' bits are the same, this represents a node
1079 * that will be migrating to itself, so no pages need move.
1081 * If no bits are left in 'tmp', or if all remaining bits left
1082 * in 'tmp' correspond to the same bit in 'to', return false
1083 * (nothing left to migrate).
1085 * This lets us pick a pair of nodes to migrate between, such that
1086 * if possible the dest node is not already occupied by some other
1087 * source node, minimizing the risk of overloading the memory on a
1088 * node that would happen if we migrated incoming memory to a node
1089 * before migrating outgoing memory source that same node.
1091 * A single scan of tmp is sufficient. As we go, we remember the
1092 * most recent <s, d> pair that moved (s != d). If we find a pair
1093 * that not only moved, but what's better, moved to an empty slot
1094 * (d is not set in tmp), then we break out then, with that pair.
1095 * Otherwise when we finish scanning from_tmp, we at least have the
1096 * most recent <s, d> pair that moved. If we get all the way through
1097 * the scan of tmp without finding any node that moved, much less
1098 * moved to an empty node, then there is nothing left worth migrating.
1102 while (!nodes_empty(tmp)) {
1104 int source = NUMA_NO_NODE;
1107 for_each_node_mask(s, tmp) {
1110 * do_migrate_pages() tries to maintain the relative
1111 * node relationship of the pages established between
1112 * threads and memory areas.
1114 * However if the number of source nodes is not equal to
1115 * the number of destination nodes we can not preserve
1116 * this node relative relationship. In that case, skip
1117 * copying memory from a node that is in the destination
1120 * Example: [2,3,4] -> [3,4,5] moves everything.
1121 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1124 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1125 (node_isset(s, *to)))
1128 d = node_remap(s, *from, *to);
1132 source = s; /* Node moved. Memorize */
1135 /* dest not in remaining from nodes? */
1136 if (!node_isset(dest, tmp))
1139 if (source == NUMA_NO_NODE)
1142 node_clear(source, tmp);
1143 err = migrate_to_node(mm, source, dest, flags);
1149 up_read(&mm->mmap_sem);
1157 * Allocate a new page for page migration based on vma policy.
1158 * Start by assuming the page is mapped by the same vma as contains @start.
1159 * Search forward from there, if not. N.B., this assumes that the
1160 * list of pages handed to migrate_pages()--which is how we get here--
1161 * is in virtual address order.
1163 static struct page *new_page(struct page *page, unsigned long start)
1165 struct vm_area_struct *vma;
1166 unsigned long uninitialized_var(address);
1168 vma = find_vma(current->mm, start);
1170 address = page_address_in_vma(page, vma);
1171 if (address != -EFAULT)
1176 if (PageHuge(page)) {
1177 return alloc_huge_page_vma(page_hstate(compound_head(page)),
1179 } else if (PageTransHuge(page)) {
1182 thp = alloc_pages_vma(GFP_TRANSHUGE, HPAGE_PMD_ORDER, vma,
1183 address, numa_node_id());
1186 prep_transhuge_page(thp);
1190 * if !vma, alloc_page_vma() will use task or system default policy
1192 return alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL,
1197 static int migrate_page_add(struct page *page, struct list_head *pagelist,
1198 unsigned long flags)
1203 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1204 const nodemask_t *to, int flags)
1209 static struct page *new_page(struct page *page, unsigned long start)
1215 static long do_mbind(unsigned long start, unsigned long len,
1216 unsigned short mode, unsigned short mode_flags,
1217 nodemask_t *nmask, unsigned long flags)
1219 struct mm_struct *mm = current->mm;
1220 struct mempolicy *new;
1224 LIST_HEAD(pagelist);
1226 if (flags & ~(unsigned long)MPOL_MF_VALID)
1228 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1231 if (start & ~PAGE_MASK)
1234 if (mode == MPOL_DEFAULT)
1235 flags &= ~MPOL_MF_STRICT;
1237 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1245 new = mpol_new(mode, mode_flags, nmask);
1247 return PTR_ERR(new);
1249 if (flags & MPOL_MF_LAZY)
1250 new->flags |= MPOL_F_MOF;
1253 * If we are using the default policy then operation
1254 * on discontinuous address spaces is okay after all
1257 flags |= MPOL_MF_DISCONTIG_OK;
1259 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1260 start, start + len, mode, mode_flags,
1261 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1263 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1265 err = migrate_prep();
1270 NODEMASK_SCRATCH(scratch);
1272 down_write(&mm->mmap_sem);
1274 err = mpol_set_nodemask(new, nmask, scratch);
1275 task_unlock(current);
1277 up_write(&mm->mmap_sem);
1280 NODEMASK_SCRATCH_FREE(scratch);
1285 ret = queue_pages_range(mm, start, end, nmask,
1286 flags | MPOL_MF_INVERT, &pagelist);
1293 err = mbind_range(mm, start, end, new);
1298 if (!list_empty(&pagelist)) {
1299 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1300 nr_failed = migrate_pages(&pagelist, new_page, NULL,
1301 start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
1303 putback_movable_pages(&pagelist);
1306 if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
1309 putback_movable_pages(&pagelist);
1312 up_write(&mm->mmap_sem);
1319 * User space interface with variable sized bitmaps for nodelists.
1322 /* Copy a node mask from user space. */
1323 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1324 unsigned long maxnode)
1328 unsigned long nlongs;
1329 unsigned long endmask;
1332 nodes_clear(*nodes);
1333 if (maxnode == 0 || !nmask)
1335 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1338 nlongs = BITS_TO_LONGS(maxnode);
1339 if ((maxnode % BITS_PER_LONG) == 0)
1342 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1345 * When the user specified more nodes than supported just check
1346 * if the non supported part is all zero.
1348 * If maxnode have more longs than MAX_NUMNODES, check
1349 * the bits in that area first. And then go through to
1350 * check the rest bits which equal or bigger than MAX_NUMNODES.
1351 * Otherwise, just check bits [MAX_NUMNODES, maxnode).
1353 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1354 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1355 if (get_user(t, nmask + k))
1357 if (k == nlongs - 1) {
1363 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1367 if (maxnode > MAX_NUMNODES && MAX_NUMNODES % BITS_PER_LONG != 0) {
1368 unsigned long valid_mask = endmask;
1370 valid_mask &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
1371 if (get_user(t, nmask + nlongs - 1))
1377 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1379 nodes_addr(*nodes)[nlongs-1] &= endmask;
1383 /* Copy a kernel node mask to user space */
1384 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1387 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1388 unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long);
1390 if (copy > nbytes) {
1391 if (copy > PAGE_SIZE)
1393 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1397 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1400 static long kernel_mbind(unsigned long start, unsigned long len,
1401 unsigned long mode, const unsigned long __user *nmask,
1402 unsigned long maxnode, unsigned int flags)
1406 unsigned short mode_flags;
1408 mode_flags = mode & MPOL_MODE_FLAGS;
1409 mode &= ~MPOL_MODE_FLAGS;
1410 if (mode >= MPOL_MAX)
1412 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1413 (mode_flags & MPOL_F_RELATIVE_NODES))
1415 err = get_nodes(&nodes, nmask, maxnode);
1418 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1421 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1422 unsigned long, mode, const unsigned long __user *, nmask,
1423 unsigned long, maxnode, unsigned int, flags)
1425 return kernel_mbind(start, len, mode, nmask, maxnode, flags);
1428 /* Set the process memory policy */
1429 static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
1430 unsigned long maxnode)
1434 unsigned short flags;
1436 flags = mode & MPOL_MODE_FLAGS;
1437 mode &= ~MPOL_MODE_FLAGS;
1438 if ((unsigned int)mode >= MPOL_MAX)
1440 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1442 err = get_nodes(&nodes, nmask, maxnode);
1445 return do_set_mempolicy(mode, flags, &nodes);
1448 SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
1449 unsigned long, maxnode)
1451 return kernel_set_mempolicy(mode, nmask, maxnode);
1454 static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
1455 const unsigned long __user *old_nodes,
1456 const unsigned long __user *new_nodes)
1458 struct mm_struct *mm = NULL;
1459 struct task_struct *task;
1460 nodemask_t task_nodes;
1464 NODEMASK_SCRATCH(scratch);
1469 old = &scratch->mask1;
1470 new = &scratch->mask2;
1472 err = get_nodes(old, old_nodes, maxnode);
1476 err = get_nodes(new, new_nodes, maxnode);
1480 /* Find the mm_struct */
1482 task = pid ? find_task_by_vpid(pid) : current;
1488 get_task_struct(task);
1493 * Check if this process has the right to modify the specified process.
1494 * Use the regular "ptrace_may_access()" checks.
1496 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
1503 task_nodes = cpuset_mems_allowed(task);
1504 /* Is the user allowed to access the target nodes? */
1505 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1510 task_nodes = cpuset_mems_allowed(current);
1511 nodes_and(*new, *new, task_nodes);
1512 if (nodes_empty(*new))
1515 nodes_and(*new, *new, node_states[N_MEMORY]);
1516 if (nodes_empty(*new))
1519 err = security_task_movememory(task);
1523 mm = get_task_mm(task);
1524 put_task_struct(task);
1531 err = do_migrate_pages(mm, old, new,
1532 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1536 NODEMASK_SCRATCH_FREE(scratch);
1541 put_task_struct(task);
1546 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1547 const unsigned long __user *, old_nodes,
1548 const unsigned long __user *, new_nodes)
1550 return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes);
1554 /* Retrieve NUMA policy */
1555 static int kernel_get_mempolicy(int __user *policy,
1556 unsigned long __user *nmask,
1557 unsigned long maxnode,
1559 unsigned long flags)
1562 int uninitialized_var(pval);
1565 if (nmask != NULL && maxnode < nr_node_ids)
1568 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1573 if (policy && put_user(pval, policy))
1577 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1582 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1583 unsigned long __user *, nmask, unsigned long, maxnode,
1584 unsigned long, addr, unsigned long, flags)
1586 return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags);
1589 #ifdef CONFIG_COMPAT
1591 COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1592 compat_ulong_t __user *, nmask,
1593 compat_ulong_t, maxnode,
1594 compat_ulong_t, addr, compat_ulong_t, flags)
1597 unsigned long __user *nm = NULL;
1598 unsigned long nr_bits, alloc_size;
1599 DECLARE_BITMAP(bm, MAX_NUMNODES);
1601 nr_bits = min_t(unsigned long, maxnode-1, nr_node_ids);
1602 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1605 nm = compat_alloc_user_space(alloc_size);
1607 err = kernel_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1609 if (!err && nmask) {
1610 unsigned long copy_size;
1611 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1612 err = copy_from_user(bm, nm, copy_size);
1613 /* ensure entire bitmap is zeroed */
1614 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1615 err |= compat_put_bitmap(nmask, bm, nr_bits);
1621 COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
1622 compat_ulong_t, maxnode)
1624 unsigned long __user *nm = NULL;
1625 unsigned long nr_bits, alloc_size;
1626 DECLARE_BITMAP(bm, MAX_NUMNODES);
1628 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1629 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1632 if (compat_get_bitmap(bm, nmask, nr_bits))
1634 nm = compat_alloc_user_space(alloc_size);
1635 if (copy_to_user(nm, bm, alloc_size))
1639 return kernel_set_mempolicy(mode, nm, nr_bits+1);
1642 COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
1643 compat_ulong_t, mode, compat_ulong_t __user *, nmask,
1644 compat_ulong_t, maxnode, compat_ulong_t, flags)
1646 unsigned long __user *nm = NULL;
1647 unsigned long nr_bits, alloc_size;
1650 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1651 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1654 if (compat_get_bitmap(nodes_addr(bm), nmask, nr_bits))
1656 nm = compat_alloc_user_space(alloc_size);
1657 if (copy_to_user(nm, nodes_addr(bm), alloc_size))
1661 return kernel_mbind(start, len, mode, nm, nr_bits+1, flags);
1664 COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
1665 compat_ulong_t, maxnode,
1666 const compat_ulong_t __user *, old_nodes,
1667 const compat_ulong_t __user *, new_nodes)
1669 unsigned long __user *old = NULL;
1670 unsigned long __user *new = NULL;
1671 nodemask_t tmp_mask;
1672 unsigned long nr_bits;
1675 nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
1676 size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1678 if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
1680 old = compat_alloc_user_space(new_nodes ? size * 2 : size);
1682 new = old + size / sizeof(unsigned long);
1683 if (copy_to_user(old, nodes_addr(tmp_mask), size))
1687 if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
1690 new = compat_alloc_user_space(size);
1691 if (copy_to_user(new, nodes_addr(tmp_mask), size))
1694 return kernel_migrate_pages(pid, nr_bits + 1, old, new);
1697 #endif /* CONFIG_COMPAT */
1699 struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
1702 struct mempolicy *pol = NULL;
1705 if (vma->vm_ops && vma->vm_ops->get_policy) {
1706 pol = vma->vm_ops->get_policy(vma, addr);
1707 } else if (vma->vm_policy) {
1708 pol = vma->vm_policy;
1711 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1712 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1713 * count on these policies which will be dropped by
1714 * mpol_cond_put() later
1716 if (mpol_needs_cond_ref(pol))
1725 * get_vma_policy(@vma, @addr)
1726 * @vma: virtual memory area whose policy is sought
1727 * @addr: address in @vma for shared policy lookup
1729 * Returns effective policy for a VMA at specified address.
1730 * Falls back to current->mempolicy or system default policy, as necessary.
1731 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1732 * count--added by the get_policy() vm_op, as appropriate--to protect against
1733 * freeing by another task. It is the caller's responsibility to free the
1734 * extra reference for shared policies.
1736 struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
1739 struct mempolicy *pol = __get_vma_policy(vma, addr);
1742 pol = get_task_policy(current);
1747 bool vma_policy_mof(struct vm_area_struct *vma)
1749 struct mempolicy *pol;
1751 if (vma->vm_ops && vma->vm_ops->get_policy) {
1754 pol = vma->vm_ops->get_policy(vma, vma->vm_start);
1755 if (pol && (pol->flags & MPOL_F_MOF))
1762 pol = vma->vm_policy;
1764 pol = get_task_policy(current);
1766 return pol->flags & MPOL_F_MOF;
1769 static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1771 enum zone_type dynamic_policy_zone = policy_zone;
1773 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1776 * if policy->v.nodes has movable memory only,
1777 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1779 * policy->v.nodes is intersect with node_states[N_MEMORY].
1780 * so if the following test faile, it implies
1781 * policy->v.nodes has movable memory only.
1783 if (!nodes_intersects(policy->v.nodes, node_states[N_HIGH_MEMORY]))
1784 dynamic_policy_zone = ZONE_MOVABLE;
1786 return zone >= dynamic_policy_zone;
1790 * Return a nodemask representing a mempolicy for filtering nodes for
1793 static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1795 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1796 if (unlikely(policy->mode == MPOL_BIND) &&
1797 apply_policy_zone(policy, gfp_zone(gfp)) &&
1798 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1799 return &policy->v.nodes;
1804 /* Return the node id preferred by the given mempolicy, or the given id */
1805 static int policy_node(gfp_t gfp, struct mempolicy *policy,
1808 if (policy->mode == MPOL_PREFERRED && !(policy->flags & MPOL_F_LOCAL))
1809 nd = policy->v.preferred_node;
1812 * __GFP_THISNODE shouldn't even be used with the bind policy
1813 * because we might easily break the expectation to stay on the
1814 * requested node and not break the policy.
1816 WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE));
1822 /* Do dynamic interleaving for a process */
1823 static unsigned interleave_nodes(struct mempolicy *policy)
1826 struct task_struct *me = current;
1828 next = next_node_in(me->il_prev, policy->v.nodes);
1829 if (next < MAX_NUMNODES)
1835 * Depending on the memory policy provide a node from which to allocate the
1838 unsigned int mempolicy_slab_node(void)
1840 struct mempolicy *policy;
1841 int node = numa_mem_id();
1846 policy = current->mempolicy;
1847 if (!policy || policy->flags & MPOL_F_LOCAL)
1850 switch (policy->mode) {
1851 case MPOL_PREFERRED:
1853 * handled MPOL_F_LOCAL above
1855 return policy->v.preferred_node;
1857 case MPOL_INTERLEAVE:
1858 return interleave_nodes(policy);
1864 * Follow bind policy behavior and start allocation at the
1867 struct zonelist *zonelist;
1868 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1869 zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK];
1870 z = first_zones_zonelist(zonelist, highest_zoneidx,
1872 return z->zone ? zone_to_nid(z->zone) : node;
1881 * Do static interleaving for a VMA with known offset @n. Returns the n'th
1882 * node in pol->v.nodes (starting from n=0), wrapping around if n exceeds the
1883 * number of present nodes.
1885 static unsigned offset_il_node(struct mempolicy *pol, unsigned long n)
1887 unsigned nnodes = nodes_weight(pol->v.nodes);
1893 return numa_node_id();
1894 target = (unsigned int)n % nnodes;
1895 nid = first_node(pol->v.nodes);
1896 for (i = 0; i < target; i++)
1897 nid = next_node(nid, pol->v.nodes);
1901 /* Determine a node number for interleave */
1902 static inline unsigned interleave_nid(struct mempolicy *pol,
1903 struct vm_area_struct *vma, unsigned long addr, int shift)
1909 * for small pages, there is no difference between
1910 * shift and PAGE_SHIFT, so the bit-shift is safe.
1911 * for huge pages, since vm_pgoff is in units of small
1912 * pages, we need to shift off the always 0 bits to get
1915 BUG_ON(shift < PAGE_SHIFT);
1916 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1917 off += (addr - vma->vm_start) >> shift;
1918 return offset_il_node(pol, off);
1920 return interleave_nodes(pol);
1923 #ifdef CONFIG_HUGETLBFS
1925 * huge_node(@vma, @addr, @gfp_flags, @mpol)
1926 * @vma: virtual memory area whose policy is sought
1927 * @addr: address in @vma for shared policy lookup and interleave policy
1928 * @gfp_flags: for requested zone
1929 * @mpol: pointer to mempolicy pointer for reference counted mempolicy
1930 * @nodemask: pointer to nodemask pointer for MPOL_BIND nodemask
1932 * Returns a nid suitable for a huge page allocation and a pointer
1933 * to the struct mempolicy for conditional unref after allocation.
1934 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1935 * @nodemask for filtering the zonelist.
1937 * Must be protected by read_mems_allowed_begin()
1939 int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags,
1940 struct mempolicy **mpol, nodemask_t **nodemask)
1944 *mpol = get_vma_policy(vma, addr);
1945 *nodemask = NULL; /* assume !MPOL_BIND */
1947 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1948 nid = interleave_nid(*mpol, vma, addr,
1949 huge_page_shift(hstate_vma(vma)));
1951 nid = policy_node(gfp_flags, *mpol, numa_node_id());
1952 if ((*mpol)->mode == MPOL_BIND)
1953 *nodemask = &(*mpol)->v.nodes;
1959 * init_nodemask_of_mempolicy
1961 * If the current task's mempolicy is "default" [NULL], return 'false'
1962 * to indicate default policy. Otherwise, extract the policy nodemask
1963 * for 'bind' or 'interleave' policy into the argument nodemask, or
1964 * initialize the argument nodemask to contain the single node for
1965 * 'preferred' or 'local' policy and return 'true' to indicate presence
1966 * of non-default mempolicy.
1968 * We don't bother with reference counting the mempolicy [mpol_get/put]
1969 * because the current task is examining it's own mempolicy and a task's
1970 * mempolicy is only ever changed by the task itself.
1972 * N.B., it is the caller's responsibility to free a returned nodemask.
1974 bool init_nodemask_of_mempolicy(nodemask_t *mask)
1976 struct mempolicy *mempolicy;
1979 if (!(mask && current->mempolicy))
1983 mempolicy = current->mempolicy;
1984 switch (mempolicy->mode) {
1985 case MPOL_PREFERRED:
1986 if (mempolicy->flags & MPOL_F_LOCAL)
1987 nid = numa_node_id();
1989 nid = mempolicy->v.preferred_node;
1990 init_nodemask_of_node(mask, nid);
1995 case MPOL_INTERLEAVE:
1996 *mask = mempolicy->v.nodes;
2002 task_unlock(current);
2009 * mempolicy_nodemask_intersects
2011 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
2012 * policy. Otherwise, check for intersection between mask and the policy
2013 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
2014 * policy, always return true since it may allocate elsewhere on fallback.
2016 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
2018 bool mempolicy_nodemask_intersects(struct task_struct *tsk,
2019 const nodemask_t *mask)
2021 struct mempolicy *mempolicy;
2027 mempolicy = tsk->mempolicy;
2031 switch (mempolicy->mode) {
2032 case MPOL_PREFERRED:
2034 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
2035 * allocate from, they may fallback to other nodes when oom.
2036 * Thus, it's possible for tsk to have allocated memory from
2041 case MPOL_INTERLEAVE:
2042 ret = nodes_intersects(mempolicy->v.nodes, *mask);
2052 /* Allocate a page in interleaved policy.
2053 Own path because it needs to do special accounting. */
2054 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
2059 page = __alloc_pages(gfp, order, nid);
2060 /* skip NUMA_INTERLEAVE_HIT counter update if numa stats is disabled */
2061 if (!static_branch_likely(&vm_numa_stat_key))
2063 if (page && page_to_nid(page) == nid) {
2065 __inc_numa_state(page_zone(page), NUMA_INTERLEAVE_HIT);
2072 * alloc_pages_vma - Allocate a page for a VMA.
2075 * %GFP_USER user allocation.
2076 * %GFP_KERNEL kernel allocations,
2077 * %GFP_HIGHMEM highmem/user allocations,
2078 * %GFP_FS allocation should not call back into a file system.
2079 * %GFP_ATOMIC don't sleep.
2081 * @order:Order of the GFP allocation.
2082 * @vma: Pointer to VMA or NULL if not available.
2083 * @addr: Virtual Address of the allocation. Must be inside the VMA.
2084 * @node: Which node to prefer for allocation (modulo policy).
2086 * This function allocates a page from the kernel page pool and applies
2087 * a NUMA policy associated with the VMA or the current process.
2088 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
2089 * mm_struct of the VMA to prevent it from going away. Should be used for
2090 * all allocations for pages that will be mapped into user space. Returns
2091 * NULL when no page can be allocated.
2094 alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
2095 unsigned long addr, int node)
2097 struct mempolicy *pol;
2102 pol = get_vma_policy(vma, addr);
2104 if (pol->mode == MPOL_INTERLEAVE) {
2107 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2109 page = alloc_page_interleave(gfp, order, nid);
2113 nmask = policy_nodemask(gfp, pol);
2114 preferred_nid = policy_node(gfp, pol, node);
2115 page = __alloc_pages_nodemask(gfp, order, preferred_nid, nmask);
2120 EXPORT_SYMBOL(alloc_pages_vma);
2123 * alloc_pages_current - Allocate pages.
2126 * %GFP_USER user allocation,
2127 * %GFP_KERNEL kernel allocation,
2128 * %GFP_HIGHMEM highmem allocation,
2129 * %GFP_FS don't call back into a file system.
2130 * %GFP_ATOMIC don't sleep.
2131 * @order: Power of two of allocation size in pages. 0 is a single page.
2133 * Allocate a page from the kernel page pool. When not in
2134 * interrupt context and apply the current process NUMA policy.
2135 * Returns NULL when no page can be allocated.
2137 struct page *alloc_pages_current(gfp_t gfp, unsigned order)
2139 struct mempolicy *pol = &default_policy;
2142 if (!in_interrupt() && !(gfp & __GFP_THISNODE))
2143 pol = get_task_policy(current);
2146 * No reference counting needed for current->mempolicy
2147 * nor system default_policy
2149 if (pol->mode == MPOL_INTERLEAVE)
2150 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
2152 page = __alloc_pages_nodemask(gfp, order,
2153 policy_node(gfp, pol, numa_node_id()),
2154 policy_nodemask(gfp, pol));
2158 EXPORT_SYMBOL(alloc_pages_current);
2160 int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
2162 struct mempolicy *pol = mpol_dup(vma_policy(src));
2165 return PTR_ERR(pol);
2166 dst->vm_policy = pol;
2171 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2172 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2173 * with the mems_allowed returned by cpuset_mems_allowed(). This
2174 * keeps mempolicies cpuset relative after its cpuset moves. See
2175 * further kernel/cpuset.c update_nodemask().
2177 * current's mempolicy may be rebinded by the other task(the task that changes
2178 * cpuset's mems), so we needn't do rebind work for current task.
2181 /* Slow path of a mempolicy duplicate */
2182 struct mempolicy *__mpol_dup(struct mempolicy *old)
2184 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2187 return ERR_PTR(-ENOMEM);
2189 /* task's mempolicy is protected by alloc_lock */
2190 if (old == current->mempolicy) {
2193 task_unlock(current);
2197 if (current_cpuset_is_being_rebound()) {
2198 nodemask_t mems = cpuset_mems_allowed(current);
2199 mpol_rebind_policy(new, &mems);
2201 atomic_set(&new->refcnt, 1);
2205 /* Slow path of a mempolicy comparison */
2206 bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2210 if (a->mode != b->mode)
2212 if (a->flags != b->flags)
2214 if (mpol_store_user_nodemask(a))
2215 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2221 case MPOL_INTERLEAVE:
2222 return !!nodes_equal(a->v.nodes, b->v.nodes);
2223 case MPOL_PREFERRED:
2224 /* a's ->flags is the same as b's */
2225 if (a->flags & MPOL_F_LOCAL)
2227 return a->v.preferred_node == b->v.preferred_node;
2235 * Shared memory backing store policy support.
2237 * Remember policies even when nobody has shared memory mapped.
2238 * The policies are kept in Red-Black tree linked from the inode.
2239 * They are protected by the sp->lock rwlock, which should be held
2240 * for any accesses to the tree.
2244 * lookup first element intersecting start-end. Caller holds sp->lock for
2245 * reading or for writing
2247 static struct sp_node *
2248 sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2250 struct rb_node *n = sp->root.rb_node;
2253 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2255 if (start >= p->end)
2257 else if (end <= p->start)
2265 struct sp_node *w = NULL;
2266 struct rb_node *prev = rb_prev(n);
2269 w = rb_entry(prev, struct sp_node, nd);
2270 if (w->end <= start)
2274 return rb_entry(n, struct sp_node, nd);
2278 * Insert a new shared policy into the list. Caller holds sp->lock for
2281 static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2283 struct rb_node **p = &sp->root.rb_node;
2284 struct rb_node *parent = NULL;
2289 nd = rb_entry(parent, struct sp_node, nd);
2290 if (new->start < nd->start)
2292 else if (new->end > nd->end)
2293 p = &(*p)->rb_right;
2297 rb_link_node(&new->nd, parent, p);
2298 rb_insert_color(&new->nd, &sp->root);
2299 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2300 new->policy ? new->policy->mode : 0);
2303 /* Find shared policy intersecting idx */
2305 mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2307 struct mempolicy *pol = NULL;
2310 if (!sp->root.rb_node)
2312 read_lock(&sp->lock);
2313 sn = sp_lookup(sp, idx, idx+1);
2315 mpol_get(sn->policy);
2318 read_unlock(&sp->lock);
2322 static void sp_free(struct sp_node *n)
2324 mpol_put(n->policy);
2325 kmem_cache_free(sn_cache, n);
2329 * mpol_misplaced - check whether current page node is valid in policy
2331 * @page: page to be checked
2332 * @vma: vm area where page mapped
2333 * @addr: virtual address where page mapped
2335 * Lookup current policy node id for vma,addr and "compare to" page's
2339 * -1 - not misplaced, page is in the right node
2340 * node - node id where the page should be
2342 * Policy determination "mimics" alloc_page_vma().
2343 * Called from fault path where we know the vma and faulting address.
2345 int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
2347 struct mempolicy *pol;
2349 int curnid = page_to_nid(page);
2350 unsigned long pgoff;
2351 int thiscpu = raw_smp_processor_id();
2352 int thisnid = cpu_to_node(thiscpu);
2353 int polnid = NUMA_NO_NODE;
2356 pol = get_vma_policy(vma, addr);
2357 if (!(pol->flags & MPOL_F_MOF))
2360 switch (pol->mode) {
2361 case MPOL_INTERLEAVE:
2362 pgoff = vma->vm_pgoff;
2363 pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
2364 polnid = offset_il_node(pol, pgoff);
2367 case MPOL_PREFERRED:
2368 if (pol->flags & MPOL_F_LOCAL)
2369 polnid = numa_node_id();
2371 polnid = pol->v.preferred_node;
2377 * allows binding to multiple nodes.
2378 * use current page if in policy nodemask,
2379 * else select nearest allowed node, if any.
2380 * If no allowed nodes, use current [!misplaced].
2382 if (node_isset(curnid, pol->v.nodes))
2384 z = first_zones_zonelist(
2385 node_zonelist(numa_node_id(), GFP_HIGHUSER),
2386 gfp_zone(GFP_HIGHUSER),
2388 polnid = zone_to_nid(z->zone);
2395 /* Migrate the page towards the node whose CPU is referencing it */
2396 if (pol->flags & MPOL_F_MORON) {
2399 if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
2403 if (curnid != polnid)
2412 * Drop the (possibly final) reference to task->mempolicy. It needs to be
2413 * dropped after task->mempolicy is set to NULL so that any allocation done as
2414 * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed
2417 void mpol_put_task_policy(struct task_struct *task)
2419 struct mempolicy *pol;
2422 pol = task->mempolicy;
2423 task->mempolicy = NULL;
2428 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2430 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2431 rb_erase(&n->nd, &sp->root);
2435 static void sp_node_init(struct sp_node *node, unsigned long start,
2436 unsigned long end, struct mempolicy *pol)
2438 node->start = start;
2443 static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2444 struct mempolicy *pol)
2447 struct mempolicy *newpol;
2449 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2453 newpol = mpol_dup(pol);
2454 if (IS_ERR(newpol)) {
2455 kmem_cache_free(sn_cache, n);
2458 newpol->flags |= MPOL_F_SHARED;
2459 sp_node_init(n, start, end, newpol);
2464 /* Replace a policy range. */
2465 static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2466 unsigned long end, struct sp_node *new)
2469 struct sp_node *n_new = NULL;
2470 struct mempolicy *mpol_new = NULL;
2474 write_lock(&sp->lock);
2475 n = sp_lookup(sp, start, end);
2476 /* Take care of old policies in the same range. */
2477 while (n && n->start < end) {
2478 struct rb_node *next = rb_next(&n->nd);
2479 if (n->start >= start) {
2485 /* Old policy spanning whole new range. */
2490 *mpol_new = *n->policy;
2491 atomic_set(&mpol_new->refcnt, 1);
2492 sp_node_init(n_new, end, n->end, mpol_new);
2494 sp_insert(sp, n_new);
2503 n = rb_entry(next, struct sp_node, nd);
2507 write_unlock(&sp->lock);
2514 kmem_cache_free(sn_cache, n_new);
2519 write_unlock(&sp->lock);
2521 n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2524 mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2531 * mpol_shared_policy_init - initialize shared policy for inode
2532 * @sp: pointer to inode shared policy
2533 * @mpol: struct mempolicy to install
2535 * Install non-NULL @mpol in inode's shared policy rb-tree.
2536 * On entry, the current task has a reference on a non-NULL @mpol.
2537 * This must be released on exit.
2538 * This is called at get_inode() calls and we can use GFP_KERNEL.
2540 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2544 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2545 rwlock_init(&sp->lock);
2548 struct vm_area_struct pvma;
2549 struct mempolicy *new;
2550 NODEMASK_SCRATCH(scratch);
2554 /* contextualize the tmpfs mount point mempolicy */
2555 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2557 goto free_scratch; /* no valid nodemask intersection */
2560 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2561 task_unlock(current);
2565 /* Create pseudo-vma that contains just the policy */
2566 vma_init(&pvma, NULL);
2567 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2568 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2571 mpol_put(new); /* drop initial ref */
2573 NODEMASK_SCRATCH_FREE(scratch);
2575 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2579 int mpol_set_shared_policy(struct shared_policy *info,
2580 struct vm_area_struct *vma, struct mempolicy *npol)
2583 struct sp_node *new = NULL;
2584 unsigned long sz = vma_pages(vma);
2586 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2588 sz, npol ? npol->mode : -1,
2589 npol ? npol->flags : -1,
2590 npol ? nodes_addr(npol->v.nodes)[0] : NUMA_NO_NODE);
2593 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2597 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2603 /* Free a backing policy store on inode delete. */
2604 void mpol_free_shared_policy(struct shared_policy *p)
2607 struct rb_node *next;
2609 if (!p->root.rb_node)
2611 write_lock(&p->lock);
2612 next = rb_first(&p->root);
2614 n = rb_entry(next, struct sp_node, nd);
2615 next = rb_next(&n->nd);
2618 write_unlock(&p->lock);
2621 #ifdef CONFIG_NUMA_BALANCING
2622 static int __initdata numabalancing_override;
2624 static void __init check_numabalancing_enable(void)
2626 bool numabalancing_default = false;
2628 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2629 numabalancing_default = true;
2631 /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
2632 if (numabalancing_override)
2633 set_numabalancing_state(numabalancing_override == 1);
2635 if (num_online_nodes() > 1 && !numabalancing_override) {
2636 pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n",
2637 numabalancing_default ? "Enabling" : "Disabling");
2638 set_numabalancing_state(numabalancing_default);
2642 static int __init setup_numabalancing(char *str)
2648 if (!strcmp(str, "enable")) {
2649 numabalancing_override = 1;
2651 } else if (!strcmp(str, "disable")) {
2652 numabalancing_override = -1;
2657 pr_warn("Unable to parse numa_balancing=\n");
2661 __setup("numa_balancing=", setup_numabalancing);
2663 static inline void __init check_numabalancing_enable(void)
2666 #endif /* CONFIG_NUMA_BALANCING */
2668 /* assumes fs == KERNEL_DS */
2669 void __init numa_policy_init(void)
2671 nodemask_t interleave_nodes;
2672 unsigned long largest = 0;
2673 int nid, prefer = 0;
2675 policy_cache = kmem_cache_create("numa_policy",
2676 sizeof(struct mempolicy),
2677 0, SLAB_PANIC, NULL);
2679 sn_cache = kmem_cache_create("shared_policy_node",
2680 sizeof(struct sp_node),
2681 0, SLAB_PANIC, NULL);
2683 for_each_node(nid) {
2684 preferred_node_policy[nid] = (struct mempolicy) {
2685 .refcnt = ATOMIC_INIT(1),
2686 .mode = MPOL_PREFERRED,
2687 .flags = MPOL_F_MOF | MPOL_F_MORON,
2688 .v = { .preferred_node = nid, },
2693 * Set interleaving policy for system init. Interleaving is only
2694 * enabled across suitably sized nodes (default is >= 16MB), or
2695 * fall back to the largest node if they're all smaller.
2697 nodes_clear(interleave_nodes);
2698 for_each_node_state(nid, N_MEMORY) {
2699 unsigned long total_pages = node_present_pages(nid);
2701 /* Preserve the largest node */
2702 if (largest < total_pages) {
2703 largest = total_pages;
2707 /* Interleave this node? */
2708 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2709 node_set(nid, interleave_nodes);
2712 /* All too small, use the largest */
2713 if (unlikely(nodes_empty(interleave_nodes)))
2714 node_set(prefer, interleave_nodes);
2716 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2717 pr_err("%s: interleaving failed\n", __func__);
2719 check_numabalancing_enable();
2722 /* Reset policy of current process to default */
2723 void numa_default_policy(void)
2725 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2729 * Parse and format mempolicy from/to strings
2733 * "local" is implemented internally by MPOL_PREFERRED with MPOL_F_LOCAL flag.
2735 static const char * const policy_modes[] =
2737 [MPOL_DEFAULT] = "default",
2738 [MPOL_PREFERRED] = "prefer",
2739 [MPOL_BIND] = "bind",
2740 [MPOL_INTERLEAVE] = "interleave",
2741 [MPOL_LOCAL] = "local",
2747 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2748 * @str: string containing mempolicy to parse
2749 * @mpol: pointer to struct mempolicy pointer, returned on success.
2752 * <mode>[=<flags>][:<nodelist>]
2754 * On success, returns 0, else 1
2756 int mpol_parse_str(char *str, struct mempolicy **mpol)
2758 struct mempolicy *new = NULL;
2759 unsigned short mode_flags;
2761 char *nodelist = strchr(str, ':');
2762 char *flags = strchr(str, '=');
2766 /* NUL-terminate mode or flags string */
2768 if (nodelist_parse(nodelist, nodes))
2770 if (!nodes_subset(nodes, node_states[N_MEMORY]))
2776 *flags++ = '\0'; /* terminate mode string */
2778 mode = match_string(policy_modes, MPOL_MAX, str);
2783 case MPOL_PREFERRED:
2785 * Insist on a nodelist of one node only
2788 char *rest = nodelist;
2789 while (isdigit(*rest))
2795 case MPOL_INTERLEAVE:
2797 * Default to online nodes with memory if no nodelist
2800 nodes = node_states[N_MEMORY];
2804 * Don't allow a nodelist; mpol_new() checks flags
2808 mode = MPOL_PREFERRED;
2812 * Insist on a empty nodelist
2819 * Insist on a nodelist
2828 * Currently, we only support two mutually exclusive
2831 if (!strcmp(flags, "static"))
2832 mode_flags |= MPOL_F_STATIC_NODES;
2833 else if (!strcmp(flags, "relative"))
2834 mode_flags |= MPOL_F_RELATIVE_NODES;
2839 new = mpol_new(mode, mode_flags, &nodes);
2844 * Save nodes for mpol_to_str() to show the tmpfs mount options
2845 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
2847 if (mode != MPOL_PREFERRED)
2848 new->v.nodes = nodes;
2850 new->v.preferred_node = first_node(nodes);
2852 new->flags |= MPOL_F_LOCAL;
2855 * Save nodes for contextualization: this will be used to "clone"
2856 * the mempolicy in a specific context [cpuset] at a later time.
2858 new->w.user_nodemask = nodes;
2863 /* Restore string for error message */
2872 #endif /* CONFIG_TMPFS */
2875 * mpol_to_str - format a mempolicy structure for printing
2876 * @buffer: to contain formatted mempolicy string
2877 * @maxlen: length of @buffer
2878 * @pol: pointer to mempolicy to be formatted
2880 * Convert @pol into a string. If @buffer is too short, truncate the string.
2881 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
2882 * longest flag, "relative", and to display at least a few node ids.
2884 void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
2887 nodemask_t nodes = NODE_MASK_NONE;
2888 unsigned short mode = MPOL_DEFAULT;
2889 unsigned short flags = 0;
2891 if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
2899 case MPOL_PREFERRED:
2900 if (flags & MPOL_F_LOCAL)
2903 node_set(pol->v.preferred_node, nodes);
2906 case MPOL_INTERLEAVE:
2907 nodes = pol->v.nodes;
2911 snprintf(p, maxlen, "unknown");
2915 p += snprintf(p, maxlen, "%s", policy_modes[mode]);
2917 if (flags & MPOL_MODE_FLAGS) {
2918 p += snprintf(p, buffer + maxlen - p, "=");
2921 * Currently, the only defined flags are mutually exclusive
2923 if (flags & MPOL_F_STATIC_NODES)
2924 p += snprintf(p, buffer + maxlen - p, "static");
2925 else if (flags & MPOL_F_RELATIVE_NODES)
2926 p += snprintf(p, buffer + maxlen - p, "relative");
2929 if (!nodes_empty(nodes))
2930 p += scnprintf(p, buffer + maxlen - p, ":%*pbl",
2931 nodemask_pr_args(&nodes));