2 * Simple NUMA memory policy for the Linux kernel.
4 * Copyright 2003,2004 Andi Kleen, SuSE Labs.
5 * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc.
6 * Subject to the GNU Public License, version 2.
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 #include <linux/mempolicy.h>
70 #include <linux/highmem.h>
71 #include <linux/hugetlb.h>
72 #include <linux/kernel.h>
73 #include <linux/sched.h>
74 #include <linux/nodemask.h>
75 #include <linux/cpuset.h>
76 #include <linux/slab.h>
77 #include <linux/string.h>
78 #include <linux/export.h>
79 #include <linux/nsproxy.h>
80 #include <linux/interrupt.h>
81 #include <linux/init.h>
82 #include <linux/compat.h>
83 #include <linux/swap.h>
84 #include <linux/seq_file.h>
85 #include <linux/proc_fs.h>
86 #include <linux/migrate.h>
87 #include <linux/ksm.h>
88 #include <linux/rmap.h>
89 #include <linux/security.h>
90 #include <linux/syscalls.h>
91 #include <linux/ctype.h>
92 #include <linux/mm_inline.h>
93 #include <linux/mmu_notifier.h>
95 #include <asm/tlbflush.h>
96 #include <asm/uaccess.h>
97 #include <linux/random.h>
102 #define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
103 #define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
105 static struct kmem_cache *policy_cache;
106 static struct kmem_cache *sn_cache;
108 /* Highest zone. An specific allocation for a zone below that is not
110 enum zone_type policy_zone = 0;
113 * run-time system-wide default policy => local allocation
115 static struct mempolicy default_policy = {
116 .refcnt = ATOMIC_INIT(1), /* never free it */
117 .mode = MPOL_PREFERRED,
118 .flags = MPOL_F_LOCAL,
121 static struct mempolicy preferred_node_policy[MAX_NUMNODES];
123 static struct mempolicy *get_task_policy(struct task_struct *p)
125 struct mempolicy *pol = p->mempolicy;
129 node = numa_node_id();
130 if (node != NUMA_NO_NODE)
131 pol = &preferred_node_policy[node];
133 /* preferred_node_policy is not initialised early in boot */
141 static const struct mempolicy_operations {
142 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
144 * If read-side task has no lock to protect task->mempolicy, write-side
145 * task will rebind the task->mempolicy by two step. The first step is
146 * setting all the newly nodes, and the second step is cleaning all the
147 * disallowed nodes. In this way, we can avoid finding no node to alloc
149 * If we have a lock to protect task->mempolicy in read-side, we do
153 * MPOL_REBIND_ONCE - do rebind work at once
154 * MPOL_REBIND_STEP1 - set all the newly nodes
155 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
157 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes,
158 enum mpol_rebind_step step);
159 } mpol_ops[MPOL_MAX];
161 /* Check that the nodemask contains at least one populated zone */
162 static int is_valid_nodemask(const nodemask_t *nodemask)
164 return nodes_intersects(*nodemask, node_states[N_MEMORY]);
167 static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
169 return pol->flags & MPOL_MODE_FLAGS;
172 static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
173 const nodemask_t *rel)
176 nodes_fold(tmp, *orig, nodes_weight(*rel));
177 nodes_onto(*ret, tmp, *rel);
180 static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
182 if (nodes_empty(*nodes))
184 pol->v.nodes = *nodes;
188 static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
191 pol->flags |= MPOL_F_LOCAL; /* local allocation */
192 else if (nodes_empty(*nodes))
193 return -EINVAL; /* no allowed nodes */
195 pol->v.preferred_node = first_node(*nodes);
199 static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
201 if (!is_valid_nodemask(nodes))
203 pol->v.nodes = *nodes;
208 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
209 * any, for the new policy. mpol_new() has already validated the nodes
210 * parameter with respect to the policy mode and flags. But, we need to
211 * handle an empty nodemask with MPOL_PREFERRED here.
213 * Must be called holding task's alloc_lock to protect task's mems_allowed
214 * and mempolicy. May also be called holding the mmap_semaphore for write.
216 static int mpol_set_nodemask(struct mempolicy *pol,
217 const nodemask_t *nodes, struct nodemask_scratch *nsc)
221 /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
225 nodes_and(nsc->mask1,
226 cpuset_current_mems_allowed, node_states[N_MEMORY]);
229 if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
230 nodes = NULL; /* explicit local allocation */
232 if (pol->flags & MPOL_F_RELATIVE_NODES)
233 mpol_relative_nodemask(&nsc->mask2, nodes,&nsc->mask1);
235 nodes_and(nsc->mask2, *nodes, nsc->mask1);
237 if (mpol_store_user_nodemask(pol))
238 pol->w.user_nodemask = *nodes;
240 pol->w.cpuset_mems_allowed =
241 cpuset_current_mems_allowed;
245 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
247 ret = mpol_ops[pol->mode].create(pol, NULL);
252 * This function just creates a new policy, does some check and simple
253 * initialization. You must invoke mpol_set_nodemask() to set nodes.
255 static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
258 struct mempolicy *policy;
260 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
261 mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE);
263 if (mode == MPOL_DEFAULT) {
264 if (nodes && !nodes_empty(*nodes))
265 return ERR_PTR(-EINVAL);
271 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
272 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
273 * All other modes require a valid pointer to a non-empty nodemask.
275 if (mode == MPOL_PREFERRED) {
276 if (nodes_empty(*nodes)) {
277 if (((flags & MPOL_F_STATIC_NODES) ||
278 (flags & MPOL_F_RELATIVE_NODES)))
279 return ERR_PTR(-EINVAL);
281 } else if (mode == MPOL_LOCAL) {
282 if (!nodes_empty(*nodes))
283 return ERR_PTR(-EINVAL);
284 mode = MPOL_PREFERRED;
285 } else if (nodes_empty(*nodes))
286 return ERR_PTR(-EINVAL);
287 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
289 return ERR_PTR(-ENOMEM);
290 atomic_set(&policy->refcnt, 1);
292 policy->flags = flags;
297 /* Slow path of a mpol destructor. */
298 void __mpol_put(struct mempolicy *p)
300 if (!atomic_dec_and_test(&p->refcnt))
302 kmem_cache_free(policy_cache, p);
305 static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes,
306 enum mpol_rebind_step step)
312 * MPOL_REBIND_ONCE - do rebind work at once
313 * MPOL_REBIND_STEP1 - set all the newly nodes
314 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
316 static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes,
317 enum mpol_rebind_step step)
321 if (pol->flags & MPOL_F_STATIC_NODES)
322 nodes_and(tmp, pol->w.user_nodemask, *nodes);
323 else if (pol->flags & MPOL_F_RELATIVE_NODES)
324 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
327 * if step == 1, we use ->w.cpuset_mems_allowed to cache the
330 if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP1) {
331 nodes_remap(tmp, pol->v.nodes,
332 pol->w.cpuset_mems_allowed, *nodes);
333 pol->w.cpuset_mems_allowed = step ? tmp : *nodes;
334 } else if (step == MPOL_REBIND_STEP2) {
335 tmp = pol->w.cpuset_mems_allowed;
336 pol->w.cpuset_mems_allowed = *nodes;
341 if (nodes_empty(tmp))
344 if (step == MPOL_REBIND_STEP1)
345 nodes_or(pol->v.nodes, pol->v.nodes, tmp);
346 else if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP2)
351 if (!node_isset(current->il_next, tmp)) {
352 current->il_next = next_node(current->il_next, tmp);
353 if (current->il_next >= MAX_NUMNODES)
354 current->il_next = first_node(tmp);
355 if (current->il_next >= MAX_NUMNODES)
356 current->il_next = numa_node_id();
360 static void mpol_rebind_preferred(struct mempolicy *pol,
361 const nodemask_t *nodes,
362 enum mpol_rebind_step step)
366 if (pol->flags & MPOL_F_STATIC_NODES) {
367 int node = first_node(pol->w.user_nodemask);
369 if (node_isset(node, *nodes)) {
370 pol->v.preferred_node = node;
371 pol->flags &= ~MPOL_F_LOCAL;
373 pol->flags |= MPOL_F_LOCAL;
374 } else if (pol->flags & MPOL_F_RELATIVE_NODES) {
375 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
376 pol->v.preferred_node = first_node(tmp);
377 } else if (!(pol->flags & MPOL_F_LOCAL)) {
378 pol->v.preferred_node = node_remap(pol->v.preferred_node,
379 pol->w.cpuset_mems_allowed,
381 pol->w.cpuset_mems_allowed = *nodes;
386 * mpol_rebind_policy - Migrate a policy to a different set of nodes
388 * If read-side task has no lock to protect task->mempolicy, write-side
389 * task will rebind the task->mempolicy by two step. The first step is
390 * setting all the newly nodes, and the second step is cleaning all the
391 * disallowed nodes. In this way, we can avoid finding no node to alloc
393 * If we have a lock to protect task->mempolicy in read-side, we do
397 * MPOL_REBIND_ONCE - do rebind work at once
398 * MPOL_REBIND_STEP1 - set all the newly nodes
399 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
401 static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask,
402 enum mpol_rebind_step step)
406 if (!mpol_store_user_nodemask(pol) && step == MPOL_REBIND_ONCE &&
407 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
410 if (step == MPOL_REBIND_STEP1 && (pol->flags & MPOL_F_REBINDING))
413 if (step == MPOL_REBIND_STEP2 && !(pol->flags & MPOL_F_REBINDING))
416 if (step == MPOL_REBIND_STEP1)
417 pol->flags |= MPOL_F_REBINDING;
418 else if (step == MPOL_REBIND_STEP2)
419 pol->flags &= ~MPOL_F_REBINDING;
420 else if (step >= MPOL_REBIND_NSTEP)
423 mpol_ops[pol->mode].rebind(pol, newmask, step);
427 * Wrapper for mpol_rebind_policy() that just requires task
428 * pointer, and updates task mempolicy.
430 * Called with task's alloc_lock held.
433 void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new,
434 enum mpol_rebind_step step)
436 mpol_rebind_policy(tsk->mempolicy, new, step);
440 * Rebind each vma in mm to new nodemask.
442 * Call holding a reference to mm. Takes mm->mmap_sem during call.
445 void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
447 struct vm_area_struct *vma;
449 down_write(&mm->mmap_sem);
450 for (vma = mm->mmap; vma; vma = vma->vm_next)
451 mpol_rebind_policy(vma->vm_policy, new, MPOL_REBIND_ONCE);
452 up_write(&mm->mmap_sem);
455 static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
457 .rebind = mpol_rebind_default,
459 [MPOL_INTERLEAVE] = {
460 .create = mpol_new_interleave,
461 .rebind = mpol_rebind_nodemask,
464 .create = mpol_new_preferred,
465 .rebind = mpol_rebind_preferred,
468 .create = mpol_new_bind,
469 .rebind = mpol_rebind_nodemask,
473 static void migrate_page_add(struct page *page, struct list_head *pagelist,
474 unsigned long flags);
476 /* Scan through pages checking if pages follow certain conditions. */
477 static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
478 unsigned long addr, unsigned long end,
479 const nodemask_t *nodes, unsigned long flags,
486 orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
491 if (!pte_present(*pte))
493 page = vm_normal_page(vma, addr, *pte);
497 * vm_normal_page() filters out zero pages, but there might
498 * still be PageReserved pages to skip, perhaps in a VDSO.
500 if (PageReserved(page))
502 nid = page_to_nid(page);
503 if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
506 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
507 migrate_page_add(page, private, flags);
510 } while (pte++, addr += PAGE_SIZE, addr != end);
511 pte_unmap_unlock(orig_pte, ptl);
515 static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
516 unsigned long addr, unsigned long end,
517 const nodemask_t *nodes, unsigned long flags,
523 pmd = pmd_offset(pud, addr);
525 next = pmd_addr_end(addr, end);
526 split_huge_page_pmd(vma, addr, pmd);
527 if (pmd_none_or_trans_huge_or_clear_bad(pmd))
529 if (check_pte_range(vma, pmd, addr, next, nodes,
532 } while (pmd++, addr = next, addr != end);
536 static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
537 unsigned long addr, unsigned long end,
538 const nodemask_t *nodes, unsigned long flags,
544 pud = pud_offset(pgd, addr);
546 next = pud_addr_end(addr, end);
547 if (pud_none_or_clear_bad(pud))
549 if (check_pmd_range(vma, pud, addr, next, nodes,
552 } while (pud++, addr = next, addr != end);
556 static inline int check_pgd_range(struct vm_area_struct *vma,
557 unsigned long addr, unsigned long end,
558 const nodemask_t *nodes, unsigned long flags,
564 pgd = pgd_offset(vma->vm_mm, addr);
566 next = pgd_addr_end(addr, end);
567 if (pgd_none_or_clear_bad(pgd))
569 if (check_pud_range(vma, pgd, addr, next, nodes,
572 } while (pgd++, addr = next, addr != end);
576 #ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE
578 * This is used to mark a range of virtual addresses to be inaccessible.
579 * These are later cleared by a NUMA hinting fault. Depending on these
580 * faults, pages may be migrated for better NUMA placement.
582 * This is assuming that NUMA faults are handled using PROT_NONE. If
583 * an architecture makes a different choice, it will need further
584 * changes to the core.
586 unsigned long change_prot_numa(struct vm_area_struct *vma,
587 unsigned long addr, unsigned long end)
590 BUILD_BUG_ON(_PAGE_NUMA != _PAGE_PROTNONE);
592 nr_updated = change_protection(vma, addr, end, vma->vm_page_prot, 0, 1);
594 count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
599 static unsigned long change_prot_numa(struct vm_area_struct *vma,
600 unsigned long addr, unsigned long end)
604 #endif /* CONFIG_ARCH_USES_NUMA_PROT_NONE */
607 * Check if all pages in a range are on a set of nodes.
608 * If pagelist != NULL then isolate pages from the LRU and
609 * put them on the pagelist.
611 static struct vm_area_struct *
612 check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
613 const nodemask_t *nodes, unsigned long flags, void *private)
616 struct vm_area_struct *first, *vma, *prev;
619 first = find_vma(mm, start);
621 return ERR_PTR(-EFAULT);
623 for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
624 unsigned long endvma = vma->vm_end;
628 if (vma->vm_start > start)
629 start = vma->vm_start;
631 if (!(flags & MPOL_MF_DISCONTIG_OK)) {
632 if (!vma->vm_next && vma->vm_end < end)
633 return ERR_PTR(-EFAULT);
634 if (prev && prev->vm_end < vma->vm_start)
635 return ERR_PTR(-EFAULT);
638 if (is_vm_hugetlb_page(vma))
641 if (flags & MPOL_MF_LAZY) {
642 change_prot_numa(vma, start, endvma);
646 if ((flags & MPOL_MF_STRICT) ||
647 ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
648 vma_migratable(vma))) {
650 err = check_pgd_range(vma, start, endvma, nodes,
653 first = ERR_PTR(err);
664 * Apply policy to a single VMA
665 * This must be called with the mmap_sem held for writing.
667 static int vma_replace_policy(struct vm_area_struct *vma,
668 struct mempolicy *pol)
671 struct mempolicy *old;
672 struct mempolicy *new;
674 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
675 vma->vm_start, vma->vm_end, vma->vm_pgoff,
676 vma->vm_ops, vma->vm_file,
677 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
683 if (vma->vm_ops && vma->vm_ops->set_policy) {
684 err = vma->vm_ops->set_policy(vma, new);
689 old = vma->vm_policy;
690 vma->vm_policy = new; /* protected by mmap_sem */
699 /* Step 2: apply policy to a range and do splits. */
700 static int mbind_range(struct mm_struct *mm, unsigned long start,
701 unsigned long end, struct mempolicy *new_pol)
703 struct vm_area_struct *next;
704 struct vm_area_struct *prev;
705 struct vm_area_struct *vma;
708 unsigned long vmstart;
711 vma = find_vma(mm, start);
712 if (!vma || vma->vm_start > start)
716 if (start > vma->vm_start)
719 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
721 vmstart = max(start, vma->vm_start);
722 vmend = min(end, vma->vm_end);
724 if (mpol_equal(vma_policy(vma), new_pol))
727 pgoff = vma->vm_pgoff +
728 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
729 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
730 vma->anon_vma, vma->vm_file, pgoff,
735 if (mpol_equal(vma_policy(vma), new_pol))
737 /* vma_merge() joined vma && vma->next, case 8 */
740 if (vma->vm_start != vmstart) {
741 err = split_vma(vma->vm_mm, vma, vmstart, 1);
745 if (vma->vm_end != vmend) {
746 err = split_vma(vma->vm_mm, vma, vmend, 0);
751 err = vma_replace_policy(vma, new_pol);
761 * Update task->flags PF_MEMPOLICY bit: set iff non-default
762 * mempolicy. Allows more rapid checking of this (combined perhaps
763 * with other PF_* flag bits) on memory allocation hot code paths.
765 * If called from outside this file, the task 'p' should -only- be
766 * a newly forked child not yet visible on the task list, because
767 * manipulating the task flags of a visible task is not safe.
769 * The above limitation is why this routine has the funny name
770 * mpol_fix_fork_child_flag().
772 * It is also safe to call this with a task pointer of current,
773 * which the static wrapper mpol_set_task_struct_flag() does,
774 * for use within this file.
777 void mpol_fix_fork_child_flag(struct task_struct *p)
780 p->flags |= PF_MEMPOLICY;
782 p->flags &= ~PF_MEMPOLICY;
785 static void mpol_set_task_struct_flag(void)
787 mpol_fix_fork_child_flag(current);
790 /* Set the process memory policy */
791 static long do_set_mempolicy(unsigned short mode, unsigned short flags,
794 struct mempolicy *new, *old;
795 struct mm_struct *mm = current->mm;
796 NODEMASK_SCRATCH(scratch);
802 new = mpol_new(mode, flags, nodes);
808 * prevent changing our mempolicy while show_numa_maps()
810 * Note: do_set_mempolicy() can be called at init time
814 down_write(&mm->mmap_sem);
816 ret = mpol_set_nodemask(new, nodes, scratch);
818 task_unlock(current);
820 up_write(&mm->mmap_sem);
824 old = current->mempolicy;
825 current->mempolicy = new;
826 mpol_set_task_struct_flag();
827 if (new && new->mode == MPOL_INTERLEAVE &&
828 nodes_weight(new->v.nodes))
829 current->il_next = first_node(new->v.nodes);
830 task_unlock(current);
832 up_write(&mm->mmap_sem);
837 NODEMASK_SCRATCH_FREE(scratch);
842 * Return nodemask for policy for get_mempolicy() query
844 * Called with task's alloc_lock held
846 static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
849 if (p == &default_policy)
855 case MPOL_INTERLEAVE:
859 if (!(p->flags & MPOL_F_LOCAL))
860 node_set(p->v.preferred_node, *nodes);
861 /* else return empty node mask for local allocation */
868 static int lookup_node(struct mm_struct *mm, unsigned long addr)
873 err = get_user_pages(current, mm, addr & PAGE_MASK, 1, 0, 0, &p, NULL);
875 err = page_to_nid(p);
881 /* Retrieve NUMA policy */
882 static long do_get_mempolicy(int *policy, nodemask_t *nmask,
883 unsigned long addr, unsigned long flags)
886 struct mm_struct *mm = current->mm;
887 struct vm_area_struct *vma = NULL;
888 struct mempolicy *pol = current->mempolicy;
891 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
894 if (flags & MPOL_F_MEMS_ALLOWED) {
895 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
897 *policy = 0; /* just so it's initialized */
899 *nmask = cpuset_current_mems_allowed;
900 task_unlock(current);
904 if (flags & MPOL_F_ADDR) {
906 * Do NOT fall back to task policy if the
907 * vma/shared policy at addr is NULL. We
908 * want to return MPOL_DEFAULT in this case.
910 down_read(&mm->mmap_sem);
911 vma = find_vma_intersection(mm, addr, addr+1);
913 up_read(&mm->mmap_sem);
916 if (vma->vm_ops && vma->vm_ops->get_policy)
917 pol = vma->vm_ops->get_policy(vma, addr);
919 pol = vma->vm_policy;
924 pol = &default_policy; /* indicates default behavior */
926 if (flags & MPOL_F_NODE) {
927 if (flags & MPOL_F_ADDR) {
928 err = lookup_node(mm, addr);
932 } else if (pol == current->mempolicy &&
933 pol->mode == MPOL_INTERLEAVE) {
934 *policy = current->il_next;
940 *policy = pol == &default_policy ? MPOL_DEFAULT :
943 * Internal mempolicy flags must be masked off before exposing
944 * the policy to userspace.
946 *policy |= (pol->flags & MPOL_MODE_FLAGS);
950 up_read(¤t->mm->mmap_sem);
956 if (mpol_store_user_nodemask(pol)) {
957 *nmask = pol->w.user_nodemask;
960 get_policy_nodemask(pol, nmask);
961 task_unlock(current);
968 up_read(¤t->mm->mmap_sem);
972 #ifdef CONFIG_MIGRATION
976 static void migrate_page_add(struct page *page, struct list_head *pagelist,
980 * Avoid migrating a page that is shared with others.
982 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
983 if (!isolate_lru_page(page)) {
984 list_add_tail(&page->lru, pagelist);
985 inc_zone_page_state(page, NR_ISOLATED_ANON +
986 page_is_file_cache(page));
991 static struct page *new_node_page(struct page *page, unsigned long node, int **x)
993 return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
997 * Migrate pages from one node to a target node.
998 * Returns error or the number of pages not migrated.
1000 static int migrate_to_node(struct mm_struct *mm, int source, int dest,
1004 LIST_HEAD(pagelist);
1008 node_set(source, nmask);
1011 * This does not "check" the range but isolates all pages that
1012 * need migration. Between passing in the full user address
1013 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
1015 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
1016 check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1017 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
1019 if (!list_empty(&pagelist)) {
1020 err = migrate_pages(&pagelist, new_node_page, dest,
1021 MIGRATE_SYNC, MR_SYSCALL);
1023 putback_lru_pages(&pagelist);
1030 * Move pages between the two nodesets so as to preserve the physical
1031 * layout as much as possible.
1033 * Returns the number of page that could not be moved.
1035 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1036 const nodemask_t *to, int flags)
1042 err = migrate_prep();
1046 down_read(&mm->mmap_sem);
1048 err = migrate_vmas(mm, from, to, flags);
1053 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
1054 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
1055 * bit in 'tmp', and return that <source, dest> pair for migration.
1056 * The pair of nodemasks 'to' and 'from' define the map.
1058 * If no pair of bits is found that way, fallback to picking some
1059 * pair of 'source' and 'dest' bits that are not the same. If the
1060 * 'source' and 'dest' bits are the same, this represents a node
1061 * that will be migrating to itself, so no pages need move.
1063 * If no bits are left in 'tmp', or if all remaining bits left
1064 * in 'tmp' correspond to the same bit in 'to', return false
1065 * (nothing left to migrate).
1067 * This lets us pick a pair of nodes to migrate between, such that
1068 * if possible the dest node is not already occupied by some other
1069 * source node, minimizing the risk of overloading the memory on a
1070 * node that would happen if we migrated incoming memory to a node
1071 * before migrating outgoing memory source that same node.
1073 * A single scan of tmp is sufficient. As we go, we remember the
1074 * most recent <s, d> pair that moved (s != d). If we find a pair
1075 * that not only moved, but what's better, moved to an empty slot
1076 * (d is not set in tmp), then we break out then, with that pair.
1077 * Otherwise when we finish scanning from_tmp, we at least have the
1078 * most recent <s, d> pair that moved. If we get all the way through
1079 * the scan of tmp without finding any node that moved, much less
1080 * moved to an empty node, then there is nothing left worth migrating.
1084 while (!nodes_empty(tmp)) {
1089 for_each_node_mask(s, tmp) {
1092 * do_migrate_pages() tries to maintain the relative
1093 * node relationship of the pages established between
1094 * threads and memory areas.
1096 * However if the number of source nodes is not equal to
1097 * the number of destination nodes we can not preserve
1098 * this node relative relationship. In that case, skip
1099 * copying memory from a node that is in the destination
1102 * Example: [2,3,4] -> [3,4,5] moves everything.
1103 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1106 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1107 (node_isset(s, *to)))
1110 d = node_remap(s, *from, *to);
1114 source = s; /* Node moved. Memorize */
1117 /* dest not in remaining from nodes? */
1118 if (!node_isset(dest, tmp))
1124 node_clear(source, tmp);
1125 err = migrate_to_node(mm, source, dest, flags);
1132 up_read(&mm->mmap_sem);
1140 * Allocate a new page for page migration based on vma policy.
1141 * Start assuming that page is mapped by vma pointed to by @private.
1142 * Search forward from there, if not. N.B., this assumes that the
1143 * list of pages handed to migrate_pages()--which is how we get here--
1144 * is in virtual address order.
1146 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1148 struct vm_area_struct *vma = (struct vm_area_struct *)private;
1149 unsigned long uninitialized_var(address);
1152 address = page_address_in_vma(page, vma);
1153 if (address != -EFAULT)
1159 * if !vma, alloc_page_vma() will use task or system default policy
1161 return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1165 static void migrate_page_add(struct page *page, struct list_head *pagelist,
1166 unsigned long flags)
1170 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1171 const nodemask_t *to, int flags)
1176 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1182 static long do_mbind(unsigned long start, unsigned long len,
1183 unsigned short mode, unsigned short mode_flags,
1184 nodemask_t *nmask, unsigned long flags)
1186 struct vm_area_struct *vma;
1187 struct mm_struct *mm = current->mm;
1188 struct mempolicy *new;
1191 LIST_HEAD(pagelist);
1193 if (flags & ~(unsigned long)MPOL_MF_VALID)
1195 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1198 if (start & ~PAGE_MASK)
1201 if (mode == MPOL_DEFAULT)
1202 flags &= ~MPOL_MF_STRICT;
1204 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1212 new = mpol_new(mode, mode_flags, nmask);
1214 return PTR_ERR(new);
1216 if (flags & MPOL_MF_LAZY)
1217 new->flags |= MPOL_F_MOF;
1220 * If we are using the default policy then operation
1221 * on discontinuous address spaces is okay after all
1224 flags |= MPOL_MF_DISCONTIG_OK;
1226 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1227 start, start + len, mode, mode_flags,
1228 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1230 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1232 err = migrate_prep();
1237 NODEMASK_SCRATCH(scratch);
1239 down_write(&mm->mmap_sem);
1241 err = mpol_set_nodemask(new, nmask, scratch);
1242 task_unlock(current);
1244 up_write(&mm->mmap_sem);
1247 NODEMASK_SCRATCH_FREE(scratch);
1252 vma = check_range(mm, start, end, nmask,
1253 flags | MPOL_MF_INVERT, &pagelist);
1255 err = PTR_ERR(vma); /* maybe ... */
1257 err = mbind_range(mm, start, end, new);
1262 if (!list_empty(&pagelist)) {
1263 WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1264 nr_failed = migrate_pages(&pagelist, new_vma_page,
1266 MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
1268 putback_lru_pages(&pagelist);
1271 if (nr_failed && (flags & MPOL_MF_STRICT))
1274 putback_lru_pages(&pagelist);
1276 up_write(&mm->mmap_sem);
1283 * User space interface with variable sized bitmaps for nodelists.
1286 /* Copy a node mask from user space. */
1287 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1288 unsigned long maxnode)
1291 unsigned long nlongs;
1292 unsigned long endmask;
1295 nodes_clear(*nodes);
1296 if (maxnode == 0 || !nmask)
1298 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1301 nlongs = BITS_TO_LONGS(maxnode);
1302 if ((maxnode % BITS_PER_LONG) == 0)
1305 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1307 /* When the user specified more nodes than supported just check
1308 if the non supported part is all zero. */
1309 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1310 if (nlongs > PAGE_SIZE/sizeof(long))
1312 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1314 if (get_user(t, nmask + k))
1316 if (k == nlongs - 1) {
1322 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1326 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1328 nodes_addr(*nodes)[nlongs-1] &= endmask;
1332 /* Copy a kernel node mask to user space */
1333 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1336 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1337 const int nbytes = BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long);
1339 if (copy > nbytes) {
1340 if (copy > PAGE_SIZE)
1342 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1346 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1349 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1350 unsigned long, mode, unsigned long __user *, nmask,
1351 unsigned long, maxnode, unsigned, flags)
1355 unsigned short mode_flags;
1357 mode_flags = mode & MPOL_MODE_FLAGS;
1358 mode &= ~MPOL_MODE_FLAGS;
1359 if (mode >= MPOL_MAX)
1361 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1362 (mode_flags & MPOL_F_RELATIVE_NODES))
1364 err = get_nodes(&nodes, nmask, maxnode);
1367 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1370 /* Set the process memory policy */
1371 SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
1372 unsigned long, maxnode)
1376 unsigned short flags;
1378 flags = mode & MPOL_MODE_FLAGS;
1379 mode &= ~MPOL_MODE_FLAGS;
1380 if ((unsigned int)mode >= MPOL_MAX)
1382 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1384 err = get_nodes(&nodes, nmask, maxnode);
1387 return do_set_mempolicy(mode, flags, &nodes);
1390 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1391 const unsigned long __user *, old_nodes,
1392 const unsigned long __user *, new_nodes)
1394 const struct cred *cred = current_cred(), *tcred;
1395 struct mm_struct *mm = NULL;
1396 struct task_struct *task;
1397 nodemask_t task_nodes;
1401 NODEMASK_SCRATCH(scratch);
1406 old = &scratch->mask1;
1407 new = &scratch->mask2;
1409 err = get_nodes(old, old_nodes, maxnode);
1413 err = get_nodes(new, new_nodes, maxnode);
1417 /* Find the mm_struct */
1419 task = pid ? find_task_by_vpid(pid) : current;
1425 get_task_struct(task);
1430 * Check if this process has the right to modify the specified
1431 * process. The right exists if the process has administrative
1432 * capabilities, superuser privileges or the same
1433 * userid as the target process.
1435 tcred = __task_cred(task);
1436 if (!uid_eq(cred->euid, tcred->suid) && !uid_eq(cred->euid, tcred->uid) &&
1437 !uid_eq(cred->uid, tcred->suid) && !uid_eq(cred->uid, tcred->uid) &&
1438 !capable(CAP_SYS_NICE)) {
1445 task_nodes = cpuset_mems_allowed(task);
1446 /* Is the user allowed to access the target nodes? */
1447 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1452 if (!nodes_subset(*new, node_states[N_MEMORY])) {
1457 err = security_task_movememory(task);
1461 mm = get_task_mm(task);
1462 put_task_struct(task);
1469 err = do_migrate_pages(mm, old, new,
1470 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1474 NODEMASK_SCRATCH_FREE(scratch);
1479 put_task_struct(task);
1485 /* Retrieve NUMA policy */
1486 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1487 unsigned long __user *, nmask, unsigned long, maxnode,
1488 unsigned long, addr, unsigned long, flags)
1491 int uninitialized_var(pval);
1494 if (nmask != NULL && maxnode < MAX_NUMNODES)
1497 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1502 if (policy && put_user(pval, policy))
1506 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1511 #ifdef CONFIG_COMPAT
1513 asmlinkage long compat_sys_get_mempolicy(int __user *policy,
1514 compat_ulong_t __user *nmask,
1515 compat_ulong_t maxnode,
1516 compat_ulong_t addr, compat_ulong_t flags)
1519 unsigned long __user *nm = NULL;
1520 unsigned long nr_bits, alloc_size;
1521 DECLARE_BITMAP(bm, MAX_NUMNODES);
1523 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1524 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1527 nm = compat_alloc_user_space(alloc_size);
1529 err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1531 if (!err && nmask) {
1532 unsigned long copy_size;
1533 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1534 err = copy_from_user(bm, nm, copy_size);
1535 /* ensure entire bitmap is zeroed */
1536 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1537 err |= compat_put_bitmap(nmask, bm, nr_bits);
1543 asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
1544 compat_ulong_t maxnode)
1547 unsigned long __user *nm = NULL;
1548 unsigned long nr_bits, alloc_size;
1549 DECLARE_BITMAP(bm, MAX_NUMNODES);
1551 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1552 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1555 err = compat_get_bitmap(bm, nmask, nr_bits);
1556 nm = compat_alloc_user_space(alloc_size);
1557 err |= copy_to_user(nm, bm, alloc_size);
1563 return sys_set_mempolicy(mode, nm, nr_bits+1);
1566 asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
1567 compat_ulong_t mode, compat_ulong_t __user *nmask,
1568 compat_ulong_t maxnode, compat_ulong_t flags)
1571 unsigned long __user *nm = NULL;
1572 unsigned long nr_bits, alloc_size;
1575 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1576 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1579 err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
1580 nm = compat_alloc_user_space(alloc_size);
1581 err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
1587 return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
1593 * get_vma_policy(@task, @vma, @addr)
1594 * @task - task for fallback if vma policy == default
1595 * @vma - virtual memory area whose policy is sought
1596 * @addr - address in @vma for shared policy lookup
1598 * Returns effective policy for a VMA at specified address.
1599 * Falls back to @task or system default policy, as necessary.
1600 * Current or other task's task mempolicy and non-shared vma policies must be
1601 * protected by task_lock(task) by the caller.
1602 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1603 * count--added by the get_policy() vm_op, as appropriate--to protect against
1604 * freeing by another task. It is the caller's responsibility to free the
1605 * extra reference for shared policies.
1607 struct mempolicy *get_vma_policy(struct task_struct *task,
1608 struct vm_area_struct *vma, unsigned long addr)
1610 struct mempolicy *pol = get_task_policy(task);
1613 if (vma->vm_ops && vma->vm_ops->get_policy) {
1614 struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
1618 } else if (vma->vm_policy) {
1619 pol = vma->vm_policy;
1622 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1623 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1624 * count on these policies which will be dropped by
1625 * mpol_cond_put() later
1627 if (mpol_needs_cond_ref(pol))
1632 pol = &default_policy;
1636 static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
1638 enum zone_type dynamic_policy_zone = policy_zone;
1640 BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
1643 * if policy->v.nodes has movable memory only,
1644 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
1646 * policy->v.nodes is intersect with node_states[N_MEMORY].
1647 * so if the following test faile, it implies
1648 * policy->v.nodes has movable memory only.
1650 if (!nodes_intersects(policy->v.nodes, node_states[N_HIGH_MEMORY]))
1651 dynamic_policy_zone = ZONE_MOVABLE;
1653 return zone >= dynamic_policy_zone;
1657 * Return a nodemask representing a mempolicy for filtering nodes for
1660 static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1662 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1663 if (unlikely(policy->mode == MPOL_BIND) &&
1664 apply_policy_zone(policy, gfp_zone(gfp)) &&
1665 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1666 return &policy->v.nodes;
1671 /* Return a zonelist indicated by gfp for node representing a mempolicy */
1672 static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
1675 switch (policy->mode) {
1676 case MPOL_PREFERRED:
1677 if (!(policy->flags & MPOL_F_LOCAL))
1678 nd = policy->v.preferred_node;
1682 * Normally, MPOL_BIND allocations are node-local within the
1683 * allowed nodemask. However, if __GFP_THISNODE is set and the
1684 * current node isn't part of the mask, we use the zonelist for
1685 * the first node in the mask instead.
1687 if (unlikely(gfp & __GFP_THISNODE) &&
1688 unlikely(!node_isset(nd, policy->v.nodes)))
1689 nd = first_node(policy->v.nodes);
1694 return node_zonelist(nd, gfp);
1697 /* Do dynamic interleaving for a process */
1698 static unsigned interleave_nodes(struct mempolicy *policy)
1701 struct task_struct *me = current;
1704 next = next_node(nid, policy->v.nodes);
1705 if (next >= MAX_NUMNODES)
1706 next = first_node(policy->v.nodes);
1707 if (next < MAX_NUMNODES)
1713 * Depending on the memory policy provide a node from which to allocate the
1715 * @policy must be protected by freeing by the caller. If @policy is
1716 * the current task's mempolicy, this protection is implicit, as only the
1717 * task can change it's policy. The system default policy requires no
1720 unsigned slab_node(void)
1722 struct mempolicy *policy;
1725 return numa_node_id();
1727 policy = current->mempolicy;
1728 if (!policy || policy->flags & MPOL_F_LOCAL)
1729 return numa_node_id();
1731 switch (policy->mode) {
1732 case MPOL_PREFERRED:
1734 * handled MPOL_F_LOCAL above
1736 return policy->v.preferred_node;
1738 case MPOL_INTERLEAVE:
1739 return interleave_nodes(policy);
1743 * Follow bind policy behavior and start allocation at the
1746 struct zonelist *zonelist;
1748 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1749 zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
1750 (void)first_zones_zonelist(zonelist, highest_zoneidx,
1753 return zone ? zone->node : numa_node_id();
1761 /* Do static interleaving for a VMA with known offset. */
1762 static unsigned offset_il_node(struct mempolicy *pol,
1763 struct vm_area_struct *vma, unsigned long off)
1765 unsigned nnodes = nodes_weight(pol->v.nodes);
1771 return numa_node_id();
1772 target = (unsigned int)off % nnodes;
1775 nid = next_node(nid, pol->v.nodes);
1777 } while (c <= target);
1781 /* Determine a node number for interleave */
1782 static inline unsigned interleave_nid(struct mempolicy *pol,
1783 struct vm_area_struct *vma, unsigned long addr, int shift)
1789 * for small pages, there is no difference between
1790 * shift and PAGE_SHIFT, so the bit-shift is safe.
1791 * for huge pages, since vm_pgoff is in units of small
1792 * pages, we need to shift off the always 0 bits to get
1795 BUG_ON(shift < PAGE_SHIFT);
1796 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1797 off += (addr - vma->vm_start) >> shift;
1798 return offset_il_node(pol, vma, off);
1800 return interleave_nodes(pol);
1804 * Return the bit number of a random bit set in the nodemask.
1805 * (returns -1 if nodemask is empty)
1807 int node_random(const nodemask_t *maskp)
1811 w = nodes_weight(*maskp);
1813 bit = bitmap_ord_to_pos(maskp->bits,
1814 get_random_int() % w, MAX_NUMNODES);
1818 #ifdef CONFIG_HUGETLBFS
1820 * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
1821 * @vma = virtual memory area whose policy is sought
1822 * @addr = address in @vma for shared policy lookup and interleave policy
1823 * @gfp_flags = for requested zone
1824 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
1825 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1827 * Returns a zonelist suitable for a huge page allocation and a pointer
1828 * to the struct mempolicy for conditional unref after allocation.
1829 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1830 * @nodemask for filtering the zonelist.
1832 * Must be protected by get_mems_allowed()
1834 struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1835 gfp_t gfp_flags, struct mempolicy **mpol,
1836 nodemask_t **nodemask)
1838 struct zonelist *zl;
1840 *mpol = get_vma_policy(current, vma, addr);
1841 *nodemask = NULL; /* assume !MPOL_BIND */
1843 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1844 zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1845 huge_page_shift(hstate_vma(vma))), gfp_flags);
1847 zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1848 if ((*mpol)->mode == MPOL_BIND)
1849 *nodemask = &(*mpol)->v.nodes;
1855 * init_nodemask_of_mempolicy
1857 * If the current task's mempolicy is "default" [NULL], return 'false'
1858 * to indicate default policy. Otherwise, extract the policy nodemask
1859 * for 'bind' or 'interleave' policy into the argument nodemask, or
1860 * initialize the argument nodemask to contain the single node for
1861 * 'preferred' or 'local' policy and return 'true' to indicate presence
1862 * of non-default mempolicy.
1864 * We don't bother with reference counting the mempolicy [mpol_get/put]
1865 * because the current task is examining it's own mempolicy and a task's
1866 * mempolicy is only ever changed by the task itself.
1868 * N.B., it is the caller's responsibility to free a returned nodemask.
1870 bool init_nodemask_of_mempolicy(nodemask_t *mask)
1872 struct mempolicy *mempolicy;
1875 if (!(mask && current->mempolicy))
1879 mempolicy = current->mempolicy;
1880 switch (mempolicy->mode) {
1881 case MPOL_PREFERRED:
1882 if (mempolicy->flags & MPOL_F_LOCAL)
1883 nid = numa_node_id();
1885 nid = mempolicy->v.preferred_node;
1886 init_nodemask_of_node(mask, nid);
1891 case MPOL_INTERLEAVE:
1892 *mask = mempolicy->v.nodes;
1898 task_unlock(current);
1905 * mempolicy_nodemask_intersects
1907 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
1908 * policy. Otherwise, check for intersection between mask and the policy
1909 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
1910 * policy, always return true since it may allocate elsewhere on fallback.
1912 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
1914 bool mempolicy_nodemask_intersects(struct task_struct *tsk,
1915 const nodemask_t *mask)
1917 struct mempolicy *mempolicy;
1923 mempolicy = tsk->mempolicy;
1927 switch (mempolicy->mode) {
1928 case MPOL_PREFERRED:
1930 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
1931 * allocate from, they may fallback to other nodes when oom.
1932 * Thus, it's possible for tsk to have allocated memory from
1937 case MPOL_INTERLEAVE:
1938 ret = nodes_intersects(mempolicy->v.nodes, *mask);
1948 /* Allocate a page in interleaved policy.
1949 Own path because it needs to do special accounting. */
1950 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
1953 struct zonelist *zl;
1956 zl = node_zonelist(nid, gfp);
1957 page = __alloc_pages(gfp, order, zl);
1958 if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1959 inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
1964 * alloc_pages_vma - Allocate a page for a VMA.
1967 * %GFP_USER user allocation.
1968 * %GFP_KERNEL kernel allocations,
1969 * %GFP_HIGHMEM highmem/user allocations,
1970 * %GFP_FS allocation should not call back into a file system.
1971 * %GFP_ATOMIC don't sleep.
1973 * @order:Order of the GFP allocation.
1974 * @vma: Pointer to VMA or NULL if not available.
1975 * @addr: Virtual Address of the allocation. Must be inside the VMA.
1977 * This function allocates a page from the kernel page pool and applies
1978 * a NUMA policy associated with the VMA or the current process.
1979 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
1980 * mm_struct of the VMA to prevent it from going away. Should be used for
1981 * all allocations for pages that will be mapped into
1982 * user space. Returns NULL when no page can be allocated.
1984 * Should be called with the mm_sem of the vma hold.
1987 alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
1988 unsigned long addr, int node)
1990 struct mempolicy *pol;
1992 unsigned int cpuset_mems_cookie;
1995 pol = get_vma_policy(current, vma, addr);
1996 cpuset_mems_cookie = get_mems_allowed();
1998 if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
2001 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2003 page = alloc_page_interleave(gfp, order, nid);
2004 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2009 page = __alloc_pages_nodemask(gfp, order,
2010 policy_zonelist(gfp, pol, node),
2011 policy_nodemask(gfp, pol));
2012 if (unlikely(mpol_needs_cond_ref(pol)))
2014 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2020 * alloc_pages_current - Allocate pages.
2023 * %GFP_USER user allocation,
2024 * %GFP_KERNEL kernel allocation,
2025 * %GFP_HIGHMEM highmem allocation,
2026 * %GFP_FS don't call back into a file system.
2027 * %GFP_ATOMIC don't sleep.
2028 * @order: Power of two of allocation size in pages. 0 is a single page.
2030 * Allocate a page from the kernel page pool. When not in
2031 * interrupt context and apply the current process NUMA policy.
2032 * Returns NULL when no page can be allocated.
2034 * Don't call cpuset_update_task_memory_state() unless
2035 * 1) it's ok to take cpuset_sem (can WAIT), and
2036 * 2) allocating for current task (not interrupt).
2038 struct page *alloc_pages_current(gfp_t gfp, unsigned order)
2040 struct mempolicy *pol = get_task_policy(current);
2042 unsigned int cpuset_mems_cookie;
2044 if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
2045 pol = &default_policy;
2048 cpuset_mems_cookie = get_mems_allowed();
2051 * No reference counting needed for current->mempolicy
2052 * nor system default_policy
2054 if (pol->mode == MPOL_INTERLEAVE)
2055 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
2057 page = __alloc_pages_nodemask(gfp, order,
2058 policy_zonelist(gfp, pol, numa_node_id()),
2059 policy_nodemask(gfp, pol));
2061 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2066 EXPORT_SYMBOL(alloc_pages_current);
2068 int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
2070 struct mempolicy *pol = mpol_dup(vma_policy(src));
2073 return PTR_ERR(pol);
2074 dst->vm_policy = pol;
2079 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2080 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2081 * with the mems_allowed returned by cpuset_mems_allowed(). This
2082 * keeps mempolicies cpuset relative after its cpuset moves. See
2083 * further kernel/cpuset.c update_nodemask().
2085 * current's mempolicy may be rebinded by the other task(the task that changes
2086 * cpuset's mems), so we needn't do rebind work for current task.
2089 /* Slow path of a mempolicy duplicate */
2090 struct mempolicy *__mpol_dup(struct mempolicy *old)
2092 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2095 return ERR_PTR(-ENOMEM);
2097 /* task's mempolicy is protected by alloc_lock */
2098 if (old == current->mempolicy) {
2101 task_unlock(current);
2106 if (current_cpuset_is_being_rebound()) {
2107 nodemask_t mems = cpuset_mems_allowed(current);
2108 if (new->flags & MPOL_F_REBINDING)
2109 mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
2111 mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
2114 atomic_set(&new->refcnt, 1);
2118 /* Slow path of a mempolicy comparison */
2119 bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2123 if (a->mode != b->mode)
2125 if (a->flags != b->flags)
2127 if (mpol_store_user_nodemask(a))
2128 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2134 case MPOL_INTERLEAVE:
2135 return !!nodes_equal(a->v.nodes, b->v.nodes);
2136 case MPOL_PREFERRED:
2137 return a->v.preferred_node == b->v.preferred_node;
2145 * Shared memory backing store policy support.
2147 * Remember policies even when nobody has shared memory mapped.
2148 * The policies are kept in Red-Black tree linked from the inode.
2149 * They are protected by the sp->lock spinlock, which should be held
2150 * for any accesses to the tree.
2153 /* lookup first element intersecting start-end */
2154 /* Caller holds sp->lock */
2155 static struct sp_node *
2156 sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2158 struct rb_node *n = sp->root.rb_node;
2161 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2163 if (start >= p->end)
2165 else if (end <= p->start)
2173 struct sp_node *w = NULL;
2174 struct rb_node *prev = rb_prev(n);
2177 w = rb_entry(prev, struct sp_node, nd);
2178 if (w->end <= start)
2182 return rb_entry(n, struct sp_node, nd);
2185 /* Insert a new shared policy into the list. */
2186 /* Caller holds sp->lock */
2187 static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2189 struct rb_node **p = &sp->root.rb_node;
2190 struct rb_node *parent = NULL;
2195 nd = rb_entry(parent, struct sp_node, nd);
2196 if (new->start < nd->start)
2198 else if (new->end > nd->end)
2199 p = &(*p)->rb_right;
2203 rb_link_node(&new->nd, parent, p);
2204 rb_insert_color(&new->nd, &sp->root);
2205 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2206 new->policy ? new->policy->mode : 0);
2209 /* Find shared policy intersecting idx */
2211 mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2213 struct mempolicy *pol = NULL;
2216 if (!sp->root.rb_node)
2218 spin_lock(&sp->lock);
2219 sn = sp_lookup(sp, idx, idx+1);
2221 mpol_get(sn->policy);
2224 spin_unlock(&sp->lock);
2228 static void sp_free(struct sp_node *n)
2230 mpol_put(n->policy);
2231 kmem_cache_free(sn_cache, n);
2235 * mpol_misplaced - check whether current page node is valid in policy
2237 * @page - page to be checked
2238 * @vma - vm area where page mapped
2239 * @addr - virtual address where page mapped
2241 * Lookup current policy node id for vma,addr and "compare to" page's
2245 * -1 - not misplaced, page is in the right node
2246 * node - node id where the page should be
2248 * Policy determination "mimics" alloc_page_vma().
2249 * Called from fault path where we know the vma and faulting address.
2251 int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
2253 struct mempolicy *pol;
2255 int curnid = page_to_nid(page);
2256 unsigned long pgoff;
2262 pol = get_vma_policy(current, vma, addr);
2263 if (!(pol->flags & MPOL_F_MOF))
2266 switch (pol->mode) {
2267 case MPOL_INTERLEAVE:
2268 BUG_ON(addr >= vma->vm_end);
2269 BUG_ON(addr < vma->vm_start);
2271 pgoff = vma->vm_pgoff;
2272 pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
2273 polnid = offset_il_node(pol, vma, pgoff);
2276 case MPOL_PREFERRED:
2277 if (pol->flags & MPOL_F_LOCAL)
2278 polnid = numa_node_id();
2280 polnid = pol->v.preferred_node;
2285 * allows binding to multiple nodes.
2286 * use current page if in policy nodemask,
2287 * else select nearest allowed node, if any.
2288 * If no allowed nodes, use current [!misplaced].
2290 if (node_isset(curnid, pol->v.nodes))
2292 (void)first_zones_zonelist(
2293 node_zonelist(numa_node_id(), GFP_HIGHUSER),
2294 gfp_zone(GFP_HIGHUSER),
2295 &pol->v.nodes, &zone);
2296 polnid = zone->node;
2303 /* Migrate the page towards the node whose CPU is referencing it */
2304 if (pol->flags & MPOL_F_MORON) {
2307 polnid = numa_node_id();
2310 * Multi-stage node selection is used in conjunction
2311 * with a periodic migration fault to build a temporal
2312 * task<->page relation. By using a two-stage filter we
2313 * remove short/unlikely relations.
2315 * Using P(p) ~ n_p / n_t as per frequentist
2316 * probability, we can equate a task's usage of a
2317 * particular page (n_p) per total usage of this
2318 * page (n_t) (in a given time-span) to a probability.
2320 * Our periodic faults will sample this probability and
2321 * getting the same result twice in a row, given these
2322 * samples are fully independent, is then given by
2323 * P(n)^2, provided our sample period is sufficiently
2324 * short compared to the usage pattern.
2326 * This quadric squishes small probabilities, making
2327 * it less likely we act on an unlikely task<->page
2330 last_nid = page_nid_xchg_last(page, polnid);
2331 if (last_nid != polnid)
2335 if (curnid != polnid)
2343 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2345 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2346 rb_erase(&n->nd, &sp->root);
2350 static void sp_node_init(struct sp_node *node, unsigned long start,
2351 unsigned long end, struct mempolicy *pol)
2353 node->start = start;
2358 static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2359 struct mempolicy *pol)
2362 struct mempolicy *newpol;
2364 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2368 newpol = mpol_dup(pol);
2369 if (IS_ERR(newpol)) {
2370 kmem_cache_free(sn_cache, n);
2373 newpol->flags |= MPOL_F_SHARED;
2374 sp_node_init(n, start, end, newpol);
2379 /* Replace a policy range. */
2380 static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2381 unsigned long end, struct sp_node *new)
2384 struct sp_node *n_new = NULL;
2385 struct mempolicy *mpol_new = NULL;
2389 spin_lock(&sp->lock);
2390 n = sp_lookup(sp, start, end);
2391 /* Take care of old policies in the same range. */
2392 while (n && n->start < end) {
2393 struct rb_node *next = rb_next(&n->nd);
2394 if (n->start >= start) {
2400 /* Old policy spanning whole new range. */
2405 *mpol_new = *n->policy;
2406 atomic_set(&mpol_new->refcnt, 1);
2407 sp_node_init(n_new, end, n->end, mpol_new);
2409 sp_insert(sp, n_new);
2418 n = rb_entry(next, struct sp_node, nd);
2422 spin_unlock(&sp->lock);
2429 kmem_cache_free(sn_cache, n_new);
2434 spin_unlock(&sp->lock);
2436 n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2439 mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2446 * mpol_shared_policy_init - initialize shared policy for inode
2447 * @sp: pointer to inode shared policy
2448 * @mpol: struct mempolicy to install
2450 * Install non-NULL @mpol in inode's shared policy rb-tree.
2451 * On entry, the current task has a reference on a non-NULL @mpol.
2452 * This must be released on exit.
2453 * This is called at get_inode() calls and we can use GFP_KERNEL.
2455 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2459 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2460 spin_lock_init(&sp->lock);
2463 struct vm_area_struct pvma;
2464 struct mempolicy *new;
2465 NODEMASK_SCRATCH(scratch);
2469 /* contextualize the tmpfs mount point mempolicy */
2470 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2472 goto free_scratch; /* no valid nodemask intersection */
2475 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2476 task_unlock(current);
2480 /* Create pseudo-vma that contains just the policy */
2481 memset(&pvma, 0, sizeof(struct vm_area_struct));
2482 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2483 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2486 mpol_put(new); /* drop initial ref */
2488 NODEMASK_SCRATCH_FREE(scratch);
2490 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2494 int mpol_set_shared_policy(struct shared_policy *info,
2495 struct vm_area_struct *vma, struct mempolicy *npol)
2498 struct sp_node *new = NULL;
2499 unsigned long sz = vma_pages(vma);
2501 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2503 sz, npol ? npol->mode : -1,
2504 npol ? npol->flags : -1,
2505 npol ? nodes_addr(npol->v.nodes)[0] : NUMA_NO_NODE);
2508 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2512 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2518 /* Free a backing policy store on inode delete. */
2519 void mpol_free_shared_policy(struct shared_policy *p)
2522 struct rb_node *next;
2524 if (!p->root.rb_node)
2526 spin_lock(&p->lock);
2527 next = rb_first(&p->root);
2529 n = rb_entry(next, struct sp_node, nd);
2530 next = rb_next(&n->nd);
2533 spin_unlock(&p->lock);
2536 #ifdef CONFIG_NUMA_BALANCING
2537 static bool __initdata numabalancing_override;
2539 static void __init check_numabalancing_enable(void)
2541 bool numabalancing_default = false;
2543 if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
2544 numabalancing_default = true;
2546 if (nr_node_ids > 1 && !numabalancing_override) {
2547 printk(KERN_INFO "Enabling automatic NUMA balancing. "
2548 "Configure with numa_balancing= or sysctl");
2549 set_numabalancing_state(numabalancing_default);
2553 static int __init setup_numabalancing(char *str)
2558 numabalancing_override = true;
2560 if (!strcmp(str, "enable")) {
2561 set_numabalancing_state(true);
2563 } else if (!strcmp(str, "disable")) {
2564 set_numabalancing_state(false);
2569 printk(KERN_WARNING "Unable to parse numa_balancing=\n");
2573 __setup("numa_balancing=", setup_numabalancing);
2575 static inline void __init check_numabalancing_enable(void)
2578 #endif /* CONFIG_NUMA_BALANCING */
2580 /* assumes fs == KERNEL_DS */
2581 void __init numa_policy_init(void)
2583 nodemask_t interleave_nodes;
2584 unsigned long largest = 0;
2585 int nid, prefer = 0;
2587 policy_cache = kmem_cache_create("numa_policy",
2588 sizeof(struct mempolicy),
2589 0, SLAB_PANIC, NULL);
2591 sn_cache = kmem_cache_create("shared_policy_node",
2592 sizeof(struct sp_node),
2593 0, SLAB_PANIC, NULL);
2595 for_each_node(nid) {
2596 preferred_node_policy[nid] = (struct mempolicy) {
2597 .refcnt = ATOMIC_INIT(1),
2598 .mode = MPOL_PREFERRED,
2599 .flags = MPOL_F_MOF | MPOL_F_MORON,
2600 .v = { .preferred_node = nid, },
2605 * Set interleaving policy for system init. Interleaving is only
2606 * enabled across suitably sized nodes (default is >= 16MB), or
2607 * fall back to the largest node if they're all smaller.
2609 nodes_clear(interleave_nodes);
2610 for_each_node_state(nid, N_MEMORY) {
2611 unsigned long total_pages = node_present_pages(nid);
2613 /* Preserve the largest node */
2614 if (largest < total_pages) {
2615 largest = total_pages;
2619 /* Interleave this node? */
2620 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2621 node_set(nid, interleave_nodes);
2624 /* All too small, use the largest */
2625 if (unlikely(nodes_empty(interleave_nodes)))
2626 node_set(prefer, interleave_nodes);
2628 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2629 printk("numa_policy_init: interleaving failed\n");
2631 check_numabalancing_enable();
2634 /* Reset policy of current process to default */
2635 void numa_default_policy(void)
2637 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2641 * Parse and format mempolicy from/to strings
2645 * "local" is implemented internally by MPOL_PREFERRED with MPOL_F_LOCAL flag.
2647 static const char * const policy_modes[] =
2649 [MPOL_DEFAULT] = "default",
2650 [MPOL_PREFERRED] = "prefer",
2651 [MPOL_BIND] = "bind",
2652 [MPOL_INTERLEAVE] = "interleave",
2653 [MPOL_LOCAL] = "local",
2659 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2660 * @str: string containing mempolicy to parse
2661 * @mpol: pointer to struct mempolicy pointer, returned on success.
2664 * <mode>[=<flags>][:<nodelist>]
2666 * On success, returns 0, else 1
2668 int mpol_parse_str(char *str, struct mempolicy **mpol)
2670 struct mempolicy *new = NULL;
2671 unsigned short mode;
2672 unsigned short mode_flags;
2674 char *nodelist = strchr(str, ':');
2675 char *flags = strchr(str, '=');
2679 /* NUL-terminate mode or flags string */
2681 if (nodelist_parse(nodelist, nodes))
2683 if (!nodes_subset(nodes, node_states[N_MEMORY]))
2689 *flags++ = '\0'; /* terminate mode string */
2691 for (mode = 0; mode < MPOL_MAX; mode++) {
2692 if (!strcmp(str, policy_modes[mode])) {
2696 if (mode >= MPOL_MAX)
2700 case MPOL_PREFERRED:
2702 * Insist on a nodelist of one node only
2705 char *rest = nodelist;
2706 while (isdigit(*rest))
2712 case MPOL_INTERLEAVE:
2714 * Default to online nodes with memory if no nodelist
2717 nodes = node_states[N_MEMORY];
2721 * Don't allow a nodelist; mpol_new() checks flags
2725 mode = MPOL_PREFERRED;
2729 * Insist on a empty nodelist
2736 * Insist on a nodelist
2745 * Currently, we only support two mutually exclusive
2748 if (!strcmp(flags, "static"))
2749 mode_flags |= MPOL_F_STATIC_NODES;
2750 else if (!strcmp(flags, "relative"))
2751 mode_flags |= MPOL_F_RELATIVE_NODES;
2756 new = mpol_new(mode, mode_flags, &nodes);
2761 * Save nodes for mpol_to_str() to show the tmpfs mount options
2762 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
2764 if (mode != MPOL_PREFERRED)
2765 new->v.nodes = nodes;
2767 new->v.preferred_node = first_node(nodes);
2769 new->flags |= MPOL_F_LOCAL;
2772 * Save nodes for contextualization: this will be used to "clone"
2773 * the mempolicy in a specific context [cpuset] at a later time.
2775 new->w.user_nodemask = nodes;
2780 /* Restore string for error message */
2789 #endif /* CONFIG_TMPFS */
2792 * mpol_to_str - format a mempolicy structure for printing
2793 * @buffer: to contain formatted mempolicy string
2794 * @maxlen: length of @buffer
2795 * @pol: pointer to mempolicy to be formatted
2797 * Convert a mempolicy into a string.
2798 * Returns the number of characters in buffer (if positive)
2799 * or an error (negative)
2801 int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
2806 unsigned short mode;
2807 unsigned short flags = pol ? pol->flags : 0;
2810 * Sanity check: room for longest mode, flag and some nodes
2812 VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
2814 if (!pol || pol == &default_policy)
2815 mode = MPOL_DEFAULT;
2824 case MPOL_PREFERRED:
2826 if (flags & MPOL_F_LOCAL)
2829 node_set(pol->v.preferred_node, nodes);
2834 case MPOL_INTERLEAVE:
2835 nodes = pol->v.nodes;
2842 l = strlen(policy_modes[mode]);
2843 if (buffer + maxlen < p + l + 1)
2846 strcpy(p, policy_modes[mode]);
2849 if (flags & MPOL_MODE_FLAGS) {
2850 if (buffer + maxlen < p + 2)
2855 * Currently, the only defined flags are mutually exclusive
2857 if (flags & MPOL_F_STATIC_NODES)
2858 p += snprintf(p, buffer + maxlen - p, "static");
2859 else if (flags & MPOL_F_RELATIVE_NODES)
2860 p += snprintf(p, buffer + maxlen - p, "relative");
2863 if (!nodes_empty(nodes)) {
2864 if (buffer + maxlen < p + 2)
2867 p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);