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 node -1 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>
94 #include <asm/tlbflush.h>
95 #include <asm/uaccess.h>
96 #include <linux/random.h>
101 #define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
102 #define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
104 static struct kmem_cache *policy_cache;
105 static struct kmem_cache *sn_cache;
107 /* Highest zone. An specific allocation for a zone below that is not
109 enum zone_type policy_zone = 0;
112 * run-time system-wide default policy => local allocation
114 static struct mempolicy default_policy = {
115 .refcnt = ATOMIC_INIT(1), /* never free it */
116 .mode = MPOL_PREFERRED,
117 .flags = MPOL_F_LOCAL,
120 static const struct mempolicy_operations {
121 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
123 * If read-side task has no lock to protect task->mempolicy, write-side
124 * task will rebind the task->mempolicy by two step. The first step is
125 * setting all the newly nodes, and the second step is cleaning all the
126 * disallowed nodes. In this way, we can avoid finding no node to alloc
128 * If we have a lock to protect task->mempolicy in read-side, we do
132 * MPOL_REBIND_ONCE - do rebind work at once
133 * MPOL_REBIND_STEP1 - set all the newly nodes
134 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
136 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes,
137 enum mpol_rebind_step step);
138 } mpol_ops[MPOL_MAX];
140 /* Check that the nodemask contains at least one populated zone */
141 static int is_valid_nodemask(const nodemask_t *nodemask)
145 for_each_node_mask(nd, *nodemask) {
148 for (k = 0; k <= policy_zone; k++) {
149 z = &NODE_DATA(nd)->node_zones[k];
150 if (z->present_pages > 0)
158 static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
160 return pol->flags & MPOL_MODE_FLAGS;
163 static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
164 const nodemask_t *rel)
167 nodes_fold(tmp, *orig, nodes_weight(*rel));
168 nodes_onto(*ret, tmp, *rel);
171 static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
173 if (nodes_empty(*nodes))
175 pol->v.nodes = *nodes;
179 static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
182 pol->flags |= MPOL_F_LOCAL; /* local allocation */
183 else if (nodes_empty(*nodes))
184 return -EINVAL; /* no allowed nodes */
186 pol->v.preferred_node = first_node(*nodes);
190 static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
192 if (!is_valid_nodemask(nodes))
194 pol->v.nodes = *nodes;
199 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
200 * any, for the new policy. mpol_new() has already validated the nodes
201 * parameter with respect to the policy mode and flags. But, we need to
202 * handle an empty nodemask with MPOL_PREFERRED here.
204 * Must be called holding task's alloc_lock to protect task's mems_allowed
205 * and mempolicy. May also be called holding the mmap_semaphore for write.
207 static int mpol_set_nodemask(struct mempolicy *pol,
208 const nodemask_t *nodes, struct nodemask_scratch *nsc)
212 /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
215 /* Check N_HIGH_MEMORY */
216 nodes_and(nsc->mask1,
217 cpuset_current_mems_allowed, node_states[N_HIGH_MEMORY]);
220 if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
221 nodes = NULL; /* explicit local allocation */
223 if (pol->flags & MPOL_F_RELATIVE_NODES)
224 mpol_relative_nodemask(&nsc->mask2, nodes,&nsc->mask1);
226 nodes_and(nsc->mask2, *nodes, nsc->mask1);
228 if (mpol_store_user_nodemask(pol))
229 pol->w.user_nodemask = *nodes;
231 pol->w.cpuset_mems_allowed =
232 cpuset_current_mems_allowed;
236 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
238 ret = mpol_ops[pol->mode].create(pol, NULL);
243 * This function just creates a new policy, does some check and simple
244 * initialization. You must invoke mpol_set_nodemask() to set nodes.
246 static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
249 struct mempolicy *policy;
251 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
252 mode, flags, nodes ? nodes_addr(*nodes)[0] : -1);
254 if (mode == MPOL_DEFAULT) {
255 if (nodes && !nodes_empty(*nodes))
256 return ERR_PTR(-EINVAL);
257 return NULL; /* simply delete any existing policy */
262 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
263 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
264 * All other modes require a valid pointer to a non-empty nodemask.
266 if (mode == MPOL_PREFERRED) {
267 if (nodes_empty(*nodes)) {
268 if (((flags & MPOL_F_STATIC_NODES) ||
269 (flags & MPOL_F_RELATIVE_NODES)))
270 return ERR_PTR(-EINVAL);
272 } else if (nodes_empty(*nodes))
273 return ERR_PTR(-EINVAL);
274 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
276 return ERR_PTR(-ENOMEM);
277 atomic_set(&policy->refcnt, 1);
279 policy->flags = flags;
284 /* Slow path of a mpol destructor. */
285 void __mpol_put(struct mempolicy *p)
287 if (!atomic_dec_and_test(&p->refcnt))
289 kmem_cache_free(policy_cache, p);
292 static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes,
293 enum mpol_rebind_step step)
299 * MPOL_REBIND_ONCE - do rebind work at once
300 * MPOL_REBIND_STEP1 - set all the newly nodes
301 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
303 static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes,
304 enum mpol_rebind_step step)
308 if (pol->flags & MPOL_F_STATIC_NODES)
309 nodes_and(tmp, pol->w.user_nodemask, *nodes);
310 else if (pol->flags & MPOL_F_RELATIVE_NODES)
311 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
314 * if step == 1, we use ->w.cpuset_mems_allowed to cache the
317 if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP1) {
318 nodes_remap(tmp, pol->v.nodes,
319 pol->w.cpuset_mems_allowed, *nodes);
320 pol->w.cpuset_mems_allowed = step ? tmp : *nodes;
321 } else if (step == MPOL_REBIND_STEP2) {
322 tmp = pol->w.cpuset_mems_allowed;
323 pol->w.cpuset_mems_allowed = *nodes;
328 if (nodes_empty(tmp))
331 if (step == MPOL_REBIND_STEP1)
332 nodes_or(pol->v.nodes, pol->v.nodes, tmp);
333 else if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP2)
338 if (!node_isset(current->il_next, tmp)) {
339 current->il_next = next_node(current->il_next, tmp);
340 if (current->il_next >= MAX_NUMNODES)
341 current->il_next = first_node(tmp);
342 if (current->il_next >= MAX_NUMNODES)
343 current->il_next = numa_node_id();
347 static void mpol_rebind_preferred(struct mempolicy *pol,
348 const nodemask_t *nodes,
349 enum mpol_rebind_step step)
353 if (pol->flags & MPOL_F_STATIC_NODES) {
354 int node = first_node(pol->w.user_nodemask);
356 if (node_isset(node, *nodes)) {
357 pol->v.preferred_node = node;
358 pol->flags &= ~MPOL_F_LOCAL;
360 pol->flags |= MPOL_F_LOCAL;
361 } else if (pol->flags & MPOL_F_RELATIVE_NODES) {
362 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
363 pol->v.preferred_node = first_node(tmp);
364 } else if (!(pol->flags & MPOL_F_LOCAL)) {
365 pol->v.preferred_node = node_remap(pol->v.preferred_node,
366 pol->w.cpuset_mems_allowed,
368 pol->w.cpuset_mems_allowed = *nodes;
373 * mpol_rebind_policy - Migrate a policy to a different set of nodes
375 * If read-side task has no lock to protect task->mempolicy, write-side
376 * task will rebind the task->mempolicy by two step. The first step is
377 * setting all the newly nodes, and the second step is cleaning all the
378 * disallowed nodes. In this way, we can avoid finding no node to alloc
380 * If we have a lock to protect task->mempolicy in read-side, we do
384 * MPOL_REBIND_ONCE - do rebind work at once
385 * MPOL_REBIND_STEP1 - set all the newly nodes
386 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
388 static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask,
389 enum mpol_rebind_step step)
393 if (!mpol_store_user_nodemask(pol) && step == 0 &&
394 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
397 if (step == MPOL_REBIND_STEP1 && (pol->flags & MPOL_F_REBINDING))
400 if (step == MPOL_REBIND_STEP2 && !(pol->flags & MPOL_F_REBINDING))
403 if (step == MPOL_REBIND_STEP1)
404 pol->flags |= MPOL_F_REBINDING;
405 else if (step == MPOL_REBIND_STEP2)
406 pol->flags &= ~MPOL_F_REBINDING;
407 else if (step >= MPOL_REBIND_NSTEP)
410 mpol_ops[pol->mode].rebind(pol, newmask, step);
414 * Wrapper for mpol_rebind_policy() that just requires task
415 * pointer, and updates task mempolicy.
417 * Called with task's alloc_lock held.
420 void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new,
421 enum mpol_rebind_step step)
423 mpol_rebind_policy(tsk->mempolicy, new, step);
427 * Rebind each vma in mm to new nodemask.
429 * Call holding a reference to mm. Takes mm->mmap_sem during call.
432 void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
434 struct vm_area_struct *vma;
436 down_write(&mm->mmap_sem);
437 for (vma = mm->mmap; vma; vma = vma->vm_next)
438 mpol_rebind_policy(vma->vm_policy, new, MPOL_REBIND_ONCE);
439 up_write(&mm->mmap_sem);
442 static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
444 .rebind = mpol_rebind_default,
446 [MPOL_INTERLEAVE] = {
447 .create = mpol_new_interleave,
448 .rebind = mpol_rebind_nodemask,
451 .create = mpol_new_preferred,
452 .rebind = mpol_rebind_preferred,
455 .create = mpol_new_bind,
456 .rebind = mpol_rebind_nodemask,
460 static void migrate_page_add(struct page *page, struct list_head *pagelist,
461 unsigned long flags);
463 /* Scan through pages checking if pages follow certain conditions. */
464 static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
465 unsigned long addr, unsigned long end,
466 const nodemask_t *nodes, unsigned long flags,
473 orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
478 if (!pte_present(*pte))
480 page = vm_normal_page(vma, addr, *pte);
484 * vm_normal_page() filters out zero pages, but there might
485 * still be PageReserved pages to skip, perhaps in a VDSO.
486 * And we cannot move PageKsm pages sensibly or safely yet.
488 if (PageReserved(page) || PageKsm(page))
490 nid = page_to_nid(page);
491 if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
494 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
495 migrate_page_add(page, private, flags);
498 } while (pte++, addr += PAGE_SIZE, addr != end);
499 pte_unmap_unlock(orig_pte, ptl);
503 static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
504 unsigned long addr, unsigned long end,
505 const nodemask_t *nodes, unsigned long flags,
511 pmd = pmd_offset(pud, addr);
513 next = pmd_addr_end(addr, end);
514 split_huge_page_pmd(vma->vm_mm, pmd);
515 if (pmd_none_or_trans_huge_or_clear_bad(pmd))
517 if (check_pte_range(vma, pmd, addr, next, nodes,
520 } while (pmd++, addr = next, addr != end);
524 static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
525 unsigned long addr, unsigned long end,
526 const nodemask_t *nodes, unsigned long flags,
532 pud = pud_offset(pgd, addr);
534 next = pud_addr_end(addr, end);
535 if (pud_none_or_clear_bad(pud))
537 if (check_pmd_range(vma, pud, addr, next, nodes,
540 } while (pud++, addr = next, addr != end);
544 static inline int check_pgd_range(struct vm_area_struct *vma,
545 unsigned long addr, unsigned long end,
546 const nodemask_t *nodes, unsigned long flags,
552 pgd = pgd_offset(vma->vm_mm, addr);
554 next = pgd_addr_end(addr, end);
555 if (pgd_none_or_clear_bad(pgd))
557 if (check_pud_range(vma, pgd, addr, next, nodes,
560 } while (pgd++, addr = next, addr != end);
565 * Check if all pages in a range are on a set of nodes.
566 * If pagelist != NULL then isolate pages from the LRU and
567 * put them on the pagelist.
569 static struct vm_area_struct *
570 check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
571 const nodemask_t *nodes, unsigned long flags, void *private)
574 struct vm_area_struct *first, *vma, *prev;
577 first = find_vma(mm, start);
579 return ERR_PTR(-EFAULT);
581 for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
582 if (!(flags & MPOL_MF_DISCONTIG_OK)) {
583 if (!vma->vm_next && vma->vm_end < end)
584 return ERR_PTR(-EFAULT);
585 if (prev && prev->vm_end < vma->vm_start)
586 return ERR_PTR(-EFAULT);
588 if (!is_vm_hugetlb_page(vma) &&
589 ((flags & MPOL_MF_STRICT) ||
590 ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
591 vma_migratable(vma)))) {
592 unsigned long endvma = vma->vm_end;
596 if (vma->vm_start > start)
597 start = vma->vm_start;
598 err = check_pgd_range(vma, start, endvma, nodes,
601 first = ERR_PTR(err);
611 * Apply policy to a single VMA
612 * This must be called with the mmap_sem held for writing.
614 static int vma_replace_policy(struct vm_area_struct *vma,
615 struct mempolicy *pol)
618 struct mempolicy *old;
619 struct mempolicy *new;
621 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
622 vma->vm_start, vma->vm_end, vma->vm_pgoff,
623 vma->vm_ops, vma->vm_file,
624 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
630 if (vma->vm_ops && vma->vm_ops->set_policy) {
631 err = vma->vm_ops->set_policy(vma, new);
636 old = vma->vm_policy;
637 vma->vm_policy = new; /* protected by mmap_sem */
646 /* Step 2: apply policy to a range and do splits. */
647 static int mbind_range(struct mm_struct *mm, unsigned long start,
648 unsigned long end, struct mempolicy *new_pol)
650 struct vm_area_struct *next;
651 struct vm_area_struct *prev;
652 struct vm_area_struct *vma;
655 unsigned long vmstart;
658 vma = find_vma_prev(mm, start, &prev);
659 if (!vma || vma->vm_start > start)
662 if (start > vma->vm_start)
665 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
667 vmstart = max(start, vma->vm_start);
668 vmend = min(end, vma->vm_end);
670 if (mpol_equal(vma_policy(vma), new_pol))
673 pgoff = vma->vm_pgoff +
674 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
675 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
676 vma->anon_vma, vma->vm_file, pgoff,
683 if (vma->vm_start != vmstart) {
684 err = split_vma(vma->vm_mm, vma, vmstart, 1);
688 if (vma->vm_end != vmend) {
689 err = split_vma(vma->vm_mm, vma, vmend, 0);
693 err = vma_replace_policy(vma, new_pol);
703 * Update task->flags PF_MEMPOLICY bit: set iff non-default
704 * mempolicy. Allows more rapid checking of this (combined perhaps
705 * with other PF_* flag bits) on memory allocation hot code paths.
707 * If called from outside this file, the task 'p' should -only- be
708 * a newly forked child not yet visible on the task list, because
709 * manipulating the task flags of a visible task is not safe.
711 * The above limitation is why this routine has the funny name
712 * mpol_fix_fork_child_flag().
714 * It is also safe to call this with a task pointer of current,
715 * which the static wrapper mpol_set_task_struct_flag() does,
716 * for use within this file.
719 void mpol_fix_fork_child_flag(struct task_struct *p)
722 p->flags |= PF_MEMPOLICY;
724 p->flags &= ~PF_MEMPOLICY;
727 static void mpol_set_task_struct_flag(void)
729 mpol_fix_fork_child_flag(current);
732 /* Set the process memory policy */
733 static long do_set_mempolicy(unsigned short mode, unsigned short flags,
736 struct mempolicy *new, *old;
737 struct mm_struct *mm = current->mm;
738 NODEMASK_SCRATCH(scratch);
744 new = mpol_new(mode, flags, nodes);
750 * prevent changing our mempolicy while show_numa_maps()
752 * Note: do_set_mempolicy() can be called at init time
756 down_write(&mm->mmap_sem);
758 ret = mpol_set_nodemask(new, nodes, scratch);
760 task_unlock(current);
762 up_write(&mm->mmap_sem);
766 old = current->mempolicy;
767 current->mempolicy = new;
768 mpol_set_task_struct_flag();
769 if (new && new->mode == MPOL_INTERLEAVE &&
770 nodes_weight(new->v.nodes))
771 current->il_next = first_node(new->v.nodes);
772 task_unlock(current);
774 up_write(&mm->mmap_sem);
779 NODEMASK_SCRATCH_FREE(scratch);
784 * Return nodemask for policy for get_mempolicy() query
786 * Called with task's alloc_lock held
788 static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
791 if (p == &default_policy)
797 case MPOL_INTERLEAVE:
801 if (!(p->flags & MPOL_F_LOCAL))
802 node_set(p->v.preferred_node, *nodes);
803 /* else return empty node mask for local allocation */
810 static int lookup_node(struct mm_struct *mm, unsigned long addr)
815 err = get_user_pages(current, mm, addr & PAGE_MASK, 1, 0, 0, &p, NULL);
817 err = page_to_nid(p);
823 /* Retrieve NUMA policy */
824 static long do_get_mempolicy(int *policy, nodemask_t *nmask,
825 unsigned long addr, unsigned long flags)
828 struct mm_struct *mm = current->mm;
829 struct vm_area_struct *vma = NULL;
830 struct mempolicy *pol = current->mempolicy;
833 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
836 if (flags & MPOL_F_MEMS_ALLOWED) {
837 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
839 *policy = 0; /* just so it's initialized */
841 *nmask = cpuset_current_mems_allowed;
842 task_unlock(current);
846 if (flags & MPOL_F_ADDR) {
848 * Do NOT fall back to task policy if the
849 * vma/shared policy at addr is NULL. We
850 * want to return MPOL_DEFAULT in this case.
852 down_read(&mm->mmap_sem);
853 vma = find_vma_intersection(mm, addr, addr+1);
855 up_read(&mm->mmap_sem);
858 if (vma->vm_ops && vma->vm_ops->get_policy)
859 pol = vma->vm_ops->get_policy(vma, addr);
861 pol = vma->vm_policy;
866 pol = &default_policy; /* indicates default behavior */
868 if (flags & MPOL_F_NODE) {
869 if (flags & MPOL_F_ADDR) {
870 err = lookup_node(mm, addr);
874 } else if (pol == current->mempolicy &&
875 pol->mode == MPOL_INTERLEAVE) {
876 *policy = current->il_next;
882 *policy = pol == &default_policy ? MPOL_DEFAULT :
885 * Internal mempolicy flags must be masked off before exposing
886 * the policy to userspace.
888 *policy |= (pol->flags & MPOL_MODE_FLAGS);
892 up_read(¤t->mm->mmap_sem);
898 if (mpol_store_user_nodemask(pol)) {
899 *nmask = pol->w.user_nodemask;
902 get_policy_nodemask(pol, nmask);
903 task_unlock(current);
910 up_read(¤t->mm->mmap_sem);
914 #ifdef CONFIG_MIGRATION
918 static void migrate_page_add(struct page *page, struct list_head *pagelist,
922 * Avoid migrating a page that is shared with others.
924 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
925 if (!isolate_lru_page(page)) {
926 list_add_tail(&page->lru, pagelist);
927 inc_zone_page_state(page, NR_ISOLATED_ANON +
928 page_is_file_cache(page));
933 static struct page *new_node_page(struct page *page, unsigned long node, int **x)
935 return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
939 * Migrate pages from one node to a target node.
940 * Returns error or the number of pages not migrated.
942 static int migrate_to_node(struct mm_struct *mm, int source, int dest,
948 struct vm_area_struct *vma;
951 node_set(source, nmask);
953 vma = check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
954 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
958 if (!list_empty(&pagelist)) {
959 err = migrate_pages(&pagelist, new_node_page, dest,
960 false, MIGRATE_SYNC);
962 putback_lru_pages(&pagelist);
969 * Move pages between the two nodesets so as to preserve the physical
970 * layout as much as possible.
972 * Returns the number of page that could not be moved.
974 int do_migrate_pages(struct mm_struct *mm,
975 const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
981 err = migrate_prep();
985 down_read(&mm->mmap_sem);
987 err = migrate_vmas(mm, from_nodes, to_nodes, flags);
992 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
993 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
994 * bit in 'tmp', and return that <source, dest> pair for migration.
995 * The pair of nodemasks 'to' and 'from' define the map.
997 * If no pair of bits is found that way, fallback to picking some
998 * pair of 'source' and 'dest' bits that are not the same. If the
999 * 'source' and 'dest' bits are the same, this represents a node
1000 * that will be migrating to itself, so no pages need move.
1002 * If no bits are left in 'tmp', or if all remaining bits left
1003 * in 'tmp' correspond to the same bit in 'to', return false
1004 * (nothing left to migrate).
1006 * This lets us pick a pair of nodes to migrate between, such that
1007 * if possible the dest node is not already occupied by some other
1008 * source node, minimizing the risk of overloading the memory on a
1009 * node that would happen if we migrated incoming memory to a node
1010 * before migrating outgoing memory source that same node.
1012 * A single scan of tmp is sufficient. As we go, we remember the
1013 * most recent <s, d> pair that moved (s != d). If we find a pair
1014 * that not only moved, but what's better, moved to an empty slot
1015 * (d is not set in tmp), then we break out then, with that pair.
1016 * Otherwise when we finish scanning from_tmp, we at least have the
1017 * most recent <s, d> pair that moved. If we get all the way through
1018 * the scan of tmp without finding any node that moved, much less
1019 * moved to an empty node, then there is nothing left worth migrating.
1023 while (!nodes_empty(tmp)) {
1028 for_each_node_mask(s, tmp) {
1029 d = node_remap(s, *from_nodes, *to_nodes);
1033 source = s; /* Node moved. Memorize */
1036 /* dest not in remaining from nodes? */
1037 if (!node_isset(dest, tmp))
1043 node_clear(source, tmp);
1044 err = migrate_to_node(mm, source, dest, flags);
1051 up_read(&mm->mmap_sem);
1059 * Allocate a new page for page migration based on vma policy.
1060 * Start assuming that page is mapped by vma pointed to by @private.
1061 * Search forward from there, if not. N.B., this assumes that the
1062 * list of pages handed to migrate_pages()--which is how we get here--
1063 * is in virtual address order.
1065 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1067 struct vm_area_struct *vma = (struct vm_area_struct *)private;
1068 unsigned long uninitialized_var(address);
1071 address = page_address_in_vma(page, vma);
1072 if (address != -EFAULT)
1078 * if !vma, alloc_page_vma() will use task or system default policy
1080 return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1084 static void migrate_page_add(struct page *page, struct list_head *pagelist,
1085 unsigned long flags)
1089 int do_migrate_pages(struct mm_struct *mm,
1090 const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
1095 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1101 static long do_mbind(unsigned long start, unsigned long len,
1102 unsigned short mode, unsigned short mode_flags,
1103 nodemask_t *nmask, unsigned long flags)
1105 struct vm_area_struct *vma;
1106 struct mm_struct *mm = current->mm;
1107 struct mempolicy *new;
1110 LIST_HEAD(pagelist);
1112 if (flags & ~(unsigned long)(MPOL_MF_STRICT |
1113 MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1115 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1118 if (start & ~PAGE_MASK)
1121 if (mode == MPOL_DEFAULT)
1122 flags &= ~MPOL_MF_STRICT;
1124 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1132 new = mpol_new(mode, mode_flags, nmask);
1134 return PTR_ERR(new);
1137 * If we are using the default policy then operation
1138 * on discontinuous address spaces is okay after all
1141 flags |= MPOL_MF_DISCONTIG_OK;
1143 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1144 start, start + len, mode, mode_flags,
1145 nmask ? nodes_addr(*nmask)[0] : -1);
1147 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1149 err = migrate_prep();
1154 NODEMASK_SCRATCH(scratch);
1156 down_write(&mm->mmap_sem);
1158 err = mpol_set_nodemask(new, nmask, scratch);
1159 task_unlock(current);
1161 up_write(&mm->mmap_sem);
1164 NODEMASK_SCRATCH_FREE(scratch);
1169 vma = check_range(mm, start, end, nmask,
1170 flags | MPOL_MF_INVERT, &pagelist);
1176 err = mbind_range(mm, start, end, new);
1178 if (!list_empty(&pagelist)) {
1179 nr_failed = migrate_pages(&pagelist, new_vma_page,
1183 putback_lru_pages(&pagelist);
1186 if (!err && nr_failed && (flags & MPOL_MF_STRICT))
1189 putback_lru_pages(&pagelist);
1191 up_write(&mm->mmap_sem);
1198 * User space interface with variable sized bitmaps for nodelists.
1201 /* Copy a node mask from user space. */
1202 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1203 unsigned long maxnode)
1206 unsigned long nlongs;
1207 unsigned long endmask;
1210 nodes_clear(*nodes);
1211 if (maxnode == 0 || !nmask)
1213 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1216 nlongs = BITS_TO_LONGS(maxnode);
1217 if ((maxnode % BITS_PER_LONG) == 0)
1220 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1222 /* When the user specified more nodes than supported just check
1223 if the non supported part is all zero. */
1224 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1225 if (nlongs > PAGE_SIZE/sizeof(long))
1227 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1229 if (get_user(t, nmask + k))
1231 if (k == nlongs - 1) {
1237 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1241 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1243 nodes_addr(*nodes)[nlongs-1] &= endmask;
1247 /* Copy a kernel node mask to user space */
1248 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1251 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1252 const int nbytes = BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long);
1254 if (copy > nbytes) {
1255 if (copy > PAGE_SIZE)
1257 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1261 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1264 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1265 unsigned long, mode, unsigned long __user *, nmask,
1266 unsigned long, maxnode, unsigned, flags)
1270 unsigned short mode_flags;
1272 mode_flags = mode & MPOL_MODE_FLAGS;
1273 mode &= ~MPOL_MODE_FLAGS;
1274 if (mode >= MPOL_MAX)
1276 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1277 (mode_flags & MPOL_F_RELATIVE_NODES))
1279 err = get_nodes(&nodes, nmask, maxnode);
1282 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1285 /* Set the process memory policy */
1286 SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
1287 unsigned long, maxnode)
1291 unsigned short flags;
1293 flags = mode & MPOL_MODE_FLAGS;
1294 mode &= ~MPOL_MODE_FLAGS;
1295 if ((unsigned int)mode >= MPOL_MAX)
1297 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1299 err = get_nodes(&nodes, nmask, maxnode);
1302 return do_set_mempolicy(mode, flags, &nodes);
1305 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1306 const unsigned long __user *, old_nodes,
1307 const unsigned long __user *, new_nodes)
1309 const struct cred *cred = current_cred(), *tcred;
1310 struct mm_struct *mm = NULL;
1311 struct task_struct *task;
1312 nodemask_t task_nodes;
1316 NODEMASK_SCRATCH(scratch);
1321 old = &scratch->mask1;
1322 new = &scratch->mask2;
1324 err = get_nodes(old, old_nodes, maxnode);
1328 err = get_nodes(new, new_nodes, maxnode);
1332 /* Find the mm_struct */
1334 task = pid ? find_task_by_vpid(pid) : current;
1340 mm = get_task_mm(task);
1348 * Check if this process has the right to modify the specified
1349 * process. The right exists if the process has administrative
1350 * capabilities, superuser privileges or the same
1351 * userid as the target process.
1354 tcred = __task_cred(task);
1355 if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
1356 cred->uid != tcred->suid && cred->uid != tcred->uid &&
1357 !capable(CAP_SYS_NICE)) {
1364 task_nodes = cpuset_mems_allowed(task);
1365 /* Is the user allowed to access the target nodes? */
1366 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1371 if (!nodes_subset(*new, node_states[N_HIGH_MEMORY])) {
1376 err = security_task_movememory(task);
1380 err = do_migrate_pages(mm, old, new,
1381 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1385 NODEMASK_SCRATCH_FREE(scratch);
1391 /* Retrieve NUMA policy */
1392 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1393 unsigned long __user *, nmask, unsigned long, maxnode,
1394 unsigned long, addr, unsigned long, flags)
1397 int uninitialized_var(pval);
1400 if (nmask != NULL && maxnode < MAX_NUMNODES)
1403 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1408 if (policy && put_user(pval, policy))
1412 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1417 #ifdef CONFIG_COMPAT
1419 asmlinkage long compat_sys_get_mempolicy(int __user *policy,
1420 compat_ulong_t __user *nmask,
1421 compat_ulong_t maxnode,
1422 compat_ulong_t addr, compat_ulong_t flags)
1425 unsigned long __user *nm = NULL;
1426 unsigned long nr_bits, alloc_size;
1427 DECLARE_BITMAP(bm, MAX_NUMNODES);
1429 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1430 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1433 nm = compat_alloc_user_space(alloc_size);
1435 err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1437 if (!err && nmask) {
1438 unsigned long copy_size;
1439 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1440 err = copy_from_user(bm, nm, copy_size);
1441 /* ensure entire bitmap is zeroed */
1442 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1443 err |= compat_put_bitmap(nmask, bm, nr_bits);
1449 asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
1450 compat_ulong_t maxnode)
1453 unsigned long __user *nm = NULL;
1454 unsigned long nr_bits, alloc_size;
1455 DECLARE_BITMAP(bm, MAX_NUMNODES);
1457 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1458 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1461 err = compat_get_bitmap(bm, nmask, nr_bits);
1462 nm = compat_alloc_user_space(alloc_size);
1463 err |= copy_to_user(nm, bm, alloc_size);
1469 return sys_set_mempolicy(mode, nm, nr_bits+1);
1472 asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
1473 compat_ulong_t mode, compat_ulong_t __user *nmask,
1474 compat_ulong_t maxnode, compat_ulong_t flags)
1477 unsigned long __user *nm = NULL;
1478 unsigned long nr_bits, alloc_size;
1481 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1482 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1485 err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
1486 nm = compat_alloc_user_space(alloc_size);
1487 err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
1493 return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
1499 * get_vma_policy(@task, @vma, @addr)
1500 * @task - task for fallback if vma policy == default
1501 * @vma - virtual memory area whose policy is sought
1502 * @addr - address in @vma for shared policy lookup
1504 * Returns effective policy for a VMA at specified address.
1505 * Falls back to @task or system default policy, as necessary.
1506 * Current or other task's task mempolicy and non-shared vma policies
1507 * are protected by the task's mmap_sem, which must be held for read by
1509 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1510 * count--added by the get_policy() vm_op, as appropriate--to protect against
1511 * freeing by another task. It is the caller's responsibility to free the
1512 * extra reference for shared policies.
1514 struct mempolicy *get_vma_policy(struct task_struct *task,
1515 struct vm_area_struct *vma, unsigned long addr)
1517 struct mempolicy *pol = task->mempolicy;
1520 if (vma->vm_ops && vma->vm_ops->get_policy) {
1521 struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
1525 } else if (vma->vm_policy)
1526 pol = vma->vm_policy;
1529 pol = &default_policy;
1534 * Return a nodemask representing a mempolicy for filtering nodes for
1537 static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1539 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1540 if (unlikely(policy->mode == MPOL_BIND) &&
1541 gfp_zone(gfp) >= policy_zone &&
1542 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1543 return &policy->v.nodes;
1548 /* Return a zonelist indicated by gfp for node representing a mempolicy */
1549 static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
1552 switch (policy->mode) {
1553 case MPOL_PREFERRED:
1554 if (!(policy->flags & MPOL_F_LOCAL))
1555 nd = policy->v.preferred_node;
1559 * Normally, MPOL_BIND allocations are node-local within the
1560 * allowed nodemask. However, if __GFP_THISNODE is set and the
1561 * current node isn't part of the mask, we use the zonelist for
1562 * the first node in the mask instead.
1564 if (unlikely(gfp & __GFP_THISNODE) &&
1565 unlikely(!node_isset(nd, policy->v.nodes)))
1566 nd = first_node(policy->v.nodes);
1571 return node_zonelist(nd, gfp);
1574 /* Do dynamic interleaving for a process */
1575 static unsigned interleave_nodes(struct mempolicy *policy)
1578 struct task_struct *me = current;
1581 next = next_node(nid, policy->v.nodes);
1582 if (next >= MAX_NUMNODES)
1583 next = first_node(policy->v.nodes);
1584 if (next < MAX_NUMNODES)
1590 * Depending on the memory policy provide a node from which to allocate the
1592 * @policy must be protected by freeing by the caller. If @policy is
1593 * the current task's mempolicy, this protection is implicit, as only the
1594 * task can change it's policy. The system default policy requires no
1597 unsigned slab_node(struct mempolicy *policy)
1599 if (!policy || policy->flags & MPOL_F_LOCAL)
1600 return numa_node_id();
1602 switch (policy->mode) {
1603 case MPOL_PREFERRED:
1605 * handled MPOL_F_LOCAL above
1607 return policy->v.preferred_node;
1609 case MPOL_INTERLEAVE:
1610 return interleave_nodes(policy);
1614 * Follow bind policy behavior and start allocation at the
1617 struct zonelist *zonelist;
1619 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1620 zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
1621 (void)first_zones_zonelist(zonelist, highest_zoneidx,
1624 return zone ? zone->node : numa_node_id();
1632 /* Do static interleaving for a VMA with known offset. */
1633 static unsigned offset_il_node(struct mempolicy *pol,
1634 struct vm_area_struct *vma, unsigned long off)
1636 unsigned nnodes = nodes_weight(pol->v.nodes);
1642 return numa_node_id();
1643 target = (unsigned int)off % nnodes;
1646 nid = next_node(nid, pol->v.nodes);
1648 } while (c <= target);
1652 /* Determine a node number for interleave */
1653 static inline unsigned interleave_nid(struct mempolicy *pol,
1654 struct vm_area_struct *vma, unsigned long addr, int shift)
1660 * for small pages, there is no difference between
1661 * shift and PAGE_SHIFT, so the bit-shift is safe.
1662 * for huge pages, since vm_pgoff is in units of small
1663 * pages, we need to shift off the always 0 bits to get
1666 BUG_ON(shift < PAGE_SHIFT);
1667 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1668 off += (addr - vma->vm_start) >> shift;
1669 return offset_il_node(pol, vma, off);
1671 return interleave_nodes(pol);
1675 * Return the bit number of a random bit set in the nodemask.
1676 * (returns -1 if nodemask is empty)
1678 int node_random(const nodemask_t *maskp)
1682 w = nodes_weight(*maskp);
1684 bit = bitmap_ord_to_pos(maskp->bits,
1685 get_random_int() % w, MAX_NUMNODES);
1689 #ifdef CONFIG_HUGETLBFS
1691 * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
1692 * @vma = virtual memory area whose policy is sought
1693 * @addr = address in @vma for shared policy lookup and interleave policy
1694 * @gfp_flags = for requested zone
1695 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
1696 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1698 * Returns a zonelist suitable for a huge page allocation and a pointer
1699 * to the struct mempolicy for conditional unref after allocation.
1700 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1701 * @nodemask for filtering the zonelist.
1703 * Must be protected by get_mems_allowed()
1705 struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1706 gfp_t gfp_flags, struct mempolicy **mpol,
1707 nodemask_t **nodemask)
1709 struct zonelist *zl;
1711 *mpol = get_vma_policy(current, vma, addr);
1712 *nodemask = NULL; /* assume !MPOL_BIND */
1714 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1715 zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1716 huge_page_shift(hstate_vma(vma))), gfp_flags);
1718 zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1719 if ((*mpol)->mode == MPOL_BIND)
1720 *nodemask = &(*mpol)->v.nodes;
1726 * init_nodemask_of_mempolicy
1728 * If the current task's mempolicy is "default" [NULL], return 'false'
1729 * to indicate default policy. Otherwise, extract the policy nodemask
1730 * for 'bind' or 'interleave' policy into the argument nodemask, or
1731 * initialize the argument nodemask to contain the single node for
1732 * 'preferred' or 'local' policy and return 'true' to indicate presence
1733 * of non-default mempolicy.
1735 * We don't bother with reference counting the mempolicy [mpol_get/put]
1736 * because the current task is examining it's own mempolicy and a task's
1737 * mempolicy is only ever changed by the task itself.
1739 * N.B., it is the caller's responsibility to free a returned nodemask.
1741 bool init_nodemask_of_mempolicy(nodemask_t *mask)
1743 struct mempolicy *mempolicy;
1746 if (!(mask && current->mempolicy))
1750 mempolicy = current->mempolicy;
1751 switch (mempolicy->mode) {
1752 case MPOL_PREFERRED:
1753 if (mempolicy->flags & MPOL_F_LOCAL)
1754 nid = numa_node_id();
1756 nid = mempolicy->v.preferred_node;
1757 init_nodemask_of_node(mask, nid);
1762 case MPOL_INTERLEAVE:
1763 *mask = mempolicy->v.nodes;
1769 task_unlock(current);
1776 * mempolicy_nodemask_intersects
1778 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
1779 * policy. Otherwise, check for intersection between mask and the policy
1780 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
1781 * policy, always return true since it may allocate elsewhere on fallback.
1783 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
1785 bool mempolicy_nodemask_intersects(struct task_struct *tsk,
1786 const nodemask_t *mask)
1788 struct mempolicy *mempolicy;
1794 mempolicy = tsk->mempolicy;
1798 switch (mempolicy->mode) {
1799 case MPOL_PREFERRED:
1801 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
1802 * allocate from, they may fallback to other nodes when oom.
1803 * Thus, it's possible for tsk to have allocated memory from
1808 case MPOL_INTERLEAVE:
1809 ret = nodes_intersects(mempolicy->v.nodes, *mask);
1819 /* Allocate a page in interleaved policy.
1820 Own path because it needs to do special accounting. */
1821 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
1824 struct zonelist *zl;
1827 zl = node_zonelist(nid, gfp);
1828 page = __alloc_pages(gfp, order, zl);
1829 if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1830 inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
1835 * alloc_pages_vma - Allocate a page for a VMA.
1838 * %GFP_USER user allocation.
1839 * %GFP_KERNEL kernel allocations,
1840 * %GFP_HIGHMEM highmem/user allocations,
1841 * %GFP_FS allocation should not call back into a file system.
1842 * %GFP_ATOMIC don't sleep.
1844 * @order:Order of the GFP allocation.
1845 * @vma: Pointer to VMA or NULL if not available.
1846 * @addr: Virtual Address of the allocation. Must be inside the VMA.
1848 * This function allocates a page from the kernel page pool and applies
1849 * a NUMA policy associated with the VMA or the current process.
1850 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
1851 * mm_struct of the VMA to prevent it from going away. Should be used for
1852 * all allocations for pages that will be mapped into
1853 * user space. Returns NULL when no page can be allocated.
1855 * Should be called with the mm_sem of the vma hold.
1858 alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
1859 unsigned long addr, int node)
1861 struct mempolicy *pol;
1862 struct zonelist *zl;
1864 unsigned int cpuset_mems_cookie;
1867 pol = get_vma_policy(current, vma, addr);
1868 cpuset_mems_cookie = get_mems_allowed();
1870 if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
1873 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
1875 page = alloc_page_interleave(gfp, order, nid);
1876 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1881 zl = policy_zonelist(gfp, pol, node);
1882 if (unlikely(mpol_needs_cond_ref(pol))) {
1884 * slow path: ref counted shared policy
1886 struct page *page = __alloc_pages_nodemask(gfp, order,
1887 zl, policy_nodemask(gfp, pol));
1889 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1894 * fast path: default or task policy
1896 page = __alloc_pages_nodemask(gfp, order, zl,
1897 policy_nodemask(gfp, pol));
1898 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1904 * alloc_pages_current - Allocate pages.
1907 * %GFP_USER user allocation,
1908 * %GFP_KERNEL kernel allocation,
1909 * %GFP_HIGHMEM highmem allocation,
1910 * %GFP_FS don't call back into a file system.
1911 * %GFP_ATOMIC don't sleep.
1912 * @order: Power of two of allocation size in pages. 0 is a single page.
1914 * Allocate a page from the kernel page pool. When not in
1915 * interrupt context and apply the current process NUMA policy.
1916 * Returns NULL when no page can be allocated.
1918 * Don't call cpuset_update_task_memory_state() unless
1919 * 1) it's ok to take cpuset_sem (can WAIT), and
1920 * 2) allocating for current task (not interrupt).
1922 struct page *alloc_pages_current(gfp_t gfp, unsigned order)
1924 struct mempolicy *pol = current->mempolicy;
1926 unsigned int cpuset_mems_cookie;
1928 if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
1929 pol = &default_policy;
1932 cpuset_mems_cookie = get_mems_allowed();
1935 * No reference counting needed for current->mempolicy
1936 * nor system default_policy
1938 if (pol->mode == MPOL_INTERLEAVE)
1939 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
1941 page = __alloc_pages_nodemask(gfp, order,
1942 policy_zonelist(gfp, pol, numa_node_id()),
1943 policy_nodemask(gfp, pol));
1945 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1950 EXPORT_SYMBOL(alloc_pages_current);
1953 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
1954 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
1955 * with the mems_allowed returned by cpuset_mems_allowed(). This
1956 * keeps mempolicies cpuset relative after its cpuset moves. See
1957 * further kernel/cpuset.c update_nodemask().
1959 * current's mempolicy may be rebinded by the other task(the task that changes
1960 * cpuset's mems), so we needn't do rebind work for current task.
1963 /* Slow path of a mempolicy duplicate */
1964 struct mempolicy *__mpol_dup(struct mempolicy *old)
1966 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
1969 return ERR_PTR(-ENOMEM);
1971 /* task's mempolicy is protected by alloc_lock */
1972 if (old == current->mempolicy) {
1975 task_unlock(current);
1980 if (current_cpuset_is_being_rebound()) {
1981 nodemask_t mems = cpuset_mems_allowed(current);
1982 if (new->flags & MPOL_F_REBINDING)
1983 mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
1985 mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
1988 atomic_set(&new->refcnt, 1);
1993 * If *frompol needs [has] an extra ref, copy *frompol to *tompol ,
1994 * eliminate the * MPOL_F_* flags that require conditional ref and
1995 * [NOTE!!!] drop the extra ref. Not safe to reference *frompol directly
1996 * after return. Use the returned value.
1998 * Allows use of a mempolicy for, e.g., multiple allocations with a single
1999 * policy lookup, even if the policy needs/has extra ref on lookup.
2000 * shmem_readahead needs this.
2002 struct mempolicy *__mpol_cond_copy(struct mempolicy *tompol,
2003 struct mempolicy *frompol)
2005 if (!mpol_needs_cond_ref(frompol))
2009 tompol->flags &= ~MPOL_F_SHARED; /* copy doesn't need unref */
2010 __mpol_put(frompol);
2014 /* Slow path of a mempolicy comparison */
2015 int __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2019 if (a->mode != b->mode)
2021 if (a->flags != b->flags)
2023 if (mpol_store_user_nodemask(a))
2024 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2030 case MPOL_INTERLEAVE:
2031 return nodes_equal(a->v.nodes, b->v.nodes);
2032 case MPOL_PREFERRED:
2033 return a->v.preferred_node == b->v.preferred_node;
2041 * Shared memory backing store policy support.
2043 * Remember policies even when nobody has shared memory mapped.
2044 * The policies are kept in Red-Black tree linked from the inode.
2045 * They are protected by the sp->lock spinlock, which should be held
2046 * for any accesses to the tree.
2049 /* lookup first element intersecting start-end */
2050 /* Caller holds sp->mutex */
2051 static struct sp_node *
2052 sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2054 struct rb_node *n = sp->root.rb_node;
2057 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2059 if (start >= p->end)
2061 else if (end <= p->start)
2069 struct sp_node *w = NULL;
2070 struct rb_node *prev = rb_prev(n);
2073 w = rb_entry(prev, struct sp_node, nd);
2074 if (w->end <= start)
2078 return rb_entry(n, struct sp_node, nd);
2081 /* Insert a new shared policy into the list. */
2082 /* Caller holds sp->lock */
2083 static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2085 struct rb_node **p = &sp->root.rb_node;
2086 struct rb_node *parent = NULL;
2091 nd = rb_entry(parent, struct sp_node, nd);
2092 if (new->start < nd->start)
2094 else if (new->end > nd->end)
2095 p = &(*p)->rb_right;
2099 rb_link_node(&new->nd, parent, p);
2100 rb_insert_color(&new->nd, &sp->root);
2101 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2102 new->policy ? new->policy->mode : 0);
2105 /* Find shared policy intersecting idx */
2107 mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2109 struct mempolicy *pol = NULL;
2112 if (!sp->root.rb_node)
2114 mutex_lock(&sp->mutex);
2115 sn = sp_lookup(sp, idx, idx+1);
2117 mpol_get(sn->policy);
2120 mutex_unlock(&sp->mutex);
2124 static void sp_free(struct sp_node *n)
2126 mpol_put(n->policy);
2127 kmem_cache_free(sn_cache, n);
2130 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2132 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2133 rb_erase(&n->nd, &sp->root);
2137 static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2138 struct mempolicy *pol)
2141 struct mempolicy *newpol;
2143 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2147 newpol = mpol_dup(pol);
2148 if (IS_ERR(newpol)) {
2149 kmem_cache_free(sn_cache, n);
2152 newpol->flags |= MPOL_F_SHARED;
2161 /* Replace a policy range. */
2162 static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2163 unsigned long end, struct sp_node *new)
2168 mutex_lock(&sp->mutex);
2169 n = sp_lookup(sp, start, end);
2170 /* Take care of old policies in the same range. */
2171 while (n && n->start < end) {
2172 struct rb_node *next = rb_next(&n->nd);
2173 if (n->start >= start) {
2179 /* Old policy spanning whole new range. */
2181 struct sp_node *new2;
2182 new2 = sp_alloc(end, n->end, n->policy);
2188 sp_insert(sp, new2);
2195 n = rb_entry(next, struct sp_node, nd);
2200 mutex_unlock(&sp->mutex);
2205 * mpol_shared_policy_init - initialize shared policy for inode
2206 * @sp: pointer to inode shared policy
2207 * @mpol: struct mempolicy to install
2209 * Install non-NULL @mpol in inode's shared policy rb-tree.
2210 * On entry, the current task has a reference on a non-NULL @mpol.
2211 * This must be released on exit.
2212 * This is called at get_inode() calls and we can use GFP_KERNEL.
2214 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2218 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2219 mutex_init(&sp->mutex);
2222 struct vm_area_struct pvma;
2223 struct mempolicy *new;
2224 NODEMASK_SCRATCH(scratch);
2228 /* contextualize the tmpfs mount point mempolicy */
2229 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2231 goto free_scratch; /* no valid nodemask intersection */
2234 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2235 task_unlock(current);
2239 /* Create pseudo-vma that contains just the policy */
2240 memset(&pvma, 0, sizeof(struct vm_area_struct));
2241 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2242 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2245 mpol_put(new); /* drop initial ref */
2247 NODEMASK_SCRATCH_FREE(scratch);
2249 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2253 int mpol_set_shared_policy(struct shared_policy *info,
2254 struct vm_area_struct *vma, struct mempolicy *npol)
2257 struct sp_node *new = NULL;
2258 unsigned long sz = vma_pages(vma);
2260 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2262 sz, npol ? npol->mode : -1,
2263 npol ? npol->flags : -1,
2264 npol ? nodes_addr(npol->v.nodes)[0] : -1);
2267 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2271 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2277 /* Free a backing policy store on inode delete. */
2278 void mpol_free_shared_policy(struct shared_policy *p)
2281 struct rb_node *next;
2283 if (!p->root.rb_node)
2285 mutex_lock(&p->mutex);
2286 next = rb_first(&p->root);
2288 n = rb_entry(next, struct sp_node, nd);
2289 next = rb_next(&n->nd);
2292 mutex_unlock(&p->mutex);
2295 /* assumes fs == KERNEL_DS */
2296 void __init numa_policy_init(void)
2298 nodemask_t interleave_nodes;
2299 unsigned long largest = 0;
2300 int nid, prefer = 0;
2302 policy_cache = kmem_cache_create("numa_policy",
2303 sizeof(struct mempolicy),
2304 0, SLAB_PANIC, NULL);
2306 sn_cache = kmem_cache_create("shared_policy_node",
2307 sizeof(struct sp_node),
2308 0, SLAB_PANIC, NULL);
2311 * Set interleaving policy for system init. Interleaving is only
2312 * enabled across suitably sized nodes (default is >= 16MB), or
2313 * fall back to the largest node if they're all smaller.
2315 nodes_clear(interleave_nodes);
2316 for_each_node_state(nid, N_HIGH_MEMORY) {
2317 unsigned long total_pages = node_present_pages(nid);
2319 /* Preserve the largest node */
2320 if (largest < total_pages) {
2321 largest = total_pages;
2325 /* Interleave this node? */
2326 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2327 node_set(nid, interleave_nodes);
2330 /* All too small, use the largest */
2331 if (unlikely(nodes_empty(interleave_nodes)))
2332 node_set(prefer, interleave_nodes);
2334 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2335 printk("numa_policy_init: interleaving failed\n");
2338 /* Reset policy of current process to default */
2339 void numa_default_policy(void)
2341 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2345 * Parse and format mempolicy from/to strings
2349 * "local" is pseudo-policy: MPOL_PREFERRED with MPOL_F_LOCAL flag
2350 * Used only for mpol_parse_str() and mpol_to_str()
2352 #define MPOL_LOCAL MPOL_MAX
2353 static const char * const policy_modes[] =
2355 [MPOL_DEFAULT] = "default",
2356 [MPOL_PREFERRED] = "prefer",
2357 [MPOL_BIND] = "bind",
2358 [MPOL_INTERLEAVE] = "interleave",
2359 [MPOL_LOCAL] = "local"
2365 * mpol_parse_str - parse string to mempolicy
2366 * @str: string containing mempolicy to parse
2367 * @mpol: pointer to struct mempolicy pointer, returned on success.
2368 * @no_context: flag whether to "contextualize" the mempolicy
2371 * <mode>[=<flags>][:<nodelist>]
2373 * if @no_context is true, save the input nodemask in w.user_nodemask in
2374 * the returned mempolicy. This will be used to "clone" the mempolicy in
2375 * a specific context [cpuset] at a later time. Used to parse tmpfs mpol
2376 * mount option. Note that if 'static' or 'relative' mode flags were
2377 * specified, the input nodemask will already have been saved. Saving
2378 * it again is redundant, but safe.
2380 * On success, returns 0, else 1
2382 int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context)
2384 struct mempolicy *new = NULL;
2385 unsigned short mode;
2386 unsigned short uninitialized_var(mode_flags);
2388 char *nodelist = strchr(str, ':');
2389 char *flags = strchr(str, '=');
2393 /* NUL-terminate mode or flags string */
2395 if (nodelist_parse(nodelist, nodes))
2397 if (!nodes_subset(nodes, node_states[N_HIGH_MEMORY]))
2403 *flags++ = '\0'; /* terminate mode string */
2405 for (mode = 0; mode <= MPOL_LOCAL; mode++) {
2406 if (!strcmp(str, policy_modes[mode])) {
2410 if (mode > MPOL_LOCAL)
2414 case MPOL_PREFERRED:
2416 * Insist on a nodelist of one node only
2419 char *rest = nodelist;
2420 while (isdigit(*rest))
2426 case MPOL_INTERLEAVE:
2428 * Default to online nodes with memory if no nodelist
2431 nodes = node_states[N_HIGH_MEMORY];
2435 * Don't allow a nodelist; mpol_new() checks flags
2439 mode = MPOL_PREFERRED;
2443 * Insist on a empty nodelist
2450 * Insist on a nodelist
2459 * Currently, we only support two mutually exclusive
2462 if (!strcmp(flags, "static"))
2463 mode_flags |= MPOL_F_STATIC_NODES;
2464 else if (!strcmp(flags, "relative"))
2465 mode_flags |= MPOL_F_RELATIVE_NODES;
2470 new = mpol_new(mode, mode_flags, &nodes);
2475 /* save for contextualization */
2476 new->w.user_nodemask = nodes;
2479 NODEMASK_SCRATCH(scratch);
2482 ret = mpol_set_nodemask(new, &nodes, scratch);
2483 task_unlock(current);
2486 NODEMASK_SCRATCH_FREE(scratch);
2495 /* Restore string for error message */
2504 #endif /* CONFIG_TMPFS */
2507 * mpol_to_str - format a mempolicy structure for printing
2508 * @buffer: to contain formatted mempolicy string
2509 * @maxlen: length of @buffer
2510 * @pol: pointer to mempolicy to be formatted
2511 * @no_context: "context free" mempolicy - use nodemask in w.user_nodemask
2513 * Convert a mempolicy into a string.
2514 * Returns the number of characters in buffer (if positive)
2515 * or an error (negative)
2517 int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol, int no_context)
2522 unsigned short mode;
2523 unsigned short flags = pol ? pol->flags : 0;
2526 * Sanity check: room for longest mode, flag and some nodes
2528 VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
2530 if (!pol || pol == &default_policy)
2531 mode = MPOL_DEFAULT;
2540 case MPOL_PREFERRED:
2542 if (flags & MPOL_F_LOCAL)
2543 mode = MPOL_LOCAL; /* pseudo-policy */
2545 node_set(pol->v.preferred_node, nodes);
2550 case MPOL_INTERLEAVE:
2552 nodes = pol->w.user_nodemask;
2554 nodes = pol->v.nodes;
2561 l = strlen(policy_modes[mode]);
2562 if (buffer + maxlen < p + l + 1)
2565 strcpy(p, policy_modes[mode]);
2568 if (flags & MPOL_MODE_FLAGS) {
2569 if (buffer + maxlen < p + 2)
2574 * Currently, the only defined flags are mutually exclusive
2576 if (flags & MPOL_F_STATIC_NODES)
2577 p += snprintf(p, buffer + maxlen - p, "static");
2578 else if (flags & MPOL_F_RELATIVE_NODES)
2579 p += snprintf(p, buffer + maxlen - p, "relative");
2582 if (!nodes_empty(nodes)) {
2583 if (buffer + maxlen < p + 2)
2586 p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);