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 == MPOL_REBIND_ONCE &&
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(mm, start);
659 if (!vma || vma->vm_start > start)
663 if (start > vma->vm_start)
666 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
668 vmstart = max(start, vma->vm_start);
669 vmend = min(end, vma->vm_end);
671 if (mpol_equal(vma_policy(vma), new_pol))
674 pgoff = vma->vm_pgoff +
675 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
676 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
677 vma->anon_vma, vma->vm_file, pgoff,
684 if (vma->vm_start != vmstart) {
685 err = split_vma(vma->vm_mm, vma, vmstart, 1);
689 if (vma->vm_end != vmend) {
690 err = split_vma(vma->vm_mm, vma, vmend, 0);
694 err = vma_replace_policy(vma, new_pol);
704 * Update task->flags PF_MEMPOLICY bit: set iff non-default
705 * mempolicy. Allows more rapid checking of this (combined perhaps
706 * with other PF_* flag bits) on memory allocation hot code paths.
708 * If called from outside this file, the task 'p' should -only- be
709 * a newly forked child not yet visible on the task list, because
710 * manipulating the task flags of a visible task is not safe.
712 * The above limitation is why this routine has the funny name
713 * mpol_fix_fork_child_flag().
715 * It is also safe to call this with a task pointer of current,
716 * which the static wrapper mpol_set_task_struct_flag() does,
717 * for use within this file.
720 void mpol_fix_fork_child_flag(struct task_struct *p)
723 p->flags |= PF_MEMPOLICY;
725 p->flags &= ~PF_MEMPOLICY;
728 static void mpol_set_task_struct_flag(void)
730 mpol_fix_fork_child_flag(current);
733 /* Set the process memory policy */
734 static long do_set_mempolicy(unsigned short mode, unsigned short flags,
737 struct mempolicy *new, *old;
738 struct mm_struct *mm = current->mm;
739 NODEMASK_SCRATCH(scratch);
745 new = mpol_new(mode, flags, nodes);
751 * prevent changing our mempolicy while show_numa_maps()
753 * Note: do_set_mempolicy() can be called at init time
757 down_write(&mm->mmap_sem);
759 ret = mpol_set_nodemask(new, nodes, scratch);
761 task_unlock(current);
763 up_write(&mm->mmap_sem);
767 old = current->mempolicy;
768 current->mempolicy = new;
769 mpol_set_task_struct_flag();
770 if (new && new->mode == MPOL_INTERLEAVE &&
771 nodes_weight(new->v.nodes))
772 current->il_next = first_node(new->v.nodes);
773 task_unlock(current);
775 up_write(&mm->mmap_sem);
780 NODEMASK_SCRATCH_FREE(scratch);
785 * Return nodemask for policy for get_mempolicy() query
787 * Called with task's alloc_lock held
789 static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
792 if (p == &default_policy)
798 case MPOL_INTERLEAVE:
802 if (!(p->flags & MPOL_F_LOCAL))
803 node_set(p->v.preferred_node, *nodes);
804 /* else return empty node mask for local allocation */
811 static int lookup_node(struct mm_struct *mm, unsigned long addr)
816 err = get_user_pages(current, mm, addr & PAGE_MASK, 1, 0, 0, &p, NULL);
818 err = page_to_nid(p);
824 /* Retrieve NUMA policy */
825 static long do_get_mempolicy(int *policy, nodemask_t *nmask,
826 unsigned long addr, unsigned long flags)
829 struct mm_struct *mm = current->mm;
830 struct vm_area_struct *vma = NULL;
831 struct mempolicy *pol = current->mempolicy;
834 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
837 if (flags & MPOL_F_MEMS_ALLOWED) {
838 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
840 *policy = 0; /* just so it's initialized */
842 *nmask = cpuset_current_mems_allowed;
843 task_unlock(current);
847 if (flags & MPOL_F_ADDR) {
849 * Do NOT fall back to task policy if the
850 * vma/shared policy at addr is NULL. We
851 * want to return MPOL_DEFAULT in this case.
853 down_read(&mm->mmap_sem);
854 vma = find_vma_intersection(mm, addr, addr+1);
856 up_read(&mm->mmap_sem);
859 if (vma->vm_ops && vma->vm_ops->get_policy)
860 pol = vma->vm_ops->get_policy(vma, addr);
862 pol = vma->vm_policy;
867 pol = &default_policy; /* indicates default behavior */
869 if (flags & MPOL_F_NODE) {
870 if (flags & MPOL_F_ADDR) {
871 err = lookup_node(mm, addr);
875 } else if (pol == current->mempolicy &&
876 pol->mode == MPOL_INTERLEAVE) {
877 *policy = current->il_next;
883 *policy = pol == &default_policy ? MPOL_DEFAULT :
886 * Internal mempolicy flags must be masked off before exposing
887 * the policy to userspace.
889 *policy |= (pol->flags & MPOL_MODE_FLAGS);
893 up_read(¤t->mm->mmap_sem);
899 if (mpol_store_user_nodemask(pol)) {
900 *nmask = pol->w.user_nodemask;
903 get_policy_nodemask(pol, nmask);
904 task_unlock(current);
911 up_read(¤t->mm->mmap_sem);
915 #ifdef CONFIG_MIGRATION
919 static void migrate_page_add(struct page *page, struct list_head *pagelist,
923 * Avoid migrating a page that is shared with others.
925 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
926 if (!isolate_lru_page(page)) {
927 list_add_tail(&page->lru, pagelist);
928 inc_zone_page_state(page, NR_ISOLATED_ANON +
929 page_is_file_cache(page));
934 static struct page *new_node_page(struct page *page, unsigned long node, int **x)
936 return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
940 * Migrate pages from one node to a target node.
941 * Returns error or the number of pages not migrated.
943 static int migrate_to_node(struct mm_struct *mm, int source, int dest,
949 struct vm_area_struct *vma;
952 node_set(source, nmask);
954 vma = check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
955 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
959 if (!list_empty(&pagelist)) {
960 err = migrate_pages(&pagelist, new_node_page, dest,
961 false, MIGRATE_SYNC);
963 putback_lru_pages(&pagelist);
970 * Move pages between the two nodesets so as to preserve the physical
971 * layout as much as possible.
973 * Returns the number of page that could not be moved.
975 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
976 const nodemask_t *to, int flags)
982 err = migrate_prep();
986 down_read(&mm->mmap_sem);
988 err = migrate_vmas(mm, from, to, flags);
993 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
994 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
995 * bit in 'tmp', and return that <source, dest> pair for migration.
996 * The pair of nodemasks 'to' and 'from' define the map.
998 * If no pair of bits is found that way, fallback to picking some
999 * pair of 'source' and 'dest' bits that are not the same. If the
1000 * 'source' and 'dest' bits are the same, this represents a node
1001 * that will be migrating to itself, so no pages need move.
1003 * If no bits are left in 'tmp', or if all remaining bits left
1004 * in 'tmp' correspond to the same bit in 'to', return false
1005 * (nothing left to migrate).
1007 * This lets us pick a pair of nodes to migrate between, such that
1008 * if possible the dest node is not already occupied by some other
1009 * source node, minimizing the risk of overloading the memory on a
1010 * node that would happen if we migrated incoming memory to a node
1011 * before migrating outgoing memory source that same node.
1013 * A single scan of tmp is sufficient. As we go, we remember the
1014 * most recent <s, d> pair that moved (s != d). If we find a pair
1015 * that not only moved, but what's better, moved to an empty slot
1016 * (d is not set in tmp), then we break out then, with that pair.
1017 * Otherwise when we finish scanning from_tmp, we at least have the
1018 * most recent <s, d> pair that moved. If we get all the way through
1019 * the scan of tmp without finding any node that moved, much less
1020 * moved to an empty node, then there is nothing left worth migrating.
1024 while (!nodes_empty(tmp)) {
1029 for_each_node_mask(s, tmp) {
1032 * do_migrate_pages() tries to maintain the relative
1033 * node relationship of the pages established between
1034 * threads and memory areas.
1036 * However if the number of source nodes is not equal to
1037 * the number of destination nodes we can not preserve
1038 * this node relative relationship. In that case, skip
1039 * copying memory from a node that is in the destination
1042 * Example: [2,3,4] -> [3,4,5] moves everything.
1043 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1046 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1047 (node_isset(s, *to)))
1050 d = node_remap(s, *from, *to);
1054 source = s; /* Node moved. Memorize */
1057 /* dest not in remaining from nodes? */
1058 if (!node_isset(dest, tmp))
1064 node_clear(source, tmp);
1065 err = migrate_to_node(mm, source, dest, flags);
1072 up_read(&mm->mmap_sem);
1080 * Allocate a new page for page migration based on vma policy.
1081 * Start assuming that page is mapped by vma pointed to by @private.
1082 * Search forward from there, if not. N.B., this assumes that the
1083 * list of pages handed to migrate_pages()--which is how we get here--
1084 * is in virtual address order.
1086 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1088 struct vm_area_struct *vma = (struct vm_area_struct *)private;
1089 unsigned long uninitialized_var(address);
1092 address = page_address_in_vma(page, vma);
1093 if (address != -EFAULT)
1099 * if !vma, alloc_page_vma() will use task or system default policy
1101 return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1105 static void migrate_page_add(struct page *page, struct list_head *pagelist,
1106 unsigned long flags)
1110 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1111 const nodemask_t *to, int flags)
1116 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1122 static long do_mbind(unsigned long start, unsigned long len,
1123 unsigned short mode, unsigned short mode_flags,
1124 nodemask_t *nmask, unsigned long flags)
1126 struct vm_area_struct *vma;
1127 struct mm_struct *mm = current->mm;
1128 struct mempolicy *new;
1131 LIST_HEAD(pagelist);
1133 if (flags & ~(unsigned long)(MPOL_MF_STRICT |
1134 MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1136 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1139 if (start & ~PAGE_MASK)
1142 if (mode == MPOL_DEFAULT)
1143 flags &= ~MPOL_MF_STRICT;
1145 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1153 new = mpol_new(mode, mode_flags, nmask);
1155 return PTR_ERR(new);
1158 * If we are using the default policy then operation
1159 * on discontinuous address spaces is okay after all
1162 flags |= MPOL_MF_DISCONTIG_OK;
1164 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1165 start, start + len, mode, mode_flags,
1166 nmask ? nodes_addr(*nmask)[0] : -1);
1168 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1170 err = migrate_prep();
1175 NODEMASK_SCRATCH(scratch);
1177 down_write(&mm->mmap_sem);
1179 err = mpol_set_nodemask(new, nmask, scratch);
1180 task_unlock(current);
1182 up_write(&mm->mmap_sem);
1185 NODEMASK_SCRATCH_FREE(scratch);
1190 vma = check_range(mm, start, end, nmask,
1191 flags | MPOL_MF_INVERT, &pagelist);
1197 err = mbind_range(mm, start, end, new);
1199 if (!list_empty(&pagelist)) {
1200 nr_failed = migrate_pages(&pagelist, new_vma_page,
1202 false, MIGRATE_SYNC);
1204 putback_lru_pages(&pagelist);
1207 if (!err && nr_failed && (flags & MPOL_MF_STRICT))
1210 putback_lru_pages(&pagelist);
1212 up_write(&mm->mmap_sem);
1219 * User space interface with variable sized bitmaps for nodelists.
1222 /* Copy a node mask from user space. */
1223 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1224 unsigned long maxnode)
1227 unsigned long nlongs;
1228 unsigned long endmask;
1231 nodes_clear(*nodes);
1232 if (maxnode == 0 || !nmask)
1234 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1237 nlongs = BITS_TO_LONGS(maxnode);
1238 if ((maxnode % BITS_PER_LONG) == 0)
1241 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1243 /* When the user specified more nodes than supported just check
1244 if the non supported part is all zero. */
1245 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1246 if (nlongs > PAGE_SIZE/sizeof(long))
1248 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1250 if (get_user(t, nmask + k))
1252 if (k == nlongs - 1) {
1258 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1262 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1264 nodes_addr(*nodes)[nlongs-1] &= endmask;
1268 /* Copy a kernel node mask to user space */
1269 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1272 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1273 const int nbytes = BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long);
1275 if (copy > nbytes) {
1276 if (copy > PAGE_SIZE)
1278 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1282 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1285 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1286 unsigned long, mode, unsigned long __user *, nmask,
1287 unsigned long, maxnode, unsigned, flags)
1291 unsigned short mode_flags;
1293 mode_flags = mode & MPOL_MODE_FLAGS;
1294 mode &= ~MPOL_MODE_FLAGS;
1295 if (mode >= MPOL_MAX)
1297 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1298 (mode_flags & MPOL_F_RELATIVE_NODES))
1300 err = get_nodes(&nodes, nmask, maxnode);
1303 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1306 /* Set the process memory policy */
1307 SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
1308 unsigned long, maxnode)
1312 unsigned short flags;
1314 flags = mode & MPOL_MODE_FLAGS;
1315 mode &= ~MPOL_MODE_FLAGS;
1316 if ((unsigned int)mode >= MPOL_MAX)
1318 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1320 err = get_nodes(&nodes, nmask, maxnode);
1323 return do_set_mempolicy(mode, flags, &nodes);
1326 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1327 const unsigned long __user *, old_nodes,
1328 const unsigned long __user *, new_nodes)
1330 const struct cred *cred = current_cred(), *tcred;
1331 struct mm_struct *mm = NULL;
1332 struct task_struct *task;
1333 nodemask_t task_nodes;
1337 NODEMASK_SCRATCH(scratch);
1342 old = &scratch->mask1;
1343 new = &scratch->mask2;
1345 err = get_nodes(old, old_nodes, maxnode);
1349 err = get_nodes(new, new_nodes, maxnode);
1353 /* Find the mm_struct */
1355 task = pid ? find_task_by_vpid(pid) : current;
1361 get_task_struct(task);
1366 * Check if this process has the right to modify the specified
1367 * process. The right exists if the process has administrative
1368 * capabilities, superuser privileges or the same
1369 * userid as the target process.
1371 tcred = __task_cred(task);
1372 if (!uid_eq(cred->euid, tcred->suid) && !uid_eq(cred->euid, tcred->uid) &&
1373 !uid_eq(cred->uid, tcred->suid) && !uid_eq(cred->uid, tcred->uid) &&
1374 !capable(CAP_SYS_NICE)) {
1381 task_nodes = cpuset_mems_allowed(task);
1382 /* Is the user allowed to access the target nodes? */
1383 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1388 if (!nodes_subset(*new, node_states[N_HIGH_MEMORY])) {
1393 err = security_task_movememory(task);
1397 mm = get_task_mm(task);
1398 put_task_struct(task);
1405 err = do_migrate_pages(mm, old, new,
1406 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1410 NODEMASK_SCRATCH_FREE(scratch);
1415 put_task_struct(task);
1421 /* Retrieve NUMA policy */
1422 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1423 unsigned long __user *, nmask, unsigned long, maxnode,
1424 unsigned long, addr, unsigned long, flags)
1427 int uninitialized_var(pval);
1430 if (nmask != NULL && maxnode < MAX_NUMNODES)
1433 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1438 if (policy && put_user(pval, policy))
1442 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1447 #ifdef CONFIG_COMPAT
1449 asmlinkage long compat_sys_get_mempolicy(int __user *policy,
1450 compat_ulong_t __user *nmask,
1451 compat_ulong_t maxnode,
1452 compat_ulong_t addr, compat_ulong_t flags)
1455 unsigned long __user *nm = NULL;
1456 unsigned long nr_bits, alloc_size;
1457 DECLARE_BITMAP(bm, MAX_NUMNODES);
1459 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1460 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1463 nm = compat_alloc_user_space(alloc_size);
1465 err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1467 if (!err && nmask) {
1468 unsigned long copy_size;
1469 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1470 err = copy_from_user(bm, nm, copy_size);
1471 /* ensure entire bitmap is zeroed */
1472 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1473 err |= compat_put_bitmap(nmask, bm, nr_bits);
1479 asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
1480 compat_ulong_t maxnode)
1483 unsigned long __user *nm = NULL;
1484 unsigned long nr_bits, alloc_size;
1485 DECLARE_BITMAP(bm, MAX_NUMNODES);
1487 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1488 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1491 err = compat_get_bitmap(bm, nmask, nr_bits);
1492 nm = compat_alloc_user_space(alloc_size);
1493 err |= copy_to_user(nm, bm, alloc_size);
1499 return sys_set_mempolicy(mode, nm, nr_bits+1);
1502 asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
1503 compat_ulong_t mode, compat_ulong_t __user *nmask,
1504 compat_ulong_t maxnode, compat_ulong_t flags)
1507 unsigned long __user *nm = NULL;
1508 unsigned long nr_bits, alloc_size;
1511 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1512 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1515 err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
1516 nm = compat_alloc_user_space(alloc_size);
1517 err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
1523 return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
1529 * get_vma_policy(@task, @vma, @addr)
1530 * @task - task for fallback if vma policy == default
1531 * @vma - virtual memory area whose policy is sought
1532 * @addr - address in @vma for shared policy lookup
1534 * Returns effective policy for a VMA at specified address.
1535 * Falls back to @task or system default policy, as necessary.
1536 * Current or other task's task mempolicy and non-shared vma policies
1537 * are protected by the task's mmap_sem, which must be held for read by
1539 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1540 * count--added by the get_policy() vm_op, as appropriate--to protect against
1541 * freeing by another task. It is the caller's responsibility to free the
1542 * extra reference for shared policies.
1544 struct mempolicy *get_vma_policy(struct task_struct *task,
1545 struct vm_area_struct *vma, unsigned long addr)
1547 struct mempolicy *pol = task->mempolicy;
1550 if (vma->vm_ops && vma->vm_ops->get_policy) {
1551 struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
1555 } else if (vma->vm_policy) {
1556 pol = vma->vm_policy;
1559 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1560 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1561 * count on these policies which will be dropped by
1562 * mpol_cond_put() later
1564 if (mpol_needs_cond_ref(pol))
1569 pol = &default_policy;
1574 * Return a nodemask representing a mempolicy for filtering nodes for
1577 static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1579 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1580 if (unlikely(policy->mode == MPOL_BIND) &&
1581 gfp_zone(gfp) >= policy_zone &&
1582 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1583 return &policy->v.nodes;
1588 /* Return a zonelist indicated by gfp for node representing a mempolicy */
1589 static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
1592 switch (policy->mode) {
1593 case MPOL_PREFERRED:
1594 if (!(policy->flags & MPOL_F_LOCAL))
1595 nd = policy->v.preferred_node;
1599 * Normally, MPOL_BIND allocations are node-local within the
1600 * allowed nodemask. However, if __GFP_THISNODE is set and the
1601 * current node isn't part of the mask, we use the zonelist for
1602 * the first node in the mask instead.
1604 if (unlikely(gfp & __GFP_THISNODE) &&
1605 unlikely(!node_isset(nd, policy->v.nodes)))
1606 nd = first_node(policy->v.nodes);
1611 return node_zonelist(nd, gfp);
1614 /* Do dynamic interleaving for a process */
1615 static unsigned interleave_nodes(struct mempolicy *policy)
1618 struct task_struct *me = current;
1621 next = next_node(nid, policy->v.nodes);
1622 if (next >= MAX_NUMNODES)
1623 next = first_node(policy->v.nodes);
1624 if (next < MAX_NUMNODES)
1630 * Depending on the memory policy provide a node from which to allocate the
1632 * @policy must be protected by freeing by the caller. If @policy is
1633 * the current task's mempolicy, this protection is implicit, as only the
1634 * task can change it's policy. The system default policy requires no
1637 unsigned slab_node(void)
1639 struct mempolicy *policy;
1642 return numa_node_id();
1644 policy = current->mempolicy;
1645 if (!policy || policy->flags & MPOL_F_LOCAL)
1646 return numa_node_id();
1648 switch (policy->mode) {
1649 case MPOL_PREFERRED:
1651 * handled MPOL_F_LOCAL above
1653 return policy->v.preferred_node;
1655 case MPOL_INTERLEAVE:
1656 return interleave_nodes(policy);
1660 * Follow bind policy behavior and start allocation at the
1663 struct zonelist *zonelist;
1665 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1666 zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
1667 (void)first_zones_zonelist(zonelist, highest_zoneidx,
1670 return zone ? zone->node : numa_node_id();
1678 /* Do static interleaving for a VMA with known offset. */
1679 static unsigned offset_il_node(struct mempolicy *pol,
1680 struct vm_area_struct *vma, unsigned long off)
1682 unsigned nnodes = nodes_weight(pol->v.nodes);
1688 return numa_node_id();
1689 target = (unsigned int)off % nnodes;
1692 nid = next_node(nid, pol->v.nodes);
1694 } while (c <= target);
1698 /* Determine a node number for interleave */
1699 static inline unsigned interleave_nid(struct mempolicy *pol,
1700 struct vm_area_struct *vma, unsigned long addr, int shift)
1706 * for small pages, there is no difference between
1707 * shift and PAGE_SHIFT, so the bit-shift is safe.
1708 * for huge pages, since vm_pgoff is in units of small
1709 * pages, we need to shift off the always 0 bits to get
1712 BUG_ON(shift < PAGE_SHIFT);
1713 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1714 off += (addr - vma->vm_start) >> shift;
1715 return offset_il_node(pol, vma, off);
1717 return interleave_nodes(pol);
1721 * Return the bit number of a random bit set in the nodemask.
1722 * (returns -1 if nodemask is empty)
1724 int node_random(const nodemask_t *maskp)
1728 w = nodes_weight(*maskp);
1730 bit = bitmap_ord_to_pos(maskp->bits,
1731 get_random_int() % w, MAX_NUMNODES);
1735 #ifdef CONFIG_HUGETLBFS
1737 * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
1738 * @vma = virtual memory area whose policy is sought
1739 * @addr = address in @vma for shared policy lookup and interleave policy
1740 * @gfp_flags = for requested zone
1741 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
1742 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1744 * Returns a zonelist suitable for a huge page allocation and a pointer
1745 * to the struct mempolicy for conditional unref after allocation.
1746 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1747 * @nodemask for filtering the zonelist.
1749 * Must be protected by get_mems_allowed()
1751 struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1752 gfp_t gfp_flags, struct mempolicy **mpol,
1753 nodemask_t **nodemask)
1755 struct zonelist *zl;
1757 *mpol = get_vma_policy(current, vma, addr);
1758 *nodemask = NULL; /* assume !MPOL_BIND */
1760 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1761 zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1762 huge_page_shift(hstate_vma(vma))), gfp_flags);
1764 zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1765 if ((*mpol)->mode == MPOL_BIND)
1766 *nodemask = &(*mpol)->v.nodes;
1772 * init_nodemask_of_mempolicy
1774 * If the current task's mempolicy is "default" [NULL], return 'false'
1775 * to indicate default policy. Otherwise, extract the policy nodemask
1776 * for 'bind' or 'interleave' policy into the argument nodemask, or
1777 * initialize the argument nodemask to contain the single node for
1778 * 'preferred' or 'local' policy and return 'true' to indicate presence
1779 * of non-default mempolicy.
1781 * We don't bother with reference counting the mempolicy [mpol_get/put]
1782 * because the current task is examining it's own mempolicy and a task's
1783 * mempolicy is only ever changed by the task itself.
1785 * N.B., it is the caller's responsibility to free a returned nodemask.
1787 bool init_nodemask_of_mempolicy(nodemask_t *mask)
1789 struct mempolicy *mempolicy;
1792 if (!(mask && current->mempolicy))
1796 mempolicy = current->mempolicy;
1797 switch (mempolicy->mode) {
1798 case MPOL_PREFERRED:
1799 if (mempolicy->flags & MPOL_F_LOCAL)
1800 nid = numa_node_id();
1802 nid = mempolicy->v.preferred_node;
1803 init_nodemask_of_node(mask, nid);
1808 case MPOL_INTERLEAVE:
1809 *mask = mempolicy->v.nodes;
1815 task_unlock(current);
1822 * mempolicy_nodemask_intersects
1824 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
1825 * policy. Otherwise, check for intersection between mask and the policy
1826 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
1827 * policy, always return true since it may allocate elsewhere on fallback.
1829 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
1831 bool mempolicy_nodemask_intersects(struct task_struct *tsk,
1832 const nodemask_t *mask)
1834 struct mempolicy *mempolicy;
1840 mempolicy = tsk->mempolicy;
1844 switch (mempolicy->mode) {
1845 case MPOL_PREFERRED:
1847 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
1848 * allocate from, they may fallback to other nodes when oom.
1849 * Thus, it's possible for tsk to have allocated memory from
1854 case MPOL_INTERLEAVE:
1855 ret = nodes_intersects(mempolicy->v.nodes, *mask);
1865 /* Allocate a page in interleaved policy.
1866 Own path because it needs to do special accounting. */
1867 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
1870 struct zonelist *zl;
1873 zl = node_zonelist(nid, gfp);
1874 page = __alloc_pages(gfp, order, zl);
1875 if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1876 inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
1881 * alloc_pages_vma - Allocate a page for a VMA.
1884 * %GFP_USER user allocation.
1885 * %GFP_KERNEL kernel allocations,
1886 * %GFP_HIGHMEM highmem/user allocations,
1887 * %GFP_FS allocation should not call back into a file system.
1888 * %GFP_ATOMIC don't sleep.
1890 * @order:Order of the GFP allocation.
1891 * @vma: Pointer to VMA or NULL if not available.
1892 * @addr: Virtual Address of the allocation. Must be inside the VMA.
1894 * This function allocates a page from the kernel page pool and applies
1895 * a NUMA policy associated with the VMA or the current process.
1896 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
1897 * mm_struct of the VMA to prevent it from going away. Should be used for
1898 * all allocations for pages that will be mapped into
1899 * user space. Returns NULL when no page can be allocated.
1901 * Should be called with the mm_sem of the vma hold.
1904 alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
1905 unsigned long addr, int node)
1907 struct mempolicy *pol;
1908 struct zonelist *zl;
1910 unsigned int cpuset_mems_cookie;
1913 pol = get_vma_policy(current, vma, addr);
1914 cpuset_mems_cookie = get_mems_allowed();
1916 if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
1919 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
1921 page = alloc_page_interleave(gfp, order, nid);
1922 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1927 zl = policy_zonelist(gfp, pol, node);
1928 if (unlikely(mpol_needs_cond_ref(pol))) {
1930 * slow path: ref counted shared policy
1932 struct page *page = __alloc_pages_nodemask(gfp, order,
1933 zl, policy_nodemask(gfp, pol));
1935 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1940 * fast path: default or task policy
1942 page = __alloc_pages_nodemask(gfp, order, zl,
1943 policy_nodemask(gfp, pol));
1944 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1950 * alloc_pages_current - Allocate pages.
1953 * %GFP_USER user allocation,
1954 * %GFP_KERNEL kernel allocation,
1955 * %GFP_HIGHMEM highmem allocation,
1956 * %GFP_FS don't call back into a file system.
1957 * %GFP_ATOMIC don't sleep.
1958 * @order: Power of two of allocation size in pages. 0 is a single page.
1960 * Allocate a page from the kernel page pool. When not in
1961 * interrupt context and apply the current process NUMA policy.
1962 * Returns NULL when no page can be allocated.
1964 * Don't call cpuset_update_task_memory_state() unless
1965 * 1) it's ok to take cpuset_sem (can WAIT), and
1966 * 2) allocating for current task (not interrupt).
1968 struct page *alloc_pages_current(gfp_t gfp, unsigned order)
1970 struct mempolicy *pol = current->mempolicy;
1972 unsigned int cpuset_mems_cookie;
1974 if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
1975 pol = &default_policy;
1978 cpuset_mems_cookie = get_mems_allowed();
1981 * No reference counting needed for current->mempolicy
1982 * nor system default_policy
1984 if (pol->mode == MPOL_INTERLEAVE)
1985 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
1987 page = __alloc_pages_nodemask(gfp, order,
1988 policy_zonelist(gfp, pol, numa_node_id()),
1989 policy_nodemask(gfp, pol));
1991 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1996 EXPORT_SYMBOL(alloc_pages_current);
1999 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2000 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2001 * with the mems_allowed returned by cpuset_mems_allowed(). This
2002 * keeps mempolicies cpuset relative after its cpuset moves. See
2003 * further kernel/cpuset.c update_nodemask().
2005 * current's mempolicy may be rebinded by the other task(the task that changes
2006 * cpuset's mems), so we needn't do rebind work for current task.
2009 /* Slow path of a mempolicy duplicate */
2010 struct mempolicy *__mpol_dup(struct mempolicy *old)
2012 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2015 return ERR_PTR(-ENOMEM);
2017 /* task's mempolicy is protected by alloc_lock */
2018 if (old == current->mempolicy) {
2021 task_unlock(current);
2026 if (current_cpuset_is_being_rebound()) {
2027 nodemask_t mems = cpuset_mems_allowed(current);
2028 if (new->flags & MPOL_F_REBINDING)
2029 mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
2031 mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
2034 atomic_set(&new->refcnt, 1);
2039 * If *frompol needs [has] an extra ref, copy *frompol to *tompol ,
2040 * eliminate the * MPOL_F_* flags that require conditional ref and
2041 * [NOTE!!!] drop the extra ref. Not safe to reference *frompol directly
2042 * after return. Use the returned value.
2044 * Allows use of a mempolicy for, e.g., multiple allocations with a single
2045 * policy lookup, even if the policy needs/has extra ref on lookup.
2046 * shmem_readahead needs this.
2048 struct mempolicy *__mpol_cond_copy(struct mempolicy *tompol,
2049 struct mempolicy *frompol)
2051 if (!mpol_needs_cond_ref(frompol))
2055 tompol->flags &= ~MPOL_F_SHARED; /* copy doesn't need unref */
2056 __mpol_put(frompol);
2060 /* Slow path of a mempolicy comparison */
2061 bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2065 if (a->mode != b->mode)
2067 if (a->flags != b->flags)
2069 if (mpol_store_user_nodemask(a))
2070 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2076 case MPOL_INTERLEAVE:
2077 return !!nodes_equal(a->v.nodes, b->v.nodes);
2078 case MPOL_PREFERRED:
2079 return a->v.preferred_node == b->v.preferred_node;
2087 * Shared memory backing store policy support.
2089 * Remember policies even when nobody has shared memory mapped.
2090 * The policies are kept in Red-Black tree linked from the inode.
2091 * They are protected by the sp->lock spinlock, which should be held
2092 * for any accesses to the tree.
2095 /* lookup first element intersecting start-end */
2096 /* Caller holds sp->mutex */
2097 static struct sp_node *
2098 sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2100 struct rb_node *n = sp->root.rb_node;
2103 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2105 if (start >= p->end)
2107 else if (end <= p->start)
2115 struct sp_node *w = NULL;
2116 struct rb_node *prev = rb_prev(n);
2119 w = rb_entry(prev, struct sp_node, nd);
2120 if (w->end <= start)
2124 return rb_entry(n, struct sp_node, nd);
2127 /* Insert a new shared policy into the list. */
2128 /* Caller holds sp->lock */
2129 static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2131 struct rb_node **p = &sp->root.rb_node;
2132 struct rb_node *parent = NULL;
2137 nd = rb_entry(parent, struct sp_node, nd);
2138 if (new->start < nd->start)
2140 else if (new->end > nd->end)
2141 p = &(*p)->rb_right;
2145 rb_link_node(&new->nd, parent, p);
2146 rb_insert_color(&new->nd, &sp->root);
2147 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2148 new->policy ? new->policy->mode : 0);
2151 /* Find shared policy intersecting idx */
2153 mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2155 struct mempolicy *pol = NULL;
2158 if (!sp->root.rb_node)
2160 mutex_lock(&sp->mutex);
2161 sn = sp_lookup(sp, idx, idx+1);
2163 mpol_get(sn->policy);
2166 mutex_unlock(&sp->mutex);
2170 static void sp_free(struct sp_node *n)
2172 mpol_put(n->policy);
2173 kmem_cache_free(sn_cache, n);
2176 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2178 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2179 rb_erase(&n->nd, &sp->root);
2183 static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2184 struct mempolicy *pol)
2187 struct mempolicy *newpol;
2189 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2193 newpol = mpol_dup(pol);
2194 if (IS_ERR(newpol)) {
2195 kmem_cache_free(sn_cache, n);
2198 newpol->flags |= MPOL_F_SHARED;
2207 /* Replace a policy range. */
2208 static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2209 unsigned long end, struct sp_node *new)
2214 mutex_lock(&sp->mutex);
2215 n = sp_lookup(sp, start, end);
2216 /* Take care of old policies in the same range. */
2217 while (n && n->start < end) {
2218 struct rb_node *next = rb_next(&n->nd);
2219 if (n->start >= start) {
2225 /* Old policy spanning whole new range. */
2227 struct sp_node *new2;
2228 new2 = sp_alloc(end, n->end, n->policy);
2234 sp_insert(sp, new2);
2241 n = rb_entry(next, struct sp_node, nd);
2246 mutex_unlock(&sp->mutex);
2251 * mpol_shared_policy_init - initialize shared policy for inode
2252 * @sp: pointer to inode shared policy
2253 * @mpol: struct mempolicy to install
2255 * Install non-NULL @mpol in inode's shared policy rb-tree.
2256 * On entry, the current task has a reference on a non-NULL @mpol.
2257 * This must be released on exit.
2258 * This is called at get_inode() calls and we can use GFP_KERNEL.
2260 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2264 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2265 mutex_init(&sp->mutex);
2268 struct vm_area_struct pvma;
2269 struct mempolicy *new;
2270 NODEMASK_SCRATCH(scratch);
2274 /* contextualize the tmpfs mount point mempolicy */
2275 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2277 goto free_scratch; /* no valid nodemask intersection */
2280 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2281 task_unlock(current);
2285 /* Create pseudo-vma that contains just the policy */
2286 memset(&pvma, 0, sizeof(struct vm_area_struct));
2287 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2288 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2291 mpol_put(new); /* drop initial ref */
2293 NODEMASK_SCRATCH_FREE(scratch);
2295 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2299 int mpol_set_shared_policy(struct shared_policy *info,
2300 struct vm_area_struct *vma, struct mempolicy *npol)
2303 struct sp_node *new = NULL;
2304 unsigned long sz = vma_pages(vma);
2306 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2308 sz, npol ? npol->mode : -1,
2309 npol ? npol->flags : -1,
2310 npol ? nodes_addr(npol->v.nodes)[0] : -1);
2313 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2317 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2323 /* Free a backing policy store on inode delete. */
2324 void mpol_free_shared_policy(struct shared_policy *p)
2327 struct rb_node *next;
2329 if (!p->root.rb_node)
2331 mutex_lock(&p->mutex);
2332 next = rb_first(&p->root);
2334 n = rb_entry(next, struct sp_node, nd);
2335 next = rb_next(&n->nd);
2338 mutex_unlock(&p->mutex);
2341 /* assumes fs == KERNEL_DS */
2342 void __init numa_policy_init(void)
2344 nodemask_t interleave_nodes;
2345 unsigned long largest = 0;
2346 int nid, prefer = 0;
2348 policy_cache = kmem_cache_create("numa_policy",
2349 sizeof(struct mempolicy),
2350 0, SLAB_PANIC, NULL);
2352 sn_cache = kmem_cache_create("shared_policy_node",
2353 sizeof(struct sp_node),
2354 0, SLAB_PANIC, NULL);
2357 * Set interleaving policy for system init. Interleaving is only
2358 * enabled across suitably sized nodes (default is >= 16MB), or
2359 * fall back to the largest node if they're all smaller.
2361 nodes_clear(interleave_nodes);
2362 for_each_node_state(nid, N_HIGH_MEMORY) {
2363 unsigned long total_pages = node_present_pages(nid);
2365 /* Preserve the largest node */
2366 if (largest < total_pages) {
2367 largest = total_pages;
2371 /* Interleave this node? */
2372 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2373 node_set(nid, interleave_nodes);
2376 /* All too small, use the largest */
2377 if (unlikely(nodes_empty(interleave_nodes)))
2378 node_set(prefer, interleave_nodes);
2380 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2381 printk("numa_policy_init: interleaving failed\n");
2384 /* Reset policy of current process to default */
2385 void numa_default_policy(void)
2387 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2391 * Parse and format mempolicy from/to strings
2395 * "local" is pseudo-policy: MPOL_PREFERRED with MPOL_F_LOCAL flag
2396 * Used only for mpol_parse_str() and mpol_to_str()
2398 #define MPOL_LOCAL MPOL_MAX
2399 static const char * const policy_modes[] =
2401 [MPOL_DEFAULT] = "default",
2402 [MPOL_PREFERRED] = "prefer",
2403 [MPOL_BIND] = "bind",
2404 [MPOL_INTERLEAVE] = "interleave",
2405 [MPOL_LOCAL] = "local"
2411 * mpol_parse_str - parse string to mempolicy
2412 * @str: string containing mempolicy to parse
2413 * @mpol: pointer to struct mempolicy pointer, returned on success.
2414 * @no_context: flag whether to "contextualize" the mempolicy
2417 * <mode>[=<flags>][:<nodelist>]
2419 * if @no_context is true, save the input nodemask in w.user_nodemask in
2420 * the returned mempolicy. This will be used to "clone" the mempolicy in
2421 * a specific context [cpuset] at a later time. Used to parse tmpfs mpol
2422 * mount option. Note that if 'static' or 'relative' mode flags were
2423 * specified, the input nodemask will already have been saved. Saving
2424 * it again is redundant, but safe.
2426 * On success, returns 0, else 1
2428 int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context)
2430 struct mempolicy *new = NULL;
2431 unsigned short mode;
2432 unsigned short uninitialized_var(mode_flags);
2434 char *nodelist = strchr(str, ':');
2435 char *flags = strchr(str, '=');
2439 /* NUL-terminate mode or flags string */
2441 if (nodelist_parse(nodelist, nodes))
2443 if (!nodes_subset(nodes, node_states[N_HIGH_MEMORY]))
2449 *flags++ = '\0'; /* terminate mode string */
2451 for (mode = 0; mode <= MPOL_LOCAL; mode++) {
2452 if (!strcmp(str, policy_modes[mode])) {
2456 if (mode > MPOL_LOCAL)
2460 case MPOL_PREFERRED:
2462 * Insist on a nodelist of one node only
2465 char *rest = nodelist;
2466 while (isdigit(*rest))
2472 case MPOL_INTERLEAVE:
2474 * Default to online nodes with memory if no nodelist
2477 nodes = node_states[N_HIGH_MEMORY];
2481 * Don't allow a nodelist; mpol_new() checks flags
2485 mode = MPOL_PREFERRED;
2489 * Insist on a empty nodelist
2496 * Insist on a nodelist
2505 * Currently, we only support two mutually exclusive
2508 if (!strcmp(flags, "static"))
2509 mode_flags |= MPOL_F_STATIC_NODES;
2510 else if (!strcmp(flags, "relative"))
2511 mode_flags |= MPOL_F_RELATIVE_NODES;
2516 new = mpol_new(mode, mode_flags, &nodes);
2521 /* save for contextualization */
2522 new->w.user_nodemask = nodes;
2525 NODEMASK_SCRATCH(scratch);
2528 ret = mpol_set_nodemask(new, &nodes, scratch);
2529 task_unlock(current);
2532 NODEMASK_SCRATCH_FREE(scratch);
2541 /* Restore string for error message */
2550 #endif /* CONFIG_TMPFS */
2553 * mpol_to_str - format a mempolicy structure for printing
2554 * @buffer: to contain formatted mempolicy string
2555 * @maxlen: length of @buffer
2556 * @pol: pointer to mempolicy to be formatted
2557 * @no_context: "context free" mempolicy - use nodemask in w.user_nodemask
2559 * Convert a mempolicy into a string.
2560 * Returns the number of characters in buffer (if positive)
2561 * or an error (negative)
2563 int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol, int no_context)
2568 unsigned short mode;
2569 unsigned short flags = pol ? pol->flags : 0;
2572 * Sanity check: room for longest mode, flag and some nodes
2574 VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
2576 if (!pol || pol == &default_policy)
2577 mode = MPOL_DEFAULT;
2586 case MPOL_PREFERRED:
2588 if (flags & MPOL_F_LOCAL)
2589 mode = MPOL_LOCAL; /* pseudo-policy */
2591 node_set(pol->v.preferred_node, nodes);
2596 case MPOL_INTERLEAVE:
2598 nodes = pol->w.user_nodemask;
2600 nodes = pol->v.nodes;
2607 l = strlen(policy_modes[mode]);
2608 if (buffer + maxlen < p + l + 1)
2611 strcpy(p, policy_modes[mode]);
2614 if (flags & MPOL_MODE_FLAGS) {
2615 if (buffer + maxlen < p + 2)
2620 * Currently, the only defined flags are mutually exclusive
2622 if (flags & MPOL_F_STATIC_NODES)
2623 p += snprintf(p, buffer + maxlen - p, "static");
2624 else if (flags & MPOL_F_RELATIVE_NODES)
2625 p += snprintf(p, buffer + maxlen - p, "relative");
2628 if (!nodes_empty(nodes)) {
2629 if (buffer + maxlen < p + 2)
2632 p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);