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,
951 node_set(source, nmask);
954 * This does not "check" the range but isolates all pages that
955 * need migration. Between passing in the full user address
956 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
958 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
959 check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
960 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
962 if (!list_empty(&pagelist)) {
963 err = migrate_pages(&pagelist, new_node_page, dest,
967 putback_lru_pages(&pagelist);
974 * Move pages between the two nodesets so as to preserve the physical
975 * layout as much as possible.
977 * Returns the number of page that could not be moved.
979 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
980 const nodemask_t *to, int flags)
986 err = migrate_prep();
990 down_read(&mm->mmap_sem);
992 err = migrate_vmas(mm, from, to, flags);
997 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
998 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
999 * bit in 'tmp', and return that <source, dest> pair for migration.
1000 * The pair of nodemasks 'to' and 'from' define the map.
1002 * If no pair of bits is found that way, fallback to picking some
1003 * pair of 'source' and 'dest' bits that are not the same. If the
1004 * 'source' and 'dest' bits are the same, this represents a node
1005 * that will be migrating to itself, so no pages need move.
1007 * If no bits are left in 'tmp', or if all remaining bits left
1008 * in 'tmp' correspond to the same bit in 'to', return false
1009 * (nothing left to migrate).
1011 * This lets us pick a pair of nodes to migrate between, such that
1012 * if possible the dest node is not already occupied by some other
1013 * source node, minimizing the risk of overloading the memory on a
1014 * node that would happen if we migrated incoming memory to a node
1015 * before migrating outgoing memory source that same node.
1017 * A single scan of tmp is sufficient. As we go, we remember the
1018 * most recent <s, d> pair that moved (s != d). If we find a pair
1019 * that not only moved, but what's better, moved to an empty slot
1020 * (d is not set in tmp), then we break out then, with that pair.
1021 * Otherwise when we finish scanning from_tmp, we at least have the
1022 * most recent <s, d> pair that moved. If we get all the way through
1023 * the scan of tmp without finding any node that moved, much less
1024 * moved to an empty node, then there is nothing left worth migrating.
1028 while (!nodes_empty(tmp)) {
1033 for_each_node_mask(s, tmp) {
1036 * do_migrate_pages() tries to maintain the relative
1037 * node relationship of the pages established between
1038 * threads and memory areas.
1040 * However if the number of source nodes is not equal to
1041 * the number of destination nodes we can not preserve
1042 * this node relative relationship. In that case, skip
1043 * copying memory from a node that is in the destination
1046 * Example: [2,3,4] -> [3,4,5] moves everything.
1047 * [0-7] - > [3,4,5] moves only 0,1,2,6,7.
1050 if ((nodes_weight(*from) != nodes_weight(*to)) &&
1051 (node_isset(s, *to)))
1054 d = node_remap(s, *from, *to);
1058 source = s; /* Node moved. Memorize */
1061 /* dest not in remaining from nodes? */
1062 if (!node_isset(dest, tmp))
1068 node_clear(source, tmp);
1069 err = migrate_to_node(mm, source, dest, flags);
1076 up_read(&mm->mmap_sem);
1084 * Allocate a new page for page migration based on vma policy.
1085 * Start assuming that page is mapped by vma pointed to by @private.
1086 * Search forward from there, if not. N.B., this assumes that the
1087 * list of pages handed to migrate_pages()--which is how we get here--
1088 * is in virtual address order.
1090 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1092 struct vm_area_struct *vma = (struct vm_area_struct *)private;
1093 unsigned long uninitialized_var(address);
1096 address = page_address_in_vma(page, vma);
1097 if (address != -EFAULT)
1103 * if !vma, alloc_page_vma() will use task or system default policy
1105 return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1109 static void migrate_page_add(struct page *page, struct list_head *pagelist,
1110 unsigned long flags)
1114 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
1115 const nodemask_t *to, int flags)
1120 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1126 static long do_mbind(unsigned long start, unsigned long len,
1127 unsigned short mode, unsigned short mode_flags,
1128 nodemask_t *nmask, unsigned long flags)
1130 struct vm_area_struct *vma;
1131 struct mm_struct *mm = current->mm;
1132 struct mempolicy *new;
1135 LIST_HEAD(pagelist);
1137 if (flags & ~(unsigned long)(MPOL_MF_STRICT |
1138 MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1140 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1143 if (start & ~PAGE_MASK)
1146 if (mode == MPOL_DEFAULT)
1147 flags &= ~MPOL_MF_STRICT;
1149 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1157 new = mpol_new(mode, mode_flags, nmask);
1159 return PTR_ERR(new);
1162 * If we are using the default policy then operation
1163 * on discontinuous address spaces is okay after all
1166 flags |= MPOL_MF_DISCONTIG_OK;
1168 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1169 start, start + len, mode, mode_flags,
1170 nmask ? nodes_addr(*nmask)[0] : -1);
1172 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1174 err = migrate_prep();
1179 NODEMASK_SCRATCH(scratch);
1181 down_write(&mm->mmap_sem);
1183 err = mpol_set_nodemask(new, nmask, scratch);
1184 task_unlock(current);
1186 up_write(&mm->mmap_sem);
1189 NODEMASK_SCRATCH_FREE(scratch);
1194 vma = check_range(mm, start, end, nmask,
1195 flags | MPOL_MF_INVERT, &pagelist);
1201 err = mbind_range(mm, start, end, new);
1203 if (!list_empty(&pagelist)) {
1204 nr_failed = migrate_pages(&pagelist, new_vma_page,
1206 false, MIGRATE_SYNC,
1207 MR_MEMPOLICY_MBIND);
1209 putback_lru_pages(&pagelist);
1212 if (!err && nr_failed && (flags & MPOL_MF_STRICT))
1215 putback_lru_pages(&pagelist);
1217 up_write(&mm->mmap_sem);
1224 * User space interface with variable sized bitmaps for nodelists.
1227 /* Copy a node mask from user space. */
1228 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1229 unsigned long maxnode)
1232 unsigned long nlongs;
1233 unsigned long endmask;
1236 nodes_clear(*nodes);
1237 if (maxnode == 0 || !nmask)
1239 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1242 nlongs = BITS_TO_LONGS(maxnode);
1243 if ((maxnode % BITS_PER_LONG) == 0)
1246 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1248 /* When the user specified more nodes than supported just check
1249 if the non supported part is all zero. */
1250 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1251 if (nlongs > PAGE_SIZE/sizeof(long))
1253 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1255 if (get_user(t, nmask + k))
1257 if (k == nlongs - 1) {
1263 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1267 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1269 nodes_addr(*nodes)[nlongs-1] &= endmask;
1273 /* Copy a kernel node mask to user space */
1274 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1277 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1278 const int nbytes = BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long);
1280 if (copy > nbytes) {
1281 if (copy > PAGE_SIZE)
1283 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1287 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1290 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1291 unsigned long, mode, unsigned long __user *, nmask,
1292 unsigned long, maxnode, unsigned, flags)
1296 unsigned short mode_flags;
1298 mode_flags = mode & MPOL_MODE_FLAGS;
1299 mode &= ~MPOL_MODE_FLAGS;
1300 if (mode >= MPOL_MAX)
1302 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1303 (mode_flags & MPOL_F_RELATIVE_NODES))
1305 err = get_nodes(&nodes, nmask, maxnode);
1308 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1311 /* Set the process memory policy */
1312 SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
1313 unsigned long, maxnode)
1317 unsigned short flags;
1319 flags = mode & MPOL_MODE_FLAGS;
1320 mode &= ~MPOL_MODE_FLAGS;
1321 if ((unsigned int)mode >= MPOL_MAX)
1323 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1325 err = get_nodes(&nodes, nmask, maxnode);
1328 return do_set_mempolicy(mode, flags, &nodes);
1331 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1332 const unsigned long __user *, old_nodes,
1333 const unsigned long __user *, new_nodes)
1335 const struct cred *cred = current_cred(), *tcred;
1336 struct mm_struct *mm = NULL;
1337 struct task_struct *task;
1338 nodemask_t task_nodes;
1342 NODEMASK_SCRATCH(scratch);
1347 old = &scratch->mask1;
1348 new = &scratch->mask2;
1350 err = get_nodes(old, old_nodes, maxnode);
1354 err = get_nodes(new, new_nodes, maxnode);
1358 /* Find the mm_struct */
1360 task = pid ? find_task_by_vpid(pid) : current;
1366 get_task_struct(task);
1371 * Check if this process has the right to modify the specified
1372 * process. The right exists if the process has administrative
1373 * capabilities, superuser privileges or the same
1374 * userid as the target process.
1376 tcred = __task_cred(task);
1377 if (!uid_eq(cred->euid, tcred->suid) && !uid_eq(cred->euid, tcred->uid) &&
1378 !uid_eq(cred->uid, tcred->suid) && !uid_eq(cred->uid, tcred->uid) &&
1379 !capable(CAP_SYS_NICE)) {
1386 task_nodes = cpuset_mems_allowed(task);
1387 /* Is the user allowed to access the target nodes? */
1388 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1393 if (!nodes_subset(*new, node_states[N_HIGH_MEMORY])) {
1398 err = security_task_movememory(task);
1402 mm = get_task_mm(task);
1403 put_task_struct(task);
1410 err = do_migrate_pages(mm, old, new,
1411 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1415 NODEMASK_SCRATCH_FREE(scratch);
1420 put_task_struct(task);
1426 /* Retrieve NUMA policy */
1427 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1428 unsigned long __user *, nmask, unsigned long, maxnode,
1429 unsigned long, addr, unsigned long, flags)
1432 int uninitialized_var(pval);
1435 if (nmask != NULL && maxnode < MAX_NUMNODES)
1438 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1443 if (policy && put_user(pval, policy))
1447 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1452 #ifdef CONFIG_COMPAT
1454 asmlinkage long compat_sys_get_mempolicy(int __user *policy,
1455 compat_ulong_t __user *nmask,
1456 compat_ulong_t maxnode,
1457 compat_ulong_t addr, compat_ulong_t flags)
1460 unsigned long __user *nm = NULL;
1461 unsigned long nr_bits, alloc_size;
1462 DECLARE_BITMAP(bm, MAX_NUMNODES);
1464 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1465 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1468 nm = compat_alloc_user_space(alloc_size);
1470 err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1472 if (!err && nmask) {
1473 unsigned long copy_size;
1474 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1475 err = copy_from_user(bm, nm, copy_size);
1476 /* ensure entire bitmap is zeroed */
1477 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1478 err |= compat_put_bitmap(nmask, bm, nr_bits);
1484 asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
1485 compat_ulong_t maxnode)
1488 unsigned long __user *nm = NULL;
1489 unsigned long nr_bits, alloc_size;
1490 DECLARE_BITMAP(bm, MAX_NUMNODES);
1492 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1493 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1496 err = compat_get_bitmap(bm, nmask, nr_bits);
1497 nm = compat_alloc_user_space(alloc_size);
1498 err |= copy_to_user(nm, bm, alloc_size);
1504 return sys_set_mempolicy(mode, nm, nr_bits+1);
1507 asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
1508 compat_ulong_t mode, compat_ulong_t __user *nmask,
1509 compat_ulong_t maxnode, compat_ulong_t flags)
1512 unsigned long __user *nm = NULL;
1513 unsigned long nr_bits, alloc_size;
1516 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1517 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1520 err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
1521 nm = compat_alloc_user_space(alloc_size);
1522 err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
1528 return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
1534 * get_vma_policy(@task, @vma, @addr)
1535 * @task - task for fallback if vma policy == default
1536 * @vma - virtual memory area whose policy is sought
1537 * @addr - address in @vma for shared policy lookup
1539 * Returns effective policy for a VMA at specified address.
1540 * Falls back to @task or system default policy, as necessary.
1541 * Current or other task's task mempolicy and non-shared vma policies must be
1542 * protected by task_lock(task) by the caller.
1543 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1544 * count--added by the get_policy() vm_op, as appropriate--to protect against
1545 * freeing by another task. It is the caller's responsibility to free the
1546 * extra reference for shared policies.
1548 struct mempolicy *get_vma_policy(struct task_struct *task,
1549 struct vm_area_struct *vma, unsigned long addr)
1551 struct mempolicy *pol = task->mempolicy;
1554 if (vma->vm_ops && vma->vm_ops->get_policy) {
1555 struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
1559 } else if (vma->vm_policy) {
1560 pol = vma->vm_policy;
1563 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1564 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1565 * count on these policies which will be dropped by
1566 * mpol_cond_put() later
1568 if (mpol_needs_cond_ref(pol))
1573 pol = &default_policy;
1578 * Return a nodemask representing a mempolicy for filtering nodes for
1581 static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1583 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1584 if (unlikely(policy->mode == MPOL_BIND) &&
1585 gfp_zone(gfp) >= policy_zone &&
1586 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1587 return &policy->v.nodes;
1592 /* Return a zonelist indicated by gfp for node representing a mempolicy */
1593 static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
1596 switch (policy->mode) {
1597 case MPOL_PREFERRED:
1598 if (!(policy->flags & MPOL_F_LOCAL))
1599 nd = policy->v.preferred_node;
1603 * Normally, MPOL_BIND allocations are node-local within the
1604 * allowed nodemask. However, if __GFP_THISNODE is set and the
1605 * current node isn't part of the mask, we use the zonelist for
1606 * the first node in the mask instead.
1608 if (unlikely(gfp & __GFP_THISNODE) &&
1609 unlikely(!node_isset(nd, policy->v.nodes)))
1610 nd = first_node(policy->v.nodes);
1615 return node_zonelist(nd, gfp);
1618 /* Do dynamic interleaving for a process */
1619 static unsigned interleave_nodes(struct mempolicy *policy)
1622 struct task_struct *me = current;
1625 next = next_node(nid, policy->v.nodes);
1626 if (next >= MAX_NUMNODES)
1627 next = first_node(policy->v.nodes);
1628 if (next < MAX_NUMNODES)
1634 * Depending on the memory policy provide a node from which to allocate the
1636 * @policy must be protected by freeing by the caller. If @policy is
1637 * the current task's mempolicy, this protection is implicit, as only the
1638 * task can change it's policy. The system default policy requires no
1641 unsigned slab_node(void)
1643 struct mempolicy *policy;
1646 return numa_node_id();
1648 policy = current->mempolicy;
1649 if (!policy || policy->flags & MPOL_F_LOCAL)
1650 return numa_node_id();
1652 switch (policy->mode) {
1653 case MPOL_PREFERRED:
1655 * handled MPOL_F_LOCAL above
1657 return policy->v.preferred_node;
1659 case MPOL_INTERLEAVE:
1660 return interleave_nodes(policy);
1664 * Follow bind policy behavior and start allocation at the
1667 struct zonelist *zonelist;
1669 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1670 zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
1671 (void)first_zones_zonelist(zonelist, highest_zoneidx,
1674 return zone ? zone->node : numa_node_id();
1682 /* Do static interleaving for a VMA with known offset. */
1683 static unsigned offset_il_node(struct mempolicy *pol,
1684 struct vm_area_struct *vma, unsigned long off)
1686 unsigned nnodes = nodes_weight(pol->v.nodes);
1692 return numa_node_id();
1693 target = (unsigned int)off % nnodes;
1696 nid = next_node(nid, pol->v.nodes);
1698 } while (c <= target);
1702 /* Determine a node number for interleave */
1703 static inline unsigned interleave_nid(struct mempolicy *pol,
1704 struct vm_area_struct *vma, unsigned long addr, int shift)
1710 * for small pages, there is no difference between
1711 * shift and PAGE_SHIFT, so the bit-shift is safe.
1712 * for huge pages, since vm_pgoff is in units of small
1713 * pages, we need to shift off the always 0 bits to get
1716 BUG_ON(shift < PAGE_SHIFT);
1717 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1718 off += (addr - vma->vm_start) >> shift;
1719 return offset_il_node(pol, vma, off);
1721 return interleave_nodes(pol);
1725 * Return the bit number of a random bit set in the nodemask.
1726 * (returns -1 if nodemask is empty)
1728 int node_random(const nodemask_t *maskp)
1732 w = nodes_weight(*maskp);
1734 bit = bitmap_ord_to_pos(maskp->bits,
1735 get_random_int() % w, MAX_NUMNODES);
1739 #ifdef CONFIG_HUGETLBFS
1741 * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
1742 * @vma = virtual memory area whose policy is sought
1743 * @addr = address in @vma for shared policy lookup and interleave policy
1744 * @gfp_flags = for requested zone
1745 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
1746 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1748 * Returns a zonelist suitable for a huge page allocation and a pointer
1749 * to the struct mempolicy for conditional unref after allocation.
1750 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1751 * @nodemask for filtering the zonelist.
1753 * Must be protected by get_mems_allowed()
1755 struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1756 gfp_t gfp_flags, struct mempolicy **mpol,
1757 nodemask_t **nodemask)
1759 struct zonelist *zl;
1761 *mpol = get_vma_policy(current, vma, addr);
1762 *nodemask = NULL; /* assume !MPOL_BIND */
1764 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1765 zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1766 huge_page_shift(hstate_vma(vma))), gfp_flags);
1768 zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1769 if ((*mpol)->mode == MPOL_BIND)
1770 *nodemask = &(*mpol)->v.nodes;
1776 * init_nodemask_of_mempolicy
1778 * If the current task's mempolicy is "default" [NULL], return 'false'
1779 * to indicate default policy. Otherwise, extract the policy nodemask
1780 * for 'bind' or 'interleave' policy into the argument nodemask, or
1781 * initialize the argument nodemask to contain the single node for
1782 * 'preferred' or 'local' policy and return 'true' to indicate presence
1783 * of non-default mempolicy.
1785 * We don't bother with reference counting the mempolicy [mpol_get/put]
1786 * because the current task is examining it's own mempolicy and a task's
1787 * mempolicy is only ever changed by the task itself.
1789 * N.B., it is the caller's responsibility to free a returned nodemask.
1791 bool init_nodemask_of_mempolicy(nodemask_t *mask)
1793 struct mempolicy *mempolicy;
1796 if (!(mask && current->mempolicy))
1800 mempolicy = current->mempolicy;
1801 switch (mempolicy->mode) {
1802 case MPOL_PREFERRED:
1803 if (mempolicy->flags & MPOL_F_LOCAL)
1804 nid = numa_node_id();
1806 nid = mempolicy->v.preferred_node;
1807 init_nodemask_of_node(mask, nid);
1812 case MPOL_INTERLEAVE:
1813 *mask = mempolicy->v.nodes;
1819 task_unlock(current);
1826 * mempolicy_nodemask_intersects
1828 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
1829 * policy. Otherwise, check for intersection between mask and the policy
1830 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
1831 * policy, always return true since it may allocate elsewhere on fallback.
1833 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
1835 bool mempolicy_nodemask_intersects(struct task_struct *tsk,
1836 const nodemask_t *mask)
1838 struct mempolicy *mempolicy;
1844 mempolicy = tsk->mempolicy;
1848 switch (mempolicy->mode) {
1849 case MPOL_PREFERRED:
1851 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
1852 * allocate from, they may fallback to other nodes when oom.
1853 * Thus, it's possible for tsk to have allocated memory from
1858 case MPOL_INTERLEAVE:
1859 ret = nodes_intersects(mempolicy->v.nodes, *mask);
1869 /* Allocate a page in interleaved policy.
1870 Own path because it needs to do special accounting. */
1871 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
1874 struct zonelist *zl;
1877 zl = node_zonelist(nid, gfp);
1878 page = __alloc_pages(gfp, order, zl);
1879 if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1880 inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
1885 * alloc_pages_vma - Allocate a page for a VMA.
1888 * %GFP_USER user allocation.
1889 * %GFP_KERNEL kernel allocations,
1890 * %GFP_HIGHMEM highmem/user allocations,
1891 * %GFP_FS allocation should not call back into a file system.
1892 * %GFP_ATOMIC don't sleep.
1894 * @order:Order of the GFP allocation.
1895 * @vma: Pointer to VMA or NULL if not available.
1896 * @addr: Virtual Address of the allocation. Must be inside the VMA.
1898 * This function allocates a page from the kernel page pool and applies
1899 * a NUMA policy associated with the VMA or the current process.
1900 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
1901 * mm_struct of the VMA to prevent it from going away. Should be used for
1902 * all allocations for pages that will be mapped into
1903 * user space. Returns NULL when no page can be allocated.
1905 * Should be called with the mm_sem of the vma hold.
1908 alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
1909 unsigned long addr, int node)
1911 struct mempolicy *pol;
1912 struct zonelist *zl;
1914 unsigned int cpuset_mems_cookie;
1917 pol = get_vma_policy(current, vma, addr);
1918 cpuset_mems_cookie = get_mems_allowed();
1920 if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
1923 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
1925 page = alloc_page_interleave(gfp, order, nid);
1926 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1931 zl = policy_zonelist(gfp, pol, node);
1932 if (unlikely(mpol_needs_cond_ref(pol))) {
1934 * slow path: ref counted shared policy
1936 struct page *page = __alloc_pages_nodemask(gfp, order,
1937 zl, policy_nodemask(gfp, pol));
1939 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1944 * fast path: default or task policy
1946 page = __alloc_pages_nodemask(gfp, order, zl,
1947 policy_nodemask(gfp, pol));
1948 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1954 * alloc_pages_current - Allocate pages.
1957 * %GFP_USER user allocation,
1958 * %GFP_KERNEL kernel allocation,
1959 * %GFP_HIGHMEM highmem allocation,
1960 * %GFP_FS don't call back into a file system.
1961 * %GFP_ATOMIC don't sleep.
1962 * @order: Power of two of allocation size in pages. 0 is a single page.
1964 * Allocate a page from the kernel page pool. When not in
1965 * interrupt context and apply the current process NUMA policy.
1966 * Returns NULL when no page can be allocated.
1968 * Don't call cpuset_update_task_memory_state() unless
1969 * 1) it's ok to take cpuset_sem (can WAIT), and
1970 * 2) allocating for current task (not interrupt).
1972 struct page *alloc_pages_current(gfp_t gfp, unsigned order)
1974 struct mempolicy *pol = current->mempolicy;
1976 unsigned int cpuset_mems_cookie;
1978 if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
1979 pol = &default_policy;
1982 cpuset_mems_cookie = get_mems_allowed();
1985 * No reference counting needed for current->mempolicy
1986 * nor system default_policy
1988 if (pol->mode == MPOL_INTERLEAVE)
1989 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
1991 page = __alloc_pages_nodemask(gfp, order,
1992 policy_zonelist(gfp, pol, numa_node_id()),
1993 policy_nodemask(gfp, pol));
1995 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2000 EXPORT_SYMBOL(alloc_pages_current);
2003 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2004 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
2005 * with the mems_allowed returned by cpuset_mems_allowed(). This
2006 * keeps mempolicies cpuset relative after its cpuset moves. See
2007 * further kernel/cpuset.c update_nodemask().
2009 * current's mempolicy may be rebinded by the other task(the task that changes
2010 * cpuset's mems), so we needn't do rebind work for current task.
2013 /* Slow path of a mempolicy duplicate */
2014 struct mempolicy *__mpol_dup(struct mempolicy *old)
2016 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
2019 return ERR_PTR(-ENOMEM);
2021 /* task's mempolicy is protected by alloc_lock */
2022 if (old == current->mempolicy) {
2025 task_unlock(current);
2030 if (current_cpuset_is_being_rebound()) {
2031 nodemask_t mems = cpuset_mems_allowed(current);
2032 if (new->flags & MPOL_F_REBINDING)
2033 mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
2035 mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
2038 atomic_set(&new->refcnt, 1);
2043 * If *frompol needs [has] an extra ref, copy *frompol to *tompol ,
2044 * eliminate the * MPOL_F_* flags that require conditional ref and
2045 * [NOTE!!!] drop the extra ref. Not safe to reference *frompol directly
2046 * after return. Use the returned value.
2048 * Allows use of a mempolicy for, e.g., multiple allocations with a single
2049 * policy lookup, even if the policy needs/has extra ref on lookup.
2050 * shmem_readahead needs this.
2052 struct mempolicy *__mpol_cond_copy(struct mempolicy *tompol,
2053 struct mempolicy *frompol)
2055 if (!mpol_needs_cond_ref(frompol))
2059 tompol->flags &= ~MPOL_F_SHARED; /* copy doesn't need unref */
2060 __mpol_put(frompol);
2064 /* Slow path of a mempolicy comparison */
2065 bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2069 if (a->mode != b->mode)
2071 if (a->flags != b->flags)
2073 if (mpol_store_user_nodemask(a))
2074 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2080 case MPOL_INTERLEAVE:
2081 return !!nodes_equal(a->v.nodes, b->v.nodes);
2082 case MPOL_PREFERRED:
2083 return a->v.preferred_node == b->v.preferred_node;
2091 * Shared memory backing store policy support.
2093 * Remember policies even when nobody has shared memory mapped.
2094 * The policies are kept in Red-Black tree linked from the inode.
2095 * They are protected by the sp->lock spinlock, which should be held
2096 * for any accesses to the tree.
2099 /* lookup first element intersecting start-end */
2100 /* Caller holds sp->mutex */
2101 static struct sp_node *
2102 sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2104 struct rb_node *n = sp->root.rb_node;
2107 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2109 if (start >= p->end)
2111 else if (end <= p->start)
2119 struct sp_node *w = NULL;
2120 struct rb_node *prev = rb_prev(n);
2123 w = rb_entry(prev, struct sp_node, nd);
2124 if (w->end <= start)
2128 return rb_entry(n, struct sp_node, nd);
2131 /* Insert a new shared policy into the list. */
2132 /* Caller holds sp->lock */
2133 static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2135 struct rb_node **p = &sp->root.rb_node;
2136 struct rb_node *parent = NULL;
2141 nd = rb_entry(parent, struct sp_node, nd);
2142 if (new->start < nd->start)
2144 else if (new->end > nd->end)
2145 p = &(*p)->rb_right;
2149 rb_link_node(&new->nd, parent, p);
2150 rb_insert_color(&new->nd, &sp->root);
2151 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2152 new->policy ? new->policy->mode : 0);
2155 /* Find shared policy intersecting idx */
2157 mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2159 struct mempolicy *pol = NULL;
2162 if (!sp->root.rb_node)
2164 mutex_lock(&sp->mutex);
2165 sn = sp_lookup(sp, idx, idx+1);
2167 mpol_get(sn->policy);
2170 mutex_unlock(&sp->mutex);
2174 static void sp_free(struct sp_node *n)
2176 mpol_put(n->policy);
2177 kmem_cache_free(sn_cache, n);
2180 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2182 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2183 rb_erase(&n->nd, &sp->root);
2187 static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2188 struct mempolicy *pol)
2191 struct mempolicy *newpol;
2193 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2197 newpol = mpol_dup(pol);
2198 if (IS_ERR(newpol)) {
2199 kmem_cache_free(sn_cache, n);
2202 newpol->flags |= MPOL_F_SHARED;
2211 /* Replace a policy range. */
2212 static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2213 unsigned long end, struct sp_node *new)
2218 mutex_lock(&sp->mutex);
2219 n = sp_lookup(sp, start, end);
2220 /* Take care of old policies in the same range. */
2221 while (n && n->start < end) {
2222 struct rb_node *next = rb_next(&n->nd);
2223 if (n->start >= start) {
2229 /* Old policy spanning whole new range. */
2231 struct sp_node *new2;
2232 new2 = sp_alloc(end, n->end, n->policy);
2238 sp_insert(sp, new2);
2245 n = rb_entry(next, struct sp_node, nd);
2250 mutex_unlock(&sp->mutex);
2255 * mpol_shared_policy_init - initialize shared policy for inode
2256 * @sp: pointer to inode shared policy
2257 * @mpol: struct mempolicy to install
2259 * Install non-NULL @mpol in inode's shared policy rb-tree.
2260 * On entry, the current task has a reference on a non-NULL @mpol.
2261 * This must be released on exit.
2262 * This is called at get_inode() calls and we can use GFP_KERNEL.
2264 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2268 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2269 mutex_init(&sp->mutex);
2272 struct vm_area_struct pvma;
2273 struct mempolicy *new;
2274 NODEMASK_SCRATCH(scratch);
2278 /* contextualize the tmpfs mount point mempolicy */
2279 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2281 goto free_scratch; /* no valid nodemask intersection */
2284 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2285 task_unlock(current);
2289 /* Create pseudo-vma that contains just the policy */
2290 memset(&pvma, 0, sizeof(struct vm_area_struct));
2291 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2292 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2295 mpol_put(new); /* drop initial ref */
2297 NODEMASK_SCRATCH_FREE(scratch);
2299 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2303 int mpol_set_shared_policy(struct shared_policy *info,
2304 struct vm_area_struct *vma, struct mempolicy *npol)
2307 struct sp_node *new = NULL;
2308 unsigned long sz = vma_pages(vma);
2310 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2312 sz, npol ? npol->mode : -1,
2313 npol ? npol->flags : -1,
2314 npol ? nodes_addr(npol->v.nodes)[0] : -1);
2317 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2321 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2327 /* Free a backing policy store on inode delete. */
2328 void mpol_free_shared_policy(struct shared_policy *p)
2331 struct rb_node *next;
2333 if (!p->root.rb_node)
2335 mutex_lock(&p->mutex);
2336 next = rb_first(&p->root);
2338 n = rb_entry(next, struct sp_node, nd);
2339 next = rb_next(&n->nd);
2342 mutex_unlock(&p->mutex);
2345 /* assumes fs == KERNEL_DS */
2346 void __init numa_policy_init(void)
2348 nodemask_t interleave_nodes;
2349 unsigned long largest = 0;
2350 int nid, prefer = 0;
2352 policy_cache = kmem_cache_create("numa_policy",
2353 sizeof(struct mempolicy),
2354 0, SLAB_PANIC, NULL);
2356 sn_cache = kmem_cache_create("shared_policy_node",
2357 sizeof(struct sp_node),
2358 0, SLAB_PANIC, NULL);
2361 * Set interleaving policy for system init. Interleaving is only
2362 * enabled across suitably sized nodes (default is >= 16MB), or
2363 * fall back to the largest node if they're all smaller.
2365 nodes_clear(interleave_nodes);
2366 for_each_node_state(nid, N_HIGH_MEMORY) {
2367 unsigned long total_pages = node_present_pages(nid);
2369 /* Preserve the largest node */
2370 if (largest < total_pages) {
2371 largest = total_pages;
2375 /* Interleave this node? */
2376 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2377 node_set(nid, interleave_nodes);
2380 /* All too small, use the largest */
2381 if (unlikely(nodes_empty(interleave_nodes)))
2382 node_set(prefer, interleave_nodes);
2384 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2385 printk("numa_policy_init: interleaving failed\n");
2388 /* Reset policy of current process to default */
2389 void numa_default_policy(void)
2391 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2395 * Parse and format mempolicy from/to strings
2399 * "local" is pseudo-policy: MPOL_PREFERRED with MPOL_F_LOCAL flag
2400 * Used only for mpol_parse_str() and mpol_to_str()
2402 #define MPOL_LOCAL MPOL_MAX
2403 static const char * const policy_modes[] =
2405 [MPOL_DEFAULT] = "default",
2406 [MPOL_PREFERRED] = "prefer",
2407 [MPOL_BIND] = "bind",
2408 [MPOL_INTERLEAVE] = "interleave",
2409 [MPOL_LOCAL] = "local"
2415 * mpol_parse_str - parse string to mempolicy
2416 * @str: string containing mempolicy to parse
2417 * @mpol: pointer to struct mempolicy pointer, returned on success.
2418 * @no_context: flag whether to "contextualize" the mempolicy
2421 * <mode>[=<flags>][:<nodelist>]
2423 * if @no_context is true, save the input nodemask in w.user_nodemask in
2424 * the returned mempolicy. This will be used to "clone" the mempolicy in
2425 * a specific context [cpuset] at a later time. Used to parse tmpfs mpol
2426 * mount option. Note that if 'static' or 'relative' mode flags were
2427 * specified, the input nodemask will already have been saved. Saving
2428 * it again is redundant, but safe.
2430 * On success, returns 0, else 1
2432 int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context)
2434 struct mempolicy *new = NULL;
2435 unsigned short mode;
2436 unsigned short uninitialized_var(mode_flags);
2438 char *nodelist = strchr(str, ':');
2439 char *flags = strchr(str, '=');
2443 /* NUL-terminate mode or flags string */
2445 if (nodelist_parse(nodelist, nodes))
2447 if (!nodes_subset(nodes, node_states[N_HIGH_MEMORY]))
2453 *flags++ = '\0'; /* terminate mode string */
2455 for (mode = 0; mode <= MPOL_LOCAL; mode++) {
2456 if (!strcmp(str, policy_modes[mode])) {
2460 if (mode > MPOL_LOCAL)
2464 case MPOL_PREFERRED:
2466 * Insist on a nodelist of one node only
2469 char *rest = nodelist;
2470 while (isdigit(*rest))
2476 case MPOL_INTERLEAVE:
2478 * Default to online nodes with memory if no nodelist
2481 nodes = node_states[N_HIGH_MEMORY];
2485 * Don't allow a nodelist; mpol_new() checks flags
2489 mode = MPOL_PREFERRED;
2493 * Insist on a empty nodelist
2500 * Insist on a nodelist
2509 * Currently, we only support two mutually exclusive
2512 if (!strcmp(flags, "static"))
2513 mode_flags |= MPOL_F_STATIC_NODES;
2514 else if (!strcmp(flags, "relative"))
2515 mode_flags |= MPOL_F_RELATIVE_NODES;
2520 new = mpol_new(mode, mode_flags, &nodes);
2525 /* save for contextualization */
2526 new->w.user_nodemask = nodes;
2529 NODEMASK_SCRATCH(scratch);
2532 ret = mpol_set_nodemask(new, &nodes, scratch);
2533 task_unlock(current);
2536 NODEMASK_SCRATCH_FREE(scratch);
2545 /* Restore string for error message */
2554 #endif /* CONFIG_TMPFS */
2557 * mpol_to_str - format a mempolicy structure for printing
2558 * @buffer: to contain formatted mempolicy string
2559 * @maxlen: length of @buffer
2560 * @pol: pointer to mempolicy to be formatted
2561 * @no_context: "context free" mempolicy - use nodemask in w.user_nodemask
2563 * Convert a mempolicy into a string.
2564 * Returns the number of characters in buffer (if positive)
2565 * or an error (negative)
2567 int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol, int no_context)
2572 unsigned short mode;
2573 unsigned short flags = pol ? pol->flags : 0;
2576 * Sanity check: room for longest mode, flag and some nodes
2578 VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
2580 if (!pol || pol == &default_policy)
2581 mode = MPOL_DEFAULT;
2590 case MPOL_PREFERRED:
2592 if (flags & MPOL_F_LOCAL)
2593 mode = MPOL_LOCAL; /* pseudo-policy */
2595 node_set(pol->v.preferred_node, nodes);
2600 case MPOL_INTERLEAVE:
2602 nodes = pol->w.user_nodemask;
2604 nodes = pol->v.nodes;
2611 l = strlen(policy_modes[mode]);
2612 if (buffer + maxlen < p + l + 1)
2615 strcpy(p, policy_modes[mode]);
2618 if (flags & MPOL_MODE_FLAGS) {
2619 if (buffer + maxlen < p + 2)
2624 * Currently, the only defined flags are mutually exclusive
2626 if (flags & MPOL_F_STATIC_NODES)
2627 p += snprintf(p, buffer + maxlen - p, "static");
2628 else if (flags & MPOL_F_RELATIVE_NODES)
2629 p += snprintf(p, buffer + maxlen - p, "relative");
2632 if (!nodes_empty(nodes)) {
2633 if (buffer + maxlen < p + 2)
2636 p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);