2 * Simple NUMA memory policy for the Linux kernel.
4 * Copyright 2003,2004 Andi Kleen, SuSE Labs.
5 * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc.
6 * Subject to the GNU Public License, version 2.
8 * NUMA policy allows the user to give hints in which node(s) memory should
11 * Support four policies per VMA and per process:
13 * The VMA policy has priority over the process policy for a page fault.
15 * interleave Allocate memory interleaved over a set of nodes,
16 * with normal fallback if it fails.
17 * For VMA based allocations this interleaves based on the
18 * offset into the backing object or offset into the mapping
19 * for anonymous memory. For process policy an process counter
22 * bind Only allocate memory on a specific set of nodes,
24 * FIXME: memory is allocated starting with the first node
25 * to the last. It would be better if bind would truly restrict
26 * the allocation to memory nodes instead
28 * preferred Try a specific node first before normal fallback.
29 * As a special case node -1 here means do the allocation
30 * on the local CPU. This is normally identical to default,
31 * but useful to set in a VMA when you have a non default
34 * default Allocate on the local node first, or when on a VMA
35 * use the process policy. This is what Linux always did
36 * in a NUMA aware kernel and still does by, ahem, default.
38 * The process policy is applied for most non interrupt memory allocations
39 * in that process' context. Interrupts ignore the policies and always
40 * try to allocate on the local CPU. The VMA policy is only applied for memory
41 * allocations for a VMA in the VM.
43 * Currently there are a few corner cases in swapping where the policy
44 * is not applied, but the majority should be handled. When process policy
45 * is used it is not remembered over swap outs/swap ins.
47 * Only the highest zone in the zone hierarchy gets policied. Allocations
48 * requesting a lower zone just use default policy. This implies that
49 * on systems with highmem kernel lowmem allocation don't get policied.
50 * Same with GFP_DMA allocations.
52 * For shmfs/tmpfs/hugetlbfs shared memory the policy is shared between
53 * all users and remembered even when nobody has memory mapped.
57 fix mmap readahead to honour policy and enable policy for any page cache
59 statistics for bigpages
60 global policy for page cache? currently it uses process policy. Requires
62 handle mremap for shared memory (currently ignored for the policy)
64 make bind policy root only? It can trigger oom much faster and the
65 kernel is not always grateful with that.
68 #include <linux/mempolicy.h>
70 #include <linux/highmem.h>
71 #include <linux/hugetlb.h>
72 #include <linux/kernel.h>
73 #include <linux/sched.h>
74 #include <linux/nodemask.h>
75 #include <linux/cpuset.h>
76 #include <linux/slab.h>
77 #include <linux/string.h>
78 #include <linux/export.h>
79 #include <linux/nsproxy.h>
80 #include <linux/interrupt.h>
81 #include <linux/init.h>
82 #include <linux/compat.h>
83 #include <linux/swap.h>
84 #include <linux/seq_file.h>
85 #include <linux/proc_fs.h>
86 #include <linux/migrate.h>
87 #include <linux/ksm.h>
88 #include <linux/rmap.h>
89 #include <linux/security.h>
90 #include <linux/syscalls.h>
91 #include <linux/ctype.h>
92 #include <linux/mm_inline.h>
94 #include <asm/tlbflush.h>
95 #include <asm/uaccess.h>
96 #include <linux/random.h>
101 #define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
102 #define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
104 static struct kmem_cache *policy_cache;
105 static struct kmem_cache *sn_cache;
107 /* Highest zone. An specific allocation for a zone below that is not
109 enum zone_type policy_zone = 0;
112 * run-time system-wide default policy => local allocation
114 static struct mempolicy default_policy = {
115 .refcnt = ATOMIC_INIT(1), /* never free it */
116 .mode = MPOL_PREFERRED,
117 .flags = MPOL_F_LOCAL,
120 static const struct mempolicy_operations {
121 int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
123 * If read-side task has no lock to protect task->mempolicy, write-side
124 * task will rebind the task->mempolicy by two step. The first step is
125 * setting all the newly nodes, and the second step is cleaning all the
126 * disallowed nodes. In this way, we can avoid finding no node to alloc
128 * If we have a lock to protect task->mempolicy in read-side, we do
132 * MPOL_REBIND_ONCE - do rebind work at once
133 * MPOL_REBIND_STEP1 - set all the newly nodes
134 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
136 void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes,
137 enum mpol_rebind_step step);
138 } mpol_ops[MPOL_MAX];
140 /* Check that the nodemask contains at least one populated zone */
141 static int is_valid_nodemask(const nodemask_t *nodemask)
145 for_each_node_mask(nd, *nodemask) {
148 for (k = 0; k <= policy_zone; k++) {
149 z = &NODE_DATA(nd)->node_zones[k];
150 if (z->present_pages > 0)
158 static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
160 return pol->flags & MPOL_MODE_FLAGS;
163 static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
164 const nodemask_t *rel)
167 nodes_fold(tmp, *orig, nodes_weight(*rel));
168 nodes_onto(*ret, tmp, *rel);
171 static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
173 if (nodes_empty(*nodes))
175 pol->v.nodes = *nodes;
179 static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
182 pol->flags |= MPOL_F_LOCAL; /* local allocation */
183 else if (nodes_empty(*nodes))
184 return -EINVAL; /* no allowed nodes */
186 pol->v.preferred_node = first_node(*nodes);
190 static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
192 if (!is_valid_nodemask(nodes))
194 pol->v.nodes = *nodes;
199 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
200 * any, for the new policy. mpol_new() has already validated the nodes
201 * parameter with respect to the policy mode and flags. But, we need to
202 * handle an empty nodemask with MPOL_PREFERRED here.
204 * Must be called holding task's alloc_lock to protect task's mems_allowed
205 * and mempolicy. May also be called holding the mmap_semaphore for write.
207 static int mpol_set_nodemask(struct mempolicy *pol,
208 const nodemask_t *nodes, struct nodemask_scratch *nsc)
212 /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
215 /* Check N_HIGH_MEMORY */
216 nodes_and(nsc->mask1,
217 cpuset_current_mems_allowed, node_states[N_HIGH_MEMORY]);
220 if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
221 nodes = NULL; /* explicit local allocation */
223 if (pol->flags & MPOL_F_RELATIVE_NODES)
224 mpol_relative_nodemask(&nsc->mask2, nodes,&nsc->mask1);
226 nodes_and(nsc->mask2, *nodes, nsc->mask1);
228 if (mpol_store_user_nodemask(pol))
229 pol->w.user_nodemask = *nodes;
231 pol->w.cpuset_mems_allowed =
232 cpuset_current_mems_allowed;
236 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
238 ret = mpol_ops[pol->mode].create(pol, NULL);
243 * This function just creates a new policy, does some check and simple
244 * initialization. You must invoke mpol_set_nodemask() to set nodes.
246 static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
249 struct mempolicy *policy;
251 pr_debug("setting mode %d flags %d nodes[0] %lx\n",
252 mode, flags, nodes ? nodes_addr(*nodes)[0] : -1);
254 if (mode == MPOL_DEFAULT) {
255 if (nodes && !nodes_empty(*nodes))
256 return ERR_PTR(-EINVAL);
257 return NULL; /* simply delete any existing policy */
262 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
263 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
264 * All other modes require a valid pointer to a non-empty nodemask.
266 if (mode == MPOL_PREFERRED) {
267 if (nodes_empty(*nodes)) {
268 if (((flags & MPOL_F_STATIC_NODES) ||
269 (flags & MPOL_F_RELATIVE_NODES)))
270 return ERR_PTR(-EINVAL);
272 } else if (nodes_empty(*nodes))
273 return ERR_PTR(-EINVAL);
274 policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
276 return ERR_PTR(-ENOMEM);
277 atomic_set(&policy->refcnt, 1);
279 policy->flags = flags;
284 /* Slow path of a mpol destructor. */
285 void __mpol_put(struct mempolicy *p)
287 if (!atomic_dec_and_test(&p->refcnt))
289 kmem_cache_free(policy_cache, p);
292 static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes,
293 enum mpol_rebind_step step)
299 * MPOL_REBIND_ONCE - do rebind work at once
300 * MPOL_REBIND_STEP1 - set all the newly nodes
301 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
303 static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes,
304 enum mpol_rebind_step step)
308 if (pol->flags & MPOL_F_STATIC_NODES)
309 nodes_and(tmp, pol->w.user_nodemask, *nodes);
310 else if (pol->flags & MPOL_F_RELATIVE_NODES)
311 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
314 * if step == 1, we use ->w.cpuset_mems_allowed to cache the
317 if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP1) {
318 nodes_remap(tmp, pol->v.nodes,
319 pol->w.cpuset_mems_allowed, *nodes);
320 pol->w.cpuset_mems_allowed = step ? tmp : *nodes;
321 } else if (step == MPOL_REBIND_STEP2) {
322 tmp = pol->w.cpuset_mems_allowed;
323 pol->w.cpuset_mems_allowed = *nodes;
328 if (nodes_empty(tmp))
331 if (step == MPOL_REBIND_STEP1)
332 nodes_or(pol->v.nodes, pol->v.nodes, tmp);
333 else if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP2)
338 if (!node_isset(current->il_next, tmp)) {
339 current->il_next = next_node(current->il_next, tmp);
340 if (current->il_next >= MAX_NUMNODES)
341 current->il_next = first_node(tmp);
342 if (current->il_next >= MAX_NUMNODES)
343 current->il_next = numa_node_id();
347 static void mpol_rebind_preferred(struct mempolicy *pol,
348 const nodemask_t *nodes,
349 enum mpol_rebind_step step)
353 if (pol->flags & MPOL_F_STATIC_NODES) {
354 int node = first_node(pol->w.user_nodemask);
356 if (node_isset(node, *nodes)) {
357 pol->v.preferred_node = node;
358 pol->flags &= ~MPOL_F_LOCAL;
360 pol->flags |= MPOL_F_LOCAL;
361 } else if (pol->flags & MPOL_F_RELATIVE_NODES) {
362 mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
363 pol->v.preferred_node = first_node(tmp);
364 } else if (!(pol->flags & MPOL_F_LOCAL)) {
365 pol->v.preferred_node = node_remap(pol->v.preferred_node,
366 pol->w.cpuset_mems_allowed,
368 pol->w.cpuset_mems_allowed = *nodes;
373 * mpol_rebind_policy - Migrate a policy to a different set of nodes
375 * If read-side task has no lock to protect task->mempolicy, write-side
376 * task will rebind the task->mempolicy by two step. The first step is
377 * setting all the newly nodes, and the second step is cleaning all the
378 * disallowed nodes. In this way, we can avoid finding no node to alloc
380 * If we have a lock to protect task->mempolicy in read-side, we do
384 * MPOL_REBIND_ONCE - do rebind work at once
385 * MPOL_REBIND_STEP1 - set all the newly nodes
386 * MPOL_REBIND_STEP2 - clean all the disallowed nodes
388 static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask,
389 enum mpol_rebind_step step)
393 if (!mpol_store_user_nodemask(pol) && step == 0 &&
394 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
397 if (step == MPOL_REBIND_STEP1 && (pol->flags & MPOL_F_REBINDING))
400 if (step == MPOL_REBIND_STEP2 && !(pol->flags & MPOL_F_REBINDING))
403 if (step == MPOL_REBIND_STEP1)
404 pol->flags |= MPOL_F_REBINDING;
405 else if (step == MPOL_REBIND_STEP2)
406 pol->flags &= ~MPOL_F_REBINDING;
407 else if (step >= MPOL_REBIND_NSTEP)
410 mpol_ops[pol->mode].rebind(pol, newmask, step);
414 * Wrapper for mpol_rebind_policy() that just requires task
415 * pointer, and updates task mempolicy.
417 * Called with task's alloc_lock held.
420 void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new,
421 enum mpol_rebind_step step)
423 mpol_rebind_policy(tsk->mempolicy, new, step);
427 * Rebind each vma in mm to new nodemask.
429 * Call holding a reference to mm. Takes mm->mmap_sem during call.
432 void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
434 struct vm_area_struct *vma;
436 down_write(&mm->mmap_sem);
437 for (vma = mm->mmap; vma; vma = vma->vm_next)
438 mpol_rebind_policy(vma->vm_policy, new, MPOL_REBIND_ONCE);
439 up_write(&mm->mmap_sem);
442 static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
444 .rebind = mpol_rebind_default,
446 [MPOL_INTERLEAVE] = {
447 .create = mpol_new_interleave,
448 .rebind = mpol_rebind_nodemask,
451 .create = mpol_new_preferred,
452 .rebind = mpol_rebind_preferred,
455 .create = mpol_new_bind,
456 .rebind = mpol_rebind_nodemask,
460 static void migrate_page_add(struct page *page, struct list_head *pagelist,
461 unsigned long flags);
463 /* Scan through pages checking if pages follow certain conditions. */
464 static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
465 unsigned long addr, unsigned long end,
466 const nodemask_t *nodes, unsigned long flags,
473 orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
478 if (!pte_present(*pte))
480 page = vm_normal_page(vma, addr, *pte);
484 * vm_normal_page() filters out zero pages, but there might
485 * still be PageReserved pages to skip, perhaps in a VDSO.
486 * And we cannot move PageKsm pages sensibly or safely yet.
488 if (PageReserved(page) || PageKsm(page))
490 nid = page_to_nid(page);
491 if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
494 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
495 migrate_page_add(page, private, flags);
498 } while (pte++, addr += PAGE_SIZE, addr != end);
499 pte_unmap_unlock(orig_pte, ptl);
503 static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
504 unsigned long addr, unsigned long end,
505 const nodemask_t *nodes, unsigned long flags,
511 pmd = pmd_offset(pud, addr);
513 next = pmd_addr_end(addr, end);
514 split_huge_page_pmd(vma->vm_mm, pmd);
515 if (pmd_none_or_trans_huge_or_clear_bad(pmd))
517 if (check_pte_range(vma, pmd, addr, next, nodes,
520 } while (pmd++, addr = next, addr != end);
524 static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
525 unsigned long addr, unsigned long end,
526 const nodemask_t *nodes, unsigned long flags,
532 pud = pud_offset(pgd, addr);
534 next = pud_addr_end(addr, end);
535 if (pud_none_or_clear_bad(pud))
537 if (check_pmd_range(vma, pud, addr, next, nodes,
540 } while (pud++, addr = next, addr != end);
544 static inline int check_pgd_range(struct vm_area_struct *vma,
545 unsigned long addr, unsigned long end,
546 const nodemask_t *nodes, unsigned long flags,
552 pgd = pgd_offset(vma->vm_mm, addr);
554 next = pgd_addr_end(addr, end);
555 if (pgd_none_or_clear_bad(pgd))
557 if (check_pud_range(vma, pgd, addr, next, nodes,
560 } while (pgd++, addr = next, addr != end);
565 * Check if all pages in a range are on a set of nodes.
566 * If pagelist != NULL then isolate pages from the LRU and
567 * put them on the pagelist.
569 static struct vm_area_struct *
570 check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
571 const nodemask_t *nodes, unsigned long flags, void *private)
574 struct vm_area_struct *first, *vma, *prev;
577 first = find_vma(mm, start);
579 return ERR_PTR(-EFAULT);
581 for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
582 if (!(flags & MPOL_MF_DISCONTIG_OK)) {
583 if (!vma->vm_next && vma->vm_end < end)
584 return ERR_PTR(-EFAULT);
585 if (prev && prev->vm_end < vma->vm_start)
586 return ERR_PTR(-EFAULT);
588 if (!is_vm_hugetlb_page(vma) &&
589 ((flags & MPOL_MF_STRICT) ||
590 ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
591 vma_migratable(vma)))) {
592 unsigned long endvma = vma->vm_end;
596 if (vma->vm_start > start)
597 start = vma->vm_start;
598 err = check_pgd_range(vma, start, endvma, nodes,
601 first = ERR_PTR(err);
611 * Apply policy to a single VMA
612 * This must be called with the mmap_sem held for writing.
614 static int vma_replace_policy(struct vm_area_struct *vma,
615 struct mempolicy *pol)
618 struct mempolicy *old;
619 struct mempolicy *new;
621 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
622 vma->vm_start, vma->vm_end, vma->vm_pgoff,
623 vma->vm_ops, vma->vm_file,
624 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
630 if (vma->vm_ops && vma->vm_ops->set_policy) {
631 err = vma->vm_ops->set_policy(vma, new);
636 old = vma->vm_policy;
637 vma->vm_policy = new; /* protected by mmap_sem */
646 /* Step 2: apply policy to a range and do splits. */
647 static int mbind_range(struct mm_struct *mm, unsigned long start,
648 unsigned long end, struct mempolicy *new_pol)
650 struct vm_area_struct *next;
651 struct vm_area_struct *prev;
652 struct vm_area_struct *vma;
655 unsigned long vmstart;
658 vma = find_vma_prev(mm, start, &prev);
659 if (!vma || vma->vm_start > start)
662 if (start > vma->vm_start)
665 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
667 vmstart = max(start, vma->vm_start);
668 vmend = min(end, vma->vm_end);
670 if (mpol_equal(vma_policy(vma), new_pol))
673 pgoff = vma->vm_pgoff +
674 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
675 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
676 vma->anon_vma, vma->vm_file, pgoff,
683 if (vma->vm_start != vmstart) {
684 err = split_vma(vma->vm_mm, vma, vmstart, 1);
688 if (vma->vm_end != vmend) {
689 err = split_vma(vma->vm_mm, vma, vmend, 0);
693 err = vma_replace_policy(vma, new_pol);
703 * Update task->flags PF_MEMPOLICY bit: set iff non-default
704 * mempolicy. Allows more rapid checking of this (combined perhaps
705 * with other PF_* flag bits) on memory allocation hot code paths.
707 * If called from outside this file, the task 'p' should -only- be
708 * a newly forked child not yet visible on the task list, because
709 * manipulating the task flags of a visible task is not safe.
711 * The above limitation is why this routine has the funny name
712 * mpol_fix_fork_child_flag().
714 * It is also safe to call this with a task pointer of current,
715 * which the static wrapper mpol_set_task_struct_flag() does,
716 * for use within this file.
719 void mpol_fix_fork_child_flag(struct task_struct *p)
722 p->flags |= PF_MEMPOLICY;
724 p->flags &= ~PF_MEMPOLICY;
727 static void mpol_set_task_struct_flag(void)
729 mpol_fix_fork_child_flag(current);
732 /* Set the process memory policy */
733 static long do_set_mempolicy(unsigned short mode, unsigned short flags,
736 struct mempolicy *new, *old;
737 struct mm_struct *mm = current->mm;
738 NODEMASK_SCRATCH(scratch);
744 new = mpol_new(mode, flags, nodes);
750 * prevent changing our mempolicy while show_numa_maps()
752 * Note: do_set_mempolicy() can be called at init time
756 down_write(&mm->mmap_sem);
758 ret = mpol_set_nodemask(new, nodes, scratch);
760 task_unlock(current);
762 up_write(&mm->mmap_sem);
766 old = current->mempolicy;
767 current->mempolicy = new;
768 mpol_set_task_struct_flag();
769 if (new && new->mode == MPOL_INTERLEAVE &&
770 nodes_weight(new->v.nodes))
771 current->il_next = first_node(new->v.nodes);
772 task_unlock(current);
774 up_write(&mm->mmap_sem);
779 NODEMASK_SCRATCH_FREE(scratch);
784 * Return nodemask for policy for get_mempolicy() query
786 * Called with task's alloc_lock held
788 static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
791 if (p == &default_policy)
797 case MPOL_INTERLEAVE:
801 if (!(p->flags & MPOL_F_LOCAL))
802 node_set(p->v.preferred_node, *nodes);
803 /* else return empty node mask for local allocation */
810 static int lookup_node(struct mm_struct *mm, unsigned long addr)
815 err = get_user_pages(current, mm, addr & PAGE_MASK, 1, 0, 0, &p, NULL);
817 err = page_to_nid(p);
823 /* Retrieve NUMA policy */
824 static long do_get_mempolicy(int *policy, nodemask_t *nmask,
825 unsigned long addr, unsigned long flags)
828 struct mm_struct *mm = current->mm;
829 struct vm_area_struct *vma = NULL;
830 struct mempolicy *pol = current->mempolicy;
833 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
836 if (flags & MPOL_F_MEMS_ALLOWED) {
837 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
839 *policy = 0; /* just so it's initialized */
841 *nmask = cpuset_current_mems_allowed;
842 task_unlock(current);
846 if (flags & MPOL_F_ADDR) {
848 * Do NOT fall back to task policy if the
849 * vma/shared policy at addr is NULL. We
850 * want to return MPOL_DEFAULT in this case.
852 down_read(&mm->mmap_sem);
853 vma = find_vma_intersection(mm, addr, addr+1);
855 up_read(&mm->mmap_sem);
858 if (vma->vm_ops && vma->vm_ops->get_policy)
859 pol = vma->vm_ops->get_policy(vma, addr);
861 pol = vma->vm_policy;
866 pol = &default_policy; /* indicates default behavior */
868 if (flags & MPOL_F_NODE) {
869 if (flags & MPOL_F_ADDR) {
870 err = lookup_node(mm, addr);
874 } else if (pol == current->mempolicy &&
875 pol->mode == MPOL_INTERLEAVE) {
876 *policy = current->il_next;
882 *policy = pol == &default_policy ? MPOL_DEFAULT :
885 * Internal mempolicy flags must be masked off before exposing
886 * the policy to userspace.
888 *policy |= (pol->flags & MPOL_MODE_FLAGS);
892 up_read(¤t->mm->mmap_sem);
898 if (mpol_store_user_nodemask(pol)) {
899 *nmask = pol->w.user_nodemask;
902 get_policy_nodemask(pol, nmask);
903 task_unlock(current);
910 up_read(¤t->mm->mmap_sem);
914 #ifdef CONFIG_MIGRATION
918 static void migrate_page_add(struct page *page, struct list_head *pagelist,
922 * Avoid migrating a page that is shared with others.
924 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
925 if (!isolate_lru_page(page)) {
926 list_add_tail(&page->lru, pagelist);
927 inc_zone_page_state(page, NR_ISOLATED_ANON +
928 page_is_file_cache(page));
933 static struct page *new_node_page(struct page *page, unsigned long node, int **x)
935 return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
939 * Migrate pages from one node to a target node.
940 * Returns error or the number of pages not migrated.
942 static int migrate_to_node(struct mm_struct *mm, int source, int dest,
950 node_set(source, nmask);
953 * This does not "check" the range but isolates all pages that
954 * need migration. Between passing in the full user address
955 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
957 VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
958 check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
959 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
961 if (!list_empty(&pagelist)) {
962 err = migrate_pages(&pagelist, new_node_page, dest,
963 false, MIGRATE_SYNC);
965 putback_lru_pages(&pagelist);
972 * Move pages between the two nodesets so as to preserve the physical
973 * layout as much as possible.
975 * Returns the number of page that could not be moved.
977 int do_migrate_pages(struct mm_struct *mm,
978 const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
984 err = migrate_prep();
988 down_read(&mm->mmap_sem);
990 err = migrate_vmas(mm, from_nodes, to_nodes, flags);
995 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
996 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
997 * bit in 'tmp', and return that <source, dest> pair for migration.
998 * The pair of nodemasks 'to' and 'from' define the map.
1000 * If no pair of bits is found that way, fallback to picking some
1001 * pair of 'source' and 'dest' bits that are not the same. If the
1002 * 'source' and 'dest' bits are the same, this represents a node
1003 * that will be migrating to itself, so no pages need move.
1005 * If no bits are left in 'tmp', or if all remaining bits left
1006 * in 'tmp' correspond to the same bit in 'to', return false
1007 * (nothing left to migrate).
1009 * This lets us pick a pair of nodes to migrate between, such that
1010 * if possible the dest node is not already occupied by some other
1011 * source node, minimizing the risk of overloading the memory on a
1012 * node that would happen if we migrated incoming memory to a node
1013 * before migrating outgoing memory source that same node.
1015 * A single scan of tmp is sufficient. As we go, we remember the
1016 * most recent <s, d> pair that moved (s != d). If we find a pair
1017 * that not only moved, but what's better, moved to an empty slot
1018 * (d is not set in tmp), then we break out then, with that pair.
1019 * Otherwise when we finish scanning from_tmp, we at least have the
1020 * most recent <s, d> pair that moved. If we get all the way through
1021 * the scan of tmp without finding any node that moved, much less
1022 * moved to an empty node, then there is nothing left worth migrating.
1026 while (!nodes_empty(tmp)) {
1031 for_each_node_mask(s, tmp) {
1032 d = node_remap(s, *from_nodes, *to_nodes);
1036 source = s; /* Node moved. Memorize */
1039 /* dest not in remaining from nodes? */
1040 if (!node_isset(dest, tmp))
1046 node_clear(source, tmp);
1047 err = migrate_to_node(mm, source, dest, flags);
1054 up_read(&mm->mmap_sem);
1062 * Allocate a new page for page migration based on vma policy.
1063 * Start assuming that page is mapped by vma pointed to by @private.
1064 * Search forward from there, if not. N.B., this assumes that the
1065 * list of pages handed to migrate_pages()--which is how we get here--
1066 * is in virtual address order.
1068 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1070 struct vm_area_struct *vma = (struct vm_area_struct *)private;
1071 unsigned long uninitialized_var(address);
1074 address = page_address_in_vma(page, vma);
1075 if (address != -EFAULT)
1081 * if !vma, alloc_page_vma() will use task or system default policy
1083 return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1087 static void migrate_page_add(struct page *page, struct list_head *pagelist,
1088 unsigned long flags)
1092 int do_migrate_pages(struct mm_struct *mm,
1093 const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
1098 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1104 static long do_mbind(unsigned long start, unsigned long len,
1105 unsigned short mode, unsigned short mode_flags,
1106 nodemask_t *nmask, unsigned long flags)
1108 struct vm_area_struct *vma;
1109 struct mm_struct *mm = current->mm;
1110 struct mempolicy *new;
1113 LIST_HEAD(pagelist);
1115 if (flags & ~(unsigned long)(MPOL_MF_STRICT |
1116 MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1118 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1121 if (start & ~PAGE_MASK)
1124 if (mode == MPOL_DEFAULT)
1125 flags &= ~MPOL_MF_STRICT;
1127 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1135 new = mpol_new(mode, mode_flags, nmask);
1137 return PTR_ERR(new);
1140 * If we are using the default policy then operation
1141 * on discontinuous address spaces is okay after all
1144 flags |= MPOL_MF_DISCONTIG_OK;
1146 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1147 start, start + len, mode, mode_flags,
1148 nmask ? nodes_addr(*nmask)[0] : -1);
1150 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1152 err = migrate_prep();
1157 NODEMASK_SCRATCH(scratch);
1159 down_write(&mm->mmap_sem);
1161 err = mpol_set_nodemask(new, nmask, scratch);
1162 task_unlock(current);
1164 up_write(&mm->mmap_sem);
1167 NODEMASK_SCRATCH_FREE(scratch);
1172 vma = check_range(mm, start, end, nmask,
1173 flags | MPOL_MF_INVERT, &pagelist);
1179 err = mbind_range(mm, start, end, new);
1181 if (!list_empty(&pagelist)) {
1182 nr_failed = migrate_pages(&pagelist, new_vma_page,
1186 putback_lru_pages(&pagelist);
1189 if (!err && nr_failed && (flags & MPOL_MF_STRICT))
1192 putback_lru_pages(&pagelist);
1194 up_write(&mm->mmap_sem);
1201 * User space interface with variable sized bitmaps for nodelists.
1204 /* Copy a node mask from user space. */
1205 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1206 unsigned long maxnode)
1209 unsigned long nlongs;
1210 unsigned long endmask;
1213 nodes_clear(*nodes);
1214 if (maxnode == 0 || !nmask)
1216 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1219 nlongs = BITS_TO_LONGS(maxnode);
1220 if ((maxnode % BITS_PER_LONG) == 0)
1223 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1225 /* When the user specified more nodes than supported just check
1226 if the non supported part is all zero. */
1227 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1228 if (nlongs > PAGE_SIZE/sizeof(long))
1230 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1232 if (get_user(t, nmask + k))
1234 if (k == nlongs - 1) {
1240 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1244 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1246 nodes_addr(*nodes)[nlongs-1] &= endmask;
1250 /* Copy a kernel node mask to user space */
1251 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1254 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1255 const int nbytes = BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long);
1257 if (copy > nbytes) {
1258 if (copy > PAGE_SIZE)
1260 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1264 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1267 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1268 unsigned long, mode, unsigned long __user *, nmask,
1269 unsigned long, maxnode, unsigned, flags)
1273 unsigned short mode_flags;
1275 mode_flags = mode & MPOL_MODE_FLAGS;
1276 mode &= ~MPOL_MODE_FLAGS;
1277 if (mode >= MPOL_MAX)
1279 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1280 (mode_flags & MPOL_F_RELATIVE_NODES))
1282 err = get_nodes(&nodes, nmask, maxnode);
1285 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1288 /* Set the process memory policy */
1289 SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
1290 unsigned long, maxnode)
1294 unsigned short flags;
1296 flags = mode & MPOL_MODE_FLAGS;
1297 mode &= ~MPOL_MODE_FLAGS;
1298 if ((unsigned int)mode >= MPOL_MAX)
1300 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1302 err = get_nodes(&nodes, nmask, maxnode);
1305 return do_set_mempolicy(mode, flags, &nodes);
1308 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1309 const unsigned long __user *, old_nodes,
1310 const unsigned long __user *, new_nodes)
1312 const struct cred *cred = current_cred(), *tcred;
1313 struct mm_struct *mm = NULL;
1314 struct task_struct *task;
1315 nodemask_t task_nodes;
1319 NODEMASK_SCRATCH(scratch);
1324 old = &scratch->mask1;
1325 new = &scratch->mask2;
1327 err = get_nodes(old, old_nodes, maxnode);
1331 err = get_nodes(new, new_nodes, maxnode);
1335 /* Find the mm_struct */
1337 task = pid ? find_task_by_vpid(pid) : current;
1343 mm = get_task_mm(task);
1351 * Check if this process has the right to modify the specified
1352 * process. The right exists if the process has administrative
1353 * capabilities, superuser privileges or the same
1354 * userid as the target process.
1357 tcred = __task_cred(task);
1358 if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
1359 cred->uid != tcred->suid && cred->uid != tcred->uid &&
1360 !capable(CAP_SYS_NICE)) {
1367 task_nodes = cpuset_mems_allowed(task);
1368 /* Is the user allowed to access the target nodes? */
1369 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1374 if (!nodes_subset(*new, node_states[N_HIGH_MEMORY])) {
1379 err = security_task_movememory(task);
1383 err = do_migrate_pages(mm, old, new,
1384 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1388 NODEMASK_SCRATCH_FREE(scratch);
1394 /* Retrieve NUMA policy */
1395 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1396 unsigned long __user *, nmask, unsigned long, maxnode,
1397 unsigned long, addr, unsigned long, flags)
1400 int uninitialized_var(pval);
1403 if (nmask != NULL && maxnode < MAX_NUMNODES)
1406 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1411 if (policy && put_user(pval, policy))
1415 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1420 #ifdef CONFIG_COMPAT
1422 asmlinkage long compat_sys_get_mempolicy(int __user *policy,
1423 compat_ulong_t __user *nmask,
1424 compat_ulong_t maxnode,
1425 compat_ulong_t addr, compat_ulong_t flags)
1428 unsigned long __user *nm = NULL;
1429 unsigned long nr_bits, alloc_size;
1430 DECLARE_BITMAP(bm, MAX_NUMNODES);
1432 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1433 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1436 nm = compat_alloc_user_space(alloc_size);
1438 err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1440 if (!err && nmask) {
1441 unsigned long copy_size;
1442 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1443 err = copy_from_user(bm, nm, copy_size);
1444 /* ensure entire bitmap is zeroed */
1445 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1446 err |= compat_put_bitmap(nmask, bm, nr_bits);
1452 asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
1453 compat_ulong_t maxnode)
1456 unsigned long __user *nm = NULL;
1457 unsigned long nr_bits, alloc_size;
1458 DECLARE_BITMAP(bm, MAX_NUMNODES);
1460 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1461 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1464 err = compat_get_bitmap(bm, nmask, nr_bits);
1465 nm = compat_alloc_user_space(alloc_size);
1466 err |= copy_to_user(nm, bm, alloc_size);
1472 return sys_set_mempolicy(mode, nm, nr_bits+1);
1475 asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
1476 compat_ulong_t mode, compat_ulong_t __user *nmask,
1477 compat_ulong_t maxnode, compat_ulong_t flags)
1480 unsigned long __user *nm = NULL;
1481 unsigned long nr_bits, alloc_size;
1484 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1485 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1488 err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
1489 nm = compat_alloc_user_space(alloc_size);
1490 err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
1496 return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
1502 * get_vma_policy(@task, @vma, @addr)
1503 * @task - task for fallback if vma policy == default
1504 * @vma - virtual memory area whose policy is sought
1505 * @addr - address in @vma for shared policy lookup
1507 * Returns effective policy for a VMA at specified address.
1508 * Falls back to @task or system default policy, as necessary.
1509 * Current or other task's task mempolicy and non-shared vma policies
1510 * are protected by the task's mmap_sem, which must be held for read by
1512 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1513 * count--added by the get_policy() vm_op, as appropriate--to protect against
1514 * freeing by another task. It is the caller's responsibility to free the
1515 * extra reference for shared policies.
1517 struct mempolicy *get_vma_policy(struct task_struct *task,
1518 struct vm_area_struct *vma, unsigned long addr)
1520 struct mempolicy *pol = task->mempolicy;
1523 if (vma->vm_ops && vma->vm_ops->get_policy) {
1524 struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
1528 } else if (vma->vm_policy) {
1529 pol = vma->vm_policy;
1532 * shmem_alloc_page() passes MPOL_F_SHARED policy with
1533 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
1534 * count on these policies which will be dropped by
1535 * mpol_cond_put() later
1537 if (mpol_needs_cond_ref(pol))
1542 pol = &default_policy;
1547 * Return a nodemask representing a mempolicy for filtering nodes for
1550 static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1552 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1553 if (unlikely(policy->mode == MPOL_BIND) &&
1554 gfp_zone(gfp) >= policy_zone &&
1555 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1556 return &policy->v.nodes;
1561 /* Return a zonelist indicated by gfp for node representing a mempolicy */
1562 static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
1565 switch (policy->mode) {
1566 case MPOL_PREFERRED:
1567 if (!(policy->flags & MPOL_F_LOCAL))
1568 nd = policy->v.preferred_node;
1572 * Normally, MPOL_BIND allocations are node-local within the
1573 * allowed nodemask. However, if __GFP_THISNODE is set and the
1574 * current node isn't part of the mask, we use the zonelist for
1575 * the first node in the mask instead.
1577 if (unlikely(gfp & __GFP_THISNODE) &&
1578 unlikely(!node_isset(nd, policy->v.nodes)))
1579 nd = first_node(policy->v.nodes);
1584 return node_zonelist(nd, gfp);
1587 /* Do dynamic interleaving for a process */
1588 static unsigned interleave_nodes(struct mempolicy *policy)
1591 struct task_struct *me = current;
1594 next = next_node(nid, policy->v.nodes);
1595 if (next >= MAX_NUMNODES)
1596 next = first_node(policy->v.nodes);
1597 if (next < MAX_NUMNODES)
1603 * Depending on the memory policy provide a node from which to allocate the
1605 * @policy must be protected by freeing by the caller. If @policy is
1606 * the current task's mempolicy, this protection is implicit, as only the
1607 * task can change it's policy. The system default policy requires no
1610 unsigned slab_node(struct mempolicy *policy)
1612 if (!policy || policy->flags & MPOL_F_LOCAL)
1613 return numa_node_id();
1615 switch (policy->mode) {
1616 case MPOL_PREFERRED:
1618 * handled MPOL_F_LOCAL above
1620 return policy->v.preferred_node;
1622 case MPOL_INTERLEAVE:
1623 return interleave_nodes(policy);
1627 * Follow bind policy behavior and start allocation at the
1630 struct zonelist *zonelist;
1632 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1633 zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
1634 (void)first_zones_zonelist(zonelist, highest_zoneidx,
1637 return zone ? zone->node : numa_node_id();
1645 /* Do static interleaving for a VMA with known offset. */
1646 static unsigned offset_il_node(struct mempolicy *pol,
1647 struct vm_area_struct *vma, unsigned long off)
1649 unsigned nnodes = nodes_weight(pol->v.nodes);
1655 return numa_node_id();
1656 target = (unsigned int)off % nnodes;
1659 nid = next_node(nid, pol->v.nodes);
1661 } while (c <= target);
1665 /* Determine a node number for interleave */
1666 static inline unsigned interleave_nid(struct mempolicy *pol,
1667 struct vm_area_struct *vma, unsigned long addr, int shift)
1673 * for small pages, there is no difference between
1674 * shift and PAGE_SHIFT, so the bit-shift is safe.
1675 * for huge pages, since vm_pgoff is in units of small
1676 * pages, we need to shift off the always 0 bits to get
1679 BUG_ON(shift < PAGE_SHIFT);
1680 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1681 off += (addr - vma->vm_start) >> shift;
1682 return offset_il_node(pol, vma, off);
1684 return interleave_nodes(pol);
1688 * Return the bit number of a random bit set in the nodemask.
1689 * (returns -1 if nodemask is empty)
1691 int node_random(const nodemask_t *maskp)
1695 w = nodes_weight(*maskp);
1697 bit = bitmap_ord_to_pos(maskp->bits,
1698 get_random_int() % w, MAX_NUMNODES);
1702 #ifdef CONFIG_HUGETLBFS
1704 * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
1705 * @vma = virtual memory area whose policy is sought
1706 * @addr = address in @vma for shared policy lookup and interleave policy
1707 * @gfp_flags = for requested zone
1708 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
1709 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1711 * Returns a zonelist suitable for a huge page allocation and a pointer
1712 * to the struct mempolicy for conditional unref after allocation.
1713 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1714 * @nodemask for filtering the zonelist.
1716 * Must be protected by get_mems_allowed()
1718 struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1719 gfp_t gfp_flags, struct mempolicy **mpol,
1720 nodemask_t **nodemask)
1722 struct zonelist *zl;
1724 *mpol = get_vma_policy(current, vma, addr);
1725 *nodemask = NULL; /* assume !MPOL_BIND */
1727 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1728 zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1729 huge_page_shift(hstate_vma(vma))), gfp_flags);
1731 zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1732 if ((*mpol)->mode == MPOL_BIND)
1733 *nodemask = &(*mpol)->v.nodes;
1739 * init_nodemask_of_mempolicy
1741 * If the current task's mempolicy is "default" [NULL], return 'false'
1742 * to indicate default policy. Otherwise, extract the policy nodemask
1743 * for 'bind' or 'interleave' policy into the argument nodemask, or
1744 * initialize the argument nodemask to contain the single node for
1745 * 'preferred' or 'local' policy and return 'true' to indicate presence
1746 * of non-default mempolicy.
1748 * We don't bother with reference counting the mempolicy [mpol_get/put]
1749 * because the current task is examining it's own mempolicy and a task's
1750 * mempolicy is only ever changed by the task itself.
1752 * N.B., it is the caller's responsibility to free a returned nodemask.
1754 bool init_nodemask_of_mempolicy(nodemask_t *mask)
1756 struct mempolicy *mempolicy;
1759 if (!(mask && current->mempolicy))
1763 mempolicy = current->mempolicy;
1764 switch (mempolicy->mode) {
1765 case MPOL_PREFERRED:
1766 if (mempolicy->flags & MPOL_F_LOCAL)
1767 nid = numa_node_id();
1769 nid = mempolicy->v.preferred_node;
1770 init_nodemask_of_node(mask, nid);
1775 case MPOL_INTERLEAVE:
1776 *mask = mempolicy->v.nodes;
1782 task_unlock(current);
1789 * mempolicy_nodemask_intersects
1791 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
1792 * policy. Otherwise, check for intersection between mask and the policy
1793 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
1794 * policy, always return true since it may allocate elsewhere on fallback.
1796 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
1798 bool mempolicy_nodemask_intersects(struct task_struct *tsk,
1799 const nodemask_t *mask)
1801 struct mempolicy *mempolicy;
1807 mempolicy = tsk->mempolicy;
1811 switch (mempolicy->mode) {
1812 case MPOL_PREFERRED:
1814 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
1815 * allocate from, they may fallback to other nodes when oom.
1816 * Thus, it's possible for tsk to have allocated memory from
1821 case MPOL_INTERLEAVE:
1822 ret = nodes_intersects(mempolicy->v.nodes, *mask);
1832 /* Allocate a page in interleaved policy.
1833 Own path because it needs to do special accounting. */
1834 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
1837 struct zonelist *zl;
1840 zl = node_zonelist(nid, gfp);
1841 page = __alloc_pages(gfp, order, zl);
1842 if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1843 inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
1848 * alloc_pages_vma - Allocate a page for a VMA.
1851 * %GFP_USER user allocation.
1852 * %GFP_KERNEL kernel allocations,
1853 * %GFP_HIGHMEM highmem/user allocations,
1854 * %GFP_FS allocation should not call back into a file system.
1855 * %GFP_ATOMIC don't sleep.
1857 * @order:Order of the GFP allocation.
1858 * @vma: Pointer to VMA or NULL if not available.
1859 * @addr: Virtual Address of the allocation. Must be inside the VMA.
1861 * This function allocates a page from the kernel page pool and applies
1862 * a NUMA policy associated with the VMA or the current process.
1863 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
1864 * mm_struct of the VMA to prevent it from going away. Should be used for
1865 * all allocations for pages that will be mapped into
1866 * user space. Returns NULL when no page can be allocated.
1868 * Should be called with the mm_sem of the vma hold.
1871 alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
1872 unsigned long addr, int node)
1874 struct mempolicy *pol;
1875 struct zonelist *zl;
1877 unsigned int cpuset_mems_cookie;
1880 pol = get_vma_policy(current, vma, addr);
1881 cpuset_mems_cookie = get_mems_allowed();
1883 if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
1886 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
1888 page = alloc_page_interleave(gfp, order, nid);
1889 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1894 zl = policy_zonelist(gfp, pol, node);
1895 if (unlikely(mpol_needs_cond_ref(pol))) {
1897 * slow path: ref counted shared policy
1899 struct page *page = __alloc_pages_nodemask(gfp, order,
1900 zl, policy_nodemask(gfp, pol));
1902 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1907 * fast path: default or task policy
1909 page = __alloc_pages_nodemask(gfp, order, zl,
1910 policy_nodemask(gfp, pol));
1911 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1917 * alloc_pages_current - Allocate pages.
1920 * %GFP_USER user allocation,
1921 * %GFP_KERNEL kernel allocation,
1922 * %GFP_HIGHMEM highmem allocation,
1923 * %GFP_FS don't call back into a file system.
1924 * %GFP_ATOMIC don't sleep.
1925 * @order: Power of two of allocation size in pages. 0 is a single page.
1927 * Allocate a page from the kernel page pool. When not in
1928 * interrupt context and apply the current process NUMA policy.
1929 * Returns NULL when no page can be allocated.
1931 * Don't call cpuset_update_task_memory_state() unless
1932 * 1) it's ok to take cpuset_sem (can WAIT), and
1933 * 2) allocating for current task (not interrupt).
1935 struct page *alloc_pages_current(gfp_t gfp, unsigned order)
1937 struct mempolicy *pol = current->mempolicy;
1939 unsigned int cpuset_mems_cookie;
1941 if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
1942 pol = &default_policy;
1945 cpuset_mems_cookie = get_mems_allowed();
1948 * No reference counting needed for current->mempolicy
1949 * nor system default_policy
1951 if (pol->mode == MPOL_INTERLEAVE)
1952 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
1954 page = __alloc_pages_nodemask(gfp, order,
1955 policy_zonelist(gfp, pol, numa_node_id()),
1956 policy_nodemask(gfp, pol));
1958 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
1963 EXPORT_SYMBOL(alloc_pages_current);
1966 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
1967 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
1968 * with the mems_allowed returned by cpuset_mems_allowed(). This
1969 * keeps mempolicies cpuset relative after its cpuset moves. See
1970 * further kernel/cpuset.c update_nodemask().
1972 * current's mempolicy may be rebinded by the other task(the task that changes
1973 * cpuset's mems), so we needn't do rebind work for current task.
1976 /* Slow path of a mempolicy duplicate */
1977 struct mempolicy *__mpol_dup(struct mempolicy *old)
1979 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
1982 return ERR_PTR(-ENOMEM);
1984 /* task's mempolicy is protected by alloc_lock */
1985 if (old == current->mempolicy) {
1988 task_unlock(current);
1993 if (current_cpuset_is_being_rebound()) {
1994 nodemask_t mems = cpuset_mems_allowed(current);
1995 if (new->flags & MPOL_F_REBINDING)
1996 mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
1998 mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
2001 atomic_set(&new->refcnt, 1);
2005 /* Slow path of a mempolicy comparison */
2006 int __mpol_equal(struct mempolicy *a, struct mempolicy *b)
2010 if (a->mode != b->mode)
2012 if (a->flags != b->flags)
2014 if (mpol_store_user_nodemask(a))
2015 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2021 case MPOL_INTERLEAVE:
2022 return nodes_equal(a->v.nodes, b->v.nodes);
2023 case MPOL_PREFERRED:
2024 return a->v.preferred_node == b->v.preferred_node;
2032 * Shared memory backing store policy support.
2034 * Remember policies even when nobody has shared memory mapped.
2035 * The policies are kept in Red-Black tree linked from the inode.
2036 * They are protected by the sp->lock spinlock, which should be held
2037 * for any accesses to the tree.
2040 /* lookup first element intersecting start-end */
2041 /* Caller holds sp->mutex */
2042 static struct sp_node *
2043 sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2045 struct rb_node *n = sp->root.rb_node;
2048 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2050 if (start >= p->end)
2052 else if (end <= p->start)
2060 struct sp_node *w = NULL;
2061 struct rb_node *prev = rb_prev(n);
2064 w = rb_entry(prev, struct sp_node, nd);
2065 if (w->end <= start)
2069 return rb_entry(n, struct sp_node, nd);
2072 /* Insert a new shared policy into the list. */
2073 /* Caller holds sp->lock */
2074 static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2076 struct rb_node **p = &sp->root.rb_node;
2077 struct rb_node *parent = NULL;
2082 nd = rb_entry(parent, struct sp_node, nd);
2083 if (new->start < nd->start)
2085 else if (new->end > nd->end)
2086 p = &(*p)->rb_right;
2090 rb_link_node(&new->nd, parent, p);
2091 rb_insert_color(&new->nd, &sp->root);
2092 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2093 new->policy ? new->policy->mode : 0);
2096 /* Find shared policy intersecting idx */
2098 mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2100 struct mempolicy *pol = NULL;
2103 if (!sp->root.rb_node)
2105 mutex_lock(&sp->mutex);
2106 sn = sp_lookup(sp, idx, idx+1);
2108 mpol_get(sn->policy);
2111 mutex_unlock(&sp->mutex);
2115 static void sp_free(struct sp_node *n)
2117 mpol_put(n->policy);
2118 kmem_cache_free(sn_cache, n);
2121 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2123 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2124 rb_erase(&n->nd, &sp->root);
2128 static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2129 struct mempolicy *pol)
2132 struct mempolicy *newpol;
2134 n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2138 newpol = mpol_dup(pol);
2139 if (IS_ERR(newpol)) {
2140 kmem_cache_free(sn_cache, n);
2143 newpol->flags |= MPOL_F_SHARED;
2152 /* Replace a policy range. */
2153 static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2154 unsigned long end, struct sp_node *new)
2159 mutex_lock(&sp->mutex);
2160 n = sp_lookup(sp, start, end);
2161 /* Take care of old policies in the same range. */
2162 while (n && n->start < end) {
2163 struct rb_node *next = rb_next(&n->nd);
2164 if (n->start >= start) {
2170 /* Old policy spanning whole new range. */
2172 struct sp_node *new2;
2173 new2 = sp_alloc(end, n->end, n->policy);
2179 sp_insert(sp, new2);
2186 n = rb_entry(next, struct sp_node, nd);
2191 mutex_unlock(&sp->mutex);
2196 * mpol_shared_policy_init - initialize shared policy for inode
2197 * @sp: pointer to inode shared policy
2198 * @mpol: struct mempolicy to install
2200 * Install non-NULL @mpol in inode's shared policy rb-tree.
2201 * On entry, the current task has a reference on a non-NULL @mpol.
2202 * This must be released on exit.
2203 * This is called at get_inode() calls and we can use GFP_KERNEL.
2205 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2209 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2210 mutex_init(&sp->mutex);
2213 struct vm_area_struct pvma;
2214 struct mempolicy *new;
2215 NODEMASK_SCRATCH(scratch);
2219 /* contextualize the tmpfs mount point mempolicy */
2220 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2222 goto free_scratch; /* no valid nodemask intersection */
2225 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2226 task_unlock(current);
2230 /* Create pseudo-vma that contains just the policy */
2231 memset(&pvma, 0, sizeof(struct vm_area_struct));
2232 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2233 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2236 mpol_put(new); /* drop initial ref */
2238 NODEMASK_SCRATCH_FREE(scratch);
2240 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2244 int mpol_set_shared_policy(struct shared_policy *info,
2245 struct vm_area_struct *vma, struct mempolicy *npol)
2248 struct sp_node *new = NULL;
2249 unsigned long sz = vma_pages(vma);
2251 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2253 sz, npol ? npol->mode : -1,
2254 npol ? npol->flags : -1,
2255 npol ? nodes_addr(npol->v.nodes)[0] : -1);
2258 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2262 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2268 /* Free a backing policy store on inode delete. */
2269 void mpol_free_shared_policy(struct shared_policy *p)
2272 struct rb_node *next;
2274 if (!p->root.rb_node)
2276 mutex_lock(&p->mutex);
2277 next = rb_first(&p->root);
2279 n = rb_entry(next, struct sp_node, nd);
2280 next = rb_next(&n->nd);
2283 mutex_unlock(&p->mutex);
2286 /* assumes fs == KERNEL_DS */
2287 void __init numa_policy_init(void)
2289 nodemask_t interleave_nodes;
2290 unsigned long largest = 0;
2291 int nid, prefer = 0;
2293 policy_cache = kmem_cache_create("numa_policy",
2294 sizeof(struct mempolicy),
2295 0, SLAB_PANIC, NULL);
2297 sn_cache = kmem_cache_create("shared_policy_node",
2298 sizeof(struct sp_node),
2299 0, SLAB_PANIC, NULL);
2302 * Set interleaving policy for system init. Interleaving is only
2303 * enabled across suitably sized nodes (default is >= 16MB), or
2304 * fall back to the largest node if they're all smaller.
2306 nodes_clear(interleave_nodes);
2307 for_each_node_state(nid, N_HIGH_MEMORY) {
2308 unsigned long total_pages = node_present_pages(nid);
2310 /* Preserve the largest node */
2311 if (largest < total_pages) {
2312 largest = total_pages;
2316 /* Interleave this node? */
2317 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2318 node_set(nid, interleave_nodes);
2321 /* All too small, use the largest */
2322 if (unlikely(nodes_empty(interleave_nodes)))
2323 node_set(prefer, interleave_nodes);
2325 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2326 printk("numa_policy_init: interleaving failed\n");
2329 /* Reset policy of current process to default */
2330 void numa_default_policy(void)
2332 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2336 * Parse and format mempolicy from/to strings
2340 * "local" is implemented internally by MPOL_PREFERRED with MPOL_F_LOCAL flag.
2342 #define MPOL_LOCAL MPOL_MAX
2343 static const char * const policy_modes[] =
2345 [MPOL_DEFAULT] = "default",
2346 [MPOL_PREFERRED] = "prefer",
2347 [MPOL_BIND] = "bind",
2348 [MPOL_INTERLEAVE] = "interleave",
2349 [MPOL_LOCAL] = "local"
2355 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2356 * @str: string containing mempolicy to parse
2357 * @mpol: pointer to struct mempolicy pointer, returned on success.
2358 * @unused: redundant argument, to be removed later.
2361 * <mode>[=<flags>][:<nodelist>]
2363 * On success, returns 0, else 1
2365 int mpol_parse_str(char *str, struct mempolicy **mpol, int unused)
2367 struct mempolicy *new = NULL;
2368 unsigned short mode;
2369 unsigned short mode_flags;
2371 char *nodelist = strchr(str, ':');
2372 char *flags = strchr(str, '=');
2376 /* NUL-terminate mode or flags string */
2378 if (nodelist_parse(nodelist, nodes))
2380 if (!nodes_subset(nodes, node_states[N_HIGH_MEMORY]))
2386 *flags++ = '\0'; /* terminate mode string */
2388 for (mode = 0; mode <= MPOL_LOCAL; mode++) {
2389 if (!strcmp(str, policy_modes[mode])) {
2393 if (mode > MPOL_LOCAL)
2397 case MPOL_PREFERRED:
2399 * Insist on a nodelist of one node only
2402 char *rest = nodelist;
2403 while (isdigit(*rest))
2409 case MPOL_INTERLEAVE:
2411 * Default to online nodes with memory if no nodelist
2414 nodes = node_states[N_HIGH_MEMORY];
2418 * Don't allow a nodelist; mpol_new() checks flags
2422 mode = MPOL_PREFERRED;
2426 * Insist on a empty nodelist
2433 * Insist on a nodelist
2442 * Currently, we only support two mutually exclusive
2445 if (!strcmp(flags, "static"))
2446 mode_flags |= MPOL_F_STATIC_NODES;
2447 else if (!strcmp(flags, "relative"))
2448 mode_flags |= MPOL_F_RELATIVE_NODES;
2453 new = mpol_new(mode, mode_flags, &nodes);
2458 * Save nodes for mpol_to_str() to show the tmpfs mount options
2459 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
2461 if (mode != MPOL_PREFERRED)
2462 new->v.nodes = nodes;
2464 new->v.preferred_node = first_node(nodes);
2466 new->flags |= MPOL_F_LOCAL;
2469 * Save nodes for contextualization: this will be used to "clone"
2470 * the mempolicy in a specific context [cpuset] at a later time.
2472 new->w.user_nodemask = nodes;
2477 /* Restore string for error message */
2486 #endif /* CONFIG_TMPFS */
2489 * mpol_to_str - format a mempolicy structure for printing
2490 * @buffer: to contain formatted mempolicy string
2491 * @maxlen: length of @buffer
2492 * @pol: pointer to mempolicy to be formatted
2493 * @unused: redundant argument, to be removed later.
2495 * Convert a mempolicy into a string.
2496 * Returns the number of characters in buffer (if positive)
2497 * or an error (negative)
2499 int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol, int unused)
2504 unsigned short mode;
2505 unsigned short flags = pol ? pol->flags : 0;
2508 * Sanity check: room for longest mode, flag and some nodes
2510 VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
2512 if (!pol || pol == &default_policy)
2513 mode = MPOL_DEFAULT;
2522 case MPOL_PREFERRED:
2524 if (flags & MPOL_F_LOCAL)
2527 node_set(pol->v.preferred_node, nodes);
2532 case MPOL_INTERLEAVE:
2533 nodes = pol->v.nodes;
2540 l = strlen(policy_modes[mode]);
2541 if (buffer + maxlen < p + l + 1)
2544 strcpy(p, policy_modes[mode]);
2547 if (flags & MPOL_MODE_FLAGS) {
2548 if (buffer + maxlen < p + 2)
2553 * Currently, the only defined flags are mutually exclusive
2555 if (flags & MPOL_F_STATIC_NODES)
2556 p += snprintf(p, buffer + maxlen - p, "static");
2557 else if (flags & MPOL_F_RELATIVE_NODES)
2558 p += snprintf(p, buffer + maxlen - p, "relative");
2561 if (!nodes_empty(nodes)) {
2562 if (buffer + maxlen < p + 2)
2565 p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);