Merge branch 'nf' of git://1984.lsi.us.es/net
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / mempolicy.c
blobadc395481813532efe82dced222e79115b075b0e
1 /*
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
9 * be allocated.
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
20 * is used.
22 * bind Only allocate memory on a specific set of nodes,
23 * no fallback.
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
32 * process policy.
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.
56 /* Notebook:
57 fix mmap readahead to honour policy and enable policy for any page cache
58 object
59 statistics for bigpages
60 global policy for page cache? currently it uses process policy. Requires
61 first item above.
62 handle mremap for shared memory (currently ignored for the policy)
63 grows down?
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>
69 #include <linux/mm.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>
98 #include "internal.h"
100 /* Internal flags */
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
108 policied. */
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
127 * page.
128 * If we have a lock to protect task->mempolicy in read-side, we do
129 * rebind directly.
131 * step:
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)
143 int nd, k;
145 for_each_node_mask(nd, *nodemask) {
146 struct zone *z;
148 for (k = 0; k <= policy_zone; k++) {
149 z = &NODE_DATA(nd)->node_zones[k];
150 if (z->present_pages > 0)
151 return 1;
155 return 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)
166 nodemask_t tmp;
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))
174 return -EINVAL;
175 pol->v.nodes = *nodes;
176 return 0;
179 static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
181 if (!nodes)
182 pol->flags |= MPOL_F_LOCAL; /* local allocation */
183 else if (nodes_empty(*nodes))
184 return -EINVAL; /* no allowed nodes */
185 else
186 pol->v.preferred_node = first_node(*nodes);
187 return 0;
190 static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
192 if (!is_valid_nodemask(nodes))
193 return -EINVAL;
194 pol->v.nodes = *nodes;
195 return 0;
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)
210 int ret;
212 /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
213 if (pol == NULL)
214 return 0;
215 /* Check N_HIGH_MEMORY */
216 nodes_and(nsc->mask1,
217 cpuset_current_mems_allowed, node_states[N_HIGH_MEMORY]);
219 VM_BUG_ON(!nodes);
220 if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
221 nodes = NULL; /* explicit local allocation */
222 else {
223 if (pol->flags & MPOL_F_RELATIVE_NODES)
224 mpol_relative_nodemask(&nsc->mask2, nodes,&nsc->mask1);
225 else
226 nodes_and(nsc->mask2, *nodes, nsc->mask1);
228 if (mpol_store_user_nodemask(pol))
229 pol->w.user_nodemask = *nodes;
230 else
231 pol->w.cpuset_mems_allowed =
232 cpuset_current_mems_allowed;
235 if (nodes)
236 ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
237 else
238 ret = mpol_ops[pol->mode].create(pol, NULL);
239 return ret;
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,
247 nodemask_t *nodes)
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 */
259 VM_BUG_ON(!nodes);
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);
275 if (!policy)
276 return ERR_PTR(-ENOMEM);
277 atomic_set(&policy->refcnt, 1);
278 policy->mode = mode;
279 policy->flags = flags;
281 return policy;
284 /* Slow path of a mpol destructor. */
285 void __mpol_put(struct mempolicy *p)
287 if (!atomic_dec_and_test(&p->refcnt))
288 return;
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)
298 * 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)
306 nodemask_t tmp;
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);
312 else {
314 * if step == 1, we use ->w.cpuset_mems_allowed to cache the
315 * result
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;
324 } else
325 BUG();
328 if (nodes_empty(tmp))
329 tmp = *nodes;
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)
334 pol->v.nodes = tmp;
335 else
336 BUG();
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)
351 nodemask_t tmp;
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;
359 } else
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,
367 *nodes);
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
379 * page.
380 * If we have a lock to protect task->mempolicy in read-side, we do
381 * rebind directly.
383 * step:
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)
391 if (!pol)
392 return;
393 if (!mpol_store_user_nodemask(pol) && step == 0 &&
394 nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
395 return;
397 if (step == MPOL_REBIND_STEP1 && (pol->flags & MPOL_F_REBINDING))
398 return;
400 if (step == MPOL_REBIND_STEP2 && !(pol->flags & MPOL_F_REBINDING))
401 BUG();
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)
408 BUG();
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] = {
443 [MPOL_DEFAULT] = {
444 .rebind = mpol_rebind_default,
446 [MPOL_INTERLEAVE] = {
447 .create = mpol_new_interleave,
448 .rebind = mpol_rebind_nodemask,
450 [MPOL_PREFERRED] = {
451 .create = mpol_new_preferred,
452 .rebind = mpol_rebind_preferred,
454 [MPOL_BIND] = {
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,
467 void *private)
469 pte_t *orig_pte;
470 pte_t *pte;
471 spinlock_t *ptl;
473 orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
474 do {
475 struct page *page;
476 int nid;
478 if (!pte_present(*pte))
479 continue;
480 page = vm_normal_page(vma, addr, *pte);
481 if (!page)
482 continue;
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))
489 continue;
490 nid = page_to_nid(page);
491 if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
492 continue;
494 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
495 migrate_page_add(page, private, flags);
496 else
497 break;
498 } while (pte++, addr += PAGE_SIZE, addr != end);
499 pte_unmap_unlock(orig_pte, ptl);
500 return addr != end;
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,
506 void *private)
508 pmd_t *pmd;
509 unsigned long next;
511 pmd = pmd_offset(pud, addr);
512 do {
513 next = pmd_addr_end(addr, end);
514 split_huge_page_pmd(vma->vm_mm, pmd);
515 if (pmd_none_or_clear_bad(pmd))
516 continue;
517 if (check_pte_range(vma, pmd, addr, next, nodes,
518 flags, private))
519 return -EIO;
520 } while (pmd++, addr = next, addr != end);
521 return 0;
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,
527 void *private)
529 pud_t *pud;
530 unsigned long next;
532 pud = pud_offset(pgd, addr);
533 do {
534 next = pud_addr_end(addr, end);
535 if (pud_none_or_clear_bad(pud))
536 continue;
537 if (check_pmd_range(vma, pud, addr, next, nodes,
538 flags, private))
539 return -EIO;
540 } while (pud++, addr = next, addr != end);
541 return 0;
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,
547 void *private)
549 pgd_t *pgd;
550 unsigned long next;
552 pgd = pgd_offset(vma->vm_mm, addr);
553 do {
554 next = pgd_addr_end(addr, end);
555 if (pgd_none_or_clear_bad(pgd))
556 continue;
557 if (check_pud_range(vma, pgd, addr, next, nodes,
558 flags, private))
559 return -EIO;
560 } while (pgd++, addr = next, addr != end);
561 return 0;
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)
573 int err;
574 struct vm_area_struct *first, *vma, *prev;
577 first = find_vma(mm, start);
578 if (!first)
579 return ERR_PTR(-EFAULT);
580 prev = NULL;
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;
594 if (endvma > end)
595 endvma = end;
596 if (vma->vm_start > start)
597 start = vma->vm_start;
598 err = check_pgd_range(vma, start, endvma, nodes,
599 flags, private);
600 if (err) {
601 first = ERR_PTR(err);
602 break;
605 prev = vma;
607 return first;
610 /* Apply policy to a single VMA */
611 static int policy_vma(struct vm_area_struct *vma, struct mempolicy *new)
613 int err = 0;
614 struct mempolicy *old = vma->vm_policy;
616 pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
617 vma->vm_start, vma->vm_end, vma->vm_pgoff,
618 vma->vm_ops, vma->vm_file,
619 vma->vm_ops ? vma->vm_ops->set_policy : NULL);
621 if (vma->vm_ops && vma->vm_ops->set_policy)
622 err = vma->vm_ops->set_policy(vma, new);
623 if (!err) {
624 mpol_get(new);
625 vma->vm_policy = new;
626 mpol_put(old);
628 return err;
631 /* Step 2: apply policy to a range and do splits. */
632 static int mbind_range(struct mm_struct *mm, unsigned long start,
633 unsigned long end, struct mempolicy *new_pol)
635 struct vm_area_struct *next;
636 struct vm_area_struct *prev;
637 struct vm_area_struct *vma;
638 int err = 0;
639 unsigned long vmstart;
640 unsigned long vmend;
642 vma = find_vma_prev(mm, start, &prev);
643 if (!vma || vma->vm_start > start)
644 return -EFAULT;
646 for (; vma && vma->vm_start < end; prev = vma, vma = next) {
647 next = vma->vm_next;
648 vmstart = max(start, vma->vm_start);
649 vmend = min(end, vma->vm_end);
651 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
652 vma->anon_vma, vma->vm_file, vma->vm_pgoff,
653 new_pol);
654 if (prev) {
655 vma = prev;
656 next = vma->vm_next;
657 continue;
659 if (vma->vm_start != vmstart) {
660 err = split_vma(vma->vm_mm, vma, vmstart, 1);
661 if (err)
662 goto out;
664 if (vma->vm_end != vmend) {
665 err = split_vma(vma->vm_mm, vma, vmend, 0);
666 if (err)
667 goto out;
669 err = policy_vma(vma, new_pol);
670 if (err)
671 goto out;
674 out:
675 return err;
679 * Update task->flags PF_MEMPOLICY bit: set iff non-default
680 * mempolicy. Allows more rapid checking of this (combined perhaps
681 * with other PF_* flag bits) on memory allocation hot code paths.
683 * If called from outside this file, the task 'p' should -only- be
684 * a newly forked child not yet visible on the task list, because
685 * manipulating the task flags of a visible task is not safe.
687 * The above limitation is why this routine has the funny name
688 * mpol_fix_fork_child_flag().
690 * It is also safe to call this with a task pointer of current,
691 * which the static wrapper mpol_set_task_struct_flag() does,
692 * for use within this file.
695 void mpol_fix_fork_child_flag(struct task_struct *p)
697 if (p->mempolicy)
698 p->flags |= PF_MEMPOLICY;
699 else
700 p->flags &= ~PF_MEMPOLICY;
703 static void mpol_set_task_struct_flag(void)
705 mpol_fix_fork_child_flag(current);
708 /* Set the process memory policy */
709 static long do_set_mempolicy(unsigned short mode, unsigned short flags,
710 nodemask_t *nodes)
712 struct mempolicy *new, *old;
713 struct mm_struct *mm = current->mm;
714 NODEMASK_SCRATCH(scratch);
715 int ret;
717 if (!scratch)
718 return -ENOMEM;
720 new = mpol_new(mode, flags, nodes);
721 if (IS_ERR(new)) {
722 ret = PTR_ERR(new);
723 goto out;
726 * prevent changing our mempolicy while show_numa_maps()
727 * is using it.
728 * Note: do_set_mempolicy() can be called at init time
729 * with no 'mm'.
731 if (mm)
732 down_write(&mm->mmap_sem);
733 task_lock(current);
734 ret = mpol_set_nodemask(new, nodes, scratch);
735 if (ret) {
736 task_unlock(current);
737 if (mm)
738 up_write(&mm->mmap_sem);
739 mpol_put(new);
740 goto out;
742 old = current->mempolicy;
743 current->mempolicy = new;
744 mpol_set_task_struct_flag();
745 if (new && new->mode == MPOL_INTERLEAVE &&
746 nodes_weight(new->v.nodes))
747 current->il_next = first_node(new->v.nodes);
748 task_unlock(current);
749 if (mm)
750 up_write(&mm->mmap_sem);
752 mpol_put(old);
753 ret = 0;
754 out:
755 NODEMASK_SCRATCH_FREE(scratch);
756 return ret;
760 * Return nodemask for policy for get_mempolicy() query
762 * Called with task's alloc_lock held
764 static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
766 nodes_clear(*nodes);
767 if (p == &default_policy)
768 return;
770 switch (p->mode) {
771 case MPOL_BIND:
772 /* Fall through */
773 case MPOL_INTERLEAVE:
774 *nodes = p->v.nodes;
775 break;
776 case MPOL_PREFERRED:
777 if (!(p->flags & MPOL_F_LOCAL))
778 node_set(p->v.preferred_node, *nodes);
779 /* else return empty node mask for local allocation */
780 break;
781 default:
782 BUG();
786 static int lookup_node(struct mm_struct *mm, unsigned long addr)
788 struct page *p;
789 int err;
791 err = get_user_pages(current, mm, addr & PAGE_MASK, 1, 0, 0, &p, NULL);
792 if (err >= 0) {
793 err = page_to_nid(p);
794 put_page(p);
796 return err;
799 /* Retrieve NUMA policy */
800 static long do_get_mempolicy(int *policy, nodemask_t *nmask,
801 unsigned long addr, unsigned long flags)
803 int err;
804 struct mm_struct *mm = current->mm;
805 struct vm_area_struct *vma = NULL;
806 struct mempolicy *pol = current->mempolicy;
808 if (flags &
809 ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
810 return -EINVAL;
812 if (flags & MPOL_F_MEMS_ALLOWED) {
813 if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
814 return -EINVAL;
815 *policy = 0; /* just so it's initialized */
816 task_lock(current);
817 *nmask = cpuset_current_mems_allowed;
818 task_unlock(current);
819 return 0;
822 if (flags & MPOL_F_ADDR) {
824 * Do NOT fall back to task policy if the
825 * vma/shared policy at addr is NULL. We
826 * want to return MPOL_DEFAULT in this case.
828 down_read(&mm->mmap_sem);
829 vma = find_vma_intersection(mm, addr, addr+1);
830 if (!vma) {
831 up_read(&mm->mmap_sem);
832 return -EFAULT;
834 if (vma->vm_ops && vma->vm_ops->get_policy)
835 pol = vma->vm_ops->get_policy(vma, addr);
836 else
837 pol = vma->vm_policy;
838 } else if (addr)
839 return -EINVAL;
841 if (!pol)
842 pol = &default_policy; /* indicates default behavior */
844 if (flags & MPOL_F_NODE) {
845 if (flags & MPOL_F_ADDR) {
846 err = lookup_node(mm, addr);
847 if (err < 0)
848 goto out;
849 *policy = err;
850 } else if (pol == current->mempolicy &&
851 pol->mode == MPOL_INTERLEAVE) {
852 *policy = current->il_next;
853 } else {
854 err = -EINVAL;
855 goto out;
857 } else {
858 *policy = pol == &default_policy ? MPOL_DEFAULT :
859 pol->mode;
861 * Internal mempolicy flags must be masked off before exposing
862 * the policy to userspace.
864 *policy |= (pol->flags & MPOL_MODE_FLAGS);
867 if (vma) {
868 up_read(&current->mm->mmap_sem);
869 vma = NULL;
872 err = 0;
873 if (nmask) {
874 if (mpol_store_user_nodemask(pol)) {
875 *nmask = pol->w.user_nodemask;
876 } else {
877 task_lock(current);
878 get_policy_nodemask(pol, nmask);
879 task_unlock(current);
883 out:
884 mpol_cond_put(pol);
885 if (vma)
886 up_read(&current->mm->mmap_sem);
887 return err;
890 #ifdef CONFIG_MIGRATION
892 * page migration
894 static void migrate_page_add(struct page *page, struct list_head *pagelist,
895 unsigned long flags)
898 * Avoid migrating a page that is shared with others.
900 if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
901 if (!isolate_lru_page(page)) {
902 list_add_tail(&page->lru, pagelist);
903 inc_zone_page_state(page, NR_ISOLATED_ANON +
904 page_is_file_cache(page));
909 static struct page *new_node_page(struct page *page, unsigned long node, int **x)
911 return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
915 * Migrate pages from one node to a target node.
916 * Returns error or the number of pages not migrated.
918 static int migrate_to_node(struct mm_struct *mm, int source, int dest,
919 int flags)
921 nodemask_t nmask;
922 LIST_HEAD(pagelist);
923 int err = 0;
924 struct vm_area_struct *vma;
926 nodes_clear(nmask);
927 node_set(source, nmask);
929 vma = check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
930 flags | MPOL_MF_DISCONTIG_OK, &pagelist);
931 if (IS_ERR(vma))
932 return PTR_ERR(vma);
934 if (!list_empty(&pagelist)) {
935 err = migrate_pages(&pagelist, new_node_page, dest,
936 false, true);
937 if (err)
938 putback_lru_pages(&pagelist);
941 return err;
945 * Move pages between the two nodesets so as to preserve the physical
946 * layout as much as possible.
948 * Returns the number of page that could not be moved.
950 int do_migrate_pages(struct mm_struct *mm,
951 const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
953 int busy = 0;
954 int err;
955 nodemask_t tmp;
957 err = migrate_prep();
958 if (err)
959 return err;
961 down_read(&mm->mmap_sem);
963 err = migrate_vmas(mm, from_nodes, to_nodes, flags);
964 if (err)
965 goto out;
968 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
969 * bit in 'to' is not also set in 'tmp'. Clear the found 'source'
970 * bit in 'tmp', and return that <source, dest> pair for migration.
971 * The pair of nodemasks 'to' and 'from' define the map.
973 * If no pair of bits is found that way, fallback to picking some
974 * pair of 'source' and 'dest' bits that are not the same. If the
975 * 'source' and 'dest' bits are the same, this represents a node
976 * that will be migrating to itself, so no pages need move.
978 * If no bits are left in 'tmp', or if all remaining bits left
979 * in 'tmp' correspond to the same bit in 'to', return false
980 * (nothing left to migrate).
982 * This lets us pick a pair of nodes to migrate between, such that
983 * if possible the dest node is not already occupied by some other
984 * source node, minimizing the risk of overloading the memory on a
985 * node that would happen if we migrated incoming memory to a node
986 * before migrating outgoing memory source that same node.
988 * A single scan of tmp is sufficient. As we go, we remember the
989 * most recent <s, d> pair that moved (s != d). If we find a pair
990 * that not only moved, but what's better, moved to an empty slot
991 * (d is not set in tmp), then we break out then, with that pair.
992 * Otherwise when we finish scanning from_tmp, we at least have the
993 * most recent <s, d> pair that moved. If we get all the way through
994 * the scan of tmp without finding any node that moved, much less
995 * moved to an empty node, then there is nothing left worth migrating.
998 tmp = *from_nodes;
999 while (!nodes_empty(tmp)) {
1000 int s,d;
1001 int source = -1;
1002 int dest = 0;
1004 for_each_node_mask(s, tmp) {
1005 d = node_remap(s, *from_nodes, *to_nodes);
1006 if (s == d)
1007 continue;
1009 source = s; /* Node moved. Memorize */
1010 dest = d;
1012 /* dest not in remaining from nodes? */
1013 if (!node_isset(dest, tmp))
1014 break;
1016 if (source == -1)
1017 break;
1019 node_clear(source, tmp);
1020 err = migrate_to_node(mm, source, dest, flags);
1021 if (err > 0)
1022 busy += err;
1023 if (err < 0)
1024 break;
1026 out:
1027 up_read(&mm->mmap_sem);
1028 if (err < 0)
1029 return err;
1030 return busy;
1035 * Allocate a new page for page migration based on vma policy.
1036 * Start assuming that page is mapped by vma pointed to by @private.
1037 * Search forward from there, if not. N.B., this assumes that the
1038 * list of pages handed to migrate_pages()--which is how we get here--
1039 * is in virtual address order.
1041 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1043 struct vm_area_struct *vma = (struct vm_area_struct *)private;
1044 unsigned long uninitialized_var(address);
1046 while (vma) {
1047 address = page_address_in_vma(page, vma);
1048 if (address != -EFAULT)
1049 break;
1050 vma = vma->vm_next;
1054 * if !vma, alloc_page_vma() will use task or system default policy
1056 return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1058 #else
1060 static void migrate_page_add(struct page *page, struct list_head *pagelist,
1061 unsigned long flags)
1065 int do_migrate_pages(struct mm_struct *mm,
1066 const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
1068 return -ENOSYS;
1071 static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1073 return NULL;
1075 #endif
1077 static long do_mbind(unsigned long start, unsigned long len,
1078 unsigned short mode, unsigned short mode_flags,
1079 nodemask_t *nmask, unsigned long flags)
1081 struct vm_area_struct *vma;
1082 struct mm_struct *mm = current->mm;
1083 struct mempolicy *new;
1084 unsigned long end;
1085 int err;
1086 LIST_HEAD(pagelist);
1088 if (flags & ~(unsigned long)(MPOL_MF_STRICT |
1089 MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
1090 return -EINVAL;
1091 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1092 return -EPERM;
1094 if (start & ~PAGE_MASK)
1095 return -EINVAL;
1097 if (mode == MPOL_DEFAULT)
1098 flags &= ~MPOL_MF_STRICT;
1100 len = (len + PAGE_SIZE - 1) & PAGE_MASK;
1101 end = start + len;
1103 if (end < start)
1104 return -EINVAL;
1105 if (end == start)
1106 return 0;
1108 new = mpol_new(mode, mode_flags, nmask);
1109 if (IS_ERR(new))
1110 return PTR_ERR(new);
1113 * If we are using the default policy then operation
1114 * on discontinuous address spaces is okay after all
1116 if (!new)
1117 flags |= MPOL_MF_DISCONTIG_OK;
1119 pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
1120 start, start + len, mode, mode_flags,
1121 nmask ? nodes_addr(*nmask)[0] : -1);
1123 if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
1125 err = migrate_prep();
1126 if (err)
1127 goto mpol_out;
1130 NODEMASK_SCRATCH(scratch);
1131 if (scratch) {
1132 down_write(&mm->mmap_sem);
1133 task_lock(current);
1134 err = mpol_set_nodemask(new, nmask, scratch);
1135 task_unlock(current);
1136 if (err)
1137 up_write(&mm->mmap_sem);
1138 } else
1139 err = -ENOMEM;
1140 NODEMASK_SCRATCH_FREE(scratch);
1142 if (err)
1143 goto mpol_out;
1145 vma = check_range(mm, start, end, nmask,
1146 flags | MPOL_MF_INVERT, &pagelist);
1148 err = PTR_ERR(vma);
1149 if (!IS_ERR(vma)) {
1150 int nr_failed = 0;
1152 err = mbind_range(mm, start, end, new);
1154 if (!list_empty(&pagelist)) {
1155 nr_failed = migrate_pages(&pagelist, new_vma_page,
1156 (unsigned long)vma,
1157 false, true);
1158 if (nr_failed)
1159 putback_lru_pages(&pagelist);
1162 if (!err && nr_failed && (flags & MPOL_MF_STRICT))
1163 err = -EIO;
1164 } else
1165 putback_lru_pages(&pagelist);
1167 up_write(&mm->mmap_sem);
1168 mpol_out:
1169 mpol_put(new);
1170 return err;
1174 * User space interface with variable sized bitmaps for nodelists.
1177 /* Copy a node mask from user space. */
1178 static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1179 unsigned long maxnode)
1181 unsigned long k;
1182 unsigned long nlongs;
1183 unsigned long endmask;
1185 --maxnode;
1186 nodes_clear(*nodes);
1187 if (maxnode == 0 || !nmask)
1188 return 0;
1189 if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
1190 return -EINVAL;
1192 nlongs = BITS_TO_LONGS(maxnode);
1193 if ((maxnode % BITS_PER_LONG) == 0)
1194 endmask = ~0UL;
1195 else
1196 endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
1198 /* When the user specified more nodes than supported just check
1199 if the non supported part is all zero. */
1200 if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
1201 if (nlongs > PAGE_SIZE/sizeof(long))
1202 return -EINVAL;
1203 for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
1204 unsigned long t;
1205 if (get_user(t, nmask + k))
1206 return -EFAULT;
1207 if (k == nlongs - 1) {
1208 if (t & endmask)
1209 return -EINVAL;
1210 } else if (t)
1211 return -EINVAL;
1213 nlongs = BITS_TO_LONGS(MAX_NUMNODES);
1214 endmask = ~0UL;
1217 if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
1218 return -EFAULT;
1219 nodes_addr(*nodes)[nlongs-1] &= endmask;
1220 return 0;
1223 /* Copy a kernel node mask to user space */
1224 static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
1225 nodemask_t *nodes)
1227 unsigned long copy = ALIGN(maxnode-1, 64) / 8;
1228 const int nbytes = BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long);
1230 if (copy > nbytes) {
1231 if (copy > PAGE_SIZE)
1232 return -EINVAL;
1233 if (clear_user((char __user *)mask + nbytes, copy - nbytes))
1234 return -EFAULT;
1235 copy = nbytes;
1237 return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
1240 SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
1241 unsigned long, mode, unsigned long __user *, nmask,
1242 unsigned long, maxnode, unsigned, flags)
1244 nodemask_t nodes;
1245 int err;
1246 unsigned short mode_flags;
1248 mode_flags = mode & MPOL_MODE_FLAGS;
1249 mode &= ~MPOL_MODE_FLAGS;
1250 if (mode >= MPOL_MAX)
1251 return -EINVAL;
1252 if ((mode_flags & MPOL_F_STATIC_NODES) &&
1253 (mode_flags & MPOL_F_RELATIVE_NODES))
1254 return -EINVAL;
1255 err = get_nodes(&nodes, nmask, maxnode);
1256 if (err)
1257 return err;
1258 return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1261 /* Set the process memory policy */
1262 SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
1263 unsigned long, maxnode)
1265 int err;
1266 nodemask_t nodes;
1267 unsigned short flags;
1269 flags = mode & MPOL_MODE_FLAGS;
1270 mode &= ~MPOL_MODE_FLAGS;
1271 if ((unsigned int)mode >= MPOL_MAX)
1272 return -EINVAL;
1273 if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
1274 return -EINVAL;
1275 err = get_nodes(&nodes, nmask, maxnode);
1276 if (err)
1277 return err;
1278 return do_set_mempolicy(mode, flags, &nodes);
1281 SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
1282 const unsigned long __user *, old_nodes,
1283 const unsigned long __user *, new_nodes)
1285 const struct cred *cred = current_cred(), *tcred;
1286 struct mm_struct *mm = NULL;
1287 struct task_struct *task;
1288 nodemask_t task_nodes;
1289 int err;
1290 nodemask_t *old;
1291 nodemask_t *new;
1292 NODEMASK_SCRATCH(scratch);
1294 if (!scratch)
1295 return -ENOMEM;
1297 old = &scratch->mask1;
1298 new = &scratch->mask2;
1300 err = get_nodes(old, old_nodes, maxnode);
1301 if (err)
1302 goto out;
1304 err = get_nodes(new, new_nodes, maxnode);
1305 if (err)
1306 goto out;
1308 /* Find the mm_struct */
1309 rcu_read_lock();
1310 task = pid ? find_task_by_vpid(pid) : current;
1311 if (!task) {
1312 rcu_read_unlock();
1313 err = -ESRCH;
1314 goto out;
1316 mm = get_task_mm(task);
1317 rcu_read_unlock();
1319 err = -EINVAL;
1320 if (!mm)
1321 goto out;
1324 * Check if this process has the right to modify the specified
1325 * process. The right exists if the process has administrative
1326 * capabilities, superuser privileges or the same
1327 * userid as the target process.
1329 rcu_read_lock();
1330 tcred = __task_cred(task);
1331 if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
1332 cred->uid != tcred->suid && cred->uid != tcred->uid &&
1333 !capable(CAP_SYS_NICE)) {
1334 rcu_read_unlock();
1335 err = -EPERM;
1336 goto out;
1338 rcu_read_unlock();
1340 task_nodes = cpuset_mems_allowed(task);
1341 /* Is the user allowed to access the target nodes? */
1342 if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1343 err = -EPERM;
1344 goto out;
1347 if (!nodes_subset(*new, node_states[N_HIGH_MEMORY])) {
1348 err = -EINVAL;
1349 goto out;
1352 err = security_task_movememory(task);
1353 if (err)
1354 goto out;
1356 err = do_migrate_pages(mm, old, new,
1357 capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1358 out:
1359 if (mm)
1360 mmput(mm);
1361 NODEMASK_SCRATCH_FREE(scratch);
1363 return err;
1367 /* Retrieve NUMA policy */
1368 SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
1369 unsigned long __user *, nmask, unsigned long, maxnode,
1370 unsigned long, addr, unsigned long, flags)
1372 int err;
1373 int uninitialized_var(pval);
1374 nodemask_t nodes;
1376 if (nmask != NULL && maxnode < MAX_NUMNODES)
1377 return -EINVAL;
1379 err = do_get_mempolicy(&pval, &nodes, addr, flags);
1381 if (err)
1382 return err;
1384 if (policy && put_user(pval, policy))
1385 return -EFAULT;
1387 if (nmask)
1388 err = copy_nodes_to_user(nmask, maxnode, &nodes);
1390 return err;
1393 #ifdef CONFIG_COMPAT
1395 asmlinkage long compat_sys_get_mempolicy(int __user *policy,
1396 compat_ulong_t __user *nmask,
1397 compat_ulong_t maxnode,
1398 compat_ulong_t addr, compat_ulong_t flags)
1400 long err;
1401 unsigned long __user *nm = NULL;
1402 unsigned long nr_bits, alloc_size;
1403 DECLARE_BITMAP(bm, MAX_NUMNODES);
1405 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1406 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1408 if (nmask)
1409 nm = compat_alloc_user_space(alloc_size);
1411 err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
1413 if (!err && nmask) {
1414 unsigned long copy_size;
1415 copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
1416 err = copy_from_user(bm, nm, copy_size);
1417 /* ensure entire bitmap is zeroed */
1418 err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
1419 err |= compat_put_bitmap(nmask, bm, nr_bits);
1422 return err;
1425 asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
1426 compat_ulong_t maxnode)
1428 long err = 0;
1429 unsigned long __user *nm = NULL;
1430 unsigned long nr_bits, alloc_size;
1431 DECLARE_BITMAP(bm, MAX_NUMNODES);
1433 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1434 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1436 if (nmask) {
1437 err = compat_get_bitmap(bm, nmask, nr_bits);
1438 nm = compat_alloc_user_space(alloc_size);
1439 err |= copy_to_user(nm, bm, alloc_size);
1442 if (err)
1443 return -EFAULT;
1445 return sys_set_mempolicy(mode, nm, nr_bits+1);
1448 asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
1449 compat_ulong_t mode, compat_ulong_t __user *nmask,
1450 compat_ulong_t maxnode, compat_ulong_t flags)
1452 long err = 0;
1453 unsigned long __user *nm = NULL;
1454 unsigned long nr_bits, alloc_size;
1455 nodemask_t bm;
1457 nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
1458 alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
1460 if (nmask) {
1461 err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
1462 nm = compat_alloc_user_space(alloc_size);
1463 err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
1466 if (err)
1467 return -EFAULT;
1469 return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
1472 #endif
1475 * get_vma_policy(@task, @vma, @addr)
1476 * @task - task for fallback if vma policy == default
1477 * @vma - virtual memory area whose policy is sought
1478 * @addr - address in @vma for shared policy lookup
1480 * Returns effective policy for a VMA at specified address.
1481 * Falls back to @task or system default policy, as necessary.
1482 * Current or other task's task mempolicy and non-shared vma policies
1483 * are protected by the task's mmap_sem, which must be held for read by
1484 * the caller.
1485 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
1486 * count--added by the get_policy() vm_op, as appropriate--to protect against
1487 * freeing by another task. It is the caller's responsibility to free the
1488 * extra reference for shared policies.
1490 struct mempolicy *get_vma_policy(struct task_struct *task,
1491 struct vm_area_struct *vma, unsigned long addr)
1493 struct mempolicy *pol = task->mempolicy;
1495 if (vma) {
1496 if (vma->vm_ops && vma->vm_ops->get_policy) {
1497 struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
1498 addr);
1499 if (vpol)
1500 pol = vpol;
1501 } else if (vma->vm_policy)
1502 pol = vma->vm_policy;
1504 if (!pol)
1505 pol = &default_policy;
1506 return pol;
1510 * Return a nodemask representing a mempolicy for filtering nodes for
1511 * page allocation
1513 static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1515 /* Lower zones don't get a nodemask applied for MPOL_BIND */
1516 if (unlikely(policy->mode == MPOL_BIND) &&
1517 gfp_zone(gfp) >= policy_zone &&
1518 cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
1519 return &policy->v.nodes;
1521 return NULL;
1524 /* Return a zonelist indicated by gfp for node representing a mempolicy */
1525 static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
1526 int nd)
1528 switch (policy->mode) {
1529 case MPOL_PREFERRED:
1530 if (!(policy->flags & MPOL_F_LOCAL))
1531 nd = policy->v.preferred_node;
1532 break;
1533 case MPOL_BIND:
1535 * Normally, MPOL_BIND allocations are node-local within the
1536 * allowed nodemask. However, if __GFP_THISNODE is set and the
1537 * current node isn't part of the mask, we use the zonelist for
1538 * the first node in the mask instead.
1540 if (unlikely(gfp & __GFP_THISNODE) &&
1541 unlikely(!node_isset(nd, policy->v.nodes)))
1542 nd = first_node(policy->v.nodes);
1543 break;
1544 default:
1545 BUG();
1547 return node_zonelist(nd, gfp);
1550 /* Do dynamic interleaving for a process */
1551 static unsigned interleave_nodes(struct mempolicy *policy)
1553 unsigned nid, next;
1554 struct task_struct *me = current;
1556 nid = me->il_next;
1557 next = next_node(nid, policy->v.nodes);
1558 if (next >= MAX_NUMNODES)
1559 next = first_node(policy->v.nodes);
1560 if (next < MAX_NUMNODES)
1561 me->il_next = next;
1562 return nid;
1566 * Depending on the memory policy provide a node from which to allocate the
1567 * next slab entry.
1568 * @policy must be protected by freeing by the caller. If @policy is
1569 * the current task's mempolicy, this protection is implicit, as only the
1570 * task can change it's policy. The system default policy requires no
1571 * such protection.
1573 unsigned slab_node(struct mempolicy *policy)
1575 if (!policy || policy->flags & MPOL_F_LOCAL)
1576 return numa_node_id();
1578 switch (policy->mode) {
1579 case MPOL_PREFERRED:
1581 * handled MPOL_F_LOCAL above
1583 return policy->v.preferred_node;
1585 case MPOL_INTERLEAVE:
1586 return interleave_nodes(policy);
1588 case MPOL_BIND: {
1590 * Follow bind policy behavior and start allocation at the
1591 * first node.
1593 struct zonelist *zonelist;
1594 struct zone *zone;
1595 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
1596 zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
1597 (void)first_zones_zonelist(zonelist, highest_zoneidx,
1598 &policy->v.nodes,
1599 &zone);
1600 return zone ? zone->node : numa_node_id();
1603 default:
1604 BUG();
1608 /* Do static interleaving for a VMA with known offset. */
1609 static unsigned offset_il_node(struct mempolicy *pol,
1610 struct vm_area_struct *vma, unsigned long off)
1612 unsigned nnodes = nodes_weight(pol->v.nodes);
1613 unsigned target;
1614 int c;
1615 int nid = -1;
1617 if (!nnodes)
1618 return numa_node_id();
1619 target = (unsigned int)off % nnodes;
1620 c = 0;
1621 do {
1622 nid = next_node(nid, pol->v.nodes);
1623 c++;
1624 } while (c <= target);
1625 return nid;
1628 /* Determine a node number for interleave */
1629 static inline unsigned interleave_nid(struct mempolicy *pol,
1630 struct vm_area_struct *vma, unsigned long addr, int shift)
1632 if (vma) {
1633 unsigned long off;
1636 * for small pages, there is no difference between
1637 * shift and PAGE_SHIFT, so the bit-shift is safe.
1638 * for huge pages, since vm_pgoff is in units of small
1639 * pages, we need to shift off the always 0 bits to get
1640 * a useful offset.
1642 BUG_ON(shift < PAGE_SHIFT);
1643 off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1644 off += (addr - vma->vm_start) >> shift;
1645 return offset_il_node(pol, vma, off);
1646 } else
1647 return interleave_nodes(pol);
1651 * Return the bit number of a random bit set in the nodemask.
1652 * (returns -1 if nodemask is empty)
1654 int node_random(const nodemask_t *maskp)
1656 int w, bit = -1;
1658 w = nodes_weight(*maskp);
1659 if (w)
1660 bit = bitmap_ord_to_pos(maskp->bits,
1661 get_random_int() % w, MAX_NUMNODES);
1662 return bit;
1665 #ifdef CONFIG_HUGETLBFS
1667 * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
1668 * @vma = virtual memory area whose policy is sought
1669 * @addr = address in @vma for shared policy lookup and interleave policy
1670 * @gfp_flags = for requested zone
1671 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
1672 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1674 * Returns a zonelist suitable for a huge page allocation and a pointer
1675 * to the struct mempolicy for conditional unref after allocation.
1676 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
1677 * @nodemask for filtering the zonelist.
1679 * Must be protected by get_mems_allowed()
1681 struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1682 gfp_t gfp_flags, struct mempolicy **mpol,
1683 nodemask_t **nodemask)
1685 struct zonelist *zl;
1687 *mpol = get_vma_policy(current, vma, addr);
1688 *nodemask = NULL; /* assume !MPOL_BIND */
1690 if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
1691 zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1692 huge_page_shift(hstate_vma(vma))), gfp_flags);
1693 } else {
1694 zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1695 if ((*mpol)->mode == MPOL_BIND)
1696 *nodemask = &(*mpol)->v.nodes;
1698 return zl;
1702 * init_nodemask_of_mempolicy
1704 * If the current task's mempolicy is "default" [NULL], return 'false'
1705 * to indicate default policy. Otherwise, extract the policy nodemask
1706 * for 'bind' or 'interleave' policy into the argument nodemask, or
1707 * initialize the argument nodemask to contain the single node for
1708 * 'preferred' or 'local' policy and return 'true' to indicate presence
1709 * of non-default mempolicy.
1711 * We don't bother with reference counting the mempolicy [mpol_get/put]
1712 * because the current task is examining it's own mempolicy and a task's
1713 * mempolicy is only ever changed by the task itself.
1715 * N.B., it is the caller's responsibility to free a returned nodemask.
1717 bool init_nodemask_of_mempolicy(nodemask_t *mask)
1719 struct mempolicy *mempolicy;
1720 int nid;
1722 if (!(mask && current->mempolicy))
1723 return false;
1725 task_lock(current);
1726 mempolicy = current->mempolicy;
1727 switch (mempolicy->mode) {
1728 case MPOL_PREFERRED:
1729 if (mempolicy->flags & MPOL_F_LOCAL)
1730 nid = numa_node_id();
1731 else
1732 nid = mempolicy->v.preferred_node;
1733 init_nodemask_of_node(mask, nid);
1734 break;
1736 case MPOL_BIND:
1737 /* Fall through */
1738 case MPOL_INTERLEAVE:
1739 *mask = mempolicy->v.nodes;
1740 break;
1742 default:
1743 BUG();
1745 task_unlock(current);
1747 return true;
1749 #endif
1752 * mempolicy_nodemask_intersects
1754 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
1755 * policy. Otherwise, check for intersection between mask and the policy
1756 * nodemask for 'bind' or 'interleave' policy. For 'perferred' or 'local'
1757 * policy, always return true since it may allocate elsewhere on fallback.
1759 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
1761 bool mempolicy_nodemask_intersects(struct task_struct *tsk,
1762 const nodemask_t *mask)
1764 struct mempolicy *mempolicy;
1765 bool ret = true;
1767 if (!mask)
1768 return ret;
1769 task_lock(tsk);
1770 mempolicy = tsk->mempolicy;
1771 if (!mempolicy)
1772 goto out;
1774 switch (mempolicy->mode) {
1775 case MPOL_PREFERRED:
1777 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
1778 * allocate from, they may fallback to other nodes when oom.
1779 * Thus, it's possible for tsk to have allocated memory from
1780 * nodes in mask.
1782 break;
1783 case MPOL_BIND:
1784 case MPOL_INTERLEAVE:
1785 ret = nodes_intersects(mempolicy->v.nodes, *mask);
1786 break;
1787 default:
1788 BUG();
1790 out:
1791 task_unlock(tsk);
1792 return ret;
1795 /* Allocate a page in interleaved policy.
1796 Own path because it needs to do special accounting. */
1797 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
1798 unsigned nid)
1800 struct zonelist *zl;
1801 struct page *page;
1803 zl = node_zonelist(nid, gfp);
1804 page = __alloc_pages(gfp, order, zl);
1805 if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1806 inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
1807 return page;
1811 * alloc_pages_vma - Allocate a page for a VMA.
1813 * @gfp:
1814 * %GFP_USER user allocation.
1815 * %GFP_KERNEL kernel allocations,
1816 * %GFP_HIGHMEM highmem/user allocations,
1817 * %GFP_FS allocation should not call back into a file system.
1818 * %GFP_ATOMIC don't sleep.
1820 * @order:Order of the GFP allocation.
1821 * @vma: Pointer to VMA or NULL if not available.
1822 * @addr: Virtual Address of the allocation. Must be inside the VMA.
1824 * This function allocates a page from the kernel page pool and applies
1825 * a NUMA policy associated with the VMA or the current process.
1826 * When VMA is not NULL caller must hold down_read on the mmap_sem of the
1827 * mm_struct of the VMA to prevent it from going away. Should be used for
1828 * all allocations for pages that will be mapped into
1829 * user space. Returns NULL when no page can be allocated.
1831 * Should be called with the mm_sem of the vma hold.
1833 struct page *
1834 alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
1835 unsigned long addr, int node)
1837 struct mempolicy *pol = get_vma_policy(current, vma, addr);
1838 struct zonelist *zl;
1839 struct page *page;
1841 get_mems_allowed();
1842 if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
1843 unsigned nid;
1845 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
1846 mpol_cond_put(pol);
1847 page = alloc_page_interleave(gfp, order, nid);
1848 put_mems_allowed();
1849 return page;
1851 zl = policy_zonelist(gfp, pol, node);
1852 if (unlikely(mpol_needs_cond_ref(pol))) {
1854 * slow path: ref counted shared policy
1856 struct page *page = __alloc_pages_nodemask(gfp, order,
1857 zl, policy_nodemask(gfp, pol));
1858 __mpol_put(pol);
1859 put_mems_allowed();
1860 return page;
1863 * fast path: default or task policy
1865 page = __alloc_pages_nodemask(gfp, order, zl,
1866 policy_nodemask(gfp, pol));
1867 put_mems_allowed();
1868 return page;
1872 * alloc_pages_current - Allocate pages.
1874 * @gfp:
1875 * %GFP_USER user allocation,
1876 * %GFP_KERNEL kernel allocation,
1877 * %GFP_HIGHMEM highmem allocation,
1878 * %GFP_FS don't call back into a file system.
1879 * %GFP_ATOMIC don't sleep.
1880 * @order: Power of two of allocation size in pages. 0 is a single page.
1882 * Allocate a page from the kernel page pool. When not in
1883 * interrupt context and apply the current process NUMA policy.
1884 * Returns NULL when no page can be allocated.
1886 * Don't call cpuset_update_task_memory_state() unless
1887 * 1) it's ok to take cpuset_sem (can WAIT), and
1888 * 2) allocating for current task (not interrupt).
1890 struct page *alloc_pages_current(gfp_t gfp, unsigned order)
1892 struct mempolicy *pol = current->mempolicy;
1893 struct page *page;
1895 if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
1896 pol = &default_policy;
1898 get_mems_allowed();
1900 * No reference counting needed for current->mempolicy
1901 * nor system default_policy
1903 if (pol->mode == MPOL_INTERLEAVE)
1904 page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
1905 else
1906 page = __alloc_pages_nodemask(gfp, order,
1907 policy_zonelist(gfp, pol, numa_node_id()),
1908 policy_nodemask(gfp, pol));
1909 put_mems_allowed();
1910 return page;
1912 EXPORT_SYMBOL(alloc_pages_current);
1915 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
1916 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
1917 * with the mems_allowed returned by cpuset_mems_allowed(). This
1918 * keeps mempolicies cpuset relative after its cpuset moves. See
1919 * further kernel/cpuset.c update_nodemask().
1921 * current's mempolicy may be rebinded by the other task(the task that changes
1922 * cpuset's mems), so we needn't do rebind work for current task.
1925 /* Slow path of a mempolicy duplicate */
1926 struct mempolicy *__mpol_dup(struct mempolicy *old)
1928 struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
1930 if (!new)
1931 return ERR_PTR(-ENOMEM);
1933 /* task's mempolicy is protected by alloc_lock */
1934 if (old == current->mempolicy) {
1935 task_lock(current);
1936 *new = *old;
1937 task_unlock(current);
1938 } else
1939 *new = *old;
1941 rcu_read_lock();
1942 if (current_cpuset_is_being_rebound()) {
1943 nodemask_t mems = cpuset_mems_allowed(current);
1944 if (new->flags & MPOL_F_REBINDING)
1945 mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
1946 else
1947 mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
1949 rcu_read_unlock();
1950 atomic_set(&new->refcnt, 1);
1951 return new;
1955 * If *frompol needs [has] an extra ref, copy *frompol to *tompol ,
1956 * eliminate the * MPOL_F_* flags that require conditional ref and
1957 * [NOTE!!!] drop the extra ref. Not safe to reference *frompol directly
1958 * after return. Use the returned value.
1960 * Allows use of a mempolicy for, e.g., multiple allocations with a single
1961 * policy lookup, even if the policy needs/has extra ref on lookup.
1962 * shmem_readahead needs this.
1964 struct mempolicy *__mpol_cond_copy(struct mempolicy *tompol,
1965 struct mempolicy *frompol)
1967 if (!mpol_needs_cond_ref(frompol))
1968 return frompol;
1970 *tompol = *frompol;
1971 tompol->flags &= ~MPOL_F_SHARED; /* copy doesn't need unref */
1972 __mpol_put(frompol);
1973 return tompol;
1976 /* Slow path of a mempolicy comparison */
1977 int __mpol_equal(struct mempolicy *a, struct mempolicy *b)
1979 if (!a || !b)
1980 return 0;
1981 if (a->mode != b->mode)
1982 return 0;
1983 if (a->flags != b->flags)
1984 return 0;
1985 if (mpol_store_user_nodemask(a))
1986 if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
1987 return 0;
1989 switch (a->mode) {
1990 case MPOL_BIND:
1991 /* Fall through */
1992 case MPOL_INTERLEAVE:
1993 return nodes_equal(a->v.nodes, b->v.nodes);
1994 case MPOL_PREFERRED:
1995 return a->v.preferred_node == b->v.preferred_node;
1996 default:
1997 BUG();
1998 return 0;
2003 * Shared memory backing store policy support.
2005 * Remember policies even when nobody has shared memory mapped.
2006 * The policies are kept in Red-Black tree linked from the inode.
2007 * They are protected by the sp->lock spinlock, which should be held
2008 * for any accesses to the tree.
2011 /* lookup first element intersecting start-end */
2012 /* Caller holds sp->lock */
2013 static struct sp_node *
2014 sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
2016 struct rb_node *n = sp->root.rb_node;
2018 while (n) {
2019 struct sp_node *p = rb_entry(n, struct sp_node, nd);
2021 if (start >= p->end)
2022 n = n->rb_right;
2023 else if (end <= p->start)
2024 n = n->rb_left;
2025 else
2026 break;
2028 if (!n)
2029 return NULL;
2030 for (;;) {
2031 struct sp_node *w = NULL;
2032 struct rb_node *prev = rb_prev(n);
2033 if (!prev)
2034 break;
2035 w = rb_entry(prev, struct sp_node, nd);
2036 if (w->end <= start)
2037 break;
2038 n = prev;
2040 return rb_entry(n, struct sp_node, nd);
2043 /* Insert a new shared policy into the list. */
2044 /* Caller holds sp->lock */
2045 static void sp_insert(struct shared_policy *sp, struct sp_node *new)
2047 struct rb_node **p = &sp->root.rb_node;
2048 struct rb_node *parent = NULL;
2049 struct sp_node *nd;
2051 while (*p) {
2052 parent = *p;
2053 nd = rb_entry(parent, struct sp_node, nd);
2054 if (new->start < nd->start)
2055 p = &(*p)->rb_left;
2056 else if (new->end > nd->end)
2057 p = &(*p)->rb_right;
2058 else
2059 BUG();
2061 rb_link_node(&new->nd, parent, p);
2062 rb_insert_color(&new->nd, &sp->root);
2063 pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2064 new->policy ? new->policy->mode : 0);
2067 /* Find shared policy intersecting idx */
2068 struct mempolicy *
2069 mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
2071 struct mempolicy *pol = NULL;
2072 struct sp_node *sn;
2074 if (!sp->root.rb_node)
2075 return NULL;
2076 spin_lock(&sp->lock);
2077 sn = sp_lookup(sp, idx, idx+1);
2078 if (sn) {
2079 mpol_get(sn->policy);
2080 pol = sn->policy;
2082 spin_unlock(&sp->lock);
2083 return pol;
2086 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
2088 pr_debug("deleting %lx-l%lx\n", n->start, n->end);
2089 rb_erase(&n->nd, &sp->root);
2090 mpol_put(n->policy);
2091 kmem_cache_free(sn_cache, n);
2094 static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
2095 struct mempolicy *pol)
2097 struct sp_node *n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
2099 if (!n)
2100 return NULL;
2101 n->start = start;
2102 n->end = end;
2103 mpol_get(pol);
2104 pol->flags |= MPOL_F_SHARED; /* for unref */
2105 n->policy = pol;
2106 return n;
2109 /* Replace a policy range. */
2110 static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
2111 unsigned long end, struct sp_node *new)
2113 struct sp_node *n, *new2 = NULL;
2115 restart:
2116 spin_lock(&sp->lock);
2117 n = sp_lookup(sp, start, end);
2118 /* Take care of old policies in the same range. */
2119 while (n && n->start < end) {
2120 struct rb_node *next = rb_next(&n->nd);
2121 if (n->start >= start) {
2122 if (n->end <= end)
2123 sp_delete(sp, n);
2124 else
2125 n->start = end;
2126 } else {
2127 /* Old policy spanning whole new range. */
2128 if (n->end > end) {
2129 if (!new2) {
2130 spin_unlock(&sp->lock);
2131 new2 = sp_alloc(end, n->end, n->policy);
2132 if (!new2)
2133 return -ENOMEM;
2134 goto restart;
2136 n->end = start;
2137 sp_insert(sp, new2);
2138 new2 = NULL;
2139 break;
2140 } else
2141 n->end = start;
2143 if (!next)
2144 break;
2145 n = rb_entry(next, struct sp_node, nd);
2147 if (new)
2148 sp_insert(sp, new);
2149 spin_unlock(&sp->lock);
2150 if (new2) {
2151 mpol_put(new2->policy);
2152 kmem_cache_free(sn_cache, new2);
2154 return 0;
2158 * mpol_shared_policy_init - initialize shared policy for inode
2159 * @sp: pointer to inode shared policy
2160 * @mpol: struct mempolicy to install
2162 * Install non-NULL @mpol in inode's shared policy rb-tree.
2163 * On entry, the current task has a reference on a non-NULL @mpol.
2164 * This must be released on exit.
2165 * This is called at get_inode() calls and we can use GFP_KERNEL.
2167 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
2169 int ret;
2171 sp->root = RB_ROOT; /* empty tree == default mempolicy */
2172 spin_lock_init(&sp->lock);
2174 if (mpol) {
2175 struct vm_area_struct pvma;
2176 struct mempolicy *new;
2177 NODEMASK_SCRATCH(scratch);
2179 if (!scratch)
2180 goto put_mpol;
2181 /* contextualize the tmpfs mount point mempolicy */
2182 new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2183 if (IS_ERR(new))
2184 goto free_scratch; /* no valid nodemask intersection */
2186 task_lock(current);
2187 ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2188 task_unlock(current);
2189 if (ret)
2190 goto put_new;
2192 /* Create pseudo-vma that contains just the policy */
2193 memset(&pvma, 0, sizeof(struct vm_area_struct));
2194 pvma.vm_end = TASK_SIZE; /* policy covers entire file */
2195 mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
2197 put_new:
2198 mpol_put(new); /* drop initial ref */
2199 free_scratch:
2200 NODEMASK_SCRATCH_FREE(scratch);
2201 put_mpol:
2202 mpol_put(mpol); /* drop our incoming ref on sb mpol */
2206 int mpol_set_shared_policy(struct shared_policy *info,
2207 struct vm_area_struct *vma, struct mempolicy *npol)
2209 int err;
2210 struct sp_node *new = NULL;
2211 unsigned long sz = vma_pages(vma);
2213 pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
2214 vma->vm_pgoff,
2215 sz, npol ? npol->mode : -1,
2216 npol ? npol->flags : -1,
2217 npol ? nodes_addr(npol->v.nodes)[0] : -1);
2219 if (npol) {
2220 new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
2221 if (!new)
2222 return -ENOMEM;
2224 err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
2225 if (err && new)
2226 kmem_cache_free(sn_cache, new);
2227 return err;
2230 /* Free a backing policy store on inode delete. */
2231 void mpol_free_shared_policy(struct shared_policy *p)
2233 struct sp_node *n;
2234 struct rb_node *next;
2236 if (!p->root.rb_node)
2237 return;
2238 spin_lock(&p->lock);
2239 next = rb_first(&p->root);
2240 while (next) {
2241 n = rb_entry(next, struct sp_node, nd);
2242 next = rb_next(&n->nd);
2243 rb_erase(&n->nd, &p->root);
2244 mpol_put(n->policy);
2245 kmem_cache_free(sn_cache, n);
2247 spin_unlock(&p->lock);
2250 /* assumes fs == KERNEL_DS */
2251 void __init numa_policy_init(void)
2253 nodemask_t interleave_nodes;
2254 unsigned long largest = 0;
2255 int nid, prefer = 0;
2257 policy_cache = kmem_cache_create("numa_policy",
2258 sizeof(struct mempolicy),
2259 0, SLAB_PANIC, NULL);
2261 sn_cache = kmem_cache_create("shared_policy_node",
2262 sizeof(struct sp_node),
2263 0, SLAB_PANIC, NULL);
2266 * Set interleaving policy for system init. Interleaving is only
2267 * enabled across suitably sized nodes (default is >= 16MB), or
2268 * fall back to the largest node if they're all smaller.
2270 nodes_clear(interleave_nodes);
2271 for_each_node_state(nid, N_HIGH_MEMORY) {
2272 unsigned long total_pages = node_present_pages(nid);
2274 /* Preserve the largest node */
2275 if (largest < total_pages) {
2276 largest = total_pages;
2277 prefer = nid;
2280 /* Interleave this node? */
2281 if ((total_pages << PAGE_SHIFT) >= (16 << 20))
2282 node_set(nid, interleave_nodes);
2285 /* All too small, use the largest */
2286 if (unlikely(nodes_empty(interleave_nodes)))
2287 node_set(prefer, interleave_nodes);
2289 if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
2290 printk("numa_policy_init: interleaving failed\n");
2293 /* Reset policy of current process to default */
2294 void numa_default_policy(void)
2296 do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
2300 * Parse and format mempolicy from/to strings
2304 * "local" is pseudo-policy: MPOL_PREFERRED with MPOL_F_LOCAL flag
2305 * Used only for mpol_parse_str() and mpol_to_str()
2307 #define MPOL_LOCAL MPOL_MAX
2308 static const char * const policy_modes[] =
2310 [MPOL_DEFAULT] = "default",
2311 [MPOL_PREFERRED] = "prefer",
2312 [MPOL_BIND] = "bind",
2313 [MPOL_INTERLEAVE] = "interleave",
2314 [MPOL_LOCAL] = "local"
2318 #ifdef CONFIG_TMPFS
2320 * mpol_parse_str - parse string to mempolicy
2321 * @str: string containing mempolicy to parse
2322 * @mpol: pointer to struct mempolicy pointer, returned on success.
2323 * @no_context: flag whether to "contextualize" the mempolicy
2325 * Format of input:
2326 * <mode>[=<flags>][:<nodelist>]
2328 * if @no_context is true, save the input nodemask in w.user_nodemask in
2329 * the returned mempolicy. This will be used to "clone" the mempolicy in
2330 * a specific context [cpuset] at a later time. Used to parse tmpfs mpol
2331 * mount option. Note that if 'static' or 'relative' mode flags were
2332 * specified, the input nodemask will already have been saved. Saving
2333 * it again is redundant, but safe.
2335 * On success, returns 0, else 1
2337 int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context)
2339 struct mempolicy *new = NULL;
2340 unsigned short mode;
2341 unsigned short uninitialized_var(mode_flags);
2342 nodemask_t nodes;
2343 char *nodelist = strchr(str, ':');
2344 char *flags = strchr(str, '=');
2345 int err = 1;
2347 if (nodelist) {
2348 /* NUL-terminate mode or flags string */
2349 *nodelist++ = '\0';
2350 if (nodelist_parse(nodelist, nodes))
2351 goto out;
2352 if (!nodes_subset(nodes, node_states[N_HIGH_MEMORY]))
2353 goto out;
2354 } else
2355 nodes_clear(nodes);
2357 if (flags)
2358 *flags++ = '\0'; /* terminate mode string */
2360 for (mode = 0; mode <= MPOL_LOCAL; mode++) {
2361 if (!strcmp(str, policy_modes[mode])) {
2362 break;
2365 if (mode > MPOL_LOCAL)
2366 goto out;
2368 switch (mode) {
2369 case MPOL_PREFERRED:
2371 * Insist on a nodelist of one node only
2373 if (nodelist) {
2374 char *rest = nodelist;
2375 while (isdigit(*rest))
2376 rest++;
2377 if (*rest)
2378 goto out;
2380 break;
2381 case MPOL_INTERLEAVE:
2383 * Default to online nodes with memory if no nodelist
2385 if (!nodelist)
2386 nodes = node_states[N_HIGH_MEMORY];
2387 break;
2388 case MPOL_LOCAL:
2390 * Don't allow a nodelist; mpol_new() checks flags
2392 if (nodelist)
2393 goto out;
2394 mode = MPOL_PREFERRED;
2395 break;
2396 case MPOL_DEFAULT:
2398 * Insist on a empty nodelist
2400 if (!nodelist)
2401 err = 0;
2402 goto out;
2403 case MPOL_BIND:
2405 * Insist on a nodelist
2407 if (!nodelist)
2408 goto out;
2411 mode_flags = 0;
2412 if (flags) {
2414 * Currently, we only support two mutually exclusive
2415 * mode flags.
2417 if (!strcmp(flags, "static"))
2418 mode_flags |= MPOL_F_STATIC_NODES;
2419 else if (!strcmp(flags, "relative"))
2420 mode_flags |= MPOL_F_RELATIVE_NODES;
2421 else
2422 goto out;
2425 new = mpol_new(mode, mode_flags, &nodes);
2426 if (IS_ERR(new))
2427 goto out;
2429 if (no_context) {
2430 /* save for contextualization */
2431 new->w.user_nodemask = nodes;
2432 } else {
2433 int ret;
2434 NODEMASK_SCRATCH(scratch);
2435 if (scratch) {
2436 task_lock(current);
2437 ret = mpol_set_nodemask(new, &nodes, scratch);
2438 task_unlock(current);
2439 } else
2440 ret = -ENOMEM;
2441 NODEMASK_SCRATCH_FREE(scratch);
2442 if (ret) {
2443 mpol_put(new);
2444 goto out;
2447 err = 0;
2449 out:
2450 /* Restore string for error message */
2451 if (nodelist)
2452 *--nodelist = ':';
2453 if (flags)
2454 *--flags = '=';
2455 if (!err)
2456 *mpol = new;
2457 return err;
2459 #endif /* CONFIG_TMPFS */
2462 * mpol_to_str - format a mempolicy structure for printing
2463 * @buffer: to contain formatted mempolicy string
2464 * @maxlen: length of @buffer
2465 * @pol: pointer to mempolicy to be formatted
2466 * @no_context: "context free" mempolicy - use nodemask in w.user_nodemask
2468 * Convert a mempolicy into a string.
2469 * Returns the number of characters in buffer (if positive)
2470 * or an error (negative)
2472 int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol, int no_context)
2474 char *p = buffer;
2475 int l;
2476 nodemask_t nodes;
2477 unsigned short mode;
2478 unsigned short flags = pol ? pol->flags : 0;
2481 * Sanity check: room for longest mode, flag and some nodes
2483 VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
2485 if (!pol || pol == &default_policy)
2486 mode = MPOL_DEFAULT;
2487 else
2488 mode = pol->mode;
2490 switch (mode) {
2491 case MPOL_DEFAULT:
2492 nodes_clear(nodes);
2493 break;
2495 case MPOL_PREFERRED:
2496 nodes_clear(nodes);
2497 if (flags & MPOL_F_LOCAL)
2498 mode = MPOL_LOCAL; /* pseudo-policy */
2499 else
2500 node_set(pol->v.preferred_node, nodes);
2501 break;
2503 case MPOL_BIND:
2504 /* Fall through */
2505 case MPOL_INTERLEAVE:
2506 if (no_context)
2507 nodes = pol->w.user_nodemask;
2508 else
2509 nodes = pol->v.nodes;
2510 break;
2512 default:
2513 BUG();
2516 l = strlen(policy_modes[mode]);
2517 if (buffer + maxlen < p + l + 1)
2518 return -ENOSPC;
2520 strcpy(p, policy_modes[mode]);
2521 p += l;
2523 if (flags & MPOL_MODE_FLAGS) {
2524 if (buffer + maxlen < p + 2)
2525 return -ENOSPC;
2526 *p++ = '=';
2529 * Currently, the only defined flags are mutually exclusive
2531 if (flags & MPOL_F_STATIC_NODES)
2532 p += snprintf(p, buffer + maxlen - p, "static");
2533 else if (flags & MPOL_F_RELATIVE_NODES)
2534 p += snprintf(p, buffer + maxlen - p, "relative");
2537 if (!nodes_empty(nodes)) {
2538 if (buffer + maxlen < p + 2)
2539 return -ENOSPC;
2540 *p++ = ':';
2541 p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);
2543 return p - buffer;