mempolicy.c 62.7 KB
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/*
 * Simple NUMA memory policy for the Linux kernel.
 *
 * Copyright 2003,2004 Andi Kleen, SuSE Labs.
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 * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc.
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 * Subject to the GNU Public License, version 2.
 *
 * NUMA policy allows the user to give hints in which node(s) memory should
 * be allocated.
 *
 * Support four policies per VMA and per process:
 *
 * The VMA policy has priority over the process policy for a page fault.
 *
 * interleave     Allocate memory interleaved over a set of nodes,
 *                with normal fallback if it fails.
 *                For VMA based allocations this interleaves based on the
 *                offset into the backing object or offset into the mapping
 *                for anonymous memory. For process policy an process counter
 *                is used.
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 *
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 * bind           Only allocate memory on a specific set of nodes,
 *                no fallback.
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 *                FIXME: memory is allocated starting with the first node
 *                to the last. It would be better if bind would truly restrict
 *                the allocation to memory nodes instead
 *
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 * preferred       Try a specific node first before normal fallback.
 *                As a special case node -1 here means do the allocation
 *                on the local CPU. This is normally identical to default,
 *                but useful to set in a VMA when you have a non default
 *                process policy.
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 *
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 * default        Allocate on the local node first, or when on a VMA
 *                use the process policy. This is what Linux always did
 *		  in a NUMA aware kernel and still does by, ahem, default.
 *
 * The process policy is applied for most non interrupt memory allocations
 * in that process' context. Interrupts ignore the policies and always
 * try to allocate on the local CPU. The VMA policy is only applied for memory
 * allocations for a VMA in the VM.
 *
 * Currently there are a few corner cases in swapping where the policy
 * is not applied, but the majority should be handled. When process policy
 * is used it is not remembered over swap outs/swap ins.
 *
 * Only the highest zone in the zone hierarchy gets policied. Allocations
 * requesting a lower zone just use default policy. This implies that
 * on systems with highmem kernel lowmem allocation don't get policied.
 * Same with GFP_DMA allocations.
 *
 * For shmfs/tmpfs/hugetlbfs shared memory the policy is shared between
 * all users and remembered even when nobody has memory mapped.
 */

/* Notebook:
   fix mmap readahead to honour policy and enable policy for any page cache
   object
   statistics for bigpages
   global policy for page cache? currently it uses process policy. Requires
   first item above.
   handle mremap for shared memory (currently ignored for the policy)
   grows down?
   make bind policy root only? It can trigger oom much faster and the
   kernel is not always grateful with that.
*/

#include <linux/mempolicy.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/hugetlb.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/nodemask.h>
#include <linux/cpuset.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/module.h>
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#include <linux/nsproxy.h>
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#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/compat.h>
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#include <linux/swap.h>
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#include <linux/seq_file.h>
#include <linux/proc_fs.h>
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#include <linux/migrate.h>
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#include <linux/rmap.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/ctype.h>
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#include <linux/mm_inline.h>
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#include <asm/tlbflush.h>
#include <asm/uaccess.h>

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#include "internal.h"

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/* Internal flags */
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#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0)	/* Skip checks for continuous vmas */
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#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1)		/* Invert check for nodemask */
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#define MPOL_MF_STATS (MPOL_MF_INTERNAL << 2)		/* Gather statistics */
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static struct kmem_cache *policy_cache;
static struct kmem_cache *sn_cache;
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/* Highest zone. An specific allocation for a zone below that is not
   policied. */
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enum zone_type policy_zone = 0;
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/*
 * run-time system-wide default policy => local allocation
 */
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struct mempolicy default_policy = {
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	.refcnt = ATOMIC_INIT(1), /* never free it */
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	.mode = MPOL_PREFERRED,
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	.flags = MPOL_F_LOCAL,
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};

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static const struct mempolicy_operations {
	int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
	void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes);
} mpol_ops[MPOL_MAX];

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/* Check that the nodemask contains at least one populated zone */
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static int is_valid_nodemask(const nodemask_t *nodemask)
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{
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	int nd, k;
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	/* Check that there is something useful in this mask */
	k = policy_zone;

	for_each_node_mask(nd, *nodemask) {
		struct zone *z;

		for (k = 0; k <= policy_zone; k++) {
			z = &NODE_DATA(nd)->node_zones[k];
			if (z->present_pages > 0)
				return 1;
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		}
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	}
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	return 0;
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}

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static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
{
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	return pol->flags & (MPOL_F_STATIC_NODES | MPOL_F_RELATIVE_NODES);
}

static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
				   const nodemask_t *rel)
{
	nodemask_t tmp;
	nodes_fold(tmp, *orig, nodes_weight(*rel));
	nodes_onto(*ret, tmp, *rel);
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}

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static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
{
	if (nodes_empty(*nodes))
		return -EINVAL;
	pol->v.nodes = *nodes;
	return 0;
}

static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
{
	if (!nodes)
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		pol->flags |= MPOL_F_LOCAL;	/* local allocation */
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	else if (nodes_empty(*nodes))
		return -EINVAL;			/*  no allowed nodes */
	else
		pol->v.preferred_node = first_node(*nodes);
	return 0;
}

static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
{
	if (!is_valid_nodemask(nodes))
		return -EINVAL;
	pol->v.nodes = *nodes;
	return 0;
}

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/*
 * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
 * any, for the new policy.  mpol_new() has already validated the nodes
 * parameter with respect to the policy mode and flags.  But, we need to
 * handle an empty nodemask with MPOL_PREFERRED here.
 *
 * Must be called holding task's alloc_lock to protect task's mems_allowed
 * and mempolicy.  May also be called holding the mmap_semaphore for write.
 */
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static int mpol_set_nodemask(struct mempolicy *pol,
		     const nodemask_t *nodes, struct nodemask_scratch *nsc)
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{
	int ret;

	/* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
	if (pol == NULL)
		return 0;
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	/* Check N_HIGH_MEMORY */
	nodes_and(nsc->mask1,
		  cpuset_current_mems_allowed, node_states[N_HIGH_MEMORY]);
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	VM_BUG_ON(!nodes);
	if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
		nodes = NULL;	/* explicit local allocation */
	else {
		if (pol->flags & MPOL_F_RELATIVE_NODES)
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			mpol_relative_nodemask(&nsc->mask2, nodes,&nsc->mask1);
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		else
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			nodes_and(nsc->mask2, *nodes, nsc->mask1);

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		if (mpol_store_user_nodemask(pol))
			pol->w.user_nodemask = *nodes;
		else
			pol->w.cpuset_mems_allowed =
						cpuset_current_mems_allowed;
	}

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	if (nodes)
		ret = mpol_ops[pol->mode].create(pol, &nsc->mask2);
	else
		ret = mpol_ops[pol->mode].create(pol, NULL);
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	return ret;
}

/*
 * This function just creates a new policy, does some check and simple
 * initialization. You must invoke mpol_set_nodemask() to set nodes.
 */
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static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
				  nodemask_t *nodes)
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{
	struct mempolicy *policy;

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	pr_debug("setting mode %d flags %d nodes[0] %lx\n",
		 mode, flags, nodes ? nodes_addr(*nodes)[0] : -1);
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	if (mode == MPOL_DEFAULT) {
		if (nodes && !nodes_empty(*nodes))
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			return ERR_PTR(-EINVAL);
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		return NULL;	/* simply delete any existing policy */
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	}
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	VM_BUG_ON(!nodes);

	/*
	 * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
	 * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation).
	 * All other modes require a valid pointer to a non-empty nodemask.
	 */
	if (mode == MPOL_PREFERRED) {
		if (nodes_empty(*nodes)) {
			if (((flags & MPOL_F_STATIC_NODES) ||
			     (flags & MPOL_F_RELATIVE_NODES)))
				return ERR_PTR(-EINVAL);
		}
	} else if (nodes_empty(*nodes))
		return ERR_PTR(-EINVAL);
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	policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
	if (!policy)
		return ERR_PTR(-ENOMEM);
	atomic_set(&policy->refcnt, 1);
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	policy->mode = mode;
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	policy->flags = flags;
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	return policy;
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}

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/* Slow path of a mpol destructor. */
void __mpol_put(struct mempolicy *p)
{
	if (!atomic_dec_and_test(&p->refcnt))
		return;
	kmem_cache_free(policy_cache, p);
}

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static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes)
{
}

static void mpol_rebind_nodemask(struct mempolicy *pol,
				 const nodemask_t *nodes)
{
	nodemask_t tmp;

	if (pol->flags & MPOL_F_STATIC_NODES)
		nodes_and(tmp, pol->w.user_nodemask, *nodes);
	else if (pol->flags & MPOL_F_RELATIVE_NODES)
		mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
	else {
		nodes_remap(tmp, pol->v.nodes, pol->w.cpuset_mems_allowed,
			    *nodes);
		pol->w.cpuset_mems_allowed = *nodes;
	}
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	pol->v.nodes = tmp;
	if (!node_isset(current->il_next, tmp)) {
		current->il_next = next_node(current->il_next, tmp);
		if (current->il_next >= MAX_NUMNODES)
			current->il_next = first_node(tmp);
		if (current->il_next >= MAX_NUMNODES)
			current->il_next = numa_node_id();
	}
}

static void mpol_rebind_preferred(struct mempolicy *pol,
				  const nodemask_t *nodes)
{
	nodemask_t tmp;

	if (pol->flags & MPOL_F_STATIC_NODES) {
		int node = first_node(pol->w.user_nodemask);

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		if (node_isset(node, *nodes)) {
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			pol->v.preferred_node = node;
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			pol->flags &= ~MPOL_F_LOCAL;
		} else
			pol->flags |= MPOL_F_LOCAL;
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	} else if (pol->flags & MPOL_F_RELATIVE_NODES) {
		mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
		pol->v.preferred_node = first_node(tmp);
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	} else if (!(pol->flags & MPOL_F_LOCAL)) {
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		pol->v.preferred_node = node_remap(pol->v.preferred_node,
						   pol->w.cpuset_mems_allowed,
						   *nodes);
		pol->w.cpuset_mems_allowed = *nodes;
	}
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}

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/* Migrate a policy to a different set of nodes */
static void mpol_rebind_policy(struct mempolicy *pol,
			       const nodemask_t *newmask)
{
	if (!pol)
		return;
	if (!mpol_store_user_nodemask(pol) &&
	    nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
		return;
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	mpol_ops[pol->mode].rebind(pol, newmask);
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}

/*
 * Wrapper for mpol_rebind_policy() that just requires task
 * pointer, and updates task mempolicy.
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 *
 * Called with task's alloc_lock held.
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 */

void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new)
{
	mpol_rebind_policy(tsk->mempolicy, new);
}

/*
 * Rebind each vma in mm to new nodemask.
 *
 * Call holding a reference to mm.  Takes mm->mmap_sem during call.
 */

void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
{
	struct vm_area_struct *vma;

	down_write(&mm->mmap_sem);
	for (vma = mm->mmap; vma; vma = vma->vm_next)
		mpol_rebind_policy(vma->vm_policy, new);
	up_write(&mm->mmap_sem);
}

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static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
	[MPOL_DEFAULT] = {
		.rebind = mpol_rebind_default,
	},
	[MPOL_INTERLEAVE] = {
		.create = mpol_new_interleave,
		.rebind = mpol_rebind_nodemask,
	},
	[MPOL_PREFERRED] = {
		.create = mpol_new_preferred,
		.rebind = mpol_rebind_preferred,
	},
	[MPOL_BIND] = {
		.create = mpol_new_bind,
		.rebind = mpol_rebind_nodemask,
	},
};

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static void gather_stats(struct page *, void *, int pte_dirty);
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static void migrate_page_add(struct page *page, struct list_head *pagelist,
				unsigned long flags);
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/* Scan through pages checking if pages follow certain conditions. */
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static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
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		unsigned long addr, unsigned long end,
		const nodemask_t *nodes, unsigned long flags,
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		void *private)
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{
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	pte_t *orig_pte;
	pte_t *pte;
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	spinlock_t *ptl;
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	orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
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	do {
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		struct page *page;
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		int nid;
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		if (!pte_present(*pte))
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			continue;
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		page = vm_normal_page(vma, addr, *pte);
		if (!page)
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			continue;
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		/*
		 * The check for PageReserved here is important to avoid
		 * handling zero pages and other pages that may have been
		 * marked special by the system.
		 *
		 * If the PageReserved would not be checked here then f.e.
		 * the location of the zero page could have an influence
		 * on MPOL_MF_STRICT, zero pages would be counted for
		 * the per node stats, and there would be useless attempts
		 * to put zero pages on the migration list.
		 */
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		if (PageReserved(page))
			continue;
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		nid = page_to_nid(page);
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		if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
			continue;

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		if (flags & MPOL_MF_STATS)
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			gather_stats(page, private, pte_dirty(*pte));
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		else if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
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			migrate_page_add(page, private, flags);
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		else
			break;
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	} while (pte++, addr += PAGE_SIZE, addr != end);
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	pte_unmap_unlock(orig_pte, ptl);
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	return addr != end;
}

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static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
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		unsigned long addr, unsigned long end,
		const nodemask_t *nodes, unsigned long flags,
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		void *private)
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{
	pmd_t *pmd;
	unsigned long next;

	pmd = pmd_offset(pud, addr);
	do {
		next = pmd_addr_end(addr, end);
		if (pmd_none_or_clear_bad(pmd))
			continue;
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		if (check_pte_range(vma, pmd, addr, next, nodes,
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				    flags, private))
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			return -EIO;
	} while (pmd++, addr = next, addr != end);
	return 0;
}

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static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
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		unsigned long addr, unsigned long end,
		const nodemask_t *nodes, unsigned long flags,
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		void *private)
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{
	pud_t *pud;
	unsigned long next;

	pud = pud_offset(pgd, addr);
	do {
		next = pud_addr_end(addr, end);
		if (pud_none_or_clear_bad(pud))
			continue;
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		if (check_pmd_range(vma, pud, addr, next, nodes,
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				    flags, private))
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			return -EIO;
	} while (pud++, addr = next, addr != end);
	return 0;
}

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static inline int check_pgd_range(struct vm_area_struct *vma,
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		unsigned long addr, unsigned long end,
		const nodemask_t *nodes, unsigned long flags,
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		void *private)
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{
	pgd_t *pgd;
	unsigned long next;

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	pgd = pgd_offset(vma->vm_mm, addr);
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	do {
		next = pgd_addr_end(addr, end);
		if (pgd_none_or_clear_bad(pgd))
			continue;
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		if (check_pud_range(vma, pgd, addr, next, nodes,
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				    flags, private))
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			return -EIO;
	} while (pgd++, addr = next, addr != end);
	return 0;
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}

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/*
 * Check if all pages in a range are on a set of nodes.
 * If pagelist != NULL then isolate pages from the LRU and
 * put them on the pagelist.
 */
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static struct vm_area_struct *
check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
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		const nodemask_t *nodes, unsigned long flags, void *private)
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{
	int err;
	struct vm_area_struct *first, *vma, *prev;

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	first = find_vma(mm, start);
	if (!first)
		return ERR_PTR(-EFAULT);
	prev = NULL;
	for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
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		if (!(flags & MPOL_MF_DISCONTIG_OK)) {
			if (!vma->vm_next && vma->vm_end < end)
				return ERR_PTR(-EFAULT);
			if (prev && prev->vm_end < vma->vm_start)
				return ERR_PTR(-EFAULT);
		}
		if (!is_vm_hugetlb_page(vma) &&
		    ((flags & MPOL_MF_STRICT) ||
		     ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
				vma_migratable(vma)))) {
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			unsigned long endvma = vma->vm_end;
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			if (endvma > end)
				endvma = end;
			if (vma->vm_start > start)
				start = vma->vm_start;
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			err = check_pgd_range(vma, start, endvma, nodes,
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						flags, private);
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			if (err) {
				first = ERR_PTR(err);
				break;
			}
		}
		prev = vma;
	}
	return first;
}

/* Apply policy to a single VMA */
static int policy_vma(struct vm_area_struct *vma, struct mempolicy *new)
{
	int err = 0;
	struct mempolicy *old = vma->vm_policy;

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	pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
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		 vma->vm_start, vma->vm_end, vma->vm_pgoff,
		 vma->vm_ops, vma->vm_file,
		 vma->vm_ops ? vma->vm_ops->set_policy : NULL);

	if (vma->vm_ops && vma->vm_ops->set_policy)
		err = vma->vm_ops->set_policy(vma, new);
	if (!err) {
		mpol_get(new);
		vma->vm_policy = new;
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		mpol_put(old);
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	}
	return err;
}

/* Step 2: apply policy to a range and do splits. */
static int mbind_range(struct vm_area_struct *vma, unsigned long start,
		       unsigned long end, struct mempolicy *new)
{
	struct vm_area_struct *next;
	int err;

	err = 0;
	for (; vma && vma->vm_start < end; vma = next) {
		next = vma->vm_next;
		if (vma->vm_start < start)
			err = split_vma(vma->vm_mm, vma, start, 1);
		if (!err && vma->vm_end > end)
			err = split_vma(vma->vm_mm, vma, end, 0);
		if (!err)
			err = policy_vma(vma, new);
		if (err)
			break;
	}
	return err;
}

592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621
/*
 * Update task->flags PF_MEMPOLICY bit: set iff non-default
 * mempolicy.  Allows more rapid checking of this (combined perhaps
 * with other PF_* flag bits) on memory allocation hot code paths.
 *
 * If called from outside this file, the task 'p' should -only- be
 * a newly forked child not yet visible on the task list, because
 * manipulating the task flags of a visible task is not safe.
 *
 * The above limitation is why this routine has the funny name
 * mpol_fix_fork_child_flag().
 *
 * It is also safe to call this with a task pointer of current,
 * which the static wrapper mpol_set_task_struct_flag() does,
 * for use within this file.
 */

void mpol_fix_fork_child_flag(struct task_struct *p)
{
	if (p->mempolicy)
		p->flags |= PF_MEMPOLICY;
	else
		p->flags &= ~PF_MEMPOLICY;
}

static void mpol_set_task_struct_flag(void)
{
	mpol_fix_fork_child_flag(current);
}

L
Linus Torvalds 已提交
622
/* Set the process memory policy */
623 624
static long do_set_mempolicy(unsigned short mode, unsigned short flags,
			     nodemask_t *nodes)
L
Linus Torvalds 已提交
625
{
626
	struct mempolicy *new, *old;
627
	struct mm_struct *mm = current->mm;
628
	NODEMASK_SCRATCH(scratch);
629
	int ret;
L
Linus Torvalds 已提交
630

631 632
	if (!scratch)
		return -ENOMEM;
633

634 635 636 637 638
	new = mpol_new(mode, flags, nodes);
	if (IS_ERR(new)) {
		ret = PTR_ERR(new);
		goto out;
	}
639 640 641 642 643 644 645 646
	/*
	 * prevent changing our mempolicy while show_numa_maps()
	 * is using it.
	 * Note:  do_set_mempolicy() can be called at init time
	 * with no 'mm'.
	 */
	if (mm)
		down_write(&mm->mmap_sem);
647
	task_lock(current);
648
	ret = mpol_set_nodemask(new, nodes, scratch);
649 650 651 652 653
	if (ret) {
		task_unlock(current);
		if (mm)
			up_write(&mm->mmap_sem);
		mpol_put(new);
654
		goto out;
655 656
	}
	old = current->mempolicy;
L
Linus Torvalds 已提交
657
	current->mempolicy = new;
658
	mpol_set_task_struct_flag();
659
	if (new && new->mode == MPOL_INTERLEAVE &&
660
	    nodes_weight(new->v.nodes))
661
		current->il_next = first_node(new->v.nodes);
662
	task_unlock(current);
663 664 665
	if (mm)
		up_write(&mm->mmap_sem);

666
	mpol_put(old);
667 668 669 670
	ret = 0;
out:
	NODEMASK_SCRATCH_FREE(scratch);
	return ret;
L
Linus Torvalds 已提交
671 672
}

673 674
/*
 * Return nodemask for policy for get_mempolicy() query
675 676
 *
 * Called with task's alloc_lock held
677 678
 */
static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
L
Linus Torvalds 已提交
679
{
680
	nodes_clear(*nodes);
681 682 683
	if (p == &default_policy)
		return;

684
	switch (p->mode) {
685 686
	case MPOL_BIND:
		/* Fall through */
L
Linus Torvalds 已提交
687
	case MPOL_INTERLEAVE:
688
		*nodes = p->v.nodes;
L
Linus Torvalds 已提交
689 690
		break;
	case MPOL_PREFERRED:
691
		if (!(p->flags & MPOL_F_LOCAL))
692
			node_set(p->v.preferred_node, *nodes);
693
		/* else return empty node mask for local allocation */
L
Linus Torvalds 已提交
694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713
		break;
	default:
		BUG();
	}
}

static int lookup_node(struct mm_struct *mm, unsigned long addr)
{
	struct page *p;
	int err;

	err = get_user_pages(current, mm, addr & PAGE_MASK, 1, 0, 0, &p, NULL);
	if (err >= 0) {
		err = page_to_nid(p);
		put_page(p);
	}
	return err;
}

/* Retrieve NUMA policy */
A
Adrian Bunk 已提交
714 715
static long do_get_mempolicy(int *policy, nodemask_t *nmask,
			     unsigned long addr, unsigned long flags)
L
Linus Torvalds 已提交
716
{
717
	int err;
L
Linus Torvalds 已提交
718 719 720 721
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma = NULL;
	struct mempolicy *pol = current->mempolicy;

722 723
	if (flags &
		~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
L
Linus Torvalds 已提交
724
		return -EINVAL;
725 726 727 728 729

	if (flags & MPOL_F_MEMS_ALLOWED) {
		if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
			return -EINVAL;
		*policy = 0;	/* just so it's initialized */
730
		task_lock(current);
731
		*nmask  = cpuset_current_mems_allowed;
732
		task_unlock(current);
733 734 735
		return 0;
	}

L
Linus Torvalds 已提交
736
	if (flags & MPOL_F_ADDR) {
737 738 739 740 741
		/*
		 * Do NOT fall back to task policy if the
		 * vma/shared policy at addr is NULL.  We
		 * want to return MPOL_DEFAULT in this case.
		 */
L
Linus Torvalds 已提交
742 743 744 745 746 747 748 749 750 751 752 753 754 755
		down_read(&mm->mmap_sem);
		vma = find_vma_intersection(mm, addr, addr+1);
		if (!vma) {
			up_read(&mm->mmap_sem);
			return -EFAULT;
		}
		if (vma->vm_ops && vma->vm_ops->get_policy)
			pol = vma->vm_ops->get_policy(vma, addr);
		else
			pol = vma->vm_policy;
	} else if (addr)
		return -EINVAL;

	if (!pol)
756
		pol = &default_policy;	/* indicates default behavior */
L
Linus Torvalds 已提交
757 758 759 760 761 762

	if (flags & MPOL_F_NODE) {
		if (flags & MPOL_F_ADDR) {
			err = lookup_node(mm, addr);
			if (err < 0)
				goto out;
763
			*policy = err;
L
Linus Torvalds 已提交
764
		} else if (pol == current->mempolicy &&
765
				pol->mode == MPOL_INTERLEAVE) {
766
			*policy = current->il_next;
L
Linus Torvalds 已提交
767 768 769 770
		} else {
			err = -EINVAL;
			goto out;
		}
771 772 773
	} else {
		*policy = pol == &default_policy ? MPOL_DEFAULT :
						pol->mode;
774 775 776 777 778
		/*
		 * Internal mempolicy flags must be masked off before exposing
		 * the policy to userspace.
		 */
		*policy |= (pol->flags & MPOL_MODE_FLAGS);
779
	}
L
Linus Torvalds 已提交
780 781 782 783 784 785 786

	if (vma) {
		up_read(&current->mm->mmap_sem);
		vma = NULL;
	}

	err = 0;
787 788
	if (nmask) {
		task_lock(current);
789
		get_policy_nodemask(pol, nmask);
790 791
		task_unlock(current);
	}
L
Linus Torvalds 已提交
792 793

 out:
794
	mpol_cond_put(pol);
L
Linus Torvalds 已提交
795 796 797 798 799
	if (vma)
		up_read(&current->mm->mmap_sem);
	return err;
}

C
Christoph Lameter 已提交
800
#ifdef CONFIG_MIGRATION
801 802 803
/*
 * page migration
 */
804 805
static void migrate_page_add(struct page *page, struct list_head *pagelist,
				unsigned long flags)
806 807
{
	/*
808
	 * Avoid migrating a page that is shared with others.
809
	 */
810 811 812
	if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
		if (!isolate_lru_page(page)) {
			list_add_tail(&page->lru, pagelist);
813 814
			inc_zone_page_state(page, NR_ISOLATED_ANON +
					    page_is_file_cache(page));
815 816
		}
	}
817
}
818

819
static struct page *new_node_page(struct page *page, unsigned long node, int **x)
820
{
821
	return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
822 823
}

824 825 826 827
/*
 * Migrate pages from one node to a target node.
 * Returns error or the number of pages not migrated.
 */
A
Adrian Bunk 已提交
828 829
static int migrate_to_node(struct mm_struct *mm, int source, int dest,
			   int flags)
830 831 832 833 834 835 836
{
	nodemask_t nmask;
	LIST_HEAD(pagelist);
	int err = 0;

	nodes_clear(nmask);
	node_set(source, nmask);
837

838 839 840
	check_range(mm, mm->mmap->vm_start, TASK_SIZE, &nmask,
			flags | MPOL_MF_DISCONTIG_OK, &pagelist);

841
	if (!list_empty(&pagelist))
842 843
		err = migrate_pages(&pagelist, new_node_page, dest);

844
	return err;
845 846
}

847
/*
848 849
 * Move pages between the two nodesets so as to preserve the physical
 * layout as much as possible.
850 851 852 853 854 855
 *
 * Returns the number of page that could not be moved.
 */
int do_migrate_pages(struct mm_struct *mm,
	const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
{
856
	int busy = 0;
857
	int err;
858
	nodemask_t tmp;
859

860 861 862 863
	err = migrate_prep();
	if (err)
		return err;

864
	down_read(&mm->mmap_sem);
865

866 867 868 869
	err = migrate_vmas(mm, from_nodes, to_nodes, flags);
	if (err)
		goto out;

870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899
/*
 * Find a 'source' bit set in 'tmp' whose corresponding 'dest'
 * bit in 'to' is not also set in 'tmp'.  Clear the found 'source'
 * bit in 'tmp', and return that <source, dest> pair for migration.
 * The pair of nodemasks 'to' and 'from' define the map.
 *
 * If no pair of bits is found that way, fallback to picking some
 * pair of 'source' and 'dest' bits that are not the same.  If the
 * 'source' and 'dest' bits are the same, this represents a node
 * that will be migrating to itself, so no pages need move.
 *
 * If no bits are left in 'tmp', or if all remaining bits left
 * in 'tmp' correspond to the same bit in 'to', return false
 * (nothing left to migrate).
 *
 * This lets us pick a pair of nodes to migrate between, such that
 * if possible the dest node is not already occupied by some other
 * source node, minimizing the risk of overloading the memory on a
 * node that would happen if we migrated incoming memory to a node
 * before migrating outgoing memory source that same node.
 *
 * A single scan of tmp is sufficient.  As we go, we remember the
 * most recent <s, d> pair that moved (s != d).  If we find a pair
 * that not only moved, but what's better, moved to an empty slot
 * (d is not set in tmp), then we break out then, with that pair.
 * Otherwise when we finish scannng from_tmp, we at least have the
 * most recent <s, d> pair that moved.  If we get all the way through
 * the scan of tmp without finding any node that moved, much less
 * moved to an empty node, then there is nothing left worth migrating.
 */
900

901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927
	tmp = *from_nodes;
	while (!nodes_empty(tmp)) {
		int s,d;
		int source = -1;
		int dest = 0;

		for_each_node_mask(s, tmp) {
			d = node_remap(s, *from_nodes, *to_nodes);
			if (s == d)
				continue;

			source = s;	/* Node moved. Memorize */
			dest = d;

			/* dest not in remaining from nodes? */
			if (!node_isset(dest, tmp))
				break;
		}
		if (source == -1)
			break;

		node_clear(source, tmp);
		err = migrate_to_node(mm, source, dest, flags);
		if (err > 0)
			busy += err;
		if (err < 0)
			break;
928
	}
929
out:
930
	up_read(&mm->mmap_sem);
931 932 933
	if (err < 0)
		return err;
	return busy;
C
Christoph Lameter 已提交
934 935 936

}

937 938 939 940 941 942 943
/*
 * Allocate a new page for page migration based on vma policy.
 * Start assuming that page is mapped by vma pointed to by @private.
 * Search forward from there, if not.  N.B., this assumes that the
 * list of pages handed to migrate_pages()--which is how we get here--
 * is in virtual address order.
 */
944
static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
945 946
{
	struct vm_area_struct *vma = (struct vm_area_struct *)private;
947
	unsigned long uninitialized_var(address);
948

949 950 951 952 953 954 955 956 957 958 959
	while (vma) {
		address = page_address_in_vma(page, vma);
		if (address != -EFAULT)
			break;
		vma = vma->vm_next;
	}

	/*
	 * if !vma, alloc_page_vma() will use task or system default policy
	 */
	return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
960
}
C
Christoph Lameter 已提交
961 962 963 964 965
#else

static void migrate_page_add(struct page *page, struct list_head *pagelist,
				unsigned long flags)
{
966 967
}

C
Christoph Lameter 已提交
968 969 970 971 972
int do_migrate_pages(struct mm_struct *mm,
	const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
{
	return -ENOSYS;
}
973

974
static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
975 976 977
{
	return NULL;
}
C
Christoph Lameter 已提交
978 979
#endif

A
Adrian Bunk 已提交
980
static long do_mbind(unsigned long start, unsigned long len,
981 982
		     unsigned short mode, unsigned short mode_flags,
		     nodemask_t *nmask, unsigned long flags)
983 984 985 986 987 988 989 990
{
	struct vm_area_struct *vma;
	struct mm_struct *mm = current->mm;
	struct mempolicy *new;
	unsigned long end;
	int err;
	LIST_HEAD(pagelist);

991 992
	if (flags & ~(unsigned long)(MPOL_MF_STRICT |
				     MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
993
		return -EINVAL;
994
	if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010
		return -EPERM;

	if (start & ~PAGE_MASK)
		return -EINVAL;

	if (mode == MPOL_DEFAULT)
		flags &= ~MPOL_MF_STRICT;

	len = (len + PAGE_SIZE - 1) & PAGE_MASK;
	end = start + len;

	if (end < start)
		return -EINVAL;
	if (end == start)
		return 0;

1011
	new = mpol_new(mode, mode_flags, nmask);
1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
	if (IS_ERR(new))
		return PTR_ERR(new);

	/*
	 * If we are using the default policy then operation
	 * on discontinuous address spaces is okay after all
	 */
	if (!new)
		flags |= MPOL_MF_DISCONTIG_OK;

1022 1023 1024
	pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
		 start, start + len, mode, mode_flags,
		 nmask ? nodes_addr(*nmask)[0] : -1);
1025

1026 1027 1028 1029
	if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {

		err = migrate_prep();
		if (err)
K
KOSAKI Motohiro 已提交
1030
			goto mpol_out;
1031
	}
1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044
	{
		NODEMASK_SCRATCH(scratch);
		if (scratch) {
			down_write(&mm->mmap_sem);
			task_lock(current);
			err = mpol_set_nodemask(new, nmask, scratch);
			task_unlock(current);
			if (err)
				up_write(&mm->mmap_sem);
		} else
			err = -ENOMEM;
		NODEMASK_SCRATCH_FREE(scratch);
	}
K
KOSAKI Motohiro 已提交
1045 1046 1047
	if (err)
		goto mpol_out;

1048 1049 1050 1051 1052 1053 1054 1055
	vma = check_range(mm, start, end, nmask,
			  flags | MPOL_MF_INVERT, &pagelist);

	err = PTR_ERR(vma);
	if (!IS_ERR(vma)) {
		int nr_failed = 0;

		err = mbind_range(vma, start, end, new);
1056

1057
		if (!list_empty(&pagelist))
1058 1059
			nr_failed = migrate_pages(&pagelist, new_vma_page,
						(unsigned long)vma);
1060 1061 1062

		if (!err && nr_failed && (flags & MPOL_MF_STRICT))
			err = -EIO;
1063 1064
	} else
		putback_lru_pages(&pagelist);
C
Christoph Lameter 已提交
1065

1066
	up_write(&mm->mmap_sem);
K
KOSAKI Motohiro 已提交
1067
 mpol_out:
1068
	mpol_put(new);
1069 1070 1071
	return err;
}

1072 1073 1074 1075 1076
/*
 * User space interface with variable sized bitmaps for nodelists.
 */

/* Copy a node mask from user space. */
1077
static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1078 1079 1080 1081 1082 1083 1084 1085 1086 1087
		     unsigned long maxnode)
{
	unsigned long k;
	unsigned long nlongs;
	unsigned long endmask;

	--maxnode;
	nodes_clear(*nodes);
	if (maxnode == 0 || !nmask)
		return 0;
A
Andi Kleen 已提交
1088
	if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
C
Chris Wright 已提交
1089
		return -EINVAL;
1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138

	nlongs = BITS_TO_LONGS(maxnode);
	if ((maxnode % BITS_PER_LONG) == 0)
		endmask = ~0UL;
	else
		endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;

	/* When the user specified more nodes than supported just check
	   if the non supported part is all zero. */
	if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
		if (nlongs > PAGE_SIZE/sizeof(long))
			return -EINVAL;
		for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
			unsigned long t;
			if (get_user(t, nmask + k))
				return -EFAULT;
			if (k == nlongs - 1) {
				if (t & endmask)
					return -EINVAL;
			} else if (t)
				return -EINVAL;
		}
		nlongs = BITS_TO_LONGS(MAX_NUMNODES);
		endmask = ~0UL;
	}

	if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
		return -EFAULT;
	nodes_addr(*nodes)[nlongs-1] &= endmask;
	return 0;
}

/* Copy a kernel node mask to user space */
static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
			      nodemask_t *nodes)
{
	unsigned long copy = ALIGN(maxnode-1, 64) / 8;
	const int nbytes = BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long);

	if (copy > nbytes) {
		if (copy > PAGE_SIZE)
			return -EINVAL;
		if (clear_user((char __user *)mask + nbytes, copy - nbytes))
			return -EFAULT;
		copy = nbytes;
	}
	return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
}

1139 1140 1141
SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
		unsigned long, mode, unsigned long __user *, nmask,
		unsigned long, maxnode, unsigned, flags)
1142 1143 1144
{
	nodemask_t nodes;
	int err;
1145
	unsigned short mode_flags;
1146

1147 1148
	mode_flags = mode & MPOL_MODE_FLAGS;
	mode &= ~MPOL_MODE_FLAGS;
1149 1150
	if (mode >= MPOL_MAX)
		return -EINVAL;
1151 1152 1153
	if ((mode_flags & MPOL_F_STATIC_NODES) &&
	    (mode_flags & MPOL_F_RELATIVE_NODES))
		return -EINVAL;
1154 1155 1156
	err = get_nodes(&nodes, nmask, maxnode);
	if (err)
		return err;
1157
	return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1158 1159 1160
}

/* Set the process memory policy */
1161 1162
SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
		unsigned long, maxnode)
1163 1164 1165
{
	int err;
	nodemask_t nodes;
1166
	unsigned short flags;
1167

1168 1169 1170
	flags = mode & MPOL_MODE_FLAGS;
	mode &= ~MPOL_MODE_FLAGS;
	if ((unsigned int)mode >= MPOL_MAX)
1171
		return -EINVAL;
1172 1173
	if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
		return -EINVAL;
1174 1175 1176
	err = get_nodes(&nodes, nmask, maxnode);
	if (err)
		return err;
1177
	return do_set_mempolicy(mode, flags, &nodes);
1178 1179
}

1180 1181 1182
SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
		const unsigned long __user *, old_nodes,
		const unsigned long __user *, new_nodes)
1183
{
1184
	const struct cred *cred = current_cred(), *tcred;
1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201
	struct mm_struct *mm;
	struct task_struct *task;
	nodemask_t old;
	nodemask_t new;
	nodemask_t task_nodes;
	int err;

	err = get_nodes(&old, old_nodes, maxnode);
	if (err)
		return err;

	err = get_nodes(&new, new_nodes, maxnode);
	if (err)
		return err;

	/* Find the mm_struct */
	read_lock(&tasklist_lock);
1202
	task = pid ? find_task_by_vpid(pid) : current;
1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215
	if (!task) {
		read_unlock(&tasklist_lock);
		return -ESRCH;
	}
	mm = get_task_mm(task);
	read_unlock(&tasklist_lock);

	if (!mm)
		return -EINVAL;

	/*
	 * Check if this process has the right to modify the specified
	 * process. The right exists if the process has administrative
A
Alexey Dobriyan 已提交
1216
	 * capabilities, superuser privileges or the same
1217 1218
	 * userid as the target process.
	 */
1219 1220
	rcu_read_lock();
	tcred = __task_cred(task);
1221 1222
	if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
	    cred->uid  != tcred->suid && cred->uid  != tcred->uid &&
1223
	    !capable(CAP_SYS_NICE)) {
1224
		rcu_read_unlock();
1225 1226 1227
		err = -EPERM;
		goto out;
	}
1228
	rcu_read_unlock();
1229 1230 1231

	task_nodes = cpuset_mems_allowed(task);
	/* Is the user allowed to access the target nodes? */
1232
	if (!nodes_subset(new, task_nodes) && !capable(CAP_SYS_NICE)) {
1233 1234 1235 1236
		err = -EPERM;
		goto out;
	}

1237
	if (!nodes_subset(new, node_states[N_HIGH_MEMORY])) {
1238 1239 1240 1241
		err = -EINVAL;
		goto out;
	}

1242 1243 1244 1245
	err = security_task_movememory(task);
	if (err)
		goto out;

1246
	err = do_migrate_pages(mm, &old, &new,
1247
		capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1248 1249 1250 1251 1252 1253
out:
	mmput(mm);
	return err;
}


1254
/* Retrieve NUMA policy */
1255 1256 1257
SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
		unsigned long __user *, nmask, unsigned long, maxnode,
		unsigned long, addr, unsigned long, flags)
1258
{
A
Adrian Bunk 已提交
1259 1260
	int err;
	int uninitialized_var(pval);
1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279
	nodemask_t nodes;

	if (nmask != NULL && maxnode < MAX_NUMNODES)
		return -EINVAL;

	err = do_get_mempolicy(&pval, &nodes, addr, flags);

	if (err)
		return err;

	if (policy && put_user(pval, policy))
		return -EFAULT;

	if (nmask)
		err = copy_nodes_to_user(nmask, maxnode, &nodes);

	return err;
}

L
Linus Torvalds 已提交
1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339
#ifdef CONFIG_COMPAT

asmlinkage long compat_sys_get_mempolicy(int __user *policy,
				     compat_ulong_t __user *nmask,
				     compat_ulong_t maxnode,
				     compat_ulong_t addr, compat_ulong_t flags)
{
	long err;
	unsigned long __user *nm = NULL;
	unsigned long nr_bits, alloc_size;
	DECLARE_BITMAP(bm, MAX_NUMNODES);

	nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
	alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;

	if (nmask)
		nm = compat_alloc_user_space(alloc_size);

	err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);

	if (!err && nmask) {
		err = copy_from_user(bm, nm, alloc_size);
		/* ensure entire bitmap is zeroed */
		err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
		err |= compat_put_bitmap(nmask, bm, nr_bits);
	}

	return err;
}

asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
				     compat_ulong_t maxnode)
{
	long err = 0;
	unsigned long __user *nm = NULL;
	unsigned long nr_bits, alloc_size;
	DECLARE_BITMAP(bm, MAX_NUMNODES);

	nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
	alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;

	if (nmask) {
		err = compat_get_bitmap(bm, nmask, nr_bits);
		nm = compat_alloc_user_space(alloc_size);
		err |= copy_to_user(nm, bm, alloc_size);
	}

	if (err)
		return -EFAULT;

	return sys_set_mempolicy(mode, nm, nr_bits+1);
}

asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
			     compat_ulong_t mode, compat_ulong_t __user *nmask,
			     compat_ulong_t maxnode, compat_ulong_t flags)
{
	long err = 0;
	unsigned long __user *nm = NULL;
	unsigned long nr_bits, alloc_size;
1340
	nodemask_t bm;
L
Linus Torvalds 已提交
1341 1342 1343 1344 1345

	nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
	alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;

	if (nmask) {
1346
		err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
L
Linus Torvalds 已提交
1347
		nm = compat_alloc_user_space(alloc_size);
1348
		err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
L
Linus Torvalds 已提交
1349 1350 1351 1352 1353 1354 1355 1356 1357 1358
	}

	if (err)
		return -EFAULT;

	return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
}

#endif

1359 1360 1361 1362 1363 1364 1365 1366
/*
 * get_vma_policy(@task, @vma, @addr)
 * @task - task for fallback if vma policy == default
 * @vma   - virtual memory area whose policy is sought
 * @addr  - address in @vma for shared policy lookup
 *
 * Returns effective policy for a VMA at specified address.
 * Falls back to @task or system default policy, as necessary.
1367 1368 1369 1370 1371 1372 1373
 * Current or other task's task mempolicy and non-shared vma policies
 * are protected by the task's mmap_sem, which must be held for read by
 * the caller.
 * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
 * count--added by the get_policy() vm_op, as appropriate--to protect against
 * freeing by another task.  It is the caller's responsibility to free the
 * extra reference for shared policies.
1374
 */
1375
static struct mempolicy *get_vma_policy(struct task_struct *task,
1376
		struct vm_area_struct *vma, unsigned long addr)
L
Linus Torvalds 已提交
1377
{
1378
	struct mempolicy *pol = task->mempolicy;
L
Linus Torvalds 已提交
1379 1380

	if (vma) {
1381
		if (vma->vm_ops && vma->vm_ops->get_policy) {
1382 1383 1384 1385
			struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
									addr);
			if (vpol)
				pol = vpol;
1386
		} else if (vma->vm_policy)
L
Linus Torvalds 已提交
1387 1388 1389 1390 1391 1392 1393
			pol = vma->vm_policy;
	}
	if (!pol)
		pol = &default_policy;
	return pol;
}

1394 1395 1396 1397 1398
/*
 * Return a nodemask representing a mempolicy for filtering nodes for
 * page allocation
 */
static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1399 1400
{
	/* Lower zones don't get a nodemask applied for MPOL_BIND */
1401
	if (unlikely(policy->mode == MPOL_BIND) &&
1402 1403 1404 1405 1406 1407 1408
			gfp_zone(gfp) >= policy_zone &&
			cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
		return &policy->v.nodes;

	return NULL;
}

1409 1410
/* Return a zonelist indicated by gfp for node representing a mempolicy */
static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy)
L
Linus Torvalds 已提交
1411
{
1412
	int nd = numa_node_id();
L
Linus Torvalds 已提交
1413

1414
	switch (policy->mode) {
L
Linus Torvalds 已提交
1415
	case MPOL_PREFERRED:
1416 1417
		if (!(policy->flags & MPOL_F_LOCAL))
			nd = policy->v.preferred_node;
L
Linus Torvalds 已提交
1418 1419
		break;
	case MPOL_BIND:
1420
		/*
1421 1422 1423 1424
		 * Normally, MPOL_BIND allocations are node-local within the
		 * allowed nodemask.  However, if __GFP_THISNODE is set and the
		 * current node is part of the mask, we use the zonelist for
		 * the first node in the mask instead.
1425 1426 1427 1428 1429
		 */
		if (unlikely(gfp & __GFP_THISNODE) &&
				unlikely(!node_isset(nd, policy->v.nodes)))
			nd = first_node(policy->v.nodes);
		break;
L
Linus Torvalds 已提交
1430 1431 1432 1433 1434
	case MPOL_INTERLEAVE: /* should not happen */
		break;
	default:
		BUG();
	}
1435
	return node_zonelist(nd, gfp);
L
Linus Torvalds 已提交
1436 1437 1438 1439 1440 1441 1442 1443 1444
}

/* Do dynamic interleaving for a process */
static unsigned interleave_nodes(struct mempolicy *policy)
{
	unsigned nid, next;
	struct task_struct *me = current;

	nid = me->il_next;
1445
	next = next_node(nid, policy->v.nodes);
L
Linus Torvalds 已提交
1446
	if (next >= MAX_NUMNODES)
1447
		next = first_node(policy->v.nodes);
1448 1449
	if (next < MAX_NUMNODES)
		me->il_next = next;
L
Linus Torvalds 已提交
1450 1451 1452
	return nid;
}

1453 1454 1455
/*
 * Depending on the memory policy provide a node from which to allocate the
 * next slab entry.
1456 1457 1458 1459
 * @policy must be protected by freeing by the caller.  If @policy is
 * the current task's mempolicy, this protection is implicit, as only the
 * task can change it's policy.  The system default policy requires no
 * such protection.
1460 1461 1462
 */
unsigned slab_node(struct mempolicy *policy)
{
1463
	if (!policy || policy->flags & MPOL_F_LOCAL)
1464 1465 1466 1467
		return numa_node_id();

	switch (policy->mode) {
	case MPOL_PREFERRED:
1468 1469 1470 1471
		/*
		 * handled MPOL_F_LOCAL above
		 */
		return policy->v.preferred_node;
1472

1473 1474 1475
	case MPOL_INTERLEAVE:
		return interleave_nodes(policy);

1476
	case MPOL_BIND: {
1477 1478 1479 1480
		/*
		 * Follow bind policy behavior and start allocation at the
		 * first node.
		 */
1481 1482 1483 1484 1485 1486 1487 1488
		struct zonelist *zonelist;
		struct zone *zone;
		enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
		zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
		(void)first_zones_zonelist(zonelist, highest_zoneidx,
							&policy->v.nodes,
							&zone);
		return zone->node;
1489
	}
1490 1491

	default:
1492
		BUG();
1493 1494 1495
	}
}

L
Linus Torvalds 已提交
1496 1497 1498 1499
/* Do static interleaving for a VMA with known offset. */
static unsigned offset_il_node(struct mempolicy *pol,
		struct vm_area_struct *vma, unsigned long off)
{
1500
	unsigned nnodes = nodes_weight(pol->v.nodes);
1501
	unsigned target;
L
Linus Torvalds 已提交
1502 1503 1504
	int c;
	int nid = -1;

1505 1506 1507
	if (!nnodes)
		return numa_node_id();
	target = (unsigned int)off % nnodes;
L
Linus Torvalds 已提交
1508 1509
	c = 0;
	do {
1510
		nid = next_node(nid, pol->v.nodes);
L
Linus Torvalds 已提交
1511 1512 1513 1514 1515
		c++;
	} while (c <= target);
	return nid;
}

1516 1517 1518 1519 1520 1521 1522
/* Determine a node number for interleave */
static inline unsigned interleave_nid(struct mempolicy *pol,
		 struct vm_area_struct *vma, unsigned long addr, int shift)
{
	if (vma) {
		unsigned long off;

1523 1524 1525 1526 1527 1528 1529 1530 1531
		/*
		 * for small pages, there is no difference between
		 * shift and PAGE_SHIFT, so the bit-shift is safe.
		 * for huge pages, since vm_pgoff is in units of small
		 * pages, we need to shift off the always 0 bits to get
		 * a useful offset.
		 */
		BUG_ON(shift < PAGE_SHIFT);
		off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
1532 1533 1534 1535 1536 1537
		off += (addr - vma->vm_start) >> shift;
		return offset_il_node(pol, vma, off);
	} else
		return interleave_nodes(pol);
}

1538
#ifdef CONFIG_HUGETLBFS
1539 1540 1541 1542 1543
/*
 * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
 * @vma = virtual memory area whose policy is sought
 * @addr = address in @vma for shared policy lookup and interleave policy
 * @gfp_flags = for requested zone
1544 1545
 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1546
 *
1547 1548 1549 1550
 * Returns a zonelist suitable for a huge page allocation and a pointer
 * to the struct mempolicy for conditional unref after allocation.
 * If the effective policy is 'BIND, returns a pointer to the mempolicy's
 * @nodemask for filtering the zonelist.
1551
 */
1552
struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1553 1554
				gfp_t gfp_flags, struct mempolicy **mpol,
				nodemask_t **nodemask)
1555
{
1556
	struct zonelist *zl;
1557

1558
	*mpol = get_vma_policy(current, vma, addr);
1559
	*nodemask = NULL;	/* assume !MPOL_BIND */
1560

1561 1562
	if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
		zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1563
				huge_page_shift(hstate_vma(vma))), gfp_flags);
1564 1565 1566 1567
	} else {
		zl = policy_zonelist(gfp_flags, *mpol);
		if ((*mpol)->mode == MPOL_BIND)
			*nodemask = &(*mpol)->v.nodes;
1568 1569
	}
	return zl;
1570
}
1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617

/*
 * init_nodemask_of_mempolicy
 *
 * If the current task's mempolicy is "default" [NULL], return 'false'
 * to indicate default policy.  Otherwise, extract the policy nodemask
 * for 'bind' or 'interleave' policy into the argument nodemask, or
 * initialize the argument nodemask to contain the single node for
 * 'preferred' or 'local' policy and return 'true' to indicate presence
 * of non-default mempolicy.
 *
 * We don't bother with reference counting the mempolicy [mpol_get/put]
 * because the current task is examining it's own mempolicy and a task's
 * mempolicy is only ever changed by the task itself.
 *
 * N.B., it is the caller's responsibility to free a returned nodemask.
 */
bool init_nodemask_of_mempolicy(nodemask_t *mask)
{
	struct mempolicy *mempolicy;
	int nid;

	if (!(mask && current->mempolicy))
		return false;

	mempolicy = current->mempolicy;
	switch (mempolicy->mode) {
	case MPOL_PREFERRED:
		if (mempolicy->flags & MPOL_F_LOCAL)
			nid = numa_node_id();
		else
			nid = mempolicy->v.preferred_node;
		init_nodemask_of_node(mask, nid);
		break;

	case MPOL_BIND:
		/* Fall through */
	case MPOL_INTERLEAVE:
		*mask =  mempolicy->v.nodes;
		break;

	default:
		BUG();
	}

	return true;
}
1618
#endif
1619

L
Linus Torvalds 已提交
1620 1621
/* Allocate a page in interleaved policy.
   Own path because it needs to do special accounting. */
1622 1623
static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
					unsigned nid)
L
Linus Torvalds 已提交
1624 1625 1626 1627
{
	struct zonelist *zl;
	struct page *page;

1628
	zl = node_zonelist(nid, gfp);
L
Linus Torvalds 已提交
1629
	page = __alloc_pages(gfp, order, zl);
1630
	if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1631
		inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
L
Linus Torvalds 已提交
1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657
	return page;
}

/**
 * 	alloc_page_vma	- Allocate a page for a VMA.
 *
 * 	@gfp:
 *      %GFP_USER    user allocation.
 *      %GFP_KERNEL  kernel allocations,
 *      %GFP_HIGHMEM highmem/user allocations,
 *      %GFP_FS      allocation should not call back into a file system.
 *      %GFP_ATOMIC  don't sleep.
 *
 * 	@vma:  Pointer to VMA or NULL if not available.
 *	@addr: Virtual Address of the allocation. Must be inside the VMA.
 *
 * 	This function allocates a page from the kernel page pool and applies
 *	a NUMA policy associated with the VMA or the current process.
 *	When VMA is not NULL caller must hold down_read on the mmap_sem of the
 *	mm_struct of the VMA to prevent it from going away. Should be used for
 *	all allocations for pages that will be mapped into
 * 	user space. Returns NULL when no page can be allocated.
 *
 *	Should be called with the mm_sem of the vma hold.
 */
struct page *
A
Al Viro 已提交
1658
alloc_page_vma(gfp_t gfp, struct vm_area_struct *vma, unsigned long addr)
L
Linus Torvalds 已提交
1659
{
1660
	struct mempolicy *pol = get_vma_policy(current, vma, addr);
1661
	struct zonelist *zl;
L
Linus Torvalds 已提交
1662

1663
	if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
L
Linus Torvalds 已提交
1664
		unsigned nid;
1665 1666

		nid = interleave_nid(pol, vma, addr, PAGE_SHIFT);
1667
		mpol_cond_put(pol);
L
Linus Torvalds 已提交
1668 1669
		return alloc_page_interleave(gfp, 0, nid);
	}
1670 1671
	zl = policy_zonelist(gfp, pol);
	if (unlikely(mpol_needs_cond_ref(pol))) {
1672
		/*
1673
		 * slow path: ref counted shared policy
1674
		 */
1675
		struct page *page =  __alloc_pages_nodemask(gfp, 0,
1676
						zl, policy_nodemask(gfp, pol));
1677
		__mpol_put(pol);
1678 1679 1680 1681 1682
		return page;
	}
	/*
	 * fast path:  default or task policy
	 */
1683
	return __alloc_pages_nodemask(gfp, 0, zl, policy_nodemask(gfp, pol));
L
Linus Torvalds 已提交
1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700
}

/**
 * 	alloc_pages_current - Allocate pages.
 *
 *	@gfp:
 *		%GFP_USER   user allocation,
 *      	%GFP_KERNEL kernel allocation,
 *      	%GFP_HIGHMEM highmem allocation,
 *      	%GFP_FS     don't call back into a file system.
 *      	%GFP_ATOMIC don't sleep.
 *	@order: Power of two of allocation size in pages. 0 is a single page.
 *
 *	Allocate a page from the kernel page pool.  When not in
 *	interrupt context and apply the current process NUMA policy.
 *	Returns NULL when no page can be allocated.
 *
1701
 *	Don't call cpuset_update_task_memory_state() unless
L
Linus Torvalds 已提交
1702 1703 1704
 *	1) it's ok to take cpuset_sem (can WAIT), and
 *	2) allocating for current task (not interrupt).
 */
A
Al Viro 已提交
1705
struct page *alloc_pages_current(gfp_t gfp, unsigned order)
L
Linus Torvalds 已提交
1706 1707 1708
{
	struct mempolicy *pol = current->mempolicy;

1709
	if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
L
Linus Torvalds 已提交
1710
		pol = &default_policy;
1711 1712 1713 1714 1715

	/*
	 * No reference counting needed for current->mempolicy
	 * nor system default_policy
	 */
1716
	if (pol->mode == MPOL_INTERLEAVE)
L
Linus Torvalds 已提交
1717
		return alloc_page_interleave(gfp, order, interleave_nodes(pol));
1718
	return __alloc_pages_nodemask(gfp, order,
1719
			policy_zonelist(gfp, pol), policy_nodemask(gfp, pol));
L
Linus Torvalds 已提交
1720 1721 1722
}
EXPORT_SYMBOL(alloc_pages_current);

1723
/*
1724
 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
1725 1726 1727 1728 1729 1730
 * rebinds the mempolicy its copying by calling mpol_rebind_policy()
 * with the mems_allowed returned by cpuset_mems_allowed().  This
 * keeps mempolicies cpuset relative after its cpuset moves.  See
 * further kernel/cpuset.c update_nodemask().
 */

1731 1732
/* Slow path of a mempolicy duplicate */
struct mempolicy *__mpol_dup(struct mempolicy *old)
L
Linus Torvalds 已提交
1733 1734 1735 1736 1737
{
	struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);

	if (!new)
		return ERR_PTR(-ENOMEM);
1738 1739 1740 1741
	if (current_cpuset_is_being_rebound()) {
		nodemask_t mems = cpuset_mems_allowed(current);
		mpol_rebind_policy(old, &mems);
	}
L
Linus Torvalds 已提交
1742 1743 1744 1745 1746
	*new = *old;
	atomic_set(&new->refcnt, 1);
	return new;
}

1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768
/*
 * If *frompol needs [has] an extra ref, copy *frompol to *tompol ,
 * eliminate the * MPOL_F_* flags that require conditional ref and
 * [NOTE!!!] drop the extra ref.  Not safe to reference *frompol directly
 * after return.  Use the returned value.
 *
 * Allows use of a mempolicy for, e.g., multiple allocations with a single
 * policy lookup, even if the policy needs/has extra ref on lookup.
 * shmem_readahead needs this.
 */
struct mempolicy *__mpol_cond_copy(struct mempolicy *tompol,
						struct mempolicy *frompol)
{
	if (!mpol_needs_cond_ref(frompol))
		return frompol;

	*tompol = *frompol;
	tompol->flags &= ~MPOL_F_SHARED;	/* copy doesn't need unref */
	__mpol_put(frompol);
	return tompol;
}

1769 1770 1771 1772 1773 1774 1775 1776 1777 1778
static int mpol_match_intent(const struct mempolicy *a,
			     const struct mempolicy *b)
{
	if (a->flags != b->flags)
		return 0;
	if (!mpol_store_user_nodemask(a))
		return 1;
	return nodes_equal(a->w.user_nodemask, b->w.user_nodemask);
}

L
Linus Torvalds 已提交
1779 1780 1781 1782 1783
/* Slow path of a mempolicy comparison */
int __mpol_equal(struct mempolicy *a, struct mempolicy *b)
{
	if (!a || !b)
		return 0;
1784
	if (a->mode != b->mode)
L
Linus Torvalds 已提交
1785
		return 0;
1786
	if (a->mode != MPOL_DEFAULT && !mpol_match_intent(a, b))
1787
		return 0;
1788
	switch (a->mode) {
1789 1790
	case MPOL_BIND:
		/* Fall through */
L
Linus Torvalds 已提交
1791
	case MPOL_INTERLEAVE:
1792
		return nodes_equal(a->v.nodes, b->v.nodes);
L
Linus Torvalds 已提交
1793
	case MPOL_PREFERRED:
1794 1795
		return a->v.preferred_node == b->v.preferred_node &&
			a->flags == b->flags;
L
Linus Torvalds 已提交
1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862
	default:
		BUG();
		return 0;
	}
}

/*
 * Shared memory backing store policy support.
 *
 * Remember policies even when nobody has shared memory mapped.
 * The policies are kept in Red-Black tree linked from the inode.
 * They are protected by the sp->lock spinlock, which should be held
 * for any accesses to the tree.
 */

/* lookup first element intersecting start-end */
/* Caller holds sp->lock */
static struct sp_node *
sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
{
	struct rb_node *n = sp->root.rb_node;

	while (n) {
		struct sp_node *p = rb_entry(n, struct sp_node, nd);

		if (start >= p->end)
			n = n->rb_right;
		else if (end <= p->start)
			n = n->rb_left;
		else
			break;
	}
	if (!n)
		return NULL;
	for (;;) {
		struct sp_node *w = NULL;
		struct rb_node *prev = rb_prev(n);
		if (!prev)
			break;
		w = rb_entry(prev, struct sp_node, nd);
		if (w->end <= start)
			break;
		n = prev;
	}
	return rb_entry(n, struct sp_node, nd);
}

/* Insert a new shared policy into the list. */
/* Caller holds sp->lock */
static void sp_insert(struct shared_policy *sp, struct sp_node *new)
{
	struct rb_node **p = &sp->root.rb_node;
	struct rb_node *parent = NULL;
	struct sp_node *nd;

	while (*p) {
		parent = *p;
		nd = rb_entry(parent, struct sp_node, nd);
		if (new->start < nd->start)
			p = &(*p)->rb_left;
		else if (new->end > nd->end)
			p = &(*p)->rb_right;
		else
			BUG();
	}
	rb_link_node(&new->nd, parent, p);
	rb_insert_color(&new->nd, &sp->root);
1863
	pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
1864
		 new->policy ? new->policy->mode : 0);
L
Linus Torvalds 已提交
1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887
}

/* Find shared policy intersecting idx */
struct mempolicy *
mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
{
	struct mempolicy *pol = NULL;
	struct sp_node *sn;

	if (!sp->root.rb_node)
		return NULL;
	spin_lock(&sp->lock);
	sn = sp_lookup(sp, idx, idx+1);
	if (sn) {
		mpol_get(sn->policy);
		pol = sn->policy;
	}
	spin_unlock(&sp->lock);
	return pol;
}

static void sp_delete(struct shared_policy *sp, struct sp_node *n)
{
1888
	pr_debug("deleting %lx-l%lx\n", n->start, n->end);
L
Linus Torvalds 已提交
1889
	rb_erase(&n->nd, &sp->root);
1890
	mpol_put(n->policy);
L
Linus Torvalds 已提交
1891 1892 1893
	kmem_cache_free(sn_cache, n);
}

A
Adrian Bunk 已提交
1894 1895
static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
				struct mempolicy *pol)
L
Linus Torvalds 已提交
1896 1897 1898 1899 1900 1901 1902 1903
{
	struct sp_node *n = kmem_cache_alloc(sn_cache, GFP_KERNEL);

	if (!n)
		return NULL;
	n->start = start;
	n->end = end;
	mpol_get(pol);
1904
	pol->flags |= MPOL_F_SHARED;	/* for unref */
L
Linus Torvalds 已提交
1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950
	n->policy = pol;
	return n;
}

/* Replace a policy range. */
static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
				 unsigned long end, struct sp_node *new)
{
	struct sp_node *n, *new2 = NULL;

restart:
	spin_lock(&sp->lock);
	n = sp_lookup(sp, start, end);
	/* Take care of old policies in the same range. */
	while (n && n->start < end) {
		struct rb_node *next = rb_next(&n->nd);
		if (n->start >= start) {
			if (n->end <= end)
				sp_delete(sp, n);
			else
				n->start = end;
		} else {
			/* Old policy spanning whole new range. */
			if (n->end > end) {
				if (!new2) {
					spin_unlock(&sp->lock);
					new2 = sp_alloc(end, n->end, n->policy);
					if (!new2)
						return -ENOMEM;
					goto restart;
				}
				n->end = start;
				sp_insert(sp, new2);
				new2 = NULL;
				break;
			} else
				n->end = start;
		}
		if (!next)
			break;
		n = rb_entry(next, struct sp_node, nd);
	}
	if (new)
		sp_insert(sp, new);
	spin_unlock(&sp->lock);
	if (new2) {
1951
		mpol_put(new2->policy);
L
Linus Torvalds 已提交
1952 1953 1954 1955 1956
		kmem_cache_free(sn_cache, new2);
	}
	return 0;
}

1957 1958 1959 1960 1961 1962 1963 1964
/**
 * mpol_shared_policy_init - initialize shared policy for inode
 * @sp: pointer to inode shared policy
 * @mpol:  struct mempolicy to install
 *
 * Install non-NULL @mpol in inode's shared policy rb-tree.
 * On entry, the current task has a reference on a non-NULL @mpol.
 * This must be released on exit.
1965
 * This is called at get_inode() calls and we can use GFP_KERNEL.
1966 1967 1968
 */
void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
{
1969 1970
	int ret;

1971 1972 1973 1974 1975 1976
	sp->root = RB_ROOT;		/* empty tree == default mempolicy */
	spin_lock_init(&sp->lock);

	if (mpol) {
		struct vm_area_struct pvma;
		struct mempolicy *new;
1977
		NODEMASK_SCRATCH(scratch);
1978

1979 1980
		if (!scratch)
			return;
1981 1982
		/* contextualize the tmpfs mount point mempolicy */
		new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
1983 1984
		if (IS_ERR(new)) {
			mpol_put(mpol);	/* drop our ref on sb mpol */
1985
			NODEMASK_SCRATCH_FREE(scratch);
1986
			return;		/* no valid nodemask intersection */
1987 1988 1989
		}

		task_lock(current);
1990
		ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
1991 1992 1993
		task_unlock(current);
		mpol_put(mpol);	/* drop our ref on sb mpol */
		if (ret) {
1994
			NODEMASK_SCRATCH_FREE(scratch);
1995 1996 1997
			mpol_put(new);
			return;
		}
1998 1999 2000 2001 2002 2003

		/* Create pseudo-vma that contains just the policy */
		memset(&pvma, 0, sizeof(struct vm_area_struct));
		pvma.vm_end = TASK_SIZE;	/* policy covers entire file */
		mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
		mpol_put(new);			/* drop initial ref */
2004
		NODEMASK_SCRATCH_FREE(scratch);
2005 2006 2007
	}
}

L
Linus Torvalds 已提交
2008 2009 2010 2011 2012 2013 2014
int mpol_set_shared_policy(struct shared_policy *info,
			struct vm_area_struct *vma, struct mempolicy *npol)
{
	int err;
	struct sp_node *new = NULL;
	unsigned long sz = vma_pages(vma);

2015
	pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
L
Linus Torvalds 已提交
2016
		 vma->vm_pgoff,
2017
		 sz, npol ? npol->mode : -1,
2018
		 npol ? npol->flags : -1,
2019
		 npol ? nodes_addr(npol->v.nodes)[0] : -1);
L
Linus Torvalds 已提交
2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044

	if (npol) {
		new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
		if (!new)
			return -ENOMEM;
	}
	err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
	if (err && new)
		kmem_cache_free(sn_cache, new);
	return err;
}

/* Free a backing policy store on inode delete. */
void mpol_free_shared_policy(struct shared_policy *p)
{
	struct sp_node *n;
	struct rb_node *next;

	if (!p->root.rb_node)
		return;
	spin_lock(&p->lock);
	next = rb_first(&p->root);
	while (next) {
		n = rb_entry(next, struct sp_node, nd);
		next = rb_next(&n->nd);
2045
		rb_erase(&n->nd, &p->root);
2046
		mpol_put(n->policy);
L
Linus Torvalds 已提交
2047 2048 2049 2050 2051 2052 2053 2054
		kmem_cache_free(sn_cache, n);
	}
	spin_unlock(&p->lock);
}

/* assumes fs == KERNEL_DS */
void __init numa_policy_init(void)
{
2055 2056 2057 2058
	nodemask_t interleave_nodes;
	unsigned long largest = 0;
	int nid, prefer = 0;

L
Linus Torvalds 已提交
2059 2060
	policy_cache = kmem_cache_create("numa_policy",
					 sizeof(struct mempolicy),
2061
					 0, SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
2062 2063 2064

	sn_cache = kmem_cache_create("shared_policy_node",
				     sizeof(struct sp_node),
2065
				     0, SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
2066

2067 2068 2069 2070 2071 2072
	/*
	 * Set interleaving policy for system init. Interleaving is only
	 * enabled across suitably sized nodes (default is >= 16MB), or
	 * fall back to the largest node if they're all smaller.
	 */
	nodes_clear(interleave_nodes);
2073
	for_each_node_state(nid, N_HIGH_MEMORY) {
2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089
		unsigned long total_pages = node_present_pages(nid);

		/* Preserve the largest node */
		if (largest < total_pages) {
			largest = total_pages;
			prefer = nid;
		}

		/* Interleave this node? */
		if ((total_pages << PAGE_SHIFT) >= (16 << 20))
			node_set(nid, interleave_nodes);
	}

	/* All too small, use the largest */
	if (unlikely(nodes_empty(interleave_nodes)))
		node_set(prefer, interleave_nodes);
L
Linus Torvalds 已提交
2090

2091
	if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
L
Linus Torvalds 已提交
2092 2093 2094
		printk("numa_policy_init: interleaving failed\n");
}

2095
/* Reset policy of current process to default */
L
Linus Torvalds 已提交
2096 2097
void numa_default_policy(void)
{
2098
	do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
L
Linus Torvalds 已提交
2099
}
2100

2101 2102 2103 2104
/*
 * Parse and format mempolicy from/to strings
 */

2105
/*
2106
 * "local" is pseudo-policy:  MPOL_PREFERRED with MPOL_F_LOCAL flag
2107
 * Used only for mpol_parse_str() and mpol_to_str()
2108
 */
2109
#define MPOL_LOCAL (MPOL_INTERLEAVE + 1)
2110
static const char * const policy_types[] =
2111
	{ "default", "prefer", "bind", "interleave", "local" };
2112

2113 2114 2115 2116 2117

#ifdef CONFIG_TMPFS
/**
 * mpol_parse_str - parse string to mempolicy
 * @str:  string containing mempolicy to parse
2118 2119
 * @mpol:  pointer to struct mempolicy pointer, returned on success.
 * @no_context:  flag whether to "contextualize" the mempolicy
2120 2121 2122 2123
 *
 * Format of input:
 *	<mode>[=<flags>][:<nodelist>]
 *
2124 2125 2126 2127 2128 2129 2130 2131
 * if @no_context is true, save the input nodemask in w.user_nodemask in
 * the returned mempolicy.  This will be used to "clone" the mempolicy in
 * a specific context [cpuset] at a later time.  Used to parse tmpfs mpol
 * mount option.  Note that if 'static' or 'relative' mode flags were
 * specified, the input nodemask will already have been saved.  Saving
 * it again is redundant, but safe.
 *
 * On success, returns 0, else 1
2132
 */
2133
int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context)
2134
{
2135 2136 2137 2138
	struct mempolicy *new = NULL;
	unsigned short uninitialized_var(mode);
	unsigned short uninitialized_var(mode_flags);
	nodemask_t nodes;
2139 2140 2141 2142 2143 2144 2145 2146
	char *nodelist = strchr(str, ':');
	char *flags = strchr(str, '=');
	int i;
	int err = 1;

	if (nodelist) {
		/* NUL-terminate mode or flags string */
		*nodelist++ = '\0';
2147
		if (nodelist_parse(nodelist, nodes))
2148
			goto out;
2149
		if (!nodes_subset(nodes, node_states[N_HIGH_MEMORY]))
2150
			goto out;
2151 2152 2153
	} else
		nodes_clear(nodes);

2154 2155 2156
	if (flags)
		*flags++ = '\0';	/* terminate mode string */

2157
	for (i = 0; i <= MPOL_LOCAL; i++) {
2158
		if (!strcmp(str, policy_types[i])) {
2159
			mode = i;
2160 2161 2162
			break;
		}
	}
2163
	if (i > MPOL_LOCAL)
2164 2165
		goto out;

2166
	switch (mode) {
2167
	case MPOL_PREFERRED:
2168 2169 2170
		/*
		 * Insist on a nodelist of one node only
		 */
2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183
		if (nodelist) {
			char *rest = nodelist;
			while (isdigit(*rest))
				rest++;
			if (!*rest)
				err = 0;
		}
		break;
	case MPOL_INTERLEAVE:
		/*
		 * Default to online nodes with memory if no nodelist
		 */
		if (!nodelist)
2184
			nodes = node_states[N_HIGH_MEMORY];
2185
		err = 0;
2186
		break;
2187
	case MPOL_LOCAL:
2188
		/*
2189
		 * Don't allow a nodelist;  mpol_new() checks flags
2190
		 */
2191
		if (nodelist)
2192
			goto out;
2193
		mode = MPOL_PREFERRED;
2194
		break;
2195 2196 2197 2198 2199

	/*
	 * case MPOL_BIND:    mpol_new() enforces non-empty nodemask.
	 * case MPOL_DEFAULT: mpol_new() enforces empty nodemask, ignores flags.
	 */
2200 2201
	}

2202
	mode_flags = 0;
2203 2204 2205 2206 2207 2208
	if (flags) {
		/*
		 * Currently, we only support two mutually exclusive
		 * mode flags.
		 */
		if (!strcmp(flags, "static"))
2209
			mode_flags |= MPOL_F_STATIC_NODES;
2210
		else if (!strcmp(flags, "relative"))
2211
			mode_flags |= MPOL_F_RELATIVE_NODES;
2212 2213 2214
		else
			err = 1;
	}
2215 2216 2217 2218

	new = mpol_new(mode, mode_flags, &nodes);
	if (IS_ERR(new))
		err = 1;
2219 2220
	else {
		int ret;
2221 2222 2223 2224 2225 2226 2227 2228 2229
		NODEMASK_SCRATCH(scratch);
		if (scratch) {
			task_lock(current);
			ret = mpol_set_nodemask(new, &nodes, scratch);
			task_unlock(current);
		} else
			ret = -ENOMEM;
		NODEMASK_SCRATCH_FREE(scratch);
		if (ret) {
2230
			err = 1;
2231 2232
			mpol_put(new);
		} else if (no_context) {
2233 2234 2235 2236
			/* save for contextualization */
			new->w.user_nodemask = nodes;
		}
	}
2237

2238 2239 2240 2241 2242 2243
out:
	/* Restore string for error message */
	if (nodelist)
		*--nodelist = ':';
	if (flags)
		*--flags = '=';
2244 2245
	if (!err)
		*mpol = new;
2246 2247 2248 2249
	return err;
}
#endif /* CONFIG_TMPFS */

2250 2251 2252 2253 2254 2255 2256
/**
 * mpol_to_str - format a mempolicy structure for printing
 * @buffer:  to contain formatted mempolicy string
 * @maxlen:  length of @buffer
 * @pol:  pointer to mempolicy to be formatted
 * @no_context:  "context free" mempolicy - use nodemask in w.user_nodemask
 *
2257 2258 2259 2260
 * Convert a mempolicy into a string.
 * Returns the number of characters in buffer (if positive)
 * or an error (negative)
 */
2261
int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol, int no_context)
2262 2263 2264 2265
{
	char *p = buffer;
	int l;
	nodemask_t nodes;
2266
	unsigned short mode;
2267
	unsigned short flags = pol ? pol->flags : 0;
2268

2269 2270 2271 2272 2273
	/*
	 * Sanity check:  room for longest mode, flag and some nodes
	 */
	VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);

2274 2275 2276 2277 2278
	if (!pol || pol == &default_policy)
		mode = MPOL_DEFAULT;
	else
		mode = pol->mode;

2279 2280 2281 2282 2283 2284 2285
	switch (mode) {
	case MPOL_DEFAULT:
		nodes_clear(nodes);
		break;

	case MPOL_PREFERRED:
		nodes_clear(nodes);
2286
		if (flags & MPOL_F_LOCAL)
2287 2288
			mode = MPOL_LOCAL;	/* pseudo-policy */
		else
2289
			node_set(pol->v.preferred_node, nodes);
2290 2291 2292
		break;

	case MPOL_BIND:
2293
		/* Fall through */
2294
	case MPOL_INTERLEAVE:
2295 2296 2297 2298
		if (no_context)
			nodes = pol->w.user_nodemask;
		else
			nodes = pol->v.nodes;
2299 2300 2301 2302 2303 2304 2305
		break;

	default:
		BUG();
	}

	l = strlen(policy_types[mode]);
2306 2307
	if (buffer + maxlen < p + l + 1)
		return -ENOSPC;
2308 2309 2310 2311

	strcpy(p, policy_types[mode]);
	p += l;

2312
	if (flags & MPOL_MODE_FLAGS) {
2313 2314 2315 2316
		if (buffer + maxlen < p + 2)
			return -ENOSPC;
		*p++ = '=';

2317 2318 2319
		/*
		 * Currently, the only defined flags are mutually exclusive
		 */
2320
		if (flags & MPOL_F_STATIC_NODES)
2321 2322 2323
			p += snprintf(p, buffer + maxlen - p, "static");
		else if (flags & MPOL_F_RELATIVE_NODES)
			p += snprintf(p, buffer + maxlen - p, "relative");
2324 2325
	}

2326 2327 2328
	if (!nodes_empty(nodes)) {
		if (buffer + maxlen < p + 2)
			return -ENOSPC;
2329
		*p++ = ':';
2330 2331 2332 2333 2334 2335 2336 2337
	 	p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);
	}
	return p - buffer;
}

struct numa_maps {
	unsigned long pages;
	unsigned long anon;
C
Christoph Lameter 已提交
2338 2339
	unsigned long active;
	unsigned long writeback;
2340
	unsigned long mapcount_max;
C
Christoph Lameter 已提交
2341 2342
	unsigned long dirty;
	unsigned long swapcache;
2343 2344 2345
	unsigned long node[MAX_NUMNODES];
};

C
Christoph Lameter 已提交
2346
static void gather_stats(struct page *page, void *private, int pte_dirty)
2347 2348 2349 2350
{
	struct numa_maps *md = private;
	int count = page_mapcount(page);

C
Christoph Lameter 已提交
2351 2352 2353
	md->pages++;
	if (pte_dirty || PageDirty(page))
		md->dirty++;
2354

C
Christoph Lameter 已提交
2355 2356
	if (PageSwapCache(page))
		md->swapcache++;
2357

L
Lee Schermerhorn 已提交
2358
	if (PageActive(page) || PageUnevictable(page))
C
Christoph Lameter 已提交
2359 2360 2361 2362
		md->active++;

	if (PageWriteback(page))
		md->writeback++;
2363 2364 2365 2366

	if (PageAnon(page))
		md->anon++;

C
Christoph Lameter 已提交
2367 2368 2369
	if (count > md->mapcount_max)
		md->mapcount_max = count;

2370 2371 2372
	md->node[page_to_nid(page)]++;
}

A
Andrew Morton 已提交
2373
#ifdef CONFIG_HUGETLB_PAGE
C
Christoph Lameter 已提交
2374 2375 2376 2377 2378 2379
static void check_huge_range(struct vm_area_struct *vma,
		unsigned long start, unsigned long end,
		struct numa_maps *md)
{
	unsigned long addr;
	struct page *page;
2380 2381
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
C
Christoph Lameter 已提交
2382

2383 2384 2385
	for (addr = start; addr < end; addr += sz) {
		pte_t *ptep = huge_pte_offset(vma->vm_mm,
						addr & huge_page_mask(h));
C
Christoph Lameter 已提交
2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401
		pte_t pte;

		if (!ptep)
			continue;

		pte = *ptep;
		if (pte_none(pte))
			continue;

		page = pte_page(pte);
		if (!page)
			continue;

		gather_stats(page, md, pte_dirty(*ptep));
	}
}
A
Andrew Morton 已提交
2402 2403 2404 2405 2406 2407 2408
#else
static inline void check_huge_range(struct vm_area_struct *vma,
		unsigned long start, unsigned long end,
		struct numa_maps *md)
{
}
#endif
C
Christoph Lameter 已提交
2409

2410 2411 2412
/*
 * Display pages allocated per node and memory policy via /proc.
 */
2413 2414
int show_numa_map(struct seq_file *m, void *v)
{
2415
	struct proc_maps_private *priv = m->private;
2416 2417
	struct vm_area_struct *vma = v;
	struct numa_maps *md;
C
Christoph Lameter 已提交
2418 2419
	struct file *file = vma->vm_file;
	struct mm_struct *mm = vma->vm_mm;
2420
	struct mempolicy *pol;
2421 2422 2423
	int n;
	char buffer[50];

C
Christoph Lameter 已提交
2424
	if (!mm)
2425 2426 2427 2428 2429 2430
		return 0;

	md = kzalloc(sizeof(struct numa_maps), GFP_KERNEL);
	if (!md)
		return 0;

2431
	pol = get_vma_policy(priv->task, vma, vma->vm_start);
2432
	mpol_to_str(buffer, sizeof(buffer), pol, 0);
2433
	mpol_cond_put(pol);
C
Christoph Lameter 已提交
2434 2435 2436 2437 2438

	seq_printf(m, "%08lx %s", vma->vm_start, buffer);

	if (file) {
		seq_printf(m, " file=");
2439
		seq_path(m, &file->f_path, "\n\t= ");
C
Christoph Lameter 已提交
2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450
	} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
		seq_printf(m, " heap");
	} else if (vma->vm_start <= mm->start_stack &&
			vma->vm_end >= mm->start_stack) {
		seq_printf(m, " stack");
	}

	if (is_vm_hugetlb_page(vma)) {
		check_huge_range(vma, vma->vm_start, vma->vm_end, md);
		seq_printf(m, " huge");
	} else {
2451
		check_pgd_range(vma, vma->vm_start, vma->vm_end,
2452
			&node_states[N_HIGH_MEMORY], MPOL_MF_STATS, md);
C
Christoph Lameter 已提交
2453 2454 2455 2456
	}

	if (!md->pages)
		goto out;
2457

C
Christoph Lameter 已提交
2458 2459
	if (md->anon)
		seq_printf(m," anon=%lu",md->anon);
2460

C
Christoph Lameter 已提交
2461 2462
	if (md->dirty)
		seq_printf(m," dirty=%lu",md->dirty);
2463

C
Christoph Lameter 已提交
2464 2465
	if (md->pages != md->anon && md->pages != md->dirty)
		seq_printf(m, " mapped=%lu", md->pages);
2466

C
Christoph Lameter 已提交
2467 2468
	if (md->mapcount_max > 1)
		seq_printf(m, " mapmax=%lu", md->mapcount_max);
2469

C
Christoph Lameter 已提交
2470 2471 2472 2473 2474 2475 2476 2477 2478
	if (md->swapcache)
		seq_printf(m," swapcache=%lu", md->swapcache);

	if (md->active < md->pages && !is_vm_hugetlb_page(vma))
		seq_printf(m," active=%lu", md->active);

	if (md->writeback)
		seq_printf(m," writeback=%lu", md->writeback);

2479
	for_each_node_state(n, N_HIGH_MEMORY)
C
Christoph Lameter 已提交
2480 2481 2482 2483
		if (md->node[n])
			seq_printf(m, " N%d=%lu", n, md->node[n]);
out:
	seq_putc(m, '\n');
2484 2485 2486
	kfree(md);

	if (m->count < m->size)
2487
		m->version = (vma != priv->tail_vma) ? vma->vm_start : 0;
2488 2489
	return 0;
}