mempolicy.c 71.4 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/slab.h>
#include <linux/string.h>
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#include <linux/export.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/ksm.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 <linux/mmu_notifier.h>
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#include <asm/tlbflush.h>
#include <asm/uaccess.h>
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#include <linux/random.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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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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static 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 struct mempolicy preferred_node_policy[MAX_NUMNODES];

static struct mempolicy *get_task_policy(struct task_struct *p)
{
	struct mempolicy *pol = p->mempolicy;
	int node;

	if (!pol) {
		node = numa_node_id();
		if (node != -1)
			pol = &preferred_node_policy[node];

		/* preferred_node_policy is not initialised early in boot */
		if (!pol->mode)
			pol = NULL;
	}

	return pol;
}

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static const struct mempolicy_operations {
	int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
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	/*
	 * If read-side task has no lock to protect task->mempolicy, write-side
	 * task will rebind the task->mempolicy by two step. The first step is
	 * setting all the newly nodes, and the second step is cleaning all the
	 * disallowed nodes. In this way, we can avoid finding no node to alloc
	 * page.
	 * If we have a lock to protect task->mempolicy in read-side, we do
	 * rebind directly.
	 *
	 * step:
	 * 	MPOL_REBIND_ONCE - do rebind work at once
	 * 	MPOL_REBIND_STEP1 - set all the newly nodes
	 * 	MPOL_REBIND_STEP2 - clean all the disallowed nodes
	 */
	void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes,
			enum mpol_rebind_step step);
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} 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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	return nodes_intersects(*nodemask, node_states[N_MEMORY]);
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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_MODE_FLAGS;
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}

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_MEMORY */
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	nodes_and(nsc->mask1,
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		  cpuset_current_mems_allowed, node_states[N_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;
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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);
		}
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	} else if (mode == MPOL_LOCAL) {
		if (!nodes_empty(*nodes))
			return ERR_PTR(-EINVAL);
		mode = MPOL_PREFERRED;
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	} 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,
				enum mpol_rebind_step step)
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{
}

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/*
 * step:
 * 	MPOL_REBIND_ONCE  - do rebind work at once
 * 	MPOL_REBIND_STEP1 - set all the newly nodes
 * 	MPOL_REBIND_STEP2 - clean all the disallowed nodes
 */
static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes,
				 enum mpol_rebind_step step)
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{
	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 {
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		/*
		 * if step == 1, we use ->w.cpuset_mems_allowed to cache the
		 * result
		 */
		if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP1) {
			nodes_remap(tmp, pol->v.nodes,
					pol->w.cpuset_mems_allowed, *nodes);
			pol->w.cpuset_mems_allowed = step ? tmp : *nodes;
		} else if (step == MPOL_REBIND_STEP2) {
			tmp = pol->w.cpuset_mems_allowed;
			pol->w.cpuset_mems_allowed = *nodes;
		} else
			BUG();
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	}
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	if (nodes_empty(tmp))
		tmp = *nodes;

	if (step == MPOL_REBIND_STEP1)
		nodes_or(pol->v.nodes, pol->v.nodes, tmp);
	else if (step == MPOL_REBIND_ONCE || step == MPOL_REBIND_STEP2)
		pol->v.nodes = tmp;
	else
		BUG();

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	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,
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				  const nodemask_t *nodes,
				  enum mpol_rebind_step step)
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{
	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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/*
 * mpol_rebind_policy - Migrate a policy to a different set of nodes
 *
 * If read-side task has no lock to protect task->mempolicy, write-side
 * task will rebind the task->mempolicy by two step. The first step is
 * setting all the newly nodes, and the second step is cleaning all the
 * disallowed nodes. In this way, we can avoid finding no node to alloc
 * page.
 * If we have a lock to protect task->mempolicy in read-side, we do
 * rebind directly.
 *
 * step:
 * 	MPOL_REBIND_ONCE  - do rebind work at once
 * 	MPOL_REBIND_STEP1 - set all the newly nodes
 * 	MPOL_REBIND_STEP2 - clean all the disallowed nodes
 */
static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask,
				enum mpol_rebind_step step)
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{
	if (!pol)
		return;
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	if (!mpol_store_user_nodemask(pol) && step == MPOL_REBIND_ONCE &&
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	    nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
		return;
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	if (step == MPOL_REBIND_STEP1 && (pol->flags & MPOL_F_REBINDING))
		return;

	if (step == MPOL_REBIND_STEP2 && !(pol->flags & MPOL_F_REBINDING))
		BUG();

	if (step == MPOL_REBIND_STEP1)
		pol->flags |= MPOL_F_REBINDING;
	else if (step == MPOL_REBIND_STEP2)
		pol->flags &= ~MPOL_F_REBINDING;
	else if (step >= MPOL_REBIND_NSTEP)
		BUG();

	mpol_ops[pol->mode].rebind(pol, newmask, step);
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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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 */

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

/*
 * 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)
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		mpol_rebind_policy(vma->vm_policy, new, MPOL_REBIND_ONCE);
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	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 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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		/*
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		 * vm_normal_page() filters out zero pages, but there might
		 * still be PageReserved pages to skip, perhaps in a VDSO.
		 * And we cannot move PageKsm pages sensibly or safely yet.
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		 */
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		if (PageReserved(page) || PageKsm(page))
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			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_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);
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		split_huge_page_pmd(vma, addr, pmd);
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		if (pmd_none_or_trans_huge_or_clear_bad(pmd))
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			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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#ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE
/*
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 * This is used to mark a range of virtual addresses to be inaccessible.
 * These are later cleared by a NUMA hinting fault. Depending on these
 * faults, pages may be migrated for better NUMA placement.
 *
 * This is assuming that NUMA faults are handled using PROT_NONE. If
 * an architecture makes a different choice, it will need further
 * changes to the core.
L
Lee Schermerhorn 已提交
586
 */
587 588
unsigned long change_prot_numa(struct vm_area_struct *vma,
			unsigned long addr, unsigned long end)
L
Lee Schermerhorn 已提交
589
{
590 591
	int nr_updated;
	BUILD_BUG_ON(_PAGE_NUMA != _PAGE_PROTNONE);
L
Lee Schermerhorn 已提交
592

593
	nr_updated = change_protection(vma, addr, end, vma->vm_page_prot, 0, 1);
594 595
	if (nr_updated)
		count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
L
Lee Schermerhorn 已提交
596

597
	return nr_updated;
L
Lee Schermerhorn 已提交
598 599 600 601 602 603 604 605 606
}
#else
static unsigned long change_prot_numa(struct vm_area_struct *vma,
			unsigned long addr, unsigned long end)
{
	return 0;
}
#endif /* CONFIG_ARCH_USES_NUMA_PROT_NONE */

607 608 609 610 611
/*
 * 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.
 */
L
Linus Torvalds 已提交
612 613
static struct vm_area_struct *
check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
614
		const nodemask_t *nodes, unsigned long flags, void *private)
L
Linus Torvalds 已提交
615 616 617 618
{
	int err;
	struct vm_area_struct *first, *vma, *prev;

619

L
Linus Torvalds 已提交
620 621 622 623 624
	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) {
L
Lee Schermerhorn 已提交
625 626 627 628 629 630 631
		unsigned long endvma = vma->vm_end;

		if (endvma > end)
			endvma = end;
		if (vma->vm_start > start)
			start = vma->vm_start;

632 633 634 635 636 637
		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);
		}
L
Lee Schermerhorn 已提交
638 639 640 641 642 643 644 645 646 647

		if (is_vm_hugetlb_page(vma))
			goto next;

		if (flags & MPOL_MF_LAZY) {
			change_prot_numa(vma, start, endvma);
			goto next;
		}

		if ((flags & MPOL_MF_STRICT) ||
648
		     ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
L
Lee Schermerhorn 已提交
649
		      vma_migratable(vma))) {
650 651

			err = check_pgd_range(vma, start, endvma, nodes,
652
						flags, private);
L
Linus Torvalds 已提交
653 654 655 656 657
			if (err) {
				first = ERR_PTR(err);
				break;
			}
		}
L
Lee Schermerhorn 已提交
658
next:
L
Linus Torvalds 已提交
659 660 661 662 663
		prev = vma;
	}
	return first;
}

664 665 666 667 668 669
/*
 * Apply policy to a single VMA
 * This must be called with the mmap_sem held for writing.
 */
static int vma_replace_policy(struct vm_area_struct *vma,
						struct mempolicy *pol)
670
{
671 672 673
	int err;
	struct mempolicy *old;
	struct mempolicy *new;
674 675 676 677 678 679

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

680 681 682 683 684
	new = mpol_dup(pol);
	if (IS_ERR(new))
		return PTR_ERR(new);

	if (vma->vm_ops && vma->vm_ops->set_policy) {
685
		err = vma->vm_ops->set_policy(vma, new);
686 687
		if (err)
			goto err_out;
688
	}
689 690 691 692 693 694 695 696

	old = vma->vm_policy;
	vma->vm_policy = new; /* protected by mmap_sem */
	mpol_put(old);

	return 0;
 err_out:
	mpol_put(new);
697 698 699
	return err;
}

L
Linus Torvalds 已提交
700
/* Step 2: apply policy to a range and do splits. */
701 702
static int mbind_range(struct mm_struct *mm, unsigned long start,
		       unsigned long end, struct mempolicy *new_pol)
L
Linus Torvalds 已提交
703 704
{
	struct vm_area_struct *next;
705 706 707
	struct vm_area_struct *prev;
	struct vm_area_struct *vma;
	int err = 0;
708
	pgoff_t pgoff;
709 710
	unsigned long vmstart;
	unsigned long vmend;
L
Linus Torvalds 已提交
711

712
	vma = find_vma(mm, start);
713 714 715
	if (!vma || vma->vm_start > start)
		return -EFAULT;

716
	prev = vma->vm_prev;
717 718 719
	if (start > vma->vm_start)
		prev = vma;

720
	for (; vma && vma->vm_start < end; prev = vma, vma = next) {
L
Linus Torvalds 已提交
721
		next = vma->vm_next;
722 723 724
		vmstart = max(start, vma->vm_start);
		vmend   = min(end, vma->vm_end);

725 726 727 728 729
		if (mpol_equal(vma_policy(vma), new_pol))
			continue;

		pgoff = vma->vm_pgoff +
			((vmstart - vma->vm_start) >> PAGE_SHIFT);
730
		prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
731
				  vma->anon_vma, vma->vm_file, pgoff,
732
				  new_pol);
733 734 735 736 737 738 739 740 741 742 743 744 745 746 747
		if (prev) {
			vma = prev;
			next = vma->vm_next;
			continue;
		}
		if (vma->vm_start != vmstart) {
			err = split_vma(vma->vm_mm, vma, vmstart, 1);
			if (err)
				goto out;
		}
		if (vma->vm_end != vmend) {
			err = split_vma(vma->vm_mm, vma, vmend, 0);
			if (err)
				goto out;
		}
748
		err = vma_replace_policy(vma, new_pol);
749 750
		if (err)
			goto out;
L
Linus Torvalds 已提交
751
	}
752 753

 out:
L
Linus Torvalds 已提交
754 755 756
	return err;
}

757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786
/*
 * 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
787
/* Set the process memory policy */
788 789
static long do_set_mempolicy(unsigned short mode, unsigned short flags,
			     nodemask_t *nodes)
L
Linus Torvalds 已提交
790
{
791
	struct mempolicy *new, *old;
792
	struct mm_struct *mm = current->mm;
793
	NODEMASK_SCRATCH(scratch);
794
	int ret;
L
Linus Torvalds 已提交
795

796 797
	if (!scratch)
		return -ENOMEM;
798

799 800 801 802 803
	new = mpol_new(mode, flags, nodes);
	if (IS_ERR(new)) {
		ret = PTR_ERR(new);
		goto out;
	}
804 805 806 807 808 809 810 811
	/*
	 * 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);
812
	task_lock(current);
813
	ret = mpol_set_nodemask(new, nodes, scratch);
814 815 816 817 818
	if (ret) {
		task_unlock(current);
		if (mm)
			up_write(&mm->mmap_sem);
		mpol_put(new);
819
		goto out;
820 821
	}
	old = current->mempolicy;
L
Linus Torvalds 已提交
822
	current->mempolicy = new;
823
	mpol_set_task_struct_flag();
824
	if (new && new->mode == MPOL_INTERLEAVE &&
825
	    nodes_weight(new->v.nodes))
826
		current->il_next = first_node(new->v.nodes);
827
	task_unlock(current);
828 829 830
	if (mm)
		up_write(&mm->mmap_sem);

831
	mpol_put(old);
832 833 834 835
	ret = 0;
out:
	NODEMASK_SCRATCH_FREE(scratch);
	return ret;
L
Linus Torvalds 已提交
836 837
}

838 839
/*
 * Return nodemask for policy for get_mempolicy() query
840 841
 *
 * Called with task's alloc_lock held
842 843
 */
static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
L
Linus Torvalds 已提交
844
{
845
	nodes_clear(*nodes);
846 847 848
	if (p == &default_policy)
		return;

849
	switch (p->mode) {
850 851
	case MPOL_BIND:
		/* Fall through */
L
Linus Torvalds 已提交
852
	case MPOL_INTERLEAVE:
853
		*nodes = p->v.nodes;
L
Linus Torvalds 已提交
854 855
		break;
	case MPOL_PREFERRED:
856
		if (!(p->flags & MPOL_F_LOCAL))
857
			node_set(p->v.preferred_node, *nodes);
858
		/* else return empty node mask for local allocation */
L
Linus Torvalds 已提交
859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878
		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
879 880
static long do_get_mempolicy(int *policy, nodemask_t *nmask,
			     unsigned long addr, unsigned long flags)
L
Linus Torvalds 已提交
881
{
882
	int err;
L
Linus Torvalds 已提交
883 884 885 886
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma = NULL;
	struct mempolicy *pol = current->mempolicy;

887 888
	if (flags &
		~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
L
Linus Torvalds 已提交
889
		return -EINVAL;
890 891 892 893 894

	if (flags & MPOL_F_MEMS_ALLOWED) {
		if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
			return -EINVAL;
		*policy = 0;	/* just so it's initialized */
895
		task_lock(current);
896
		*nmask  = cpuset_current_mems_allowed;
897
		task_unlock(current);
898 899 900
		return 0;
	}

L
Linus Torvalds 已提交
901
	if (flags & MPOL_F_ADDR) {
902 903 904 905 906
		/*
		 * 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
907 908 909 910 911 912 913 914 915 916 917 918 919 920
		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)
921
		pol = &default_policy;	/* indicates default behavior */
L
Linus Torvalds 已提交
922 923 924 925 926 927

	if (flags & MPOL_F_NODE) {
		if (flags & MPOL_F_ADDR) {
			err = lookup_node(mm, addr);
			if (err < 0)
				goto out;
928
			*policy = err;
L
Linus Torvalds 已提交
929
		} else if (pol == current->mempolicy &&
930
				pol->mode == MPOL_INTERLEAVE) {
931
			*policy = current->il_next;
L
Linus Torvalds 已提交
932 933 934 935
		} else {
			err = -EINVAL;
			goto out;
		}
936 937 938
	} else {
		*policy = pol == &default_policy ? MPOL_DEFAULT :
						pol->mode;
939 940 941 942 943
		/*
		 * Internal mempolicy flags must be masked off before exposing
		 * the policy to userspace.
		 */
		*policy |= (pol->flags & MPOL_MODE_FLAGS);
944
	}
L
Linus Torvalds 已提交
945 946 947 948 949 950 951

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

	err = 0;
952
	if (nmask) {
953 954 955 956 957 958 959
		if (mpol_store_user_nodemask(pol)) {
			*nmask = pol->w.user_nodemask;
		} else {
			task_lock(current);
			get_policy_nodemask(pol, nmask);
			task_unlock(current);
		}
960
	}
L
Linus Torvalds 已提交
961 962

 out:
963
	mpol_cond_put(pol);
L
Linus Torvalds 已提交
964 965 966 967 968
	if (vma)
		up_read(&current->mm->mmap_sem);
	return err;
}

C
Christoph Lameter 已提交
969
#ifdef CONFIG_MIGRATION
970 971 972
/*
 * page migration
 */
973 974
static void migrate_page_add(struct page *page, struct list_head *pagelist,
				unsigned long flags)
975 976
{
	/*
977
	 * Avoid migrating a page that is shared with others.
978
	 */
979 980 981
	if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
		if (!isolate_lru_page(page)) {
			list_add_tail(&page->lru, pagelist);
982 983
			inc_zone_page_state(page, NR_ISOLATED_ANON +
					    page_is_file_cache(page));
984 985
		}
	}
986
}
987

988
static struct page *new_node_page(struct page *page, unsigned long node, int **x)
989
{
990
	return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
991 992
}

993 994 995 996
/*
 * Migrate pages from one node to a target node.
 * Returns error or the number of pages not migrated.
 */
A
Adrian Bunk 已提交
997 998
static int migrate_to_node(struct mm_struct *mm, int source, int dest,
			   int flags)
999 1000 1001 1002 1003 1004 1005
{
	nodemask_t nmask;
	LIST_HEAD(pagelist);
	int err = 0;

	nodes_clear(nmask);
	node_set(source, nmask);
1006

1007 1008 1009 1010 1011 1012 1013
	/*
	 * This does not "check" the range but isolates all pages that
	 * need migration.  Between passing in the full user address
	 * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
	 */
	VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
	check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1014 1015
			flags | MPOL_MF_DISCONTIG_OK, &pagelist);

1016
	if (!list_empty(&pagelist)) {
1017
		err = migrate_pages(&pagelist, new_node_page, dest,
1018 1019
							false, MIGRATE_SYNC,
							MR_SYSCALL);
1020 1021 1022
		if (err)
			putback_lru_pages(&pagelist);
	}
1023

1024
	return err;
1025 1026
}

1027
/*
1028 1029
 * Move pages between the two nodesets so as to preserve the physical
 * layout as much as possible.
1030 1031 1032
 *
 * Returns the number of page that could not be moved.
 */
1033 1034
int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
		     const nodemask_t *to, int flags)
1035
{
1036
	int busy = 0;
1037
	int err;
1038
	nodemask_t tmp;
1039

1040 1041 1042 1043
	err = migrate_prep();
	if (err)
		return err;

1044
	down_read(&mm->mmap_sem);
1045

1046
	err = migrate_vmas(mm, from, to, flags);
1047 1048 1049
	if (err)
		goto out;

1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074
	/*
	 * 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.
1075
	 * Otherwise when we finish scanning from_tmp, we at least have the
1076 1077 1078 1079
	 * 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.
	 */
1080

1081
	tmp = *from;
1082 1083 1084 1085 1086 1087
	while (!nodes_empty(tmp)) {
		int s,d;
		int source = -1;
		int dest = 0;

		for_each_node_mask(s, tmp) {
1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103

			/*
			 * do_migrate_pages() tries to maintain the relative
			 * node relationship of the pages established between
			 * threads and memory areas.
                         *
			 * However if the number of source nodes is not equal to
			 * the number of destination nodes we can not preserve
			 * this node relative relationship.  In that case, skip
			 * copying memory from a node that is in the destination
			 * mask.
			 *
			 * Example: [2,3,4] -> [3,4,5] moves everything.
			 *          [0-7] - > [3,4,5] moves only 0,1,2,6,7.
			 */

1104 1105
			if ((nodes_weight(*from) != nodes_weight(*to)) &&
						(node_isset(s, *to)))
1106 1107
				continue;

1108
			d = node_remap(s, *from, *to);
1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127
			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;
1128
	}
1129
out:
1130
	up_read(&mm->mmap_sem);
1131 1132 1133
	if (err < 0)
		return err;
	return busy;
C
Christoph Lameter 已提交
1134 1135 1136

}

1137 1138 1139 1140 1141 1142 1143
/*
 * 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.
 */
1144
static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1145 1146
{
	struct vm_area_struct *vma = (struct vm_area_struct *)private;
1147
	unsigned long uninitialized_var(address);
1148

1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159
	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);
1160
}
C
Christoph Lameter 已提交
1161 1162 1163 1164 1165
#else

static void migrate_page_add(struct page *page, struct list_head *pagelist,
				unsigned long flags)
{
1166 1167
}

1168 1169
int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
		     const nodemask_t *to, int flags)
C
Christoph Lameter 已提交
1170 1171 1172
{
	return -ENOSYS;
}
1173

1174
static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1175 1176 1177
{
	return NULL;
}
C
Christoph Lameter 已提交
1178 1179
#endif

A
Adrian Bunk 已提交
1180
static long do_mbind(unsigned long start, unsigned long len,
1181 1182
		     unsigned short mode, unsigned short mode_flags,
		     nodemask_t *nmask, unsigned long flags)
1183 1184 1185 1186 1187 1188 1189 1190
{
	struct vm_area_struct *vma;
	struct mm_struct *mm = current->mm;
	struct mempolicy *new;
	unsigned long end;
	int err;
	LIST_HEAD(pagelist);

L
Lee Schermerhorn 已提交
1191
	if (flags & ~(unsigned long)MPOL_MF_VALID)
1192
		return -EINVAL;
1193
	if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209
		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;

1210
	new = mpol_new(mode, mode_flags, nmask);
1211 1212 1213
	if (IS_ERR(new))
		return PTR_ERR(new);

L
Lee Schermerhorn 已提交
1214 1215 1216
	if (flags & MPOL_MF_LAZY)
		new->flags |= MPOL_F_MOF;

1217 1218 1219 1220 1221 1222 1223
	/*
	 * If we are using the default policy then operation
	 * on discontinuous address spaces is okay after all
	 */
	if (!new)
		flags |= MPOL_MF_DISCONTIG_OK;

1224 1225 1226
	pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
		 start, start + len, mode, mode_flags,
		 nmask ? nodes_addr(*nmask)[0] : -1);
1227

1228 1229 1230 1231
	if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {

		err = migrate_prep();
		if (err)
K
KOSAKI Motohiro 已提交
1232
			goto mpol_out;
1233
	}
1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246
	{
		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
1247 1248 1249
	if (err)
		goto mpol_out;

1250 1251 1252
	vma = check_range(mm, start, end, nmask,
			  flags | MPOL_MF_INVERT, &pagelist);

L
Lee Schermerhorn 已提交
1253
	err = PTR_ERR(vma);	/* maybe ... */
1254
	if (!IS_ERR(vma))
1255
		err = mbind_range(mm, start, end, new);
1256

L
Lee Schermerhorn 已提交
1257 1258 1259
	if (!err) {
		int nr_failed = 0;

1260
		if (!list_empty(&pagelist)) {
L
Lee Schermerhorn 已提交
1261
			WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1262
			nr_failed = migrate_pages(&pagelist, new_vma_page,
1263
						(unsigned long)vma,
1264 1265
						false, MIGRATE_SYNC,
						MR_MEMPOLICY_MBIND);
1266 1267 1268
			if (nr_failed)
				putback_lru_pages(&pagelist);
		}
1269

L
Lee Schermerhorn 已提交
1270
		if (nr_failed && (flags & MPOL_MF_STRICT))
1271
			err = -EIO;
1272 1273
	} else
		putback_lru_pages(&pagelist);
C
Christoph Lameter 已提交
1274

1275
	up_write(&mm->mmap_sem);
K
KOSAKI Motohiro 已提交
1276
 mpol_out:
1277
	mpol_put(new);
1278 1279 1280
	return err;
}

1281 1282 1283 1284 1285
/*
 * User space interface with variable sized bitmaps for nodelists.
 */

/* Copy a node mask from user space. */
1286
static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1287 1288 1289 1290 1291 1292 1293 1294 1295 1296
		     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
1297
	if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
C
Chris Wright 已提交
1298
		return -EINVAL;
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 1340 1341 1342 1343 1344 1345 1346 1347

	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;
}

1348 1349 1350
SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
		unsigned long, mode, unsigned long __user *, nmask,
		unsigned long, maxnode, unsigned, flags)
1351 1352 1353
{
	nodemask_t nodes;
	int err;
1354
	unsigned short mode_flags;
1355

1356 1357
	mode_flags = mode & MPOL_MODE_FLAGS;
	mode &= ~MPOL_MODE_FLAGS;
1358 1359
	if (mode >= MPOL_MAX)
		return -EINVAL;
1360 1361 1362
	if ((mode_flags & MPOL_F_STATIC_NODES) &&
	    (mode_flags & MPOL_F_RELATIVE_NODES))
		return -EINVAL;
1363 1364 1365
	err = get_nodes(&nodes, nmask, maxnode);
	if (err)
		return err;
1366
	return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1367 1368 1369
}

/* Set the process memory policy */
1370 1371
SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
		unsigned long, maxnode)
1372 1373 1374
{
	int err;
	nodemask_t nodes;
1375
	unsigned short flags;
1376

1377 1378 1379
	flags = mode & MPOL_MODE_FLAGS;
	mode &= ~MPOL_MODE_FLAGS;
	if ((unsigned int)mode >= MPOL_MAX)
1380
		return -EINVAL;
1381 1382
	if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
		return -EINVAL;
1383 1384 1385
	err = get_nodes(&nodes, nmask, maxnode);
	if (err)
		return err;
1386
	return do_set_mempolicy(mode, flags, &nodes);
1387 1388
}

1389 1390 1391
SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
		const unsigned long __user *, old_nodes,
		const unsigned long __user *, new_nodes)
1392
{
1393
	const struct cred *cred = current_cred(), *tcred;
1394
	struct mm_struct *mm = NULL;
1395 1396 1397
	struct task_struct *task;
	nodemask_t task_nodes;
	int err;
1398 1399 1400 1401 1402 1403
	nodemask_t *old;
	nodemask_t *new;
	NODEMASK_SCRATCH(scratch);

	if (!scratch)
		return -ENOMEM;
1404

1405 1406 1407 1408
	old = &scratch->mask1;
	new = &scratch->mask2;

	err = get_nodes(old, old_nodes, maxnode);
1409
	if (err)
1410
		goto out;
1411

1412
	err = get_nodes(new, new_nodes, maxnode);
1413
	if (err)
1414
		goto out;
1415 1416

	/* Find the mm_struct */
1417
	rcu_read_lock();
1418
	task = pid ? find_task_by_vpid(pid) : current;
1419
	if (!task) {
1420
		rcu_read_unlock();
1421 1422
		err = -ESRCH;
		goto out;
1423
	}
1424
	get_task_struct(task);
1425

1426
	err = -EINVAL;
1427 1428 1429 1430

	/*
	 * 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
1431
	 * capabilities, superuser privileges or the same
1432 1433
	 * userid as the target process.
	 */
1434
	tcred = __task_cred(task);
1435 1436
	if (!uid_eq(cred->euid, tcred->suid) && !uid_eq(cred->euid, tcred->uid) &&
	    !uid_eq(cred->uid,  tcred->suid) && !uid_eq(cred->uid,  tcred->uid) &&
1437
	    !capable(CAP_SYS_NICE)) {
1438
		rcu_read_unlock();
1439
		err = -EPERM;
1440
		goto out_put;
1441
	}
1442
	rcu_read_unlock();
1443 1444 1445

	task_nodes = cpuset_mems_allowed(task);
	/* Is the user allowed to access the target nodes? */
1446
	if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1447
		err = -EPERM;
1448
		goto out_put;
1449 1450
	}

1451
	if (!nodes_subset(*new, node_states[N_MEMORY])) {
1452
		err = -EINVAL;
1453
		goto out_put;
1454 1455
	}

1456 1457
	err = security_task_movememory(task);
	if (err)
1458
		goto out_put;
1459

1460 1461
	mm = get_task_mm(task);
	put_task_struct(task);
1462 1463

	if (!mm) {
1464
		err = -EINVAL;
1465 1466 1467 1468 1469
		goto out;
	}

	err = do_migrate_pages(mm, old, new,
		capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1470 1471 1472

	mmput(mm);
out:
1473 1474
	NODEMASK_SCRATCH_FREE(scratch);

1475
	return err;
1476 1477 1478 1479 1480

out_put:
	put_task_struct(task);
	goto out;

1481 1482 1483
}


1484
/* Retrieve NUMA policy */
1485 1486 1487
SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
		unsigned long __user *, nmask, unsigned long, maxnode,
		unsigned long, addr, unsigned long, flags)
1488
{
A
Adrian Bunk 已提交
1489 1490
	int err;
	int uninitialized_var(pval);
1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509
	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
1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530
#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) {
1531 1532 1533
		unsigned long copy_size;
		copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
		err = copy_from_user(bm, nm, copy_size);
L
Linus Torvalds 已提交
1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571
		/* 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;
1572
	nodemask_t bm;
L
Linus Torvalds 已提交
1573 1574 1575 1576 1577

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

	if (nmask) {
1578
		err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
L
Linus Torvalds 已提交
1579
		nm = compat_alloc_user_space(alloc_size);
1580
		err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
L
Linus Torvalds 已提交
1581 1582 1583 1584 1585 1586 1587 1588 1589 1590
	}

	if (err)
		return -EFAULT;

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

#endif

1591 1592 1593 1594 1595 1596 1597 1598
/*
 * 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.
1599 1600
 * Current or other task's task mempolicy and non-shared vma policies must be
 * protected by task_lock(task) by the caller.
1601 1602 1603 1604
 * 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.
1605
 */
S
Stephen Wilson 已提交
1606
struct mempolicy *get_vma_policy(struct task_struct *task,
1607
		struct vm_area_struct *vma, unsigned long addr)
L
Linus Torvalds 已提交
1608
{
M
Mel Gorman 已提交
1609
	struct mempolicy *pol = get_task_policy(task);
L
Linus Torvalds 已提交
1610 1611

	if (vma) {
1612
		if (vma->vm_ops && vma->vm_ops->get_policy) {
1613 1614 1615 1616
			struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
									addr);
			if (vpol)
				pol = vpol;
1617
		} else if (vma->vm_policy) {
L
Linus Torvalds 已提交
1618
			pol = vma->vm_policy;
1619 1620 1621 1622 1623 1624 1625 1626 1627 1628

			/*
			 * shmem_alloc_page() passes MPOL_F_SHARED policy with
			 * a pseudo vma whose vma->vm_ops=NULL. Take a reference
			 * count on these policies which will be dropped by
			 * mpol_cond_put() later
			 */
			if (mpol_needs_cond_ref(pol))
				mpol_get(pol);
		}
L
Linus Torvalds 已提交
1629 1630 1631 1632 1633 1634
	}
	if (!pol)
		pol = &default_policy;
	return pol;
}

1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
{
	enum zone_type dynamic_policy_zone = policy_zone;

	BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);

	/*
	 * if policy->v.nodes has movable memory only,
	 * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
	 *
	 * policy->v.nodes is intersect with node_states[N_MEMORY].
	 * so if the following test faile, it implies
	 * policy->v.nodes has movable memory only.
	 */
	if (!nodes_intersects(policy->v.nodes, node_states[N_HIGH_MEMORY]))
		dynamic_policy_zone = ZONE_MOVABLE;

	return zone >= dynamic_policy_zone;
}

1655 1656 1657 1658 1659
/*
 * Return a nodemask representing a mempolicy for filtering nodes for
 * page allocation
 */
static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1660 1661
{
	/* Lower zones don't get a nodemask applied for MPOL_BIND */
1662
	if (unlikely(policy->mode == MPOL_BIND) &&
1663
			apply_policy_zone(policy, gfp_zone(gfp)) &&
1664 1665 1666 1667 1668 1669
			cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
		return &policy->v.nodes;

	return NULL;
}

1670
/* Return a zonelist indicated by gfp for node representing a mempolicy */
1671 1672
static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
	int nd)
L
Linus Torvalds 已提交
1673
{
1674
	switch (policy->mode) {
L
Linus Torvalds 已提交
1675
	case MPOL_PREFERRED:
1676 1677
		if (!(policy->flags & MPOL_F_LOCAL))
			nd = policy->v.preferred_node;
L
Linus Torvalds 已提交
1678 1679
		break;
	case MPOL_BIND:
1680
		/*
1681 1682
		 * Normally, MPOL_BIND allocations are node-local within the
		 * allowed nodemask.  However, if __GFP_THISNODE is set and the
1683
		 * current node isn't part of the mask, we use the zonelist for
1684
		 * the first node in the mask instead.
1685 1686 1687 1688 1689
		 */
		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
1690 1691 1692
	default:
		BUG();
	}
1693
	return node_zonelist(nd, gfp);
L
Linus Torvalds 已提交
1694 1695 1696 1697 1698 1699 1700 1701 1702
}

/* 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;
1703
	next = next_node(nid, policy->v.nodes);
L
Linus Torvalds 已提交
1704
	if (next >= MAX_NUMNODES)
1705
		next = first_node(policy->v.nodes);
1706 1707
	if (next < MAX_NUMNODES)
		me->il_next = next;
L
Linus Torvalds 已提交
1708 1709 1710
	return nid;
}

1711 1712 1713
/*
 * Depending on the memory policy provide a node from which to allocate the
 * next slab entry.
1714 1715 1716 1717
 * @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.
1718
 */
1719
unsigned slab_node(void)
1720
{
1721 1722 1723 1724 1725 1726
	struct mempolicy *policy;

	if (in_interrupt())
		return numa_node_id();

	policy = current->mempolicy;
1727
	if (!policy || policy->flags & MPOL_F_LOCAL)
1728 1729 1730 1731
		return numa_node_id();

	switch (policy->mode) {
	case MPOL_PREFERRED:
1732 1733 1734 1735
		/*
		 * handled MPOL_F_LOCAL above
		 */
		return policy->v.preferred_node;
1736

1737 1738 1739
	case MPOL_INTERLEAVE:
		return interleave_nodes(policy);

1740
	case MPOL_BIND: {
1741 1742 1743 1744
		/*
		 * Follow bind policy behavior and start allocation at the
		 * first node.
		 */
1745 1746 1747 1748 1749 1750 1751
		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);
E
Eric Dumazet 已提交
1752
		return zone ? zone->node : numa_node_id();
1753
	}
1754 1755

	default:
1756
		BUG();
1757 1758 1759
	}
}

L
Linus Torvalds 已提交
1760 1761 1762 1763
/* 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)
{
1764
	unsigned nnodes = nodes_weight(pol->v.nodes);
1765
	unsigned target;
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1766 1767 1768
	int c;
	int nid = -1;

1769 1770 1771
	if (!nnodes)
		return numa_node_id();
	target = (unsigned int)off % nnodes;
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1772 1773
	c = 0;
	do {
1774
		nid = next_node(nid, pol->v.nodes);
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1775 1776 1777 1778 1779
		c++;
	} while (c <= target);
	return nid;
}

1780 1781 1782 1783 1784 1785 1786
/* 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;

1787 1788 1789 1790 1791 1792 1793 1794 1795
		/*
		 * 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);
1796 1797 1798 1799 1800 1801
		off += (addr - vma->vm_start) >> shift;
		return offset_il_node(pol, vma, off);
	} else
		return interleave_nodes(pol);
}

1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816
/*
 * Return the bit number of a random bit set in the nodemask.
 * (returns -1 if nodemask is empty)
 */
int node_random(const nodemask_t *maskp)
{
	int w, bit = -1;

	w = nodes_weight(*maskp);
	if (w)
		bit = bitmap_ord_to_pos(maskp->bits,
			get_random_int() % w, MAX_NUMNODES);
	return bit;
}

1817
#ifdef CONFIG_HUGETLBFS
1818 1819 1820 1821 1822
/*
 * 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
1823 1824
 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1825
 *
1826 1827 1828 1829
 * 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.
1830 1831
 *
 * Must be protected by get_mems_allowed()
1832
 */
1833
struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1834 1835
				gfp_t gfp_flags, struct mempolicy **mpol,
				nodemask_t **nodemask)
1836
{
1837
	struct zonelist *zl;
1838

1839
	*mpol = get_vma_policy(current, vma, addr);
1840
	*nodemask = NULL;	/* assume !MPOL_BIND */
1841

1842 1843
	if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
		zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1844
				huge_page_shift(hstate_vma(vma))), gfp_flags);
1845
	} else {
1846
		zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1847 1848
		if ((*mpol)->mode == MPOL_BIND)
			*nodemask = &(*mpol)->v.nodes;
1849 1850
	}
	return zl;
1851
}
1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876

/*
 * 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;

1877
	task_lock(current);
1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896
	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();
	}
1897
	task_unlock(current);
1898 1899 1900

	return true;
}
1901
#endif
1902

1903 1904 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
/*
 * mempolicy_nodemask_intersects
 *
 * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
 * policy.  Otherwise, check for intersection between mask and the policy
 * nodemask for 'bind' or 'interleave' policy.  For 'perferred' or 'local'
 * policy, always return true since it may allocate elsewhere on fallback.
 *
 * Takes task_lock(tsk) to prevent freeing of its mempolicy.
 */
bool mempolicy_nodemask_intersects(struct task_struct *tsk,
					const nodemask_t *mask)
{
	struct mempolicy *mempolicy;
	bool ret = true;

	if (!mask)
		return ret;
	task_lock(tsk);
	mempolicy = tsk->mempolicy;
	if (!mempolicy)
		goto out;

	switch (mempolicy->mode) {
	case MPOL_PREFERRED:
		/*
		 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
		 * allocate from, they may fallback to other nodes when oom.
		 * Thus, it's possible for tsk to have allocated memory from
		 * nodes in mask.
		 */
		break;
	case MPOL_BIND:
	case MPOL_INTERLEAVE:
		ret = nodes_intersects(mempolicy->v.nodes, *mask);
		break;
	default:
		BUG();
	}
out:
	task_unlock(tsk);
	return ret;
}

L
Linus Torvalds 已提交
1947 1948
/* Allocate a page in interleaved policy.
   Own path because it needs to do special accounting. */
1949 1950
static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
					unsigned nid)
L
Linus Torvalds 已提交
1951 1952 1953 1954
{
	struct zonelist *zl;
	struct page *page;

1955
	zl = node_zonelist(nid, gfp);
L
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1956
	page = __alloc_pages(gfp, order, zl);
1957
	if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
1958
		inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
L
Linus Torvalds 已提交
1959 1960 1961 1962
	return page;
}

/**
1963
 * 	alloc_pages_vma	- Allocate a page for a VMA.
L
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1964 1965 1966 1967 1968 1969 1970 1971
 *
 * 	@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.
 *
1972
 *	@order:Order of the GFP allocation.
L
Linus Torvalds 已提交
1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985
 * 	@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 *
1986
alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
1987
		unsigned long addr, int node)
L
Linus Torvalds 已提交
1988
{
1989
	struct mempolicy *pol;
1990
	struct page *page;
1991 1992 1993 1994 1995
	unsigned int cpuset_mems_cookie;

retry_cpuset:
	pol = get_vma_policy(current, vma, addr);
	cpuset_mems_cookie = get_mems_allowed();
L
Linus Torvalds 已提交
1996

1997
	if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
L
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1998
		unsigned nid;
1999

2000
		nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2001
		mpol_cond_put(pol);
2002
		page = alloc_page_interleave(gfp, order, nid);
2003 2004 2005
		if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
			goto retry_cpuset;

2006
		return page;
L
Linus Torvalds 已提交
2007
	}
2008 2009
	page = __alloc_pages_nodemask(gfp, order,
				      policy_zonelist(gfp, pol, node),
2010
				      policy_nodemask(gfp, pol));
2011 2012
	if (unlikely(mpol_needs_cond_ref(pol)))
		__mpol_put(pol);
2013 2014
	if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
		goto retry_cpuset;
2015
	return page;
L
Linus Torvalds 已提交
2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032
}

/**
 * 	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.
 *
2033
 *	Don't call cpuset_update_task_memory_state() unless
L
Linus Torvalds 已提交
2034 2035 2036
 *	1) it's ok to take cpuset_sem (can WAIT), and
 *	2) allocating for current task (not interrupt).
 */
A
Al Viro 已提交
2037
struct page *alloc_pages_current(gfp_t gfp, unsigned order)
L
Linus Torvalds 已提交
2038
{
M
Mel Gorman 已提交
2039
	struct mempolicy *pol = get_task_policy(current);
2040
	struct page *page;
2041
	unsigned int cpuset_mems_cookie;
L
Linus Torvalds 已提交
2042

2043
	if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
L
Linus Torvalds 已提交
2044
		pol = &default_policy;
2045

2046 2047 2048
retry_cpuset:
	cpuset_mems_cookie = get_mems_allowed();

2049 2050 2051 2052
	/*
	 * No reference counting needed for current->mempolicy
	 * nor system default_policy
	 */
2053
	if (pol->mode == MPOL_INTERLEAVE)
2054 2055 2056
		page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
	else
		page = __alloc_pages_nodemask(gfp, order,
2057 2058
				policy_zonelist(gfp, pol, numa_node_id()),
				policy_nodemask(gfp, pol));
2059 2060 2061 2062

	if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
		goto retry_cpuset;

2063
	return page;
L
Linus Torvalds 已提交
2064 2065 2066
}
EXPORT_SYMBOL(alloc_pages_current);

2067
/*
2068
 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2069 2070 2071 2072
 * 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().
2073 2074 2075
 *
 * current's mempolicy may be rebinded by the other task(the task that changes
 * cpuset's mems), so we needn't do rebind work for current task.
2076 2077
 */

2078 2079
/* Slow path of a mempolicy duplicate */
struct mempolicy *__mpol_dup(struct mempolicy *old)
L
Linus Torvalds 已提交
2080 2081 2082 2083 2084
{
	struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);

	if (!new)
		return ERR_PTR(-ENOMEM);
2085 2086 2087 2088 2089 2090 2091 2092 2093

	/* task's mempolicy is protected by alloc_lock */
	if (old == current->mempolicy) {
		task_lock(current);
		*new = *old;
		task_unlock(current);
	} else
		*new = *old;

2094
	rcu_read_lock();
2095 2096
	if (current_cpuset_is_being_rebound()) {
		nodemask_t mems = cpuset_mems_allowed(current);
2097 2098 2099 2100
		if (new->flags & MPOL_F_REBINDING)
			mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
		else
			mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
2101
	}
2102
	rcu_read_unlock();
L
Linus Torvalds 已提交
2103 2104 2105 2106 2107
	atomic_set(&new->refcnt, 1);
	return new;
}

/* Slow path of a mempolicy comparison */
2108
bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
L
Linus Torvalds 已提交
2109 2110
{
	if (!a || !b)
2111
		return false;
2112
	if (a->mode != b->mode)
2113
		return false;
B
Bob Liu 已提交
2114
	if (a->flags != b->flags)
2115
		return false;
B
Bob Liu 已提交
2116 2117
	if (mpol_store_user_nodemask(a))
		if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2118
			return false;
B
Bob Liu 已提交
2119

2120
	switch (a->mode) {
2121 2122
	case MPOL_BIND:
		/* Fall through */
L
Linus Torvalds 已提交
2123
	case MPOL_INTERLEAVE:
2124
		return !!nodes_equal(a->v.nodes, b->v.nodes);
L
Linus Torvalds 已提交
2125
	case MPOL_PREFERRED:
2126
		return a->v.preferred_node == b->v.preferred_node;
L
Linus Torvalds 已提交
2127 2128
	default:
		BUG();
2129
		return false;
L
Linus Torvalds 已提交
2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142
	}
}

/*
 * 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 */
2143
/* Caller holds sp->lock */
L
Linus Torvalds 已提交
2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193
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);
2194
	pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2195
		 new->policy ? new->policy->mode : 0);
L
Linus Torvalds 已提交
2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206
}

/* 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;
2207
	spin_lock(&sp->lock);
L
Linus Torvalds 已提交
2208 2209 2210 2211 2212
	sn = sp_lookup(sp, idx, idx+1);
	if (sn) {
		mpol_get(sn->policy);
		pol = sn->policy;
	}
2213
	spin_unlock(&sp->lock);
L
Linus Torvalds 已提交
2214 2215 2216
	return pol;
}

2217 2218 2219 2220 2221 2222
static void sp_free(struct sp_node *n)
{
	mpol_put(n->policy);
	kmem_cache_free(sn_cache, n);
}

2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290
/**
 * mpol_misplaced - check whether current page node is valid in policy
 *
 * @page   - page to be checked
 * @vma    - vm area where page mapped
 * @addr   - virtual address where page mapped
 *
 * Lookup current policy node id for vma,addr and "compare to" page's
 * node id.
 *
 * Returns:
 *	-1	- not misplaced, page is in the right node
 *	node	- node id where the page should be
 *
 * Policy determination "mimics" alloc_page_vma().
 * Called from fault path where we know the vma and faulting address.
 */
int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
{
	struct mempolicy *pol;
	struct zone *zone;
	int curnid = page_to_nid(page);
	unsigned long pgoff;
	int polnid = -1;
	int ret = -1;

	BUG_ON(!vma);

	pol = get_vma_policy(current, vma, addr);
	if (!(pol->flags & MPOL_F_MOF))
		goto out;

	switch (pol->mode) {
	case MPOL_INTERLEAVE:
		BUG_ON(addr >= vma->vm_end);
		BUG_ON(addr < vma->vm_start);

		pgoff = vma->vm_pgoff;
		pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
		polnid = offset_il_node(pol, vma, pgoff);
		break;

	case MPOL_PREFERRED:
		if (pol->flags & MPOL_F_LOCAL)
			polnid = numa_node_id();
		else
			polnid = pol->v.preferred_node;
		break;

	case MPOL_BIND:
		/*
		 * allows binding to multiple nodes.
		 * use current page if in policy nodemask,
		 * else select nearest allowed node, if any.
		 * If no allowed nodes, use current [!misplaced].
		 */
		if (node_isset(curnid, pol->v.nodes))
			goto out;
		(void)first_zones_zonelist(
				node_zonelist(numa_node_id(), GFP_HIGHUSER),
				gfp_zone(GFP_HIGHUSER),
				&pol->v.nodes, &zone);
		polnid = zone->node;
		break;

	default:
		BUG();
	}
M
Mel Gorman 已提交
2291 2292

	/* Migrate the page towards the node whose CPU is referencing it */
2293 2294 2295
	if (pol->flags & MPOL_F_MORON) {
		int last_nid;

M
Mel Gorman 已提交
2296 2297
		polnid = numa_node_id();

2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318
		/*
		 * Multi-stage node selection is used in conjunction
		 * with a periodic migration fault to build a temporal
		 * task<->page relation. By using a two-stage filter we
		 * remove short/unlikely relations.
		 *
		 * Using P(p) ~ n_p / n_t as per frequentist
		 * probability, we can equate a task's usage of a
		 * particular page (n_p) per total usage of this
		 * page (n_t) (in a given time-span) to a probability.
		 *
		 * Our periodic faults will sample this probability and
		 * getting the same result twice in a row, given these
		 * samples are fully independent, is then given by
		 * P(n)^2, provided our sample period is sufficiently
		 * short compared to the usage pattern.
		 *
		 * This quadric squishes small probabilities, making
		 * it less likely we act on an unlikely task<->page
		 * relation.
		 */
2319
		last_nid = page_nid_xchg_last(page, polnid);
2320 2321 2322 2323
		if (last_nid != polnid)
			goto out;
	}

2324 2325 2326 2327 2328 2329 2330 2331
	if (curnid != polnid)
		ret = polnid;
out:
	mpol_cond_put(pol);

	return ret;
}

L
Linus Torvalds 已提交
2332 2333
static void sp_delete(struct shared_policy *sp, struct sp_node *n)
{
2334
	pr_debug("deleting %lx-l%lx\n", n->start, n->end);
L
Linus Torvalds 已提交
2335
	rb_erase(&n->nd, &sp->root);
2336
	sp_free(n);
L
Linus Torvalds 已提交
2337 2338
}

2339 2340 2341 2342 2343 2344 2345 2346
static void sp_node_init(struct sp_node *node, unsigned long start,
			unsigned long end, struct mempolicy *pol)
{
	node->start = start;
	node->end = end;
	node->policy = pol;
}

A
Adrian Bunk 已提交
2347 2348
static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
				struct mempolicy *pol)
L
Linus Torvalds 已提交
2349
{
2350 2351
	struct sp_node *n;
	struct mempolicy *newpol;
L
Linus Torvalds 已提交
2352

2353
	n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
L
Linus Torvalds 已提交
2354 2355
	if (!n)
		return NULL;
2356 2357 2358 2359 2360 2361 2362

	newpol = mpol_dup(pol);
	if (IS_ERR(newpol)) {
		kmem_cache_free(sn_cache, n);
		return NULL;
	}
	newpol->flags |= MPOL_F_SHARED;
2363
	sp_node_init(n, start, end, newpol);
2364

L
Linus Torvalds 已提交
2365 2366 2367 2368 2369 2370 2371
	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)
{
2372
	struct sp_node *n;
2373 2374
	struct sp_node *n_new = NULL;
	struct mempolicy *mpol_new = NULL;
2375
	int ret = 0;
L
Linus Torvalds 已提交
2376

2377 2378
restart:
	spin_lock(&sp->lock);
L
Linus Torvalds 已提交
2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390
	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) {
2391 2392 2393 2394 2395 2396 2397
				if (!n_new)
					goto alloc_new;

				*mpol_new = *n->policy;
				atomic_set(&mpol_new->refcnt, 1);
				sp_node_init(n_new, n->end, end, mpol_new);
				sp_insert(sp, n_new);
L
Linus Torvalds 已提交
2398
				n->end = start;
2399 2400
				n_new = NULL;
				mpol_new = NULL;
L
Linus Torvalds 已提交
2401 2402 2403 2404 2405 2406 2407 2408 2409 2410
				break;
			} else
				n->end = start;
		}
		if (!next)
			break;
		n = rb_entry(next, struct sp_node, nd);
	}
	if (new)
		sp_insert(sp, new);
2411 2412 2413 2414 2415 2416 2417 2418 2419
	spin_unlock(&sp->lock);
	ret = 0;

err_out:
	if (mpol_new)
		mpol_put(mpol_new);
	if (n_new)
		kmem_cache_free(sn_cache, n_new);

2420
	return ret;
2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431

alloc_new:
	spin_unlock(&sp->lock);
	ret = -ENOMEM;
	n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
	if (!n_new)
		goto err_out;
	mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
	if (!mpol_new)
		goto err_out;
	goto restart;
L
Linus Torvalds 已提交
2432 2433
}

2434 2435 2436 2437 2438 2439 2440 2441
/**
 * 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.
2442
 * This is called at get_inode() calls and we can use GFP_KERNEL.
2443 2444 2445
 */
void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
{
2446 2447
	int ret;

2448
	sp->root = RB_ROOT;		/* empty tree == default mempolicy */
2449
	spin_lock_init(&sp->lock);
2450 2451 2452 2453

	if (mpol) {
		struct vm_area_struct pvma;
		struct mempolicy *new;
2454
		NODEMASK_SCRATCH(scratch);
2455

2456
		if (!scratch)
2457
			goto put_mpol;
2458 2459
		/* contextualize the tmpfs mount point mempolicy */
		new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2460
		if (IS_ERR(new))
2461
			goto free_scratch; /* no valid nodemask intersection */
2462 2463

		task_lock(current);
2464
		ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2465
		task_unlock(current);
2466
		if (ret)
2467
			goto put_new;
2468 2469 2470 2471 2472

		/* 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 */
2473

2474
put_new:
2475
		mpol_put(new);			/* drop initial ref */
2476
free_scratch:
2477
		NODEMASK_SCRATCH_FREE(scratch);
2478 2479
put_mpol:
		mpol_put(mpol);	/* drop our incoming ref on sb mpol */
2480 2481 2482
	}
}

L
Linus Torvalds 已提交
2483 2484 2485 2486 2487 2488 2489
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);

2490
	pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
L
Linus Torvalds 已提交
2491
		 vma->vm_pgoff,
2492
		 sz, npol ? npol->mode : -1,
2493
		 npol ? npol->flags : -1,
2494
		 npol ? nodes_addr(npol->v.nodes)[0] : -1);
L
Linus Torvalds 已提交
2495 2496 2497 2498 2499 2500 2501 2502

	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)
2503
		sp_free(new);
L
Linus Torvalds 已提交
2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514
	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;
2515
	spin_lock(&p->lock);
L
Linus Torvalds 已提交
2516 2517 2518 2519
	next = rb_first(&p->root);
	while (next) {
		n = rb_entry(next, struct sp_node, nd);
		next = rb_next(&n->nd);
2520
		sp_delete(p, n);
L
Linus Torvalds 已提交
2521
	}
2522
	spin_unlock(&p->lock);
L
Linus Torvalds 已提交
2523 2524
}

2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568
#ifdef CONFIG_NUMA_BALANCING
static bool __initdata numabalancing_override;

static void __init check_numabalancing_enable(void)
{
	bool numabalancing_default = false;

	if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
		numabalancing_default = true;

	if (nr_node_ids > 1 && !numabalancing_override) {
		printk(KERN_INFO "Enabling automatic NUMA balancing. "
			"Configure with numa_balancing= or sysctl");
		set_numabalancing_state(numabalancing_default);
	}
}

static int __init setup_numabalancing(char *str)
{
	int ret = 0;
	if (!str)
		goto out;
	numabalancing_override = true;

	if (!strcmp(str, "enable")) {
		set_numabalancing_state(true);
		ret = 1;
	} else if (!strcmp(str, "disable")) {
		set_numabalancing_state(false);
		ret = 1;
	}
out:
	if (!ret)
		printk(KERN_WARNING "Unable to parse numa_balancing=\n");

	return ret;
}
__setup("numa_balancing=", setup_numabalancing);
#else
static inline void __init check_numabalancing_enable(void)
{
}
#endif /* CONFIG_NUMA_BALANCING */

L
Linus Torvalds 已提交
2569 2570 2571
/* assumes fs == KERNEL_DS */
void __init numa_policy_init(void)
{
2572 2573 2574 2575
	nodemask_t interleave_nodes;
	unsigned long largest = 0;
	int nid, prefer = 0;

L
Linus Torvalds 已提交
2576 2577
	policy_cache = kmem_cache_create("numa_policy",
					 sizeof(struct mempolicy),
2578
					 0, SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
2579 2580 2581

	sn_cache = kmem_cache_create("shared_policy_node",
				     sizeof(struct sp_node),
2582
				     0, SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
2583

M
Mel Gorman 已提交
2584 2585 2586 2587 2588 2589 2590 2591 2592
	for_each_node(nid) {
		preferred_node_policy[nid] = (struct mempolicy) {
			.refcnt = ATOMIC_INIT(1),
			.mode = MPOL_PREFERRED,
			.flags = MPOL_F_MOF | MPOL_F_MORON,
			.v = { .preferred_node = nid, },
		};
	}

2593 2594 2595 2596 2597 2598
	/*
	 * 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);
2599
	for_each_node_state(nid, N_MEMORY) {
2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615
		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
2616

2617
	if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
L
Linus Torvalds 已提交
2618
		printk("numa_policy_init: interleaving failed\n");
2619 2620

	check_numabalancing_enable();
L
Linus Torvalds 已提交
2621 2622
}

2623
/* Reset policy of current process to default */
L
Linus Torvalds 已提交
2624 2625
void numa_default_policy(void)
{
2626
	do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
L
Linus Torvalds 已提交
2627
}
2628

2629 2630 2631 2632
/*
 * Parse and format mempolicy from/to strings
 */

2633
/*
2634
 * "local" is implemented internally by MPOL_PREFERRED with MPOL_F_LOCAL flag.
2635
 */
2636 2637 2638 2639 2640 2641
static const char * const policy_modes[] =
{
	[MPOL_DEFAULT]    = "default",
	[MPOL_PREFERRED]  = "prefer",
	[MPOL_BIND]       = "bind",
	[MPOL_INTERLEAVE] = "interleave",
L
Lee Schermerhorn 已提交
2642
	[MPOL_LOCAL]      = "local",
2643
};
2644

2645 2646 2647

#ifdef CONFIG_TMPFS
/**
2648
 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2649
 * @str:  string containing mempolicy to parse
2650
 * @mpol:  pointer to struct mempolicy pointer, returned on success.
2651 2652 2653 2654
 *
 * Format of input:
 *	<mode>[=<flags>][:<nodelist>]
 *
2655
 * On success, returns 0, else 1
2656
 */
2657
int mpol_parse_str(char *str, struct mempolicy **mpol)
2658
{
2659
	struct mempolicy *new = NULL;
2660
	unsigned short mode;
2661
	unsigned short mode_flags;
2662
	nodemask_t nodes;
2663 2664 2665 2666 2667 2668 2669
	char *nodelist = strchr(str, ':');
	char *flags = strchr(str, '=');
	int err = 1;

	if (nodelist) {
		/* NUL-terminate mode or flags string */
		*nodelist++ = '\0';
2670
		if (nodelist_parse(nodelist, nodes))
2671
			goto out;
2672
		if (!nodes_subset(nodes, node_states[N_MEMORY]))
2673
			goto out;
2674 2675 2676
	} else
		nodes_clear(nodes);

2677 2678 2679
	if (flags)
		*flags++ = '\0';	/* terminate mode string */

2680
	for (mode = 0; mode < MPOL_MAX; mode++) {
2681
		if (!strcmp(str, policy_modes[mode])) {
2682 2683 2684
			break;
		}
	}
2685
	if (mode >= MPOL_MAX)
2686 2687
		goto out;

2688
	switch (mode) {
2689
	case MPOL_PREFERRED:
2690 2691 2692
		/*
		 * Insist on a nodelist of one node only
		 */
2693 2694 2695 2696
		if (nodelist) {
			char *rest = nodelist;
			while (isdigit(*rest))
				rest++;
2697 2698
			if (*rest)
				goto out;
2699 2700 2701 2702 2703 2704 2705
		}
		break;
	case MPOL_INTERLEAVE:
		/*
		 * Default to online nodes with memory if no nodelist
		 */
		if (!nodelist)
2706
			nodes = node_states[N_MEMORY];
2707
		break;
2708
	case MPOL_LOCAL:
2709
		/*
2710
		 * Don't allow a nodelist;  mpol_new() checks flags
2711
		 */
2712
		if (nodelist)
2713
			goto out;
2714
		mode = MPOL_PREFERRED;
2715
		break;
2716 2717 2718 2719 2720 2721 2722
	case MPOL_DEFAULT:
		/*
		 * Insist on a empty nodelist
		 */
		if (!nodelist)
			err = 0;
		goto out;
2723 2724 2725 2726 2727 2728
	case MPOL_BIND:
		/*
		 * Insist on a nodelist
		 */
		if (!nodelist)
			goto out;
2729 2730
	}

2731
	mode_flags = 0;
2732 2733 2734 2735 2736 2737
	if (flags) {
		/*
		 * Currently, we only support two mutually exclusive
		 * mode flags.
		 */
		if (!strcmp(flags, "static"))
2738
			mode_flags |= MPOL_F_STATIC_NODES;
2739
		else if (!strcmp(flags, "relative"))
2740
			mode_flags |= MPOL_F_RELATIVE_NODES;
2741
		else
2742
			goto out;
2743
	}
2744 2745 2746

	new = mpol_new(mode, mode_flags, &nodes);
	if (IS_ERR(new))
2747 2748
		goto out;

2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765
	/*
	 * Save nodes for mpol_to_str() to show the tmpfs mount options
	 * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
	 */
	if (mode != MPOL_PREFERRED)
		new->v.nodes = nodes;
	else if (nodelist)
		new->v.preferred_node = first_node(nodes);
	else
		new->flags |= MPOL_F_LOCAL;

	/*
	 * Save nodes for contextualization: this will be used to "clone"
	 * the mempolicy in a specific context [cpuset] at a later time.
	 */
	new->w.user_nodemask = nodes;

2766
	err = 0;
2767

2768 2769 2770 2771 2772 2773
out:
	/* Restore string for error message */
	if (nodelist)
		*--nodelist = ':';
	if (flags)
		*--flags = '=';
2774 2775
	if (!err)
		*mpol = new;
2776 2777 2778 2779
	return err;
}
#endif /* CONFIG_TMPFS */

2780 2781 2782 2783 2784 2785
/**
 * 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
 *
2786 2787 2788 2789
 * Convert a mempolicy into a string.
 * Returns the number of characters in buffer (if positive)
 * or an error (negative)
 */
2790
int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
2791 2792 2793 2794
{
	char *p = buffer;
	int l;
	nodemask_t nodes;
2795
	unsigned short mode;
2796
	unsigned short flags = pol ? pol->flags : 0;
2797

2798 2799 2800 2801 2802
	/*
	 * Sanity check:  room for longest mode, flag and some nodes
	 */
	VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);

2803 2804 2805 2806 2807
	if (!pol || pol == &default_policy)
		mode = MPOL_DEFAULT;
	else
		mode = pol->mode;

2808 2809 2810 2811 2812 2813 2814
	switch (mode) {
	case MPOL_DEFAULT:
		nodes_clear(nodes);
		break;

	case MPOL_PREFERRED:
		nodes_clear(nodes);
2815
		if (flags & MPOL_F_LOCAL)
2816
			mode = MPOL_LOCAL;
2817
		else
2818
			node_set(pol->v.preferred_node, nodes);
2819 2820 2821
		break;

	case MPOL_BIND:
2822
		/* Fall through */
2823
	case MPOL_INTERLEAVE:
2824
		nodes = pol->v.nodes;
2825 2826 2827
		break;

	default:
2828
		return -EINVAL;
2829 2830
	}

2831
	l = strlen(policy_modes[mode]);
2832 2833
	if (buffer + maxlen < p + l + 1)
		return -ENOSPC;
2834

2835
	strcpy(p, policy_modes[mode]);
2836 2837
	p += l;

2838
	if (flags & MPOL_MODE_FLAGS) {
2839 2840 2841 2842
		if (buffer + maxlen < p + 2)
			return -ENOSPC;
		*p++ = '=';

2843 2844 2845
		/*
		 * Currently, the only defined flags are mutually exclusive
		 */
2846
		if (flags & MPOL_F_STATIC_NODES)
2847 2848 2849
			p += snprintf(p, buffer + maxlen - p, "static");
		else if (flags & MPOL_F_RELATIVE_NODES)
			p += snprintf(p, buffer + maxlen - p, "relative");
2850 2851
	}

2852 2853 2854
	if (!nodes_empty(nodes)) {
		if (buffer + maxlen < p + 2)
			return -ENOSPC;
2855
		*p++ = ':';
2856 2857 2858 2859
	 	p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);
	}
	return p - buffer;
}