mempolicy.c 74.7 KB
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/*
 * Simple NUMA memory policy for the Linux kernel.
 *
 * Copyright 2003,2004 Andi Kleen, SuSE Labs.
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 * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc.
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 * Subject to the GNU Public License, version 2.
 *
 * NUMA policy allows the user to give hints in which node(s) memory should
 * be allocated.
 *
 * Support four policies per VMA and per process:
 *
 * The VMA policy has priority over the process policy for a page fault.
 *
 * interleave     Allocate memory interleaved over a set of nodes,
 *                with normal fallback if it fails.
 *                For VMA based allocations this interleaves based on the
 *                offset into the backing object or offset into the mapping
 *                for anonymous memory. For process policy an process counter
 *                is used.
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 *
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 * bind           Only allocate memory on a specific set of nodes,
 *                no fallback.
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 *                FIXME: memory is allocated starting with the first node
 *                to the last. It would be better if bind would truly restrict
 *                the allocation to memory nodes instead
 *
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 * preferred       Try a specific node first before normal fallback.
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 *                As a special case NUMA_NO_NODE here means do the allocation
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 *                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;

	if (!pol) {
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		int node = numa_node_id();
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		if (node != NUMA_NO_NODE) {
			pol = &preferred_node_policy[node];
			/*
			 * preferred_node_policy is not initialised early in
			 * boot
			 */
			if (!pol->mode)
				pol = NULL;
		}
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	}

	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",
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		 mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE);
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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,
 * and move them to the pagelist if they do.
 */
static int queue_pages_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.
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		 */
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		if (PageReserved(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 void queue_pages_hugetlb_pmd_range(struct vm_area_struct *vma,
		pmd_t *pmd, const nodemask_t *nodes, unsigned long flags,
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				    void *private)
{
#ifdef CONFIG_HUGETLB_PAGE
	int nid;
	struct page *page;
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	spinlock_t *ptl;
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	ptl = huge_pte_lock(hstate_vma(vma), vma->vm_mm, (pte_t *)pmd);
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	page = pte_page(huge_ptep_get((pte_t *)pmd));
	nid = page_to_nid(page);
	if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
		goto unlock;
	/* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
	if (flags & (MPOL_MF_MOVE_ALL) ||
	    (flags & MPOL_MF_MOVE && page_mapcount(page) == 1))
		isolate_huge_page(page, private);
unlock:
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	spin_unlock(ptl);
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#else
	BUG();
#endif
}

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static inline int queue_pages_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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		if (!pmd_present(*pmd))
			continue;
		if (pmd_huge(*pmd) && is_vm_hugetlb_page(vma)) {
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			queue_pages_hugetlb_pmd_range(vma, pmd, nodes,
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						flags, private);
			continue;
		}
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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 (queue_pages_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 queue_pages_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);
585 586
		if (pud_huge(*pud) && is_vm_hugetlb_page(vma))
			continue;
587 588
		if (pud_none_or_clear_bad(pud))
			continue;
589
		if (queue_pages_pmd_range(vma, pud, addr, next, nodes,
590
				    flags, private))
591 592 593 594 595
			return -EIO;
	} while (pud++, addr = next, addr != end);
	return 0;
}

596
static inline int queue_pages_pgd_range(struct vm_area_struct *vma,
597 598
		unsigned long addr, unsigned long end,
		const nodemask_t *nodes, unsigned long flags,
599
		void *private)
600 601 602 603
{
	pgd_t *pgd;
	unsigned long next;

N
Nick Piggin 已提交
604
	pgd = pgd_offset(vma->vm_mm, addr);
605 606 607 608
	do {
		next = pgd_addr_end(addr, end);
		if (pgd_none_or_clear_bad(pgd))
			continue;
609
		if (queue_pages_pud_range(vma, pgd, addr, next, nodes,
610
				    flags, private))
611 612 613
			return -EIO;
	} while (pgd++, addr = next, addr != end);
	return 0;
L
Linus Torvalds 已提交
614 615
}

L
Lee Schermerhorn 已提交
616 617
#ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE
/*
618 619 620 621 622 623 624
 * 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
625
 */
626 627
unsigned long change_prot_numa(struct vm_area_struct *vma,
			unsigned long addr, unsigned long end)
L
Lee Schermerhorn 已提交
628
{
629 630
	int nr_updated;
	BUILD_BUG_ON(_PAGE_NUMA != _PAGE_PROTNONE);
L
Lee Schermerhorn 已提交
631

632
	nr_updated = change_protection(vma, addr, end, vma->vm_page_prot, 0, 1);
633 634
	if (nr_updated)
		count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
L
Lee Schermerhorn 已提交
635

636
	return nr_updated;
L
Lee Schermerhorn 已提交
637 638 639 640 641 642 643 644 645
}
#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 */

646
/*
647 648 649 650 651
 * Walk through page tables and collect pages to be migrated.
 *
 * If pages found in a given range are on a set of nodes (determined by
 * @nodes and @flags,) it's isolated and queued to the pagelist which is
 * passed via @private.)
652
 */
L
Linus Torvalds 已提交
653
static struct vm_area_struct *
654
queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
655
		const nodemask_t *nodes, unsigned long flags, void *private)
L
Linus Torvalds 已提交
656 657 658 659
{
	int err;
	struct vm_area_struct *first, *vma, *prev;

660

L
Linus Torvalds 已提交
661 662 663 664 665
	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
666 667 668 669 670 671 672
		unsigned long endvma = vma->vm_end;

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

673 674 675 676 677 678
		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
679 680 681 682 683 684 685

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

		if ((flags & MPOL_MF_STRICT) ||
686
		     ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
L
Lee Schermerhorn 已提交
687
		      vma_migratable(vma))) {
688

689
			err = queue_pages_pgd_range(vma, start, endvma, nodes,
690
						flags, private);
L
Linus Torvalds 已提交
691 692 693 694 695
			if (err) {
				first = ERR_PTR(err);
				break;
			}
		}
L
Lee Schermerhorn 已提交
696
next:
L
Linus Torvalds 已提交
697 698 699 700 701
		prev = vma;
	}
	return first;
}

702 703 704 705 706 707
/*
 * 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)
708
{
709 710 711
	int err;
	struct mempolicy *old;
	struct mempolicy *new;
712 713 714 715 716 717

	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);

718 719 720 721 722
	new = mpol_dup(pol);
	if (IS_ERR(new))
		return PTR_ERR(new);

	if (vma->vm_ops && vma->vm_ops->set_policy) {
723
		err = vma->vm_ops->set_policy(vma, new);
724 725
		if (err)
			goto err_out;
726
	}
727 728 729 730 731 732 733 734

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

	return 0;
 err_out:
	mpol_put(new);
735 736 737
	return err;
}

L
Linus Torvalds 已提交
738
/* Step 2: apply policy to a range and do splits. */
739 740
static int mbind_range(struct mm_struct *mm, unsigned long start,
		       unsigned long end, struct mempolicy *new_pol)
L
Linus Torvalds 已提交
741 742
{
	struct vm_area_struct *next;
743 744 745
	struct vm_area_struct *prev;
	struct vm_area_struct *vma;
	int err = 0;
746
	pgoff_t pgoff;
747 748
	unsigned long vmstart;
	unsigned long vmend;
L
Linus Torvalds 已提交
749

750
	vma = find_vma(mm, start);
751 752 753
	if (!vma || vma->vm_start > start)
		return -EFAULT;

754
	prev = vma->vm_prev;
755 756 757
	if (start > vma->vm_start)
		prev = vma;

758
	for (; vma && vma->vm_start < end; prev = vma, vma = next) {
L
Linus Torvalds 已提交
759
		next = vma->vm_next;
760 761 762
		vmstart = max(start, vma->vm_start);
		vmend   = min(end, vma->vm_end);

763 764 765 766 767
		if (mpol_equal(vma_policy(vma), new_pol))
			continue;

		pgoff = vma->vm_pgoff +
			((vmstart - vma->vm_start) >> PAGE_SHIFT);
768
		prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
769
				  vma->anon_vma, vma->vm_file, pgoff,
770
				  new_pol);
771 772 773
		if (prev) {
			vma = prev;
			next = vma->vm_next;
774 775 776 777
			if (mpol_equal(vma_policy(vma), new_pol))
				continue;
			/* vma_merge() joined vma && vma->next, case 8 */
			goto replace;
778 779 780 781 782 783 784 785 786 787 788
		}
		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;
		}
789
 replace:
790
		err = vma_replace_policy(vma, new_pol);
791 792
		if (err)
			goto out;
L
Linus Torvalds 已提交
793
	}
794 795

 out:
L
Linus Torvalds 已提交
796 797 798
	return err;
}

799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828
/*
 * 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
829
/* Set the process memory policy */
830 831
static long do_set_mempolicy(unsigned short mode, unsigned short flags,
			     nodemask_t *nodes)
L
Linus Torvalds 已提交
832
{
833
	struct mempolicy *new, *old;
834
	struct mm_struct *mm = current->mm;
835
	NODEMASK_SCRATCH(scratch);
836
	int ret;
L
Linus Torvalds 已提交
837

838 839
	if (!scratch)
		return -ENOMEM;
840

841 842 843 844 845
	new = mpol_new(mode, flags, nodes);
	if (IS_ERR(new)) {
		ret = PTR_ERR(new);
		goto out;
	}
846 847 848 849 850 851 852 853
	/*
	 * 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);
854
	task_lock(current);
855
	ret = mpol_set_nodemask(new, nodes, scratch);
856 857 858 859 860
	if (ret) {
		task_unlock(current);
		if (mm)
			up_write(&mm->mmap_sem);
		mpol_put(new);
861
		goto out;
862 863
	}
	old = current->mempolicy;
L
Linus Torvalds 已提交
864
	current->mempolicy = new;
865
	mpol_set_task_struct_flag();
866
	if (new && new->mode == MPOL_INTERLEAVE &&
867
	    nodes_weight(new->v.nodes))
868
		current->il_next = first_node(new->v.nodes);
869
	task_unlock(current);
870 871 872
	if (mm)
		up_write(&mm->mmap_sem);

873
	mpol_put(old);
874 875 876 877
	ret = 0;
out:
	NODEMASK_SCRATCH_FREE(scratch);
	return ret;
L
Linus Torvalds 已提交
878 879
}

880 881
/*
 * Return nodemask for policy for get_mempolicy() query
882 883
 *
 * Called with task's alloc_lock held
884 885
 */
static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
L
Linus Torvalds 已提交
886
{
887
	nodes_clear(*nodes);
888 889 890
	if (p == &default_policy)
		return;

891
	switch (p->mode) {
892 893
	case MPOL_BIND:
		/* Fall through */
L
Linus Torvalds 已提交
894
	case MPOL_INTERLEAVE:
895
		*nodes = p->v.nodes;
L
Linus Torvalds 已提交
896 897
		break;
	case MPOL_PREFERRED:
898
		if (!(p->flags & MPOL_F_LOCAL))
899
			node_set(p->v.preferred_node, *nodes);
900
		/* else return empty node mask for local allocation */
L
Linus Torvalds 已提交
901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920
		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
921 922
static long do_get_mempolicy(int *policy, nodemask_t *nmask,
			     unsigned long addr, unsigned long flags)
L
Linus Torvalds 已提交
923
{
924
	int err;
L
Linus Torvalds 已提交
925 926 927 928
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma = NULL;
	struct mempolicy *pol = current->mempolicy;

929 930
	if (flags &
		~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
L
Linus Torvalds 已提交
931
		return -EINVAL;
932 933 934 935 936

	if (flags & MPOL_F_MEMS_ALLOWED) {
		if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
			return -EINVAL;
		*policy = 0;	/* just so it's initialized */
937
		task_lock(current);
938
		*nmask  = cpuset_current_mems_allowed;
939
		task_unlock(current);
940 941 942
		return 0;
	}

L
Linus Torvalds 已提交
943
	if (flags & MPOL_F_ADDR) {
944 945 946 947 948
		/*
		 * 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
949 950 951 952 953 954 955 956 957 958 959 960 961 962
		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)
963
		pol = &default_policy;	/* indicates default behavior */
L
Linus Torvalds 已提交
964 965 966 967 968 969

	if (flags & MPOL_F_NODE) {
		if (flags & MPOL_F_ADDR) {
			err = lookup_node(mm, addr);
			if (err < 0)
				goto out;
970
			*policy = err;
L
Linus Torvalds 已提交
971
		} else if (pol == current->mempolicy &&
972
				pol->mode == MPOL_INTERLEAVE) {
973
			*policy = current->il_next;
L
Linus Torvalds 已提交
974 975 976 977
		} else {
			err = -EINVAL;
			goto out;
		}
978 979 980
	} else {
		*policy = pol == &default_policy ? MPOL_DEFAULT :
						pol->mode;
981 982 983 984 985
		/*
		 * Internal mempolicy flags must be masked off before exposing
		 * the policy to userspace.
		 */
		*policy |= (pol->flags & MPOL_MODE_FLAGS);
986
	}
L
Linus Torvalds 已提交
987 988 989 990 991 992 993

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

	err = 0;
994
	if (nmask) {
995 996 997 998 999 1000 1001
		if (mpol_store_user_nodemask(pol)) {
			*nmask = pol->w.user_nodemask;
		} else {
			task_lock(current);
			get_policy_nodemask(pol, nmask);
			task_unlock(current);
		}
1002
	}
L
Linus Torvalds 已提交
1003 1004

 out:
1005
	mpol_cond_put(pol);
L
Linus Torvalds 已提交
1006 1007 1008 1009 1010
	if (vma)
		up_read(&current->mm->mmap_sem);
	return err;
}

C
Christoph Lameter 已提交
1011
#ifdef CONFIG_MIGRATION
1012 1013 1014
/*
 * page migration
 */
1015 1016
static void migrate_page_add(struct page *page, struct list_head *pagelist,
				unsigned long flags)
1017 1018
{
	/*
1019
	 * Avoid migrating a page that is shared with others.
1020
	 */
1021 1022 1023
	if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
		if (!isolate_lru_page(page)) {
			list_add_tail(&page->lru, pagelist);
1024 1025
			inc_zone_page_state(page, NR_ISOLATED_ANON +
					    page_is_file_cache(page));
1026 1027
		}
	}
1028
}
1029

1030
static struct page *new_node_page(struct page *page, unsigned long node, int **x)
1031
{
1032 1033 1034 1035 1036
	if (PageHuge(page))
		return alloc_huge_page_node(page_hstate(compound_head(page)),
					node);
	else
		return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
1037 1038
}

1039 1040 1041 1042
/*
 * Migrate pages from one node to a target node.
 * Returns error or the number of pages not migrated.
 */
A
Adrian Bunk 已提交
1043 1044
static int migrate_to_node(struct mm_struct *mm, int source, int dest,
			   int flags)
1045 1046 1047 1048 1049 1050 1051
{
	nodemask_t nmask;
	LIST_HEAD(pagelist);
	int err = 0;

	nodes_clear(nmask);
	node_set(source, nmask);
1052

1053 1054 1055 1056 1057 1058
	/*
	 * 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)));
1059
	queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
1060 1061
			flags | MPOL_MF_DISCONTIG_OK, &pagelist);

1062
	if (!list_empty(&pagelist)) {
1063
		err = migrate_pages(&pagelist, new_node_page, dest,
1064
					MIGRATE_SYNC, MR_SYSCALL);
1065
		if (err)
1066
			putback_movable_pages(&pagelist);
1067
	}
1068

1069
	return err;
1070 1071
}

1072
/*
1073 1074
 * Move pages between the two nodesets so as to preserve the physical
 * layout as much as possible.
1075 1076 1077
 *
 * Returns the number of page that could not be moved.
 */
1078 1079
int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
		     const nodemask_t *to, int flags)
1080
{
1081
	int busy = 0;
1082
	int err;
1083
	nodemask_t tmp;
1084

1085 1086 1087 1088
	err = migrate_prep();
	if (err)
		return err;

1089
	down_read(&mm->mmap_sem);
1090

1091
	err = migrate_vmas(mm, from, to, flags);
1092 1093 1094
	if (err)
		goto out;

1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119
	/*
	 * 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.
1120
	 * Otherwise when we finish scanning from_tmp, we at least have the
1121 1122 1123 1124
	 * 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.
	 */
1125

1126
	tmp = *from;
1127 1128
	while (!nodes_empty(tmp)) {
		int s,d;
J
Jianguo Wu 已提交
1129
		int source = NUMA_NO_NODE;
1130 1131 1132
		int dest = 0;

		for_each_node_mask(s, tmp) {
1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148

			/*
			 * 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.
			 */

1149 1150
			if ((nodes_weight(*from) != nodes_weight(*to)) &&
						(node_isset(s, *to)))
1151 1152
				continue;

1153
			d = node_remap(s, *from, *to);
1154 1155 1156 1157 1158 1159 1160 1161 1162 1163
			if (s == d)
				continue;

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

			/* dest not in remaining from nodes? */
			if (!node_isset(dest, tmp))
				break;
		}
J
Jianguo Wu 已提交
1164
		if (source == NUMA_NO_NODE)
1165 1166 1167 1168 1169 1170 1171 1172
			break;

		node_clear(source, tmp);
		err = migrate_to_node(mm, source, dest, flags);
		if (err > 0)
			busy += err;
		if (err < 0)
			break;
1173
	}
1174
out:
1175
	up_read(&mm->mmap_sem);
1176 1177 1178
	if (err < 0)
		return err;
	return busy;
C
Christoph Lameter 已提交
1179 1180 1181

}

1182 1183 1184 1185 1186 1187 1188
/*
 * 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.
 */
1189
static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1190 1191
{
	struct vm_area_struct *vma = (struct vm_area_struct *)private;
1192
	unsigned long uninitialized_var(address);
1193

1194 1195 1196 1197 1198 1199
	while (vma) {
		address = page_address_in_vma(page, vma);
		if (address != -EFAULT)
			break;
		vma = vma->vm_next;
	}
1200 1201 1202 1203 1204
	/*
	 * queue_pages_range() confirms that @page belongs to some vma,
	 * so vma shouldn't be NULL.
	 */
	BUG_ON(!vma);
1205

1206 1207
	if (PageHuge(page))
		return alloc_huge_page_noerr(vma, address, 1);
1208
	return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1209
}
C
Christoph Lameter 已提交
1210 1211 1212 1213 1214
#else

static void migrate_page_add(struct page *page, struct list_head *pagelist,
				unsigned long flags)
{
1215 1216
}

1217 1218
int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
		     const nodemask_t *to, int flags)
C
Christoph Lameter 已提交
1219 1220 1221
{
	return -ENOSYS;
}
1222

1223
static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
1224 1225 1226
{
	return NULL;
}
C
Christoph Lameter 已提交
1227 1228
#endif

A
Adrian Bunk 已提交
1229
static long do_mbind(unsigned long start, unsigned long len,
1230 1231
		     unsigned short mode, unsigned short mode_flags,
		     nodemask_t *nmask, unsigned long flags)
1232 1233 1234 1235 1236 1237 1238 1239
{
	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
1240
	if (flags & ~(unsigned long)MPOL_MF_VALID)
1241
		return -EINVAL;
1242
	if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258
		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;

1259
	new = mpol_new(mode, mode_flags, nmask);
1260 1261 1262
	if (IS_ERR(new))
		return PTR_ERR(new);

L
Lee Schermerhorn 已提交
1263 1264 1265
	if (flags & MPOL_MF_LAZY)
		new->flags |= MPOL_F_MOF;

1266 1267 1268 1269 1270 1271 1272
	/*
	 * If we are using the default policy then operation
	 * on discontinuous address spaces is okay after all
	 */
	if (!new)
		flags |= MPOL_MF_DISCONTIG_OK;

1273 1274
	pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n",
		 start, start + len, mode, mode_flags,
D
David Rientjes 已提交
1275
		 nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE);
1276

1277 1278 1279 1280
	if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {

		err = migrate_prep();
		if (err)
K
KOSAKI Motohiro 已提交
1281
			goto mpol_out;
1282
	}
1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295
	{
		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
1296 1297 1298
	if (err)
		goto mpol_out;

1299
	vma = queue_pages_range(mm, start, end, nmask,
1300 1301
			  flags | MPOL_MF_INVERT, &pagelist);

L
Lee Schermerhorn 已提交
1302
	err = PTR_ERR(vma);	/* maybe ... */
1303
	if (!IS_ERR(vma))
1304
		err = mbind_range(mm, start, end, new);
1305

L
Lee Schermerhorn 已提交
1306 1307 1308
	if (!err) {
		int nr_failed = 0;

1309
		if (!list_empty(&pagelist)) {
L
Lee Schermerhorn 已提交
1310
			WARN_ON_ONCE(flags & MPOL_MF_LAZY);
1311
			nr_failed = migrate_pages(&pagelist, new_vma_page,
1312 1313
					(unsigned long)vma,
					MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
1314
			if (nr_failed)
1315
				putback_movable_pages(&pagelist);
1316
		}
1317

L
Lee Schermerhorn 已提交
1318
		if (nr_failed && (flags & MPOL_MF_STRICT))
1319
			err = -EIO;
1320 1321
	} else
		putback_lru_pages(&pagelist);
C
Christoph Lameter 已提交
1322

1323
	up_write(&mm->mmap_sem);
K
KOSAKI Motohiro 已提交
1324
 mpol_out:
1325
	mpol_put(new);
1326 1327 1328
	return err;
}

1329 1330 1331 1332 1333
/*
 * User space interface with variable sized bitmaps for nodelists.
 */

/* Copy a node mask from user space. */
1334
static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
1335 1336 1337 1338 1339 1340 1341 1342 1343 1344
		     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
1345
	if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
C
Chris Wright 已提交
1346
		return -EINVAL;
1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395

	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;
}

1396 1397 1398
SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
		unsigned long, mode, unsigned long __user *, nmask,
		unsigned long, maxnode, unsigned, flags)
1399 1400 1401
{
	nodemask_t nodes;
	int err;
1402
	unsigned short mode_flags;
1403

1404 1405
	mode_flags = mode & MPOL_MODE_FLAGS;
	mode &= ~MPOL_MODE_FLAGS;
1406 1407
	if (mode >= MPOL_MAX)
		return -EINVAL;
1408 1409 1410
	if ((mode_flags & MPOL_F_STATIC_NODES) &&
	    (mode_flags & MPOL_F_RELATIVE_NODES))
		return -EINVAL;
1411 1412 1413
	err = get_nodes(&nodes, nmask, maxnode);
	if (err)
		return err;
1414
	return do_mbind(start, len, mode, mode_flags, &nodes, flags);
1415 1416 1417
}

/* Set the process memory policy */
1418 1419
SYSCALL_DEFINE3(set_mempolicy, int, mode, unsigned long __user *, nmask,
		unsigned long, maxnode)
1420 1421 1422
{
	int err;
	nodemask_t nodes;
1423
	unsigned short flags;
1424

1425 1426 1427
	flags = mode & MPOL_MODE_FLAGS;
	mode &= ~MPOL_MODE_FLAGS;
	if ((unsigned int)mode >= MPOL_MAX)
1428
		return -EINVAL;
1429 1430
	if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))
		return -EINVAL;
1431 1432 1433
	err = get_nodes(&nodes, nmask, maxnode);
	if (err)
		return err;
1434
	return do_set_mempolicy(mode, flags, &nodes);
1435 1436
}

1437 1438 1439
SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
		const unsigned long __user *, old_nodes,
		const unsigned long __user *, new_nodes)
1440
{
1441
	const struct cred *cred = current_cred(), *tcred;
1442
	struct mm_struct *mm = NULL;
1443 1444 1445
	struct task_struct *task;
	nodemask_t task_nodes;
	int err;
1446 1447 1448 1449 1450 1451
	nodemask_t *old;
	nodemask_t *new;
	NODEMASK_SCRATCH(scratch);

	if (!scratch)
		return -ENOMEM;
1452

1453 1454 1455 1456
	old = &scratch->mask1;
	new = &scratch->mask2;

	err = get_nodes(old, old_nodes, maxnode);
1457
	if (err)
1458
		goto out;
1459

1460
	err = get_nodes(new, new_nodes, maxnode);
1461
	if (err)
1462
		goto out;
1463 1464

	/* Find the mm_struct */
1465
	rcu_read_lock();
1466
	task = pid ? find_task_by_vpid(pid) : current;
1467
	if (!task) {
1468
		rcu_read_unlock();
1469 1470
		err = -ESRCH;
		goto out;
1471
	}
1472
	get_task_struct(task);
1473

1474
	err = -EINVAL;
1475 1476 1477 1478

	/*
	 * 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
1479
	 * capabilities, superuser privileges or the same
1480 1481
	 * userid as the target process.
	 */
1482
	tcred = __task_cred(task);
1483 1484
	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) &&
1485
	    !capable(CAP_SYS_NICE)) {
1486
		rcu_read_unlock();
1487
		err = -EPERM;
1488
		goto out_put;
1489
	}
1490
	rcu_read_unlock();
1491 1492 1493

	task_nodes = cpuset_mems_allowed(task);
	/* Is the user allowed to access the target nodes? */
1494
	if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
1495
		err = -EPERM;
1496
		goto out_put;
1497 1498
	}

1499
	if (!nodes_subset(*new, node_states[N_MEMORY])) {
1500
		err = -EINVAL;
1501
		goto out_put;
1502 1503
	}

1504 1505
	err = security_task_movememory(task);
	if (err)
1506
		goto out_put;
1507

1508 1509
	mm = get_task_mm(task);
	put_task_struct(task);
1510 1511

	if (!mm) {
1512
		err = -EINVAL;
1513 1514 1515 1516 1517
		goto out;
	}

	err = do_migrate_pages(mm, old, new,
		capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1518 1519 1520

	mmput(mm);
out:
1521 1522
	NODEMASK_SCRATCH_FREE(scratch);

1523
	return err;
1524 1525 1526 1527 1528

out_put:
	put_task_struct(task);
	goto out;

1529 1530 1531
}


1532
/* Retrieve NUMA policy */
1533 1534 1535
SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
		unsigned long __user *, nmask, unsigned long, maxnode,
		unsigned long, addr, unsigned long, flags)
1536
{
A
Adrian Bunk 已提交
1537 1538
	int err;
	int uninitialized_var(pval);
1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557
	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
1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578
#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) {
1579 1580 1581
		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
1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619
		/* 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;
1620
	nodemask_t bm;
L
Linus Torvalds 已提交
1621 1622 1623 1624 1625

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

	if (nmask) {
1626
		err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
L
Linus Torvalds 已提交
1627
		nm = compat_alloc_user_space(alloc_size);
1628
		err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
L
Linus Torvalds 已提交
1629 1630 1631 1632 1633 1634 1635 1636 1637 1638
	}

	if (err)
		return -EFAULT;

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

#endif

1639 1640 1641 1642 1643 1644 1645 1646
/*
 * 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.
1647 1648
 * Current or other task's task mempolicy and non-shared vma policies must be
 * protected by task_lock(task) by the caller.
1649 1650 1651 1652
 * 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.
1653
 */
S
Stephen Wilson 已提交
1654
struct mempolicy *get_vma_policy(struct task_struct *task,
1655
		struct vm_area_struct *vma, unsigned long addr)
L
Linus Torvalds 已提交
1656
{
M
Mel Gorman 已提交
1657
	struct mempolicy *pol = get_task_policy(task);
L
Linus Torvalds 已提交
1658 1659

	if (vma) {
1660
		if (vma->vm_ops && vma->vm_ops->get_policy) {
1661 1662 1663 1664
			struct mempolicy *vpol = vma->vm_ops->get_policy(vma,
									addr);
			if (vpol)
				pol = vpol;
1665
		} else if (vma->vm_policy) {
L
Linus Torvalds 已提交
1666
			pol = vma->vm_policy;
1667 1668 1669 1670 1671 1672 1673 1674 1675 1676

			/*
			 * 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
1677 1678 1679 1680 1681 1682
	}
	if (!pol)
		pol = &default_policy;
	return pol;
}

1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706
bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma)
{
	struct mempolicy *pol = get_task_policy(task);
	if (vma) {
		if (vma->vm_ops && vma->vm_ops->get_policy) {
			bool ret = false;

			pol = vma->vm_ops->get_policy(vma, vma->vm_start);
			if (pol && (pol->flags & MPOL_F_MOF))
				ret = true;
			mpol_cond_put(pol);

			return ret;
		} else if (vma->vm_policy) {
			pol = vma->vm_policy;
		}
	}

	if (!pol)
		return default_policy.flags & MPOL_F_MOF;

	return pol->flags & MPOL_F_MOF;
}

1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726
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;
}

1727 1728 1729 1730 1731
/*
 * Return a nodemask representing a mempolicy for filtering nodes for
 * page allocation
 */
static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
1732 1733
{
	/* Lower zones don't get a nodemask applied for MPOL_BIND */
1734
	if (unlikely(policy->mode == MPOL_BIND) &&
1735
			apply_policy_zone(policy, gfp_zone(gfp)) &&
1736 1737 1738 1739 1740 1741
			cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
		return &policy->v.nodes;

	return NULL;
}

1742
/* Return a zonelist indicated by gfp for node representing a mempolicy */
1743 1744
static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
	int nd)
L
Linus Torvalds 已提交
1745
{
1746
	switch (policy->mode) {
L
Linus Torvalds 已提交
1747
	case MPOL_PREFERRED:
1748 1749
		if (!(policy->flags & MPOL_F_LOCAL))
			nd = policy->v.preferred_node;
L
Linus Torvalds 已提交
1750 1751
		break;
	case MPOL_BIND:
1752
		/*
1753 1754
		 * Normally, MPOL_BIND allocations are node-local within the
		 * allowed nodemask.  However, if __GFP_THISNODE is set and the
1755
		 * current node isn't part of the mask, we use the zonelist for
1756
		 * the first node in the mask instead.
1757 1758 1759 1760 1761
		 */
		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
1762 1763 1764
	default:
		BUG();
	}
1765
	return node_zonelist(nd, gfp);
L
Linus Torvalds 已提交
1766 1767 1768 1769 1770 1771 1772 1773 1774
}

/* 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;
1775
	next = next_node(nid, policy->v.nodes);
L
Linus Torvalds 已提交
1776
	if (next >= MAX_NUMNODES)
1777
		next = first_node(policy->v.nodes);
1778 1779
	if (next < MAX_NUMNODES)
		me->il_next = next;
L
Linus Torvalds 已提交
1780 1781 1782
	return nid;
}

1783 1784 1785
/*
 * Depending on the memory policy provide a node from which to allocate the
 * next slab entry.
1786 1787 1788 1789
 * @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.
1790
 */
1791
unsigned slab_node(void)
1792
{
1793 1794 1795 1796 1797 1798
	struct mempolicy *policy;

	if (in_interrupt())
		return numa_node_id();

	policy = current->mempolicy;
1799
	if (!policy || policy->flags & MPOL_F_LOCAL)
1800 1801 1802 1803
		return numa_node_id();

	switch (policy->mode) {
	case MPOL_PREFERRED:
1804 1805 1806 1807
		/*
		 * handled MPOL_F_LOCAL above
		 */
		return policy->v.preferred_node;
1808

1809 1810 1811
	case MPOL_INTERLEAVE:
		return interleave_nodes(policy);

1812
	case MPOL_BIND: {
1813 1814 1815 1816
		/*
		 * Follow bind policy behavior and start allocation at the
		 * first node.
		 */
1817 1818 1819 1820 1821 1822 1823
		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
1824
		return zone ? zone->node : numa_node_id();
1825
	}
1826 1827

	default:
1828
		BUG();
1829 1830 1831
	}
}

L
Linus Torvalds 已提交
1832 1833 1834 1835
/* 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)
{
1836
	unsigned nnodes = nodes_weight(pol->v.nodes);
1837
	unsigned target;
L
Linus Torvalds 已提交
1838
	int c;
J
Jianguo Wu 已提交
1839
	int nid = NUMA_NO_NODE;
L
Linus Torvalds 已提交
1840

1841 1842 1843
	if (!nnodes)
		return numa_node_id();
	target = (unsigned int)off % nnodes;
L
Linus Torvalds 已提交
1844 1845
	c = 0;
	do {
1846
		nid = next_node(nid, pol->v.nodes);
L
Linus Torvalds 已提交
1847 1848 1849 1850 1851
		c++;
	} while (c <= target);
	return nid;
}

1852 1853 1854 1855 1856 1857 1858
/* 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;

1859 1860 1861 1862 1863 1864 1865 1866 1867
		/*
		 * 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);
1868 1869 1870 1871 1872 1873
		off += (addr - vma->vm_start) >> shift;
		return offset_il_node(pol, vma, off);
	} else
		return interleave_nodes(pol);
}

1874 1875
/*
 * Return the bit number of a random bit set in the nodemask.
J
Jianguo Wu 已提交
1876
 * (returns NUMA_NO_NODE if nodemask is empty)
1877 1878 1879
 */
int node_random(const nodemask_t *maskp)
{
J
Jianguo Wu 已提交
1880
	int w, bit = NUMA_NO_NODE;
1881 1882 1883 1884 1885 1886 1887 1888

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

1889
#ifdef CONFIG_HUGETLBFS
1890 1891 1892 1893 1894
/*
 * 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
1895 1896
 * @mpol = pointer to mempolicy pointer for reference counted mempolicy
 * @nodemask = pointer to nodemask pointer for MPOL_BIND nodemask
1897
 *
1898 1899 1900 1901
 * 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.
1902 1903
 *
 * Must be protected by get_mems_allowed()
1904
 */
1905
struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
1906 1907
				gfp_t gfp_flags, struct mempolicy **mpol,
				nodemask_t **nodemask)
1908
{
1909
	struct zonelist *zl;
1910

1911
	*mpol = get_vma_policy(current, vma, addr);
1912
	*nodemask = NULL;	/* assume !MPOL_BIND */
1913

1914 1915
	if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) {
		zl = node_zonelist(interleave_nid(*mpol, vma, addr,
1916
				huge_page_shift(hstate_vma(vma))), gfp_flags);
1917
	} else {
1918
		zl = policy_zonelist(gfp_flags, *mpol, numa_node_id());
1919 1920
		if ((*mpol)->mode == MPOL_BIND)
			*nodemask = &(*mpol)->v.nodes;
1921 1922
	}
	return zl;
1923
}
1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948

/*
 * 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;

1949
	task_lock(current);
1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968
	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();
	}
1969
	task_unlock(current);
1970 1971 1972

	return true;
}
1973
#endif
1974

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
/*
 * 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
2019 2020
/* Allocate a page in interleaved policy.
   Own path because it needs to do special accounting. */
2021 2022
static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
					unsigned nid)
L
Linus Torvalds 已提交
2023 2024 2025 2026
{
	struct zonelist *zl;
	struct page *page;

2027
	zl = node_zonelist(nid, gfp);
L
Linus Torvalds 已提交
2028
	page = __alloc_pages(gfp, order, zl);
2029
	if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
2030
		inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
L
Linus Torvalds 已提交
2031 2032 2033 2034
	return page;
}

/**
2035
 * 	alloc_pages_vma	- Allocate a page for a VMA.
L
Linus Torvalds 已提交
2036 2037 2038 2039 2040 2041 2042 2043
 *
 * 	@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.
 *
2044
 *	@order:Order of the GFP allocation.
L
Linus Torvalds 已提交
2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057
 * 	@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 *
2058
alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
2059
		unsigned long addr, int node)
L
Linus Torvalds 已提交
2060
{
2061
	struct mempolicy *pol;
2062
	struct page *page;
2063 2064 2065 2066 2067
	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
2068

2069
	if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
L
Linus Torvalds 已提交
2070
		unsigned nid;
2071

2072
		nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
2073
		mpol_cond_put(pol);
2074
		page = alloc_page_interleave(gfp, order, nid);
2075 2076 2077
		if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
			goto retry_cpuset;

2078
		return page;
L
Linus Torvalds 已提交
2079
	}
2080 2081
	page = __alloc_pages_nodemask(gfp, order,
				      policy_zonelist(gfp, pol, node),
2082
				      policy_nodemask(gfp, pol));
2083 2084
	if (unlikely(mpol_needs_cond_ref(pol)))
		__mpol_put(pol);
2085 2086
	if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
		goto retry_cpuset;
2087
	return page;
L
Linus Torvalds 已提交
2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104
}

/**
 * 	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.
 *
2105
 *	Don't call cpuset_update_task_memory_state() unless
L
Linus Torvalds 已提交
2106 2107 2108
 *	1) it's ok to take cpuset_sem (can WAIT), and
 *	2) allocating for current task (not interrupt).
 */
A
Al Viro 已提交
2109
struct page *alloc_pages_current(gfp_t gfp, unsigned order)
L
Linus Torvalds 已提交
2110
{
M
Mel Gorman 已提交
2111
	struct mempolicy *pol = get_task_policy(current);
2112
	struct page *page;
2113
	unsigned int cpuset_mems_cookie;
L
Linus Torvalds 已提交
2114

2115
	if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
L
Linus Torvalds 已提交
2116
		pol = &default_policy;
2117

2118 2119 2120
retry_cpuset:
	cpuset_mems_cookie = get_mems_allowed();

2121 2122 2123 2124
	/*
	 * No reference counting needed for current->mempolicy
	 * nor system default_policy
	 */
2125
	if (pol->mode == MPOL_INTERLEAVE)
2126 2127 2128
		page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
	else
		page = __alloc_pages_nodemask(gfp, order,
2129 2130
				policy_zonelist(gfp, pol, numa_node_id()),
				policy_nodemask(gfp, pol));
2131 2132 2133 2134

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

2135
	return page;
L
Linus Torvalds 已提交
2136 2137 2138
}
EXPORT_SYMBOL(alloc_pages_current);

2139 2140 2141 2142 2143 2144 2145 2146 2147 2148
int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
{
	struct mempolicy *pol = mpol_dup(vma_policy(src));

	if (IS_ERR(pol))
		return PTR_ERR(pol);
	dst->vm_policy = pol;
	return 0;
}

2149
/*
2150
 * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
2151 2152 2153 2154
 * 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().
2155 2156 2157
 *
 * 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.
2158 2159
 */

2160 2161
/* Slow path of a mempolicy duplicate */
struct mempolicy *__mpol_dup(struct mempolicy *old)
L
Linus Torvalds 已提交
2162 2163 2164 2165 2166
{
	struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);

	if (!new)
		return ERR_PTR(-ENOMEM);
2167 2168 2169 2170 2171 2172 2173 2174 2175

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

2176
	rcu_read_lock();
2177 2178
	if (current_cpuset_is_being_rebound()) {
		nodemask_t mems = cpuset_mems_allowed(current);
2179 2180 2181 2182
		if (new->flags & MPOL_F_REBINDING)
			mpol_rebind_policy(new, &mems, MPOL_REBIND_STEP2);
		else
			mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
2183
	}
2184
	rcu_read_unlock();
L
Linus Torvalds 已提交
2185 2186 2187 2188 2189
	atomic_set(&new->refcnt, 1);
	return new;
}

/* Slow path of a mempolicy comparison */
2190
bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
L
Linus Torvalds 已提交
2191 2192
{
	if (!a || !b)
2193
		return false;
2194
	if (a->mode != b->mode)
2195
		return false;
B
Bob Liu 已提交
2196
	if (a->flags != b->flags)
2197
		return false;
B
Bob Liu 已提交
2198 2199
	if (mpol_store_user_nodemask(a))
		if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask))
2200
			return false;
B
Bob Liu 已提交
2201

2202
	switch (a->mode) {
2203 2204
	case MPOL_BIND:
		/* Fall through */
L
Linus Torvalds 已提交
2205
	case MPOL_INTERLEAVE:
2206
		return !!nodes_equal(a->v.nodes, b->v.nodes);
L
Linus Torvalds 已提交
2207
	case MPOL_PREFERRED:
2208
		return a->v.preferred_node == b->v.preferred_node;
L
Linus Torvalds 已提交
2209 2210
	default:
		BUG();
2211
		return false;
L
Linus Torvalds 已提交
2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224
	}
}

/*
 * 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 */
2225
/* Caller holds sp->lock */
L
Linus Torvalds 已提交
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
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);
2276
	pr_debug("inserting %lx-%lx: %d\n", new->start, new->end,
2277
		 new->policy ? new->policy->mode : 0);
L
Linus Torvalds 已提交
2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288
}

/* 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;
2289
	spin_lock(&sp->lock);
L
Linus Torvalds 已提交
2290 2291 2292 2293 2294
	sn = sp_lookup(sp, idx, idx+1);
	if (sn) {
		mpol_get(sn->policy);
		pol = sn->policy;
	}
2295
	spin_unlock(&sp->lock);
L
Linus Torvalds 已提交
2296 2297 2298
	return pol;
}

2299 2300 2301 2302 2303 2304
static void sp_free(struct sp_node *n)
{
	mpol_put(n->policy);
	kmem_cache_free(sn_cache, n);
}

2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333
#ifdef CONFIG_NUMA_BALANCING
static bool numa_migrate_deferred(struct task_struct *p, int last_cpupid)
{
	/* Never defer a private fault */
	if (cpupid_match_pid(p, last_cpupid))
		return false;

	if (p->numa_migrate_deferred) {
		p->numa_migrate_deferred--;
		return true;
	}
	return false;
}

static inline void defer_numa_migrate(struct task_struct *p)
{
	p->numa_migrate_deferred = sysctl_numa_balancing_migrate_deferred;
}
#else
static inline bool numa_migrate_deferred(struct task_struct *p, int last_cpupid)
{
	return false;
}

static inline void defer_numa_migrate(struct task_struct *p)
{
}
#endif /* CONFIG_NUMA_BALANCING */

2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356
/**
 * 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;
2357 2358
	int thiscpu = raw_smp_processor_id();
	int thisnid = cpu_to_node(thiscpu);
2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403
	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
2404 2405

	/* Migrate the page towards the node whose CPU is referencing it */
2406
	if (pol->flags & MPOL_F_MORON) {
2407 2408
		int last_cpupid;
		int this_cpupid;
2409

2410 2411
		polnid = thisnid;
		this_cpupid = cpu_pid_to_cpupid(thiscpu, current->pid);
M
Mel Gorman 已提交
2412

2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433
		/*
		 * 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.
		 */
2434
		last_cpupid = page_cpupid_xchg_last(page, this_cpupid);
2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452
		if (!cpupid_pid_unset(last_cpupid) && cpupid_to_nid(last_cpupid) != thisnid) {

			/* See sysctl_numa_balancing_migrate_deferred comment */
			if (!cpupid_match_pid(current, last_cpupid))
				defer_numa_migrate(current);

			goto out;
		}

		/*
		 * The quadratic filter above reduces extraneous migration
		 * of shared pages somewhat. This code reduces it even more,
		 * reducing the overhead of page migrations of shared pages.
		 * This makes workloads with shared pages rely more on
		 * "move task near its memory", and less on "move memory
		 * towards its task", which is exactly what we want.
		 */
		if (numa_migrate_deferred(current, last_cpupid))
2453 2454 2455
			goto out;
	}

2456 2457 2458 2459 2460 2461 2462 2463
	if (curnid != polnid)
		ret = polnid;
out:
	mpol_cond_put(pol);

	return ret;
}

L
Linus Torvalds 已提交
2464 2465
static void sp_delete(struct shared_policy *sp, struct sp_node *n)
{
2466
	pr_debug("deleting %lx-l%lx\n", n->start, n->end);
L
Linus Torvalds 已提交
2467
	rb_erase(&n->nd, &sp->root);
2468
	sp_free(n);
L
Linus Torvalds 已提交
2469 2470
}

2471 2472 2473 2474 2475 2476 2477 2478
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
2479 2480
static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
				struct mempolicy *pol)
L
Linus Torvalds 已提交
2481
{
2482 2483
	struct sp_node *n;
	struct mempolicy *newpol;
L
Linus Torvalds 已提交
2484

2485
	n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
L
Linus Torvalds 已提交
2486 2487
	if (!n)
		return NULL;
2488 2489 2490 2491 2492 2493 2494

	newpol = mpol_dup(pol);
	if (IS_ERR(newpol)) {
		kmem_cache_free(sn_cache, n);
		return NULL;
	}
	newpol->flags |= MPOL_F_SHARED;
2495
	sp_node_init(n, start, end, newpol);
2496

L
Linus Torvalds 已提交
2497 2498 2499 2500 2501 2502 2503
	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)
{
2504
	struct sp_node *n;
2505 2506
	struct sp_node *n_new = NULL;
	struct mempolicy *mpol_new = NULL;
2507
	int ret = 0;
L
Linus Torvalds 已提交
2508

2509 2510
restart:
	spin_lock(&sp->lock);
L
Linus Torvalds 已提交
2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522
	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) {
2523 2524 2525 2526 2527
				if (!n_new)
					goto alloc_new;

				*mpol_new = *n->policy;
				atomic_set(&mpol_new->refcnt, 1);
2528
				sp_node_init(n_new, end, n->end, mpol_new);
L
Linus Torvalds 已提交
2529
				n->end = start;
2530
				sp_insert(sp, n_new);
2531 2532
				n_new = NULL;
				mpol_new = NULL;
L
Linus Torvalds 已提交
2533 2534 2535 2536 2537 2538 2539 2540 2541 2542
				break;
			} else
				n->end = start;
		}
		if (!next)
			break;
		n = rb_entry(next, struct sp_node, nd);
	}
	if (new)
		sp_insert(sp, new);
2543 2544 2545 2546 2547 2548 2549 2550 2551
	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);

2552
	return ret;
2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563

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
2564 2565
}

2566 2567 2568 2569 2570 2571 2572 2573
/**
 * 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.
2574
 * This is called at get_inode() calls and we can use GFP_KERNEL.
2575 2576 2577
 */
void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
{
2578 2579
	int ret;

2580
	sp->root = RB_ROOT;		/* empty tree == default mempolicy */
2581
	spin_lock_init(&sp->lock);
2582 2583 2584 2585

	if (mpol) {
		struct vm_area_struct pvma;
		struct mempolicy *new;
2586
		NODEMASK_SCRATCH(scratch);
2587

2588
		if (!scratch)
2589
			goto put_mpol;
2590 2591
		/* contextualize the tmpfs mount point mempolicy */
		new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
2592
		if (IS_ERR(new))
2593
			goto free_scratch; /* no valid nodemask intersection */
2594 2595

		task_lock(current);
2596
		ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
2597
		task_unlock(current);
2598
		if (ret)
2599
			goto put_new;
2600 2601 2602 2603 2604

		/* 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 */
2605

2606
put_new:
2607
		mpol_put(new);			/* drop initial ref */
2608
free_scratch:
2609
		NODEMASK_SCRATCH_FREE(scratch);
2610 2611
put_mpol:
		mpol_put(mpol);	/* drop our incoming ref on sb mpol */
2612 2613 2614
	}
}

L
Linus Torvalds 已提交
2615 2616 2617 2618 2619 2620 2621
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);

2622
	pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n",
L
Linus Torvalds 已提交
2623
		 vma->vm_pgoff,
2624
		 sz, npol ? npol->mode : -1,
2625
		 npol ? npol->flags : -1,
D
David Rientjes 已提交
2626
		 npol ? nodes_addr(npol->v.nodes)[0] : NUMA_NO_NODE);
L
Linus Torvalds 已提交
2627 2628 2629 2630 2631 2632 2633 2634

	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)
2635
		sp_free(new);
L
Linus Torvalds 已提交
2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646
	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;
2647
	spin_lock(&p->lock);
L
Linus Torvalds 已提交
2648 2649 2650 2651
	next = rb_first(&p->root);
	while (next) {
		n = rb_entry(next, struct sp_node, nd);
		next = rb_next(&n->nd);
2652
		sp_delete(p, n);
L
Linus Torvalds 已提交
2653
	}
2654
	spin_unlock(&p->lock);
L
Linus Torvalds 已提交
2655 2656
}

2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700
#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
2701 2702 2703
/* assumes fs == KERNEL_DS */
void __init numa_policy_init(void)
{
2704 2705 2706 2707
	nodemask_t interleave_nodes;
	unsigned long largest = 0;
	int nid, prefer = 0;

L
Linus Torvalds 已提交
2708 2709
	policy_cache = kmem_cache_create("numa_policy",
					 sizeof(struct mempolicy),
2710
					 0, SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
2711 2712 2713

	sn_cache = kmem_cache_create("shared_policy_node",
				     sizeof(struct sp_node),
2714
				     0, SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
2715

M
Mel Gorman 已提交
2716 2717 2718 2719 2720 2721 2722 2723 2724
	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, },
		};
	}

2725 2726 2727 2728 2729 2730
	/*
	 * 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);
2731
	for_each_node_state(nid, N_MEMORY) {
2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747
		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
2748

2749
	if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
L
Linus Torvalds 已提交
2750
		printk("numa_policy_init: interleaving failed\n");
2751 2752

	check_numabalancing_enable();
L
Linus Torvalds 已提交
2753 2754
}

2755
/* Reset policy of current process to default */
L
Linus Torvalds 已提交
2756 2757
void numa_default_policy(void)
{
2758
	do_set_mempolicy(MPOL_DEFAULT, 0, NULL);
L
Linus Torvalds 已提交
2759
}
2760

2761 2762 2763 2764
/*
 * Parse and format mempolicy from/to strings
 */

2765
/*
2766
 * "local" is implemented internally by MPOL_PREFERRED with MPOL_F_LOCAL flag.
2767
 */
2768 2769 2770 2771 2772 2773
static const char * const policy_modes[] =
{
	[MPOL_DEFAULT]    = "default",
	[MPOL_PREFERRED]  = "prefer",
	[MPOL_BIND]       = "bind",
	[MPOL_INTERLEAVE] = "interleave",
L
Lee Schermerhorn 已提交
2774
	[MPOL_LOCAL]      = "local",
2775
};
2776

2777 2778 2779

#ifdef CONFIG_TMPFS
/**
2780
 * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
2781
 * @str:  string containing mempolicy to parse
2782
 * @mpol:  pointer to struct mempolicy pointer, returned on success.
2783 2784 2785 2786
 *
 * Format of input:
 *	<mode>[=<flags>][:<nodelist>]
 *
2787
 * On success, returns 0, else 1
2788
 */
2789
int mpol_parse_str(char *str, struct mempolicy **mpol)
2790
{
2791
	struct mempolicy *new = NULL;
2792
	unsigned short mode;
2793
	unsigned short mode_flags;
2794
	nodemask_t nodes;
2795 2796 2797 2798 2799 2800 2801
	char *nodelist = strchr(str, ':');
	char *flags = strchr(str, '=');
	int err = 1;

	if (nodelist) {
		/* NUL-terminate mode or flags string */
		*nodelist++ = '\0';
2802
		if (nodelist_parse(nodelist, nodes))
2803
			goto out;
2804
		if (!nodes_subset(nodes, node_states[N_MEMORY]))
2805
			goto out;
2806 2807 2808
	} else
		nodes_clear(nodes);

2809 2810 2811
	if (flags)
		*flags++ = '\0';	/* terminate mode string */

2812
	for (mode = 0; mode < MPOL_MAX; mode++) {
2813
		if (!strcmp(str, policy_modes[mode])) {
2814 2815 2816
			break;
		}
	}
2817
	if (mode >= MPOL_MAX)
2818 2819
		goto out;

2820
	switch (mode) {
2821
	case MPOL_PREFERRED:
2822 2823 2824
		/*
		 * Insist on a nodelist of one node only
		 */
2825 2826 2827 2828
		if (nodelist) {
			char *rest = nodelist;
			while (isdigit(*rest))
				rest++;
2829 2830
			if (*rest)
				goto out;
2831 2832 2833 2834 2835 2836 2837
		}
		break;
	case MPOL_INTERLEAVE:
		/*
		 * Default to online nodes with memory if no nodelist
		 */
		if (!nodelist)
2838
			nodes = node_states[N_MEMORY];
2839
		break;
2840
	case MPOL_LOCAL:
2841
		/*
2842
		 * Don't allow a nodelist;  mpol_new() checks flags
2843
		 */
2844
		if (nodelist)
2845
			goto out;
2846
		mode = MPOL_PREFERRED;
2847
		break;
2848 2849 2850 2851 2852 2853 2854
	case MPOL_DEFAULT:
		/*
		 * Insist on a empty nodelist
		 */
		if (!nodelist)
			err = 0;
		goto out;
2855 2856 2857 2858 2859 2860
	case MPOL_BIND:
		/*
		 * Insist on a nodelist
		 */
		if (!nodelist)
			goto out;
2861 2862
	}

2863
	mode_flags = 0;
2864 2865 2866 2867 2868 2869
	if (flags) {
		/*
		 * Currently, we only support two mutually exclusive
		 * mode flags.
		 */
		if (!strcmp(flags, "static"))
2870
			mode_flags |= MPOL_F_STATIC_NODES;
2871
		else if (!strcmp(flags, "relative"))
2872
			mode_flags |= MPOL_F_RELATIVE_NODES;
2873
		else
2874
			goto out;
2875
	}
2876 2877 2878

	new = mpol_new(mode, mode_flags, &nodes);
	if (IS_ERR(new))
2879 2880
		goto out;

2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897
	/*
	 * 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;

2898
	err = 0;
2899

2900 2901 2902 2903 2904 2905
out:
	/* Restore string for error message */
	if (nodelist)
		*--nodelist = ':';
	if (flags)
		*--flags = '=';
2906 2907
	if (!err)
		*mpol = new;
2908 2909 2910 2911
	return err;
}
#endif /* CONFIG_TMPFS */

2912 2913 2914 2915 2916 2917
/**
 * 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
 *
2918 2919 2920
 * Convert @pol into a string.  If @buffer is too short, truncate the string.
 * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
 * longest flag, "relative", and to display at least a few node ids.
2921
 */
2922
void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
2923 2924
{
	char *p = buffer;
2925 2926 2927
	nodemask_t nodes = NODE_MASK_NONE;
	unsigned short mode = MPOL_DEFAULT;
	unsigned short flags = 0;
2928

2929
	if (pol && pol != &default_policy) {
2930
		mode = pol->mode;
2931 2932
		flags = pol->flags;
	}
2933

2934 2935 2936 2937
	switch (mode) {
	case MPOL_DEFAULT:
		break;
	case MPOL_PREFERRED:
2938
		if (flags & MPOL_F_LOCAL)
2939
			mode = MPOL_LOCAL;
2940
		else
2941
			node_set(pol->v.preferred_node, nodes);
2942 2943 2944
		break;
	case MPOL_BIND:
	case MPOL_INTERLEAVE:
2945
		nodes = pol->v.nodes;
2946 2947
		break;
	default:
2948 2949 2950
		WARN_ON_ONCE(1);
		snprintf(p, maxlen, "unknown");
		return;
2951 2952
	}

2953
	p += snprintf(p, maxlen, policy_modes[mode]);
2954

2955
	if (flags & MPOL_MODE_FLAGS) {
2956
		p += snprintf(p, buffer + maxlen - p, "=");
2957

2958 2959 2960
		/*
		 * Currently, the only defined flags are mutually exclusive
		 */
2961
		if (flags & MPOL_F_STATIC_NODES)
2962 2963 2964
			p += snprintf(p, buffer + maxlen - p, "static");
		else if (flags & MPOL_F_RELATIVE_NODES)
			p += snprintf(p, buffer + maxlen - p, "relative");
2965 2966
	}

2967
	if (!nodes_empty(nodes)) {
2968
		p += snprintf(p, buffer + maxlen - p, ":");
2969 2970 2971
	 	p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);
	}
}