Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1138 insertions, 0 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
new file mode 100644
index 000000000000..a3b44a671cec
--- /dev/null
+++ b/mm/mempolicy.c
@@ -0,0 +1,1138 @@
+/*
+ * Simple NUMA memory policy for the Linux kernel.
+ *
+ * Copyright 2003,2004 Andi Kleen, SuSE Labs.
+ * 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.
+ * bind           Only allocate memory on a specific set of nodes,
+ *                no fallback.
+ * preferred       Try a specific node first before normal fallback.
+ *                As a special case node -1 here means do the allocation
+ *                on the local CPU. This is normally identical to default,
+ *                but useful to set in a VMA when you have a non default
+ *                process policy.
+ * 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.
+   could replace all the switch()es with a mempolicy_ops structure.
+*/
+
+#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/mm.h>
+#include <linux/nodemask.h>
+#include <linux/cpuset.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/compat.h>
+#include <linux/mempolicy.h>
+#include <asm/tlbflush.h>
+#include <asm/uaccess.h>
+
+static kmem_cache_t *policy_cache;
+static kmem_cache_t *sn_cache;
+
+#define PDprintk(fmt...)
+
+/* Highest zone. An specific allocation for a zone below that is not
+   policied. */
+static int policy_zone;
+
+static struct mempolicy default_policy = {
+	.refcnt = ATOMIC_INIT(1), /* never free it */
+	.policy = MPOL_DEFAULT,
+};
+
+/* Check if all specified nodes are online */
+static int nodes_online(unsigned long *nodes)
+{
+	DECLARE_BITMAP(online2, MAX_NUMNODES);
+
+	bitmap_copy(online2, nodes_addr(node_online_map), MAX_NUMNODES);
+	if (bitmap_empty(online2, MAX_NUMNODES))
+		set_bit(0, online2);
+	if (!bitmap_subset(nodes, online2, MAX_NUMNODES))
+		return -EINVAL;
+	return 0;
+}
+
+/* Do sanity checking on a policy */
+static int mpol_check_policy(int mode, unsigned long *nodes)
+{
+	int empty = bitmap_empty(nodes, MAX_NUMNODES);
+
+	switch (mode) {
+	case MPOL_DEFAULT:
+		if (!empty)
+			return -EINVAL;
+		break;
+	case MPOL_BIND:
+	case MPOL_INTERLEAVE:
+		/* Preferred will only use the first bit, but allow
+		   more for now. */
+		if (empty)
+			return -EINVAL;
+		break;
+	}
+	return nodes_online(nodes);
+}
+
+/* Copy a node mask from user space. */
+static int get_nodes(unsigned long *nodes, unsigned long __user *nmask,
+		     unsigned long maxnode, int mode)
+{
+	unsigned long k;
+	unsigned long nlongs;
+	unsigned long endmask;
+
+	--maxnode;
+	bitmap_zero(nodes, MAX_NUMNODES);
+	if (maxnode == 0 || !nmask)
+		return 0;
+
+	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, nmask, nlongs*sizeof(unsigned long)))
+		return -EFAULT;
+	nodes[nlongs-1] &= endmask;
+	/* Update current mems_allowed */
+	cpuset_update_current_mems_allowed();
+	/* Ignore nodes not set in current->mems_allowed */
+	cpuset_restrict_to_mems_allowed(nodes);
+	return mpol_check_policy(mode, nodes);
+}
+
+/* Generate a custom zonelist for the BIND policy. */
+static struct zonelist *bind_zonelist(unsigned long *nodes)
+{
+	struct zonelist *zl;
+	int num, max, nd;
+
+	max = 1 + MAX_NR_ZONES * bitmap_weight(nodes, MAX_NUMNODES);
+	zl = kmalloc(sizeof(void *) * max, GFP_KERNEL);
+	if (!zl)
+		return NULL;
+	num = 0;
+	for (nd = find_first_bit(nodes, MAX_NUMNODES);
+	     nd < MAX_NUMNODES;
+	     nd = find_next_bit(nodes, MAX_NUMNODES, 1+nd)) {
+		int k;
+		for (k = MAX_NR_ZONES-1; k >= 0; k--) {
+			struct zone *z = &NODE_DATA(nd)->node_zones[k];
+			if (!z->present_pages)
+				continue;
+			zl->zones[num++] = z;
+			if (k > policy_zone)
+				policy_zone = k;
+		}
+	}
+	BUG_ON(num >= max);
+	zl->zones[num] = NULL;
+	return zl;
+}
+
+/* Create a new policy */
+static struct mempolicy *mpol_new(int mode, unsigned long *nodes)
+{
+	struct mempolicy *policy;
+
+	PDprintk("setting mode %d nodes[0] %lx\n", mode, nodes[0]);
+	if (mode == MPOL_DEFAULT)
+		return NULL;
+	policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
+	if (!policy)
+		return ERR_PTR(-ENOMEM);
+	atomic_set(&policy->refcnt, 1);
+	switch (mode) {
+	case MPOL_INTERLEAVE:
+		bitmap_copy(policy->v.nodes, nodes, MAX_NUMNODES);
+		break;
+	case MPOL_PREFERRED:
+		policy->v.preferred_node = find_first_bit(nodes, MAX_NUMNODES);
+		if (policy->v.preferred_node >= MAX_NUMNODES)
+			policy->v.preferred_node = -1;
+		break;
+	case MPOL_BIND:
+		policy->v.zonelist = bind_zonelist(nodes);
+		if (policy->v.zonelist == NULL) {
+			kmem_cache_free(policy_cache, policy);
+			return ERR_PTR(-ENOMEM);
+		}
+		break;
+	}
+	policy->policy = mode;
+	return policy;
+}
+
+/* Ensure all existing pages follow the policy. */
+static int
+verify_pages(struct mm_struct *mm,
+	     unsigned long addr, unsigned long end, unsigned long *nodes)
+{
+	while (addr < end) {
+		struct page *p;
+		pte_t *pte;
+		pmd_t *pmd;
+		pud_t *pud;
+		pgd_t *pgd;
+		pgd = pgd_offset(mm, addr);
+		if (pgd_none(*pgd)) {
+			unsigned long next = (addr + PGDIR_SIZE) & PGDIR_MASK;
+			if (next > addr)
+				break;
+			addr = next;
+			continue;
+		}
+		pud = pud_offset(pgd, addr);
+		if (pud_none(*pud)) {
+			addr = (addr + PUD_SIZE) & PUD_MASK;
+			continue;
+		}
+		pmd = pmd_offset(pud, addr);
+		if (pmd_none(*pmd)) {
+			addr = (addr + PMD_SIZE) & PMD_MASK;
+			continue;
+		}
+		p = NULL;
+		pte = pte_offset_map(pmd, addr);
+		if (pte_present(*pte))
+			p = pte_page(*pte);
+		pte_unmap(pte);
+		if (p) {
+			unsigned nid = page_to_nid(p);
+			if (!test_bit(nid, nodes))
+				return -EIO;
+		}
+		addr += PAGE_SIZE;
+	}
+	return 0;
+}
+
+/* Step 1: check the range */
+static struct vm_area_struct *
+check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
+	    unsigned long *nodes, unsigned long flags)
+{
+	int err;
+	struct vm_area_struct *first, *vma, *prev;
+
+	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) {
+		if (!vma->vm_next && vma->vm_end < end)
+			return ERR_PTR(-EFAULT);
+		if (prev && prev->vm_end < vma->vm_start)
+			return ERR_PTR(-EFAULT);
+		if ((flags & MPOL_MF_STRICT) && !is_vm_hugetlb_page(vma)) {
+			err = verify_pages(vma->vm_mm,
+					   vma->vm_start, vma->vm_end, nodes);
+			if (err) {
+				first = ERR_PTR(err);
+				break;
+			}
+		}
+		prev = vma;
+	}
+	return first;
+}
+
+/* Apply policy to a single VMA */
+static int policy_vma(struct vm_area_struct *vma, struct mempolicy *new)
+{
+	int err = 0;
+	struct mempolicy *old = vma->vm_policy;
+
+	PDprintk("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);
+
+	if (vma->vm_ops && vma->vm_ops->set_policy)
+		err = vma->vm_ops->set_policy(vma, new);
+	if (!err) {
+		mpol_get(new);
+		vma->vm_policy = new;
+		mpol_free(old);
+	}
+	return err;
+}
+
+/* Step 2: apply policy to a range and do splits. */
+static int mbind_range(struct vm_area_struct *vma, unsigned long start,
+		       unsigned long end, struct mempolicy *new)
+{
+	struct vm_area_struct *next;
+	int err;
+
+	err = 0;
+	for (; vma && vma->vm_start < end; vma = next) {
+		next = vma->vm_next;
+		if (vma->vm_start < start)
+			err = split_vma(vma->vm_mm, vma, start, 1);
+		if (!err && vma->vm_end > end)
+			err = split_vma(vma->vm_mm, vma, end, 0);
+		if (!err)
+			err = policy_vma(vma, new);
+		if (err)
+			break;
+	}
+	return err;
+}
+
+/* Change policy for a memory range */
+asmlinkage long sys_mbind(unsigned long start, unsigned long len,
+			  unsigned long mode,
+			  unsigned long __user *nmask, unsigned long maxnode,
+			  unsigned flags)
+{
+	struct vm_area_struct *vma;
+	struct mm_struct *mm = current->mm;
+	struct mempolicy *new;
+	unsigned long end;
+	DECLARE_BITMAP(nodes, MAX_NUMNODES);
+	int err;
+
+	if ((flags & ~(unsigned long)(MPOL_MF_STRICT)) || mode > MPOL_MAX)
+		return -EINVAL;
+	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;
+
+	err = get_nodes(nodes, nmask, maxnode, mode);
+	if (err)
+		return err;
+
+	new = mpol_new(mode, nodes);
+	if (IS_ERR(new))
+		return PTR_ERR(new);
+
+	PDprintk("mbind %lx-%lx mode:%ld nodes:%lx\n",start,start+len,
+			mode,nodes[0]);
+
+	down_write(&mm->mmap_sem);
+	vma = check_range(mm, start, end, nodes, flags);
+	err = PTR_ERR(vma);
+	if (!IS_ERR(vma))
+		err = mbind_range(vma, start, end, new);
+	up_write(&mm->mmap_sem);
+	mpol_free(new);
+	return err;
+}
+
+/* Set the process memory policy */
+asmlinkage long sys_set_mempolicy(int mode, unsigned long __user *nmask,
+				   unsigned long maxnode)
+{
+	int err;
+	struct mempolicy *new;
+	DECLARE_BITMAP(nodes, MAX_NUMNODES);
+
+	if (mode > MPOL_MAX)
+		return -EINVAL;
+	err = get_nodes(nodes, nmask, maxnode, mode);
+	if (err)
+		return err;
+	new = mpol_new(mode, nodes);
+	if (IS_ERR(new))
+		return PTR_ERR(new);
+	mpol_free(current->mempolicy);
+	current->mempolicy = new;
+	if (new && new->policy == MPOL_INTERLEAVE)
+		current->il_next = find_first_bit(new->v.nodes, MAX_NUMNODES);
+	return 0;
+}
+
+/* Fill a zone bitmap for a policy */
+static void get_zonemask(struct mempolicy *p, unsigned long *nodes)
+{
+	int i;
+
+	bitmap_zero(nodes, MAX_NUMNODES);
+	switch (p->policy) {
+	case MPOL_BIND:
+		for (i = 0; p->v.zonelist->zones[i]; i++)
+			__set_bit(p->v.zonelist->zones[i]->zone_pgdat->node_id, nodes);
+		break;
+	case MPOL_DEFAULT:
+		break;
+	case MPOL_INTERLEAVE:
+		bitmap_copy(nodes, p->v.nodes, MAX_NUMNODES);
+		break;
+	case MPOL_PREFERRED:
+		/* or use current node instead of online map? */
+		if (p->v.preferred_node < 0)
+			bitmap_copy(nodes, nodes_addr(node_online_map), MAX_NUMNODES);
+		else
+			__set_bit(p->v.preferred_node, nodes);
+		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;
+}
+
+/* Copy a kernel node mask to user space */
+static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
+			      void *nodes, unsigned nbytes)
+{
+	unsigned long copy = ALIGN(maxnode-1, 64) / 8;
+
+	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, copy) ? -EFAULT : 0;
+}
+
+/* Retrieve NUMA policy */
+asmlinkage long sys_get_mempolicy(int __user *policy,
+				  unsigned long __user *nmask,
+				  unsigned long maxnode,
+				  unsigned long addr, unsigned long flags)
+{
+	int err, pval;
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma = NULL;
+	struct mempolicy *pol = current->mempolicy;
+
+	if (flags & ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR))
+		return -EINVAL;
+	if (nmask != NULL && maxnode < MAX_NUMNODES)
+		return -EINVAL;
+	if (flags & MPOL_F_ADDR) {
+		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)
+		pol = &default_policy;
+
+	if (flags & MPOL_F_NODE) {
+		if (flags & MPOL_F_ADDR) {
+			err = lookup_node(mm, addr);
+			if (err < 0)
+				goto out;
+			pval = err;
+		} else if (pol == current->mempolicy &&
+				pol->policy == MPOL_INTERLEAVE) {
+			pval = current->il_next;
+		} else {
+			err = -EINVAL;
+			goto out;
+		}
+	} else
+		pval = pol->policy;
+
+	if (vma) {
+		up_read(&current->mm->mmap_sem);
+		vma = NULL;
+	}
+
+	if (policy && put_user(pval, policy))
+		return -EFAULT;
+
+	err = 0;
+	if (nmask) {
+		DECLARE_BITMAP(nodes, MAX_NUMNODES);
+		get_zonemask(pol, nodes);
+		err = copy_nodes_to_user(nmask, maxnode, nodes, sizeof(nodes));
+	}
+
+ out:
+	if (vma)
+		up_read(&current->mm->mmap_sem);
+	return err;
+}
+
+#ifdef CONFIG_COMPAT
+
+asmlinkage long compat_sys_get_mempolicy(int __user *policy,
+				     compat_ulong_t __user *nmask,
+				     compat_ulong_t maxnode,
+				     compat_ulong_t addr, compat_ulong_t flags)
+{
+	long err;
+	unsigned long __user *nm = NULL;
+	unsigned long nr_bits, alloc_size;
+	DECLARE_BITMAP(bm, MAX_NUMNODES);
+
+	nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
+	alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
+
+	if (nmask)
+		nm = compat_alloc_user_space(alloc_size);
+
+	err = sys_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
+
+	if (!err && nmask) {
+		err = copy_from_user(bm, nm, alloc_size);
+		/* ensure entire bitmap is zeroed */
+		err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
+		err |= compat_put_bitmap(nmask, bm, nr_bits);
+	}
+
+	return err;
+}
+
+asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
+				     compat_ulong_t maxnode)
+{
+	long err = 0;
+	unsigned long __user *nm = NULL;
+	unsigned long nr_bits, alloc_size;
+	DECLARE_BITMAP(bm, MAX_NUMNODES);
+
+	nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
+	alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
+
+	if (nmask) {
+		err = compat_get_bitmap(bm, nmask, nr_bits);
+		nm = compat_alloc_user_space(alloc_size);
+		err |= copy_to_user(nm, bm, alloc_size);
+	}
+
+	if (err)
+		return -EFAULT;
+
+	return sys_set_mempolicy(mode, nm, nr_bits+1);
+}
+
+asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
+			     compat_ulong_t mode, compat_ulong_t __user *nmask,
+			     compat_ulong_t maxnode, compat_ulong_t flags)
+{
+	long err = 0;
+	unsigned long __user *nm = NULL;
+	unsigned long nr_bits, alloc_size;
+	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_mbind(start, len, mode, nm, nr_bits+1, flags);
+}
+
+#endif
+
+/* Return effective policy for a VMA */
+static struct mempolicy *
+get_vma_policy(struct vm_area_struct *vma, unsigned long addr)
+{
+	struct mempolicy *pol = current->mempolicy;
+
+	if (vma) {
+		if (vma->vm_ops && vma->vm_ops->get_policy)
+		        pol = vma->vm_ops->get_policy(vma, addr);
+		else if (vma->vm_policy &&
+				vma->vm_policy->policy != MPOL_DEFAULT)
+			pol = vma->vm_policy;
+	}
+	if (!pol)
+		pol = &default_policy;
+	return pol;
+}
+
+/* Return a zonelist representing a mempolicy */
+static struct zonelist *zonelist_policy(unsigned int __nocast gfp, struct mempolicy *policy)
+{
+	int nd;
+
+	switch (policy->policy) {
+	case MPOL_PREFERRED:
+		nd = policy->v.preferred_node;
+		if (nd < 0)
+			nd = numa_node_id();
+		break;
+	case MPOL_BIND:
+		/* Lower zones don't get a policy applied */
+		/* Careful: current->mems_allowed might have moved */
+		if (gfp >= policy_zone)
+			if (cpuset_zonelist_valid_mems_allowed(policy->v.zonelist))
+				return policy->v.zonelist;
+		/*FALL THROUGH*/
+	case MPOL_INTERLEAVE: /* should not happen */
+	case MPOL_DEFAULT:
+		nd = numa_node_id();
+		break;
+	default:
+		nd = 0;
+		BUG();
+	}
+	return NODE_DATA(nd)->node_zonelists + (gfp & GFP_ZONEMASK);
+}
+
+/* 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;
+	BUG_ON(nid >= MAX_NUMNODES);
+	next = find_next_bit(policy->v.nodes, MAX_NUMNODES, 1+nid);
+	if (next >= MAX_NUMNODES)
+		next = find_first_bit(policy->v.nodes, MAX_NUMNODES);
+	me->il_next = next;
+	return nid;
+}
+
+/* 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)
+{
+	unsigned nnodes = bitmap_weight(pol->v.nodes, MAX_NUMNODES);
+	unsigned target = (unsigned)off % nnodes;
+	int c;
+	int nid = -1;
+
+	c = 0;
+	do {
+		nid = find_next_bit(pol->v.nodes, MAX_NUMNODES, nid+1);
+		c++;
+	} while (c <= target);
+	BUG_ON(nid >= MAX_NUMNODES);
+	BUG_ON(!test_bit(nid, pol->v.nodes));
+	return nid;
+}
+
+/* Allocate a page in interleaved policy.
+   Own path because it needs to do special accounting. */
+static struct page *alloc_page_interleave(unsigned int __nocast gfp, unsigned order, unsigned nid)
+{
+	struct zonelist *zl;
+	struct page *page;
+
+	BUG_ON(!node_online(nid));
+	zl = NODE_DATA(nid)->node_zonelists + (gfp & GFP_ZONEMASK);
+	page = __alloc_pages(gfp, order, zl);
+	if (page && page_zone(page) == zl->zones[0]) {
+		zl->zones[0]->pageset[get_cpu()].interleave_hit++;
+		put_cpu();
+	}
+	return page;
+}
+
+/**
+ * 	alloc_page_vma	- Allocate a page for a VMA.
+ *
+ * 	@gfp:
+ *      %GFP_USER    user allocation.
+ *      %GFP_KERNEL  kernel allocations,
+ *      %GFP_HIGHMEM highmem/user allocations,
+ *      %GFP_FS      allocation should not call back into a file system.
+ *      %GFP_ATOMIC  don't sleep.
+ *
+ * 	@vma:  Pointer to VMA or NULL if not available.
+ *	@addr: Virtual Address of the allocation. Must be inside the VMA.
+ *
+ * 	This function allocates a page from the kernel page pool and applies
+ *	a NUMA policy associated with the VMA or the current process.
+ *	When VMA is not NULL caller must hold down_read on the mmap_sem of the
+ *	mm_struct of the VMA to prevent it from going away. Should be used for
+ *	all allocations for pages that will be mapped into
+ * 	user space. Returns NULL when no page can be allocated.
+ *
+ *	Should be called with the mm_sem of the vma hold.
+ */
+struct page *
+alloc_page_vma(unsigned int __nocast gfp, struct vm_area_struct *vma, unsigned long addr)
+{
+	struct mempolicy *pol = get_vma_policy(vma, addr);
+
+	cpuset_update_current_mems_allowed();
+
+	if (unlikely(pol->policy == MPOL_INTERLEAVE)) {
+		unsigned nid;
+		if (vma) {
+			unsigned long off;
+			BUG_ON(addr >= vma->vm_end);
+			BUG_ON(addr < vma->vm_start);
+			off = vma->vm_pgoff;
+			off += (addr - vma->vm_start) >> PAGE_SHIFT;
+			nid = offset_il_node(pol, vma, off);
+		} else {
+			/* fall back to process interleaving */
+			nid = interleave_nodes(pol);
+		}
+		return alloc_page_interleave(gfp, 0, nid);
+	}
+	return __alloc_pages(gfp, 0, zonelist_policy(gfp, pol));
+}
+
+/**
+ * 	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.
+ *
+ *	Don't call cpuset_update_current_mems_allowed() unless
+ *	1) it's ok to take cpuset_sem (can WAIT), and
+ *	2) allocating for current task (not interrupt).
+ */
+struct page *alloc_pages_current(unsigned int __nocast gfp, unsigned order)
+{
+	struct mempolicy *pol = current->mempolicy;
+
+	if ((gfp & __GFP_WAIT) && !in_interrupt())
+		cpuset_update_current_mems_allowed();
+	if (!pol || in_interrupt())
+		pol = &default_policy;
+	if (pol->policy == MPOL_INTERLEAVE)
+		return alloc_page_interleave(gfp, order, interleave_nodes(pol));
+	return __alloc_pages(gfp, order, zonelist_policy(gfp, pol));
+}
+EXPORT_SYMBOL(alloc_pages_current);
+
+/* Slow path of a mempolicy copy */
+struct mempolicy *__mpol_copy(struct mempolicy *old)
+{
+	struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
+
+	if (!new)
+		return ERR_PTR(-ENOMEM);
+	*new = *old;
+	atomic_set(&new->refcnt, 1);
+	if (new->policy == MPOL_BIND) {
+		int sz = ksize(old->v.zonelist);
+		new->v.zonelist = kmalloc(sz, SLAB_KERNEL);
+		if (!new->v.zonelist) {
+			kmem_cache_free(policy_cache, new);
+			return ERR_PTR(-ENOMEM);
+		}
+		memcpy(new->v.zonelist, old->v.zonelist, sz);
+	}
+	return new;
+}
+
+/* Slow path of a mempolicy comparison */
+int __mpol_equal(struct mempolicy *a, struct mempolicy *b)
+{
+	if (!a || !b)
+		return 0;
+	if (a->policy != b->policy)
+		return 0;
+	switch (a->policy) {
+	case MPOL_DEFAULT:
+		return 1;
+	case MPOL_INTERLEAVE:
+		return bitmap_equal(a->v.nodes, b->v.nodes, MAX_NUMNODES);
+	case MPOL_PREFERRED:
+		return a->v.preferred_node == b->v.preferred_node;
+	case MPOL_BIND: {
+		int i;
+		for (i = 0; a->v.zonelist->zones[i]; i++)
+			if (a->v.zonelist->zones[i] != b->v.zonelist->zones[i])
+				return 0;
+		return b->v.zonelist->zones[i] == NULL;
+	}
+	default:
+		BUG();
+		return 0;
+	}
+}
+
+/* Slow path of a mpol destructor. */
+void __mpol_free(struct mempolicy *p)
+{
+	if (!atomic_dec_and_test(&p->refcnt))
+		return;
+	if (p->policy == MPOL_BIND)
+		kfree(p->v.zonelist);
+	p->policy = MPOL_DEFAULT;
+	kmem_cache_free(policy_cache, p);
+}
+
+/*
+ * Hugetlb policy. Same as above, just works with node numbers instead of
+ * zonelists.
+ */
+
+/* Find first node suitable for an allocation */
+int mpol_first_node(struct vm_area_struct *vma, unsigned long addr)
+{
+	struct mempolicy *pol = get_vma_policy(vma, addr);
+
+	switch (pol->policy) {
+	case MPOL_DEFAULT:
+		return numa_node_id();
+	case MPOL_BIND:
+		return pol->v.zonelist->zones[0]->zone_pgdat->node_id;
+	case MPOL_INTERLEAVE:
+		return interleave_nodes(pol);
+	case MPOL_PREFERRED:
+		return pol->v.preferred_node >= 0 ?
+				pol->v.preferred_node : numa_node_id();
+	}
+	BUG();
+	return 0;
+}
+
+/* Find secondary valid nodes for an allocation */
+int mpol_node_valid(int nid, struct vm_area_struct *vma, unsigned long addr)
+{
+	struct mempolicy *pol = get_vma_policy(vma, addr);
+
+	switch (pol->policy) {
+	case MPOL_PREFERRED:
+	case MPOL_DEFAULT:
+	case MPOL_INTERLEAVE:
+		return 1;
+	case MPOL_BIND: {
+		struct zone **z;
+		for (z = pol->v.zonelist->zones; *z; z++)
+			if ((*z)->zone_pgdat->node_id == nid)
+				return 1;
+		return 0;
+	}
+	default:
+		BUG();
+		return 0;
+	}
+}
+
+/*
+ * Shared memory backing store policy support.
+ *
+ * Remember policies even when nobody has shared memory mapped.
+ * The policies are kept in Red-Black tree linked from the inode.
+ * They are protected by the sp->lock spinlock, which should be held
+ * for any accesses to the tree.
+ */
+
+/* lookup first element intersecting start-end */
+/* Caller holds sp->lock */
+static struct sp_node *
+sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
+{
+	struct rb_node *n = sp->root.rb_node;
+
+	while (n) {
+		struct sp_node *p = rb_entry(n, struct sp_node, nd);
+
+		if (start >= p->end)
+			n = n->rb_right;
+		else if (end <= p->start)
+			n = n->rb_left;
+		else
+			break;
+	}
+	if (!n)
+		return NULL;
+	for (;;) {
+		struct sp_node *w = NULL;
+		struct rb_node *prev = rb_prev(n);
+		if (!prev)
+			break;
+		w = rb_entry(prev, struct sp_node, nd);
+		if (w->end <= start)
+			break;
+		n = prev;
+	}
+	return rb_entry(n, struct sp_node, nd);
+}
+
+/* Insert a new shared policy into the list. */
+/* Caller holds sp->lock */
+static void sp_insert(struct shared_policy *sp, struct sp_node *new)
+{
+	struct rb_node **p = &sp->root.rb_node;
+	struct rb_node *parent = NULL;
+	struct sp_node *nd;
+
+	while (*p) {
+		parent = *p;
+		nd = rb_entry(parent, struct sp_node, nd);
+		if (new->start < nd->start)
+			p = &(*p)->rb_left;
+		else if (new->end > nd->end)
+			p = &(*p)->rb_right;
+		else
+			BUG();
+	}
+	rb_link_node(&new->nd, parent, p);
+	rb_insert_color(&new->nd, &sp->root);
+	PDprintk("inserting %lx-%lx: %d\n", new->start, new->end,
+		 new->policy ? new->policy->policy : 0);
+}
+
+/* Find shared policy intersecting idx */
+struct mempolicy *
+mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
+{
+	struct mempolicy *pol = NULL;
+	struct sp_node *sn;
+
+	if (!sp->root.rb_node)
+		return NULL;
+	spin_lock(&sp->lock);
+	sn = sp_lookup(sp, idx, idx+1);
+	if (sn) {
+		mpol_get(sn->policy);
+		pol = sn->policy;
+	}
+	spin_unlock(&sp->lock);
+	return pol;
+}
+
+static void sp_delete(struct shared_policy *sp, struct sp_node *n)
+{
+	PDprintk("deleting %lx-l%x\n", n->start, n->end);
+	rb_erase(&n->nd, &sp->root);
+	mpol_free(n->policy);
+	kmem_cache_free(sn_cache, n);
+}
+
+struct sp_node *
+sp_alloc(unsigned long start, unsigned long end, struct mempolicy *pol)
+{
+	struct sp_node *n = kmem_cache_alloc(sn_cache, GFP_KERNEL);
+
+	if (!n)
+		return NULL;
+	n->start = start;
+	n->end = end;
+	mpol_get(pol);
+	n->policy = pol;
+	return n;
+}
+
+/* Replace a policy range. */
+static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
+				 unsigned long end, struct sp_node *new)
+{
+	struct sp_node *n, *new2 = NULL;
+
+restart:
+	spin_lock(&sp->lock);
+	n = sp_lookup(sp, start, end);
+	/* Take care of old policies in the same range. */
+	while (n && n->start < end) {
+		struct rb_node *next = rb_next(&n->nd);
+		if (n->start >= start) {
+			if (n->end <= end)
+				sp_delete(sp, n);
+			else
+				n->start = end;
+		} else {
+			/* Old policy spanning whole new range. */
+			if (n->end > end) {
+				if (!new2) {
+					spin_unlock(&sp->lock);
+					new2 = sp_alloc(end, n->end, n->policy);
+					if (!new2)
+						return -ENOMEM;
+					goto restart;
+				}
+				n->end = start;
+				sp_insert(sp, new2);
+				new2 = NULL;
+				break;
+			} else
+				n->end = start;
+		}
+		if (!next)
+			break;
+		n = rb_entry(next, struct sp_node, nd);
+	}
+	if (new)
+		sp_insert(sp, new);
+	spin_unlock(&sp->lock);
+	if (new2) {
+		mpol_free(new2->policy);
+		kmem_cache_free(sn_cache, new2);
+	}
+	return 0;
+}
+
+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);
+
+	PDprintk("set_shared_policy %lx sz %lu %d %lx\n",
+		 vma->vm_pgoff,
+		 sz, npol? npol->policy : -1,
+		npol ? npol->v.nodes[0] : -1);
+
+	if (npol) {
+		new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
+		if (!new)
+			return -ENOMEM;
+	}
+	err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new);
+	if (err && new)
+		kmem_cache_free(sn_cache, new);
+	return err;
+}
+
+/* Free a backing policy store on inode delete. */
+void mpol_free_shared_policy(struct shared_policy *p)
+{
+	struct sp_node *n;
+	struct rb_node *next;
+
+	if (!p->root.rb_node)
+		return;
+	spin_lock(&p->lock);
+	next = rb_first(&p->root);
+	while (next) {
+		n = rb_entry(next, struct sp_node, nd);
+		next = rb_next(&n->nd);
+		mpol_free(n->policy);
+		kmem_cache_free(sn_cache, n);
+	}
+	spin_unlock(&p->lock);
+	p->root = RB_ROOT;
+}
+
+/* assumes fs == KERNEL_DS */
+void __init numa_policy_init(void)
+{
+	policy_cache = kmem_cache_create("numa_policy",
+					 sizeof(struct mempolicy),
+					 0, SLAB_PANIC, NULL, NULL);
+
+	sn_cache = kmem_cache_create("shared_policy_node",
+				     sizeof(struct sp_node),
+				     0, SLAB_PANIC, NULL, NULL);
+
+	/* Set interleaving policy for system init. This way not all
+	   the data structures allocated at system boot end up in node zero. */
+
+	if (sys_set_mempolicy(MPOL_INTERLEAVE, nodes_addr(node_online_map),
+							MAX_NUMNODES) < 0)
+		printk("numa_policy_init: interleaving failed\n");
+}
+
+/* Reset policy of current process to default.
+ * Assumes fs == KERNEL_DS */
+void numa_default_policy(void)
+{
+	sys_set_mempolicy(MPOL_DEFAULT, NULL, 0);
+}