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Diffstat (limited to 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 1138 |
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(¤t->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(¤t->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); +} |