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Diffstat (limited to 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 3163 |
1 files changed, 3163 insertions, 0 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c new file mode 100644 index 000000000..84e11c2ca --- /dev/null +++ b/mm/mempolicy.c @@ -0,0 +1,3163 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Simple NUMA memory policy for the Linux kernel. + * + * Copyright 2003,2004 Andi Kleen, SuSE Labs. + * (C) Copyright 2005 Christoph Lameter, Silicon Graphics, Inc. + * + * 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. + * 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 + * + * preferred Try a specific node first before normal fallback. + * As a special case NUMA_NO_NODE 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. + * + * preferred many Try a set of nodes first before normal fallback. This is + * similar to preferred without the special case. + * + * 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. +*/ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/mempolicy.h> +#include <linux/pagewalk.h> +#include <linux/highmem.h> +#include <linux/hugetlb.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/sched/mm.h> +#include <linux/sched/numa_balancing.h> +#include <linux/sched/task.h> +#include <linux/nodemask.h> +#include <linux/cpuset.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/export.h> +#include <linux/nsproxy.h> +#include <linux/interrupt.h> +#include <linux/init.h> +#include <linux/compat.h> +#include <linux/ptrace.h> +#include <linux/swap.h> +#include <linux/seq_file.h> +#include <linux/proc_fs.h> +#include <linux/migrate.h> +#include <linux/ksm.h> +#include <linux/rmap.h> +#include <linux/security.h> +#include <linux/syscalls.h> +#include <linux/ctype.h> +#include <linux/mm_inline.h> +#include <linux/mmu_notifier.h> +#include <linux/printk.h> +#include <linux/swapops.h> + +#include <asm/tlbflush.h> +#include <asm/tlb.h> +#include <linux/uaccess.h> + +#include "internal.h" + +/* Internal flags */ +#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */ +#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */ + +static struct kmem_cache *policy_cache; +static struct kmem_cache *sn_cache; + +/* Highest zone. An specific allocation for a zone below that is not + policied. */ +enum zone_type policy_zone = 0; + +/* + * run-time system-wide default policy => local allocation + */ +static struct mempolicy default_policy = { + .refcnt = ATOMIC_INIT(1), /* never free it */ + .mode = MPOL_LOCAL, +}; + +static struct mempolicy preferred_node_policy[MAX_NUMNODES]; + +/** + * numa_map_to_online_node - Find closest online node + * @node: Node id to start the search + * + * Lookup the next closest node by distance if @nid is not online. + * + * Return: this @node if it is online, otherwise the closest node by distance + */ +int numa_map_to_online_node(int node) +{ + int min_dist = INT_MAX, dist, n, min_node; + + if (node == NUMA_NO_NODE || node_online(node)) + return node; + + min_node = node; + for_each_online_node(n) { + dist = node_distance(node, n); + if (dist < min_dist) { + min_dist = dist; + min_node = n; + } + } + + return min_node; +} +EXPORT_SYMBOL_GPL(numa_map_to_online_node); + +struct mempolicy *get_task_policy(struct task_struct *p) +{ + struct mempolicy *pol = p->mempolicy; + int node; + + if (pol) + return pol; + + node = numa_node_id(); + if (node != NUMA_NO_NODE) { + pol = &preferred_node_policy[node]; + /* preferred_node_policy is not initialised early in boot */ + if (pol->mode) + return pol; + } + + return &default_policy; +} + +static const struct mempolicy_operations { + int (*create)(struct mempolicy *pol, const nodemask_t *nodes); + void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes); +} mpol_ops[MPOL_MAX]; + +static inline int mpol_store_user_nodemask(const struct mempolicy *pol) +{ + return pol->flags & MPOL_MODE_FLAGS; +} + +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); +} + +static int mpol_new_nodemask(struct mempolicy *pol, const nodemask_t *nodes) +{ + if (nodes_empty(*nodes)) + return -EINVAL; + pol->nodes = *nodes; + return 0; +} + +static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes) +{ + if (nodes_empty(*nodes)) + return -EINVAL; + + nodes_clear(pol->nodes); + node_set(first_node(*nodes), pol->nodes); + return 0; +} + +/* + * 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. + * + * Must be called holding task's alloc_lock to protect task's mems_allowed + * and mempolicy. May also be called holding the mmap_lock for write. + */ +static int mpol_set_nodemask(struct mempolicy *pol, + const nodemask_t *nodes, struct nodemask_scratch *nsc) +{ + int ret; + + /* + * Default (pol==NULL) resp. local memory policies are not a + * subject of any remapping. They also do not need any special + * constructor. + */ + if (!pol || pol->mode == MPOL_LOCAL) + return 0; + + /* Check N_MEMORY */ + nodes_and(nsc->mask1, + cpuset_current_mems_allowed, node_states[N_MEMORY]); + + VM_BUG_ON(!nodes); + + if (pol->flags & MPOL_F_RELATIVE_NODES) + mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1); + else + nodes_and(nsc->mask2, *nodes, nsc->mask1); + + if (mpol_store_user_nodemask(pol)) + pol->w.user_nodemask = *nodes; + else + pol->w.cpuset_mems_allowed = cpuset_current_mems_allowed; + + ret = mpol_ops[pol->mode].create(pol, &nsc->mask2); + return ret; +} + +/* + * This function just creates a new policy, does some check and simple + * initialization. You must invoke mpol_set_nodemask() to set nodes. + */ +static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags, + nodemask_t *nodes) +{ + struct mempolicy *policy; + + pr_debug("setting mode %d flags %d nodes[0] %lx\n", + mode, flags, nodes ? nodes_addr(*nodes)[0] : NUMA_NO_NODE); + + if (mode == MPOL_DEFAULT) { + if (nodes && !nodes_empty(*nodes)) + return ERR_PTR(-EINVAL); + return NULL; + } + 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); + + mode = MPOL_LOCAL; + } + } else if (mode == MPOL_LOCAL) { + if (!nodes_empty(*nodes) || + (flags & MPOL_F_STATIC_NODES) || + (flags & MPOL_F_RELATIVE_NODES)) + return ERR_PTR(-EINVAL); + } else if (nodes_empty(*nodes)) + return ERR_PTR(-EINVAL); + policy = kmem_cache_alloc(policy_cache, GFP_KERNEL); + if (!policy) + return ERR_PTR(-ENOMEM); + atomic_set(&policy->refcnt, 1); + policy->mode = mode; + policy->flags = flags; + policy->home_node = NUMA_NO_NODE; + + return policy; +} + +/* 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); +} + +static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes) +{ +} + +static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes) +{ + nodemask_t tmp; + + if (pol->flags & MPOL_F_STATIC_NODES) + nodes_and(tmp, pol->w.user_nodemask, *nodes); + else if (pol->flags & MPOL_F_RELATIVE_NODES) + mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes); + else { + nodes_remap(tmp, pol->nodes, pol->w.cpuset_mems_allowed, + *nodes); + pol->w.cpuset_mems_allowed = *nodes; + } + + if (nodes_empty(tmp)) + tmp = *nodes; + + pol->nodes = tmp; +} + +static void mpol_rebind_preferred(struct mempolicy *pol, + const nodemask_t *nodes) +{ + pol->w.cpuset_mems_allowed = *nodes; +} + +/* + * mpol_rebind_policy - Migrate a policy to a different set of nodes + * + * Per-vma policies are protected by mmap_lock. Allocations using per-task + * policies are protected by task->mems_allowed_seq to prevent a premature + * OOM/allocation failure due to parallel nodemask modification. + */ +static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask) +{ + if (!pol || pol->mode == MPOL_LOCAL) + return; + if (!mpol_store_user_nodemask(pol) && + nodes_equal(pol->w.cpuset_mems_allowed, *newmask)) + return; + + mpol_ops[pol->mode].rebind(pol, newmask); +} + +/* + * Wrapper for mpol_rebind_policy() that just requires task + * pointer, and updates task mempolicy. + * + * Called with task's alloc_lock held. + */ + +void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new) +{ + mpol_rebind_policy(tsk->mempolicy, new); +} + +/* + * Rebind each vma in mm to new nodemask. + * + * Call holding a reference to mm. Takes mm->mmap_lock during call. + */ + +void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new) +{ + struct vm_area_struct *vma; + VMA_ITERATOR(vmi, mm, 0); + + mmap_write_lock(mm); + for_each_vma(vmi, vma) + mpol_rebind_policy(vma->vm_policy, new); + mmap_write_unlock(mm); +} + +static const struct mempolicy_operations mpol_ops[MPOL_MAX] = { + [MPOL_DEFAULT] = { + .rebind = mpol_rebind_default, + }, + [MPOL_INTERLEAVE] = { + .create = mpol_new_nodemask, + .rebind = mpol_rebind_nodemask, + }, + [MPOL_PREFERRED] = { + .create = mpol_new_preferred, + .rebind = mpol_rebind_preferred, + }, + [MPOL_BIND] = { + .create = mpol_new_nodemask, + .rebind = mpol_rebind_nodemask, + }, + [MPOL_LOCAL] = { + .rebind = mpol_rebind_default, + }, + [MPOL_PREFERRED_MANY] = { + .create = mpol_new_nodemask, + .rebind = mpol_rebind_preferred, + }, +}; + +static int migrate_folio_add(struct folio *folio, struct list_head *foliolist, + unsigned long flags); + +struct queue_pages { + struct list_head *pagelist; + unsigned long flags; + nodemask_t *nmask; + unsigned long start; + unsigned long end; + struct vm_area_struct *first; + bool has_unmovable; +}; + +/* + * Check if the page's nid is in qp->nmask. + * + * If MPOL_MF_INVERT is set in qp->flags, check if the nid is + * in the invert of qp->nmask. + */ +static inline bool queue_pages_required(struct page *page, + struct queue_pages *qp) +{ + int nid = page_to_nid(page); + unsigned long flags = qp->flags; + + return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT); +} + +/* + * queue_folios_pmd() has three possible return values: + * 0 - folios are placed on the right node or queued successfully, or + * special page is met, i.e. zero page, or unmovable page is found + * but continue walking (indicated by queue_pages.has_unmovable). + * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an + * existing folio was already on a node that does not follow the + * policy. + */ +static int queue_folios_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr, + unsigned long end, struct mm_walk *walk) + __releases(ptl) +{ + int ret = 0; + struct folio *folio; + struct queue_pages *qp = walk->private; + unsigned long flags; + + if (unlikely(is_pmd_migration_entry(*pmd))) { + ret = -EIO; + goto unlock; + } + folio = pfn_folio(pmd_pfn(*pmd)); + if (is_huge_zero_page(&folio->page)) { + walk->action = ACTION_CONTINUE; + goto unlock; + } + if (!queue_pages_required(&folio->page, qp)) + goto unlock; + + flags = qp->flags; + /* go to folio migration */ + if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) { + if (!vma_migratable(walk->vma) || + migrate_folio_add(folio, qp->pagelist, flags)) { + qp->has_unmovable = true; + goto unlock; + } + } else + ret = -EIO; +unlock: + spin_unlock(ptl); + return ret; +} + +/* + * Scan through pages checking if pages follow certain conditions, + * and move them to the pagelist if they do. + * + * queue_folios_pte_range() has three possible return values: + * 0 - folios are placed on the right node or queued successfully, or + * special page is met, i.e. zero page, or unmovable page is found + * but continue walking (indicated by queue_pages.has_unmovable). + * -EIO - only MPOL_MF_STRICT was specified and an existing folio was already + * on a node that does not follow the policy. + */ +static int queue_folios_pte_range(pmd_t *pmd, unsigned long addr, + unsigned long end, struct mm_walk *walk) +{ + struct vm_area_struct *vma = walk->vma; + struct folio *folio; + struct queue_pages *qp = walk->private; + unsigned long flags = qp->flags; + pte_t *pte, *mapped_pte; + spinlock_t *ptl; + + ptl = pmd_trans_huge_lock(pmd, vma); + if (ptl) + return queue_folios_pmd(pmd, ptl, addr, end, walk); + + if (pmd_trans_unstable(pmd)) + return 0; + + mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + for (; addr != end; pte++, addr += PAGE_SIZE) { + if (!pte_present(*pte)) + continue; + folio = vm_normal_folio(vma, addr, *pte); + if (!folio || folio_is_zone_device(folio)) + continue; + /* + * vm_normal_folio() filters out zero pages, but there might + * still be reserved folios to skip, perhaps in a VDSO. + */ + if (folio_test_reserved(folio)) + continue; + if (!queue_pages_required(&folio->page, qp)) + continue; + if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) { + /* + * MPOL_MF_STRICT must be specified if we get here. + * Continue walking vmas due to MPOL_MF_MOVE* flags. + */ + if (!vma_migratable(vma)) + qp->has_unmovable = true; + + /* + * Do not abort immediately since there may be + * temporary off LRU pages in the range. Still + * need migrate other LRU pages. + */ + if (migrate_folio_add(folio, qp->pagelist, flags)) + qp->has_unmovable = true; + } else + break; + } + pte_unmap_unlock(mapped_pte, ptl); + cond_resched(); + + return addr != end ? -EIO : 0; +} + +static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask, + unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + int ret = 0; +#ifdef CONFIG_HUGETLB_PAGE + struct queue_pages *qp = walk->private; + unsigned long flags = (qp->flags & MPOL_MF_VALID); + struct page *page; + spinlock_t *ptl; + pte_t entry; + + ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte); + entry = huge_ptep_get(pte); + if (!pte_present(entry)) + goto unlock; + page = pte_page(entry); + if (!queue_pages_required(page, qp)) + goto unlock; + + if (flags == MPOL_MF_STRICT) { + /* + * STRICT alone means only detecting misplaced page and no + * need to further check other vma. + */ + ret = -EIO; + goto unlock; + } + + if (!vma_migratable(walk->vma)) { + /* + * Must be STRICT with MOVE*, otherwise .test_walk() have + * stopped walking current vma. + * Detecting misplaced page but allow migrating pages which + * have been queued. + */ + qp->has_unmovable = true; + 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 && + !hugetlb_pmd_shared(pte))) { + if (isolate_hugetlb(page, qp->pagelist) && + (flags & MPOL_MF_STRICT)) + /* + * Failed to isolate page but allow migrating pages + * which have been queued. + */ + qp->has_unmovable = true; + } +unlock: + spin_unlock(ptl); +#else + BUG(); +#endif + return ret; +} + +#ifdef CONFIG_NUMA_BALANCING +/* + * 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. + */ +unsigned long change_prot_numa(struct vm_area_struct *vma, + unsigned long addr, unsigned long end) +{ + struct mmu_gather tlb; + int nr_updated; + + tlb_gather_mmu(&tlb, vma->vm_mm); + + nr_updated = change_protection(&tlb, vma, addr, end, PAGE_NONE, + MM_CP_PROT_NUMA); + if (nr_updated) + count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated); + + tlb_finish_mmu(&tlb); + + return nr_updated; +} +#else +static unsigned long change_prot_numa(struct vm_area_struct *vma, + unsigned long addr, unsigned long end) +{ + return 0; +} +#endif /* CONFIG_NUMA_BALANCING */ + +static int queue_pages_test_walk(unsigned long start, unsigned long end, + struct mm_walk *walk) +{ + struct vm_area_struct *next, *vma = walk->vma; + struct queue_pages *qp = walk->private; + unsigned long endvma = vma->vm_end; + unsigned long flags = qp->flags; + + /* range check first */ + VM_BUG_ON_VMA(!range_in_vma(vma, start, end), vma); + + if (!qp->first) { + qp->first = vma; + if (!(flags & MPOL_MF_DISCONTIG_OK) && + (qp->start < vma->vm_start)) + /* hole at head side of range */ + return -EFAULT; + } + next = find_vma(vma->vm_mm, vma->vm_end); + if (!(flags & MPOL_MF_DISCONTIG_OK) && + ((vma->vm_end < qp->end) && + (!next || vma->vm_end < next->vm_start))) + /* hole at middle or tail of range */ + return -EFAULT; + + /* + * Need check MPOL_MF_STRICT to return -EIO if possible + * regardless of vma_migratable + */ + if (!vma_migratable(vma) && + !(flags & MPOL_MF_STRICT)) + return 1; + + if (endvma > end) + endvma = end; + + if (flags & MPOL_MF_LAZY) { + /* Similar to task_numa_work, skip inaccessible VMAs */ + if (!is_vm_hugetlb_page(vma) && vma_is_accessible(vma) && + !(vma->vm_flags & VM_MIXEDMAP)) + change_prot_numa(vma, start, endvma); + return 1; + } + + /* queue pages from current vma */ + if (flags & MPOL_MF_VALID) + return 0; + return 1; +} + +static const struct mm_walk_ops queue_pages_walk_ops = { + .hugetlb_entry = queue_pages_hugetlb, + .pmd_entry = queue_folios_pte_range, + .test_walk = queue_pages_test_walk, +}; + +/* + * 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. + * + * queue_pages_range() has three possible return values: + * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were + * specified. + * 0 - queue pages successfully or no misplaced page. + * errno - i.e. misplaced pages with MPOL_MF_STRICT specified (-EIO) or + * memory range specified by nodemask and maxnode points outside + * your accessible address space (-EFAULT) + */ +static int +queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end, + nodemask_t *nodes, unsigned long flags, + struct list_head *pagelist) +{ + int err; + struct queue_pages qp = { + .pagelist = pagelist, + .flags = flags, + .nmask = nodes, + .start = start, + .end = end, + .first = NULL, + .has_unmovable = false, + }; + + err = walk_page_range(mm, start, end, &queue_pages_walk_ops, &qp); + + if (qp.has_unmovable) + err = 1; + if (!qp.first) + /* whole range in hole */ + err = -EFAULT; + + return err; +} + +/* + * Apply policy to a single VMA + * This must be called with the mmap_lock held for writing. + */ +static int vma_replace_policy(struct vm_area_struct *vma, + struct mempolicy *pol) +{ + int err; + struct mempolicy *old; + struct mempolicy *new; + + 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); + + new = mpol_dup(pol); + if (IS_ERR(new)) + return PTR_ERR(new); + + if (vma->vm_ops && vma->vm_ops->set_policy) { + err = vma->vm_ops->set_policy(vma, new); + if (err) + goto err_out; + } + + old = vma->vm_policy; + vma->vm_policy = new; /* protected by mmap_lock */ + mpol_put(old); + + return 0; + err_out: + mpol_put(new); + return err; +} + +/* Split or merge the VMA (if required) and apply the new policy */ +static int mbind_range(struct vma_iterator *vmi, struct vm_area_struct *vma, + struct vm_area_struct **prev, unsigned long start, + unsigned long end, struct mempolicy *new_pol) +{ + struct vm_area_struct *merged; + unsigned long vmstart, vmend; + pgoff_t pgoff; + int err; + + vmend = min(end, vma->vm_end); + if (start > vma->vm_start) { + *prev = vma; + vmstart = start; + } else { + vmstart = vma->vm_start; + } + + if (mpol_equal(vma_policy(vma), new_pol)) { + *prev = vma; + return 0; + } + + pgoff = vma->vm_pgoff + ((vmstart - vma->vm_start) >> PAGE_SHIFT); + merged = vma_merge(vma->vm_mm, *prev, vmstart, vmend, vma->vm_flags, + vma->anon_vma, vma->vm_file, pgoff, new_pol, + vma->vm_userfaultfd_ctx, anon_vma_name(vma)); + if (merged) { + *prev = merged; + /* vma_merge() invalidated the mas */ + mas_pause(&vmi->mas); + return vma_replace_policy(merged, new_pol); + } + + if (vma->vm_start != vmstart) { + err = split_vma(vma->vm_mm, vma, vmstart, 1); + if (err) + return err; + /* split_vma() invalidated the mas */ + mas_pause(&vmi->mas); + } + + if (vma->vm_end != vmend) { + err = split_vma(vma->vm_mm, vma, vmend, 0); + if (err) + return err; + /* split_vma() invalidated the mas */ + mas_pause(&vmi->mas); + } + + *prev = vma; + return vma_replace_policy(vma, new_pol); +} + +/* Set the process memory policy */ +static long do_set_mempolicy(unsigned short mode, unsigned short flags, + nodemask_t *nodes) +{ + struct mempolicy *new, *old; + NODEMASK_SCRATCH(scratch); + int ret; + + if (!scratch) + return -ENOMEM; + + new = mpol_new(mode, flags, nodes); + if (IS_ERR(new)) { + ret = PTR_ERR(new); + goto out; + } + + task_lock(current); + ret = mpol_set_nodemask(new, nodes, scratch); + if (ret) { + task_unlock(current); + mpol_put(new); + goto out; + } + + old = current->mempolicy; + current->mempolicy = new; + if (new && new->mode == MPOL_INTERLEAVE) + current->il_prev = MAX_NUMNODES-1; + task_unlock(current); + mpol_put(old); + ret = 0; +out: + NODEMASK_SCRATCH_FREE(scratch); + return ret; +} + +/* + * Return nodemask for policy for get_mempolicy() query + * + * Called with task's alloc_lock held + */ +static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes) +{ + nodes_clear(*nodes); + if (p == &default_policy) + return; + + switch (p->mode) { + case MPOL_BIND: + case MPOL_INTERLEAVE: + case MPOL_PREFERRED: + case MPOL_PREFERRED_MANY: + *nodes = p->nodes; + break; + case MPOL_LOCAL: + /* return empty node mask for local allocation */ + break; + default: + BUG(); + } +} + +static int lookup_node(struct mm_struct *mm, unsigned long addr) +{ + struct page *p = NULL; + int ret; + + ret = get_user_pages_fast(addr & PAGE_MASK, 1, 0, &p); + if (ret > 0) { + ret = page_to_nid(p); + put_page(p); + } + return ret; +} + +/* Retrieve NUMA policy */ +static long do_get_mempolicy(int *policy, nodemask_t *nmask, + unsigned long addr, unsigned long flags) +{ + int err; + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma = NULL; + struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL; + + if (flags & + ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED)) + return -EINVAL; + + if (flags & MPOL_F_MEMS_ALLOWED) { + if (flags & (MPOL_F_NODE|MPOL_F_ADDR)) + return -EINVAL; + *policy = 0; /* just so it's initialized */ + task_lock(current); + *nmask = cpuset_current_mems_allowed; + task_unlock(current); + return 0; + } + + if (flags & MPOL_F_ADDR) { + /* + * 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. + */ + mmap_read_lock(mm); + vma = vma_lookup(mm, addr); + if (!vma) { + mmap_read_unlock(mm); + 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; /* indicates default behavior */ + + if (flags & MPOL_F_NODE) { + if (flags & MPOL_F_ADDR) { + /* + * Take a refcount on the mpol, because we are about to + * drop the mmap_lock, after which only "pol" remains + * valid, "vma" is stale. + */ + pol_refcount = pol; + vma = NULL; + mpol_get(pol); + mmap_read_unlock(mm); + err = lookup_node(mm, addr); + if (err < 0) + goto out; + *policy = err; + } else if (pol == current->mempolicy && + pol->mode == MPOL_INTERLEAVE) { + *policy = next_node_in(current->il_prev, pol->nodes); + } else { + err = -EINVAL; + goto out; + } + } else { + *policy = pol == &default_policy ? MPOL_DEFAULT : + pol->mode; + /* + * Internal mempolicy flags must be masked off before exposing + * the policy to userspace. + */ + *policy |= (pol->flags & MPOL_MODE_FLAGS); + } + + err = 0; + if (nmask) { + if (mpol_store_user_nodemask(pol)) { + *nmask = pol->w.user_nodemask; + } else { + task_lock(current); + get_policy_nodemask(pol, nmask); + task_unlock(current); + } + } + + out: + mpol_cond_put(pol); + if (vma) + mmap_read_unlock(mm); + if (pol_refcount) + mpol_put(pol_refcount); + return err; +} + +#ifdef CONFIG_MIGRATION +static int migrate_folio_add(struct folio *folio, struct list_head *foliolist, + unsigned long flags) +{ + /* + * We try to migrate only unshared folios. If it is shared it + * is likely not worth migrating. + * + * To check if the folio is shared, ideally we want to make sure + * every page is mapped to the same process. Doing that is very + * expensive, so check the estimated mapcount of the folio instead. + */ + if ((flags & MPOL_MF_MOVE_ALL) || folio_estimated_sharers(folio) == 1) { + if (!folio_isolate_lru(folio)) { + list_add_tail(&folio->lru, foliolist); + node_stat_mod_folio(folio, + NR_ISOLATED_ANON + folio_is_file_lru(folio), + folio_nr_pages(folio)); + } else if (flags & MPOL_MF_STRICT) { + /* + * Non-movable folio may reach here. And, there may be + * temporary off LRU folios or non-LRU movable folios. + * Treat them as unmovable folios since they can't be + * isolated, so they can't be moved at the moment. It + * should return -EIO for this case too. + */ + return -EIO; + } + } + + return 0; +} + +/* + * Migrate pages from one node to a target node. + * Returns error or the number of pages not migrated. + */ +static int migrate_to_node(struct mm_struct *mm, int source, int dest, + int flags) +{ + nodemask_t nmask; + struct vm_area_struct *vma; + LIST_HEAD(pagelist); + int err = 0; + struct migration_target_control mtc = { + .nid = dest, + .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, + }; + + nodes_clear(nmask); + node_set(source, nmask); + + /* + * 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. + */ + vma = find_vma(mm, 0); + VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))); + queue_pages_range(mm, vma->vm_start, mm->task_size, &nmask, + flags | MPOL_MF_DISCONTIG_OK, &pagelist); + + if (!list_empty(&pagelist)) { + err = migrate_pages(&pagelist, alloc_migration_target, NULL, + (unsigned long)&mtc, MIGRATE_SYNC, MR_SYSCALL, NULL); + if (err) + putback_movable_pages(&pagelist); + } + + return err; +} + +/* + * Move pages between the two nodesets so as to preserve the physical + * layout as much as possible. + * + * Returns the number of page that could not be moved. + */ +int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, + const nodemask_t *to, int flags) +{ + int busy = 0; + int err = 0; + nodemask_t tmp; + + lru_cache_disable(); + + mmap_read_lock(mm); + + /* + * Find a 'source' bit set in 'tmp' whose corresponding 'dest' + * bit in 'to' is not also set in 'tmp'. Clear the found 'source' + * bit in 'tmp', and return that <source, dest> pair for migration. + * The pair of nodemasks 'to' and 'from' define the map. + * + * If no pair of bits is found that way, fallback to picking some + * pair of 'source' and 'dest' bits that are not the same. If the + * 'source' and 'dest' bits are the same, this represents a node + * that will be migrating to itself, so no pages need move. + * + * If no bits are left in 'tmp', or if all remaining bits left + * in 'tmp' correspond to the same bit in 'to', return false + * (nothing left to migrate). + * + * This lets us pick a pair of nodes to migrate between, such that + * if possible the dest node is not already occupied by some other + * source node, minimizing the risk of overloading the memory on a + * node that would happen if we migrated incoming memory to a node + * before migrating outgoing memory source that same node. + * + * A single scan of tmp is sufficient. As we go, we remember the + * most recent <s, d> pair that moved (s != d). If we find a pair + * that not only moved, but what's better, moved to an empty slot + * (d is not set in tmp), then we break out then, with that pair. + * Otherwise when we finish scanning from_tmp, we at least have the + * most recent <s, d> pair that moved. If we get all the way through + * the scan of tmp without finding any node that moved, much less + * moved to an empty node, then there is nothing left worth migrating. + */ + + tmp = *from; + while (!nodes_empty(tmp)) { + int s, d; + int source = NUMA_NO_NODE; + int dest = 0; + + for_each_node_mask(s, tmp) { + + /* + * 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. + */ + + if ((nodes_weight(*from) != nodes_weight(*to)) && + (node_isset(s, *to))) + continue; + + d = node_remap(s, *from, *to); + if (s == d) + continue; + + source = s; /* Node moved. Memorize */ + dest = d; + + /* dest not in remaining from nodes? */ + if (!node_isset(dest, tmp)) + break; + } + if (source == NUMA_NO_NODE) + break; + + node_clear(source, tmp); + err = migrate_to_node(mm, source, dest, flags); + if (err > 0) + busy += err; + if (err < 0) + break; + } + mmap_read_unlock(mm); + + lru_cache_enable(); + if (err < 0) + return err; + return busy; + +} + +/* + * Allocate a new page for page migration based on vma policy. + * Start by assuming the page is mapped by the same vma as contains @start. + * 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. + */ +static struct page *new_page(struct page *page, unsigned long start) +{ + struct folio *dst, *src = page_folio(page); + struct vm_area_struct *vma; + unsigned long address; + VMA_ITERATOR(vmi, current->mm, start); + gfp_t gfp = GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL; + + for_each_vma(vmi, vma) { + address = page_address_in_vma(page, vma); + if (address != -EFAULT) + break; + } + + if (folio_test_hugetlb(src)) + return alloc_huge_page_vma(page_hstate(&src->page), + vma, address); + + if (folio_test_large(src)) + gfp = GFP_TRANSHUGE; + + /* + * if !vma, vma_alloc_folio() will use task or system default policy + */ + dst = vma_alloc_folio(gfp, folio_order(src), vma, address, + folio_test_large(src)); + return &dst->page; +} +#else + +static int migrate_folio_add(struct folio *folio, struct list_head *foliolist, + unsigned long flags) +{ + return -EIO; +} + +int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, + const nodemask_t *to, int flags) +{ + return -ENOSYS; +} + +static struct page *new_page(struct page *page, unsigned long start) +{ + return NULL; +} +#endif + +static long do_mbind(unsigned long start, unsigned long len, + unsigned short mode, unsigned short mode_flags, + nodemask_t *nmask, unsigned long flags) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma, *prev; + struct vma_iterator vmi; + struct mempolicy *new; + unsigned long end; + int err; + int ret; + LIST_HEAD(pagelist); + + if (flags & ~(unsigned long)MPOL_MF_VALID) + return -EINVAL; + if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE)) + return -EPERM; + + if (start & ~PAGE_MASK) + return -EINVAL; + + if (mode == MPOL_DEFAULT) + flags &= ~MPOL_MF_STRICT; + + len = PAGE_ALIGN(len); + end = start + len; + + if (end < start) + return -EINVAL; + if (end == start) + return 0; + + new = mpol_new(mode, mode_flags, nmask); + if (IS_ERR(new)) + return PTR_ERR(new); + + if (flags & MPOL_MF_LAZY) + new->flags |= MPOL_F_MOF; + + /* + * If we are using the default policy then operation + * on discontinuous address spaces is okay after all + */ + if (!new) + flags |= MPOL_MF_DISCONTIG_OK; + + pr_debug("mbind %lx-%lx mode:%d flags:%d nodes:%lx\n", + start, start + len, mode, mode_flags, + nmask ? nodes_addr(*nmask)[0] : NUMA_NO_NODE); + + if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) { + + lru_cache_disable(); + } + { + NODEMASK_SCRATCH(scratch); + if (scratch) { + mmap_write_lock(mm); + err = mpol_set_nodemask(new, nmask, scratch); + if (err) + mmap_write_unlock(mm); + } else + err = -ENOMEM; + NODEMASK_SCRATCH_FREE(scratch); + } + if (err) + goto mpol_out; + + ret = queue_pages_range(mm, start, end, nmask, + flags | MPOL_MF_INVERT, &pagelist); + + if (ret < 0) { + err = ret; + goto up_out; + } + + vma_iter_init(&vmi, mm, start); + prev = vma_prev(&vmi); + for_each_vma_range(vmi, vma, end) { + err = mbind_range(&vmi, vma, &prev, start, end, new); + if (err) + break; + } + + if (!err) { + int nr_failed = 0; + + if (!list_empty(&pagelist)) { + WARN_ON_ONCE(flags & MPOL_MF_LAZY); + nr_failed = migrate_pages(&pagelist, new_page, NULL, + start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND, NULL); + if (nr_failed) + putback_movable_pages(&pagelist); + } + + if (((ret > 0) || nr_failed) && (flags & MPOL_MF_STRICT)) + err = -EIO; + } else { +up_out: + if (!list_empty(&pagelist)) + putback_movable_pages(&pagelist); + } + + mmap_write_unlock(mm); +mpol_out: + mpol_put(new); + if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) + lru_cache_enable(); + return err; +} + +/* + * User space interface with variable sized bitmaps for nodelists. + */ +static int get_bitmap(unsigned long *mask, const unsigned long __user *nmask, + unsigned long maxnode) +{ + unsigned long nlongs = BITS_TO_LONGS(maxnode); + int ret; + + if (in_compat_syscall()) + ret = compat_get_bitmap(mask, + (const compat_ulong_t __user *)nmask, + maxnode); + else + ret = copy_from_user(mask, nmask, + nlongs * sizeof(unsigned long)); + + if (ret) + return -EFAULT; + + if (maxnode % BITS_PER_LONG) + mask[nlongs - 1] &= (1UL << (maxnode % BITS_PER_LONG)) - 1; + + return 0; +} + +/* Copy a node mask from user space. */ +static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask, + unsigned long maxnode) +{ + --maxnode; + nodes_clear(*nodes); + if (maxnode == 0 || !nmask) + return 0; + if (maxnode > PAGE_SIZE*BITS_PER_BYTE) + return -EINVAL; + + /* + * When the user specified more nodes than supported just check + * if the non supported part is all zero, one word at a time, + * starting at the end. + */ + while (maxnode > MAX_NUMNODES) { + unsigned long bits = min_t(unsigned long, maxnode, BITS_PER_LONG); + unsigned long t; + + if (get_bitmap(&t, &nmask[(maxnode - 1) / BITS_PER_LONG], bits)) + return -EFAULT; + + if (maxnode - bits >= MAX_NUMNODES) { + maxnode -= bits; + } else { + maxnode = MAX_NUMNODES; + t &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1); + } + if (t) + return -EINVAL; + } + + return get_bitmap(nodes_addr(*nodes), nmask, maxnode); +} + +/* 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; + unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long); + bool compat = in_compat_syscall(); + + if (compat) + nbytes = BITS_TO_COMPAT_LONGS(nr_node_ids) * sizeof(compat_long_t); + + if (copy > nbytes) { + if (copy > PAGE_SIZE) + return -EINVAL; + if (clear_user((char __user *)mask + nbytes, copy - nbytes)) + return -EFAULT; + copy = nbytes; + maxnode = nr_node_ids; + } + + if (compat) + return compat_put_bitmap((compat_ulong_t __user *)mask, + nodes_addr(*nodes), maxnode); + + return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0; +} + +/* Basic parameter sanity check used by both mbind() and set_mempolicy() */ +static inline int sanitize_mpol_flags(int *mode, unsigned short *flags) +{ + *flags = *mode & MPOL_MODE_FLAGS; + *mode &= ~MPOL_MODE_FLAGS; + + if ((unsigned int)(*mode) >= MPOL_MAX) + return -EINVAL; + if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES)) + return -EINVAL; + if (*flags & MPOL_F_NUMA_BALANCING) { + if (*mode != MPOL_BIND) + return -EINVAL; + *flags |= (MPOL_F_MOF | MPOL_F_MORON); + } + return 0; +} + +static long kernel_mbind(unsigned long start, unsigned long len, + unsigned long mode, const unsigned long __user *nmask, + unsigned long maxnode, unsigned int flags) +{ + unsigned short mode_flags; + nodemask_t nodes; + int lmode = mode; + int err; + + start = untagged_addr(start); + err = sanitize_mpol_flags(&lmode, &mode_flags); + if (err) + return err; + + err = get_nodes(&nodes, nmask, maxnode); + if (err) + return err; + + return do_mbind(start, len, lmode, mode_flags, &nodes, flags); +} + +SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, len, + unsigned long, home_node, unsigned long, flags) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma, *prev; + struct mempolicy *new; + unsigned long end; + int err = -ENOENT; + VMA_ITERATOR(vmi, mm, start); + + start = untagged_addr(start); + if (start & ~PAGE_MASK) + return -EINVAL; + /* + * flags is used for future extension if any. + */ + if (flags != 0) + return -EINVAL; + + /* + * Check home_node is online to avoid accessing uninitialized + * NODE_DATA. + */ + if (home_node >= MAX_NUMNODES || !node_online(home_node)) + return -EINVAL; + + len = PAGE_ALIGN(len); + end = start + len; + + if (end < start) + return -EINVAL; + if (end == start) + return 0; + mmap_write_lock(mm); + prev = vma_prev(&vmi); + for_each_vma_range(vmi, vma, end) { + new = mpol_dup(vma_policy(vma)); + if (IS_ERR(new)) { + err = PTR_ERR(new); + break; + } + /* + * Only update home node if there is an existing vma policy + */ + if (!new) { + prev = vma; + continue; + } + + /* + * If any vma in the range got policy other than MPOL_BIND + * or MPOL_PREFERRED_MANY we return error. We don't reset + * the home node for vmas we already updated before. + */ + if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) { + mpol_put(new); + err = -EOPNOTSUPP; + break; + } + + new->home_node = home_node; + err = mbind_range(&vmi, vma, &prev, start, end, new); + mpol_put(new); + if (err) + break; + } + mmap_write_unlock(mm); + return err; +} + +SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len, + unsigned long, mode, const unsigned long __user *, nmask, + unsigned long, maxnode, unsigned int, flags) +{ + return kernel_mbind(start, len, mode, nmask, maxnode, flags); +} + +/* Set the process memory policy */ +static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask, + unsigned long maxnode) +{ + unsigned short mode_flags; + nodemask_t nodes; + int lmode = mode; + int err; + + err = sanitize_mpol_flags(&lmode, &mode_flags); + if (err) + return err; + + err = get_nodes(&nodes, nmask, maxnode); + if (err) + return err; + + return do_set_mempolicy(lmode, mode_flags, &nodes); +} + +SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask, + unsigned long, maxnode) +{ + return kernel_set_mempolicy(mode, nmask, maxnode); +} + +static int kernel_migrate_pages(pid_t pid, unsigned long maxnode, + const unsigned long __user *old_nodes, + const unsigned long __user *new_nodes) +{ + struct mm_struct *mm = NULL; + struct task_struct *task; + nodemask_t task_nodes; + int err; + nodemask_t *old; + nodemask_t *new; + NODEMASK_SCRATCH(scratch); + + if (!scratch) + return -ENOMEM; + + old = &scratch->mask1; + new = &scratch->mask2; + + err = get_nodes(old, old_nodes, maxnode); + if (err) + goto out; + + err = get_nodes(new, new_nodes, maxnode); + if (err) + goto out; + + /* Find the mm_struct */ + rcu_read_lock(); + task = pid ? find_task_by_vpid(pid) : current; + if (!task) { + rcu_read_unlock(); + err = -ESRCH; + goto out; + } + get_task_struct(task); + + err = -EINVAL; + + /* + * Check if this process has the right to modify the specified process. + * Use the regular "ptrace_may_access()" checks. + */ + if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) { + rcu_read_unlock(); + err = -EPERM; + goto out_put; + } + rcu_read_unlock(); + + task_nodes = cpuset_mems_allowed(task); + /* Is the user allowed to access the target nodes? */ + if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) { + err = -EPERM; + goto out_put; + } + + task_nodes = cpuset_mems_allowed(current); + nodes_and(*new, *new, task_nodes); + if (nodes_empty(*new)) + goto out_put; + + err = security_task_movememory(task); + if (err) + goto out_put; + + mm = get_task_mm(task); + put_task_struct(task); + + if (!mm) { + err = -EINVAL; + goto out; + } + + err = do_migrate_pages(mm, old, new, + capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE); + + mmput(mm); +out: + NODEMASK_SCRATCH_FREE(scratch); + + return err; + +out_put: + put_task_struct(task); + goto out; + +} + +SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode, + const unsigned long __user *, old_nodes, + const unsigned long __user *, new_nodes) +{ + return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes); +} + + +/* Retrieve NUMA policy */ +static int kernel_get_mempolicy(int __user *policy, + unsigned long __user *nmask, + unsigned long maxnode, + unsigned long addr, + unsigned long flags) +{ + int err; + int pval; + nodemask_t nodes; + + if (nmask != NULL && maxnode < nr_node_ids) + return -EINVAL; + + addr = untagged_addr(addr); + + 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; +} + +SYSCALL_DEFINE5(get_mempolicy, int __user *, policy, + unsigned long __user *, nmask, unsigned long, maxnode, + unsigned long, addr, unsigned long, flags) +{ + return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags); +} + +bool vma_migratable(struct vm_area_struct *vma) +{ + if (vma->vm_flags & (VM_IO | VM_PFNMAP)) + return false; + + /* + * DAX device mappings require predictable access latency, so avoid + * incurring periodic faults. + */ + if (vma_is_dax(vma)) + return false; + + if (is_vm_hugetlb_page(vma) && + !hugepage_migration_supported(hstate_vma(vma))) + return false; + + /* + * Migration allocates pages in the highest zone. If we cannot + * do so then migration (at least from node to node) is not + * possible. + */ + if (vma->vm_file && + gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping)) + < policy_zone) + return false; + return true; +} + +struct mempolicy *__get_vma_policy(struct vm_area_struct *vma, + unsigned long addr) +{ + struct mempolicy *pol = NULL; + + if (vma) { + if (vma->vm_ops && vma->vm_ops->get_policy) { + pol = vma->vm_ops->get_policy(vma, addr); + } else if (vma->vm_policy) { + pol = vma->vm_policy; + + /* + * 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); + } + } + + return pol; +} + +/* + * get_vma_policy(@vma, @addr) + * @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 current->mempolicy or system default policy, as necessary. + * 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. + */ +static struct mempolicy *get_vma_policy(struct vm_area_struct *vma, + unsigned long addr) +{ + struct mempolicy *pol = __get_vma_policy(vma, addr); + + if (!pol) + pol = get_task_policy(current); + + return pol; +} + +bool vma_policy_mof(struct vm_area_struct *vma) +{ + struct mempolicy *pol; + + 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; + } + + pol = vma->vm_policy; + if (!pol) + pol = get_task_policy(current); + + return pol->flags & MPOL_F_MOF; +} + +bool 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->nodes has movable memory only, + * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only. + * + * policy->nodes is intersect with node_states[N_MEMORY]. + * so if the following test fails, it implies + * policy->nodes has movable memory only. + */ + if (!nodes_intersects(policy->nodes, node_states[N_HIGH_MEMORY])) + dynamic_policy_zone = ZONE_MOVABLE; + + return zone >= dynamic_policy_zone; +} + +/* + * Return a nodemask representing a mempolicy for filtering nodes for + * page allocation + */ +nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy) +{ + int mode = policy->mode; + + /* Lower zones don't get a nodemask applied for MPOL_BIND */ + if (unlikely(mode == MPOL_BIND) && + apply_policy_zone(policy, gfp_zone(gfp)) && + cpuset_nodemask_valid_mems_allowed(&policy->nodes)) + return &policy->nodes; + + if (mode == MPOL_PREFERRED_MANY) + return &policy->nodes; + + return NULL; +} + +/* + * Return the preferred node id for 'prefer' mempolicy, and return + * the given id for all other policies. + * + * policy_node() is always coupled with policy_nodemask(), which + * secures the nodemask limit for 'bind' and 'prefer-many' policy. + */ +static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd) +{ + if (policy->mode == MPOL_PREFERRED) { + nd = first_node(policy->nodes); + } else { + /* + * __GFP_THISNODE shouldn't even be used with the bind policy + * because we might easily break the expectation to stay on the + * requested node and not break the policy. + */ + WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE)); + } + + if ((policy->mode == MPOL_BIND || + policy->mode == MPOL_PREFERRED_MANY) && + policy->home_node != NUMA_NO_NODE) + return policy->home_node; + + return nd; +} + +/* Do dynamic interleaving for a process */ +static unsigned interleave_nodes(struct mempolicy *policy) +{ + unsigned next; + struct task_struct *me = current; + + next = next_node_in(me->il_prev, policy->nodes); + if (next < MAX_NUMNODES) + me->il_prev = next; + return next; +} + +/* + * Depending on the memory policy provide a node from which to allocate the + * next slab entry. + */ +unsigned int mempolicy_slab_node(void) +{ + struct mempolicy *policy; + int node = numa_mem_id(); + + if (!in_task()) + return node; + + policy = current->mempolicy; + if (!policy) + return node; + + switch (policy->mode) { + case MPOL_PREFERRED: + return first_node(policy->nodes); + + case MPOL_INTERLEAVE: + return interleave_nodes(policy); + + case MPOL_BIND: + case MPOL_PREFERRED_MANY: + { + struct zoneref *z; + + /* + * Follow bind policy behavior and start allocation at the + * first node. + */ + struct zonelist *zonelist; + enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL); + zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK]; + z = first_zones_zonelist(zonelist, highest_zoneidx, + &policy->nodes); + return z->zone ? zone_to_nid(z->zone) : node; + } + case MPOL_LOCAL: + return node; + + default: + BUG(); + } +} + +/* + * Do static interleaving for a VMA with known offset @n. Returns the n'th + * node in pol->nodes (starting from n=0), wrapping around if n exceeds the + * number of present nodes. + */ +static unsigned offset_il_node(struct mempolicy *pol, unsigned long n) +{ + nodemask_t nodemask = pol->nodes; + unsigned int target, nnodes; + int i; + int nid; + /* + * The barrier will stabilize the nodemask in a register or on + * the stack so that it will stop changing under the code. + * + * Between first_node() and next_node(), pol->nodes could be changed + * by other threads. So we put pol->nodes in a local stack. + */ + barrier(); + + nnodes = nodes_weight(nodemask); + if (!nnodes) + return numa_node_id(); + target = (unsigned int)n % nnodes; + nid = first_node(nodemask); + for (i = 0; i < target; i++) + nid = next_node(nid, nodemask); + return nid; +} + +/* 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; + + /* + * 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); + off += (addr - vma->vm_start) >> shift; + return offset_il_node(pol, off); + } else + return interleave_nodes(pol); +} + +#ifdef CONFIG_HUGETLBFS +/* + * huge_node(@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 + * @mpol: pointer to mempolicy pointer for reference counted mempolicy + * @nodemask: pointer to nodemask pointer for 'bind' and 'prefer-many' policy + * + * Returns a nid suitable for a huge page allocation and a pointer + * to the struct mempolicy for conditional unref after allocation. + * If the effective policy is 'bind' or 'prefer-many', returns a pointer + * to the mempolicy's @nodemask for filtering the zonelist. + * + * Must be protected by read_mems_allowed_begin() + */ +int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags, + struct mempolicy **mpol, nodemask_t **nodemask) +{ + int nid; + int mode; + + *mpol = get_vma_policy(vma, addr); + *nodemask = NULL; + mode = (*mpol)->mode; + + if (unlikely(mode == MPOL_INTERLEAVE)) { + nid = interleave_nid(*mpol, vma, addr, + huge_page_shift(hstate_vma(vma))); + } else { + nid = policy_node(gfp_flags, *mpol, numa_node_id()); + if (mode == MPOL_BIND || mode == MPOL_PREFERRED_MANY) + *nodemask = &(*mpol)->nodes; + } + return nid; +} + +/* + * 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; + + if (!(mask && current->mempolicy)) + return false; + + task_lock(current); + mempolicy = current->mempolicy; + switch (mempolicy->mode) { + case MPOL_PREFERRED: + case MPOL_PREFERRED_MANY: + case MPOL_BIND: + case MPOL_INTERLEAVE: + *mask = mempolicy->nodes; + break; + + case MPOL_LOCAL: + init_nodemask_of_node(mask, numa_node_id()); + break; + + default: + BUG(); + } + task_unlock(current); + + return true; +} +#endif + +/* + * mempolicy_in_oom_domain + * + * If tsk's mempolicy is "bind", check for intersection between mask and + * the policy nodemask. Otherwise, return true for all other policies + * including "interleave", as a tsk with "interleave" policy may have + * memory allocated from all nodes in system. + * + * Takes task_lock(tsk) to prevent freeing of its mempolicy. + */ +bool mempolicy_in_oom_domain(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 && mempolicy->mode == MPOL_BIND) + ret = nodes_intersects(mempolicy->nodes, *mask); + task_unlock(tsk); + + return ret; +} + +/* Allocate a page in interleaved policy. + Own path because it needs to do special accounting. */ +static struct page *alloc_page_interleave(gfp_t gfp, unsigned order, + unsigned nid) +{ + struct page *page; + + page = __alloc_pages(gfp, order, nid, NULL); + /* skip NUMA_INTERLEAVE_HIT counter update if numa stats is disabled */ + if (!static_branch_likely(&vm_numa_stat_key)) + return page; + if (page && page_to_nid(page) == nid) { + preempt_disable(); + __count_numa_event(page_zone(page), NUMA_INTERLEAVE_HIT); + preempt_enable(); + } + return page; +} + +static struct page *alloc_pages_preferred_many(gfp_t gfp, unsigned int order, + int nid, struct mempolicy *pol) +{ + struct page *page; + gfp_t preferred_gfp; + + /* + * This is a two pass approach. The first pass will only try the + * preferred nodes but skip the direct reclaim and allow the + * allocation to fail, while the second pass will try all the + * nodes in system. + */ + preferred_gfp = gfp | __GFP_NOWARN; + preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL); + page = __alloc_pages(preferred_gfp, order, nid, &pol->nodes); + if (!page) + page = __alloc_pages(gfp, order, nid, NULL); + + return page; +} + +/** + * vma_alloc_folio - Allocate a folio for a VMA. + * @gfp: GFP flags. + * @order: Order of the folio. + * @vma: Pointer to VMA or NULL if not available. + * @addr: Virtual address of the allocation. Must be inside @vma. + * @hugepage: For hugepages try only the preferred node if possible. + * + * Allocate a folio for a specific address in @vma, using the appropriate + * NUMA policy. When @vma is not NULL the caller must hold the mmap_lock + * of the mm_struct of the VMA to prevent it from going away. Should be + * used for all allocations for folios that will be mapped into user space. + * + * Return: The folio on success or NULL if allocation fails. + */ +struct folio *vma_alloc_folio(gfp_t gfp, int order, struct vm_area_struct *vma, + unsigned long addr, bool hugepage) +{ + struct mempolicy *pol; + int node = numa_node_id(); + struct folio *folio; + int preferred_nid; + nodemask_t *nmask; + + pol = get_vma_policy(vma, addr); + + if (pol->mode == MPOL_INTERLEAVE) { + struct page *page; + unsigned nid; + + nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order); + mpol_cond_put(pol); + gfp |= __GFP_COMP; + page = alloc_page_interleave(gfp, order, nid); + if (page && order > 1) + prep_transhuge_page(page); + folio = (struct folio *)page; + goto out; + } + + if (pol->mode == MPOL_PREFERRED_MANY) { + struct page *page; + + node = policy_node(gfp, pol, node); + gfp |= __GFP_COMP; + page = alloc_pages_preferred_many(gfp, order, node, pol); + mpol_cond_put(pol); + if (page && order > 1) + prep_transhuge_page(page); + folio = (struct folio *)page; + goto out; + } + + if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) { + int hpage_node = node; + + /* + * For hugepage allocation and non-interleave policy which + * allows the current node (or other explicitly preferred + * node) we only try to allocate from the current/preferred + * node and don't fall back to other nodes, as the cost of + * remote accesses would likely offset THP benefits. + * + * If the policy is interleave or does not allow the current + * node in its nodemask, we allocate the standard way. + */ + if (pol->mode == MPOL_PREFERRED) + hpage_node = first_node(pol->nodes); + + nmask = policy_nodemask(gfp, pol); + if (!nmask || node_isset(hpage_node, *nmask)) { + mpol_cond_put(pol); + /* + * First, try to allocate THP only on local node, but + * don't reclaim unnecessarily, just compact. + */ + folio = __folio_alloc_node(gfp | __GFP_THISNODE | + __GFP_NORETRY, order, hpage_node); + + /* + * If hugepage allocations are configured to always + * synchronous compact or the vma has been madvised + * to prefer hugepage backing, retry allowing remote + * memory with both reclaim and compact as well. + */ + if (!folio && (gfp & __GFP_DIRECT_RECLAIM)) + folio = __folio_alloc(gfp, order, hpage_node, + nmask); + + goto out; + } + } + + nmask = policy_nodemask(gfp, pol); + preferred_nid = policy_node(gfp, pol, node); + folio = __folio_alloc(gfp, order, preferred_nid, nmask); + mpol_cond_put(pol); +out: + return folio; +} +EXPORT_SYMBOL(vma_alloc_folio); + +/** + * alloc_pages - Allocate pages. + * @gfp: GFP flags. + * @order: Power of two of number of pages to allocate. + * + * Allocate 1 << @order contiguous pages. The physical address of the + * first page is naturally aligned (eg an order-3 allocation will be aligned + * to a multiple of 8 * PAGE_SIZE bytes). The NUMA policy of the current + * process is honoured when in process context. + * + * Context: Can be called from any context, providing the appropriate GFP + * flags are used. + * Return: The page on success or NULL if allocation fails. + */ +struct page *alloc_pages(gfp_t gfp, unsigned order) +{ + struct mempolicy *pol = &default_policy; + struct page *page; + + if (!in_interrupt() && !(gfp & __GFP_THISNODE)) + pol = get_task_policy(current); + + /* + * No reference counting needed for current->mempolicy + * nor system default_policy + */ + if (pol->mode == MPOL_INTERLEAVE) + page = alloc_page_interleave(gfp, order, interleave_nodes(pol)); + else if (pol->mode == MPOL_PREFERRED_MANY) + page = alloc_pages_preferred_many(gfp, order, + policy_node(gfp, pol, numa_node_id()), pol); + else + page = __alloc_pages(gfp, order, + policy_node(gfp, pol, numa_node_id()), + policy_nodemask(gfp, pol)); + + return page; +} +EXPORT_SYMBOL(alloc_pages); + +struct folio *folio_alloc(gfp_t gfp, unsigned order) +{ + struct page *page = alloc_pages(gfp | __GFP_COMP, order); + + if (page && order > 1) + prep_transhuge_page(page); + return (struct folio *)page; +} +EXPORT_SYMBOL(folio_alloc); + +static unsigned long alloc_pages_bulk_array_interleave(gfp_t gfp, + struct mempolicy *pol, unsigned long nr_pages, + struct page **page_array) +{ + int nodes; + unsigned long nr_pages_per_node; + int delta; + int i; + unsigned long nr_allocated; + unsigned long total_allocated = 0; + + nodes = nodes_weight(pol->nodes); + nr_pages_per_node = nr_pages / nodes; + delta = nr_pages - nodes * nr_pages_per_node; + + for (i = 0; i < nodes; i++) { + if (delta) { + nr_allocated = __alloc_pages_bulk(gfp, + interleave_nodes(pol), NULL, + nr_pages_per_node + 1, NULL, + page_array); + delta--; + } else { + nr_allocated = __alloc_pages_bulk(gfp, + interleave_nodes(pol), NULL, + nr_pages_per_node, NULL, page_array); + } + + page_array += nr_allocated; + total_allocated += nr_allocated; + } + + return total_allocated; +} + +static unsigned long alloc_pages_bulk_array_preferred_many(gfp_t gfp, int nid, + struct mempolicy *pol, unsigned long nr_pages, + struct page **page_array) +{ + gfp_t preferred_gfp; + unsigned long nr_allocated = 0; + + preferred_gfp = gfp | __GFP_NOWARN; + preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL); + + nr_allocated = __alloc_pages_bulk(preferred_gfp, nid, &pol->nodes, + nr_pages, NULL, page_array); + + if (nr_allocated < nr_pages) + nr_allocated += __alloc_pages_bulk(gfp, numa_node_id(), NULL, + nr_pages - nr_allocated, NULL, + page_array + nr_allocated); + return nr_allocated; +} + +/* alloc pages bulk and mempolicy should be considered at the + * same time in some situation such as vmalloc. + * + * It can accelerate memory allocation especially interleaving + * allocate memory. + */ +unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp, + unsigned long nr_pages, struct page **page_array) +{ + struct mempolicy *pol = &default_policy; + + if (!in_interrupt() && !(gfp & __GFP_THISNODE)) + pol = get_task_policy(current); + + if (pol->mode == MPOL_INTERLEAVE) + return alloc_pages_bulk_array_interleave(gfp, pol, + nr_pages, page_array); + + if (pol->mode == MPOL_PREFERRED_MANY) + return alloc_pages_bulk_array_preferred_many(gfp, + numa_node_id(), pol, nr_pages, page_array); + + return __alloc_pages_bulk(gfp, policy_node(gfp, pol, numa_node_id()), + policy_nodemask(gfp, pol), nr_pages, NULL, + page_array); +} + +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; +} + +/* + * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it + * 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(). + * + * 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. + */ + +/* Slow path of a mempolicy duplicate */ +struct mempolicy *__mpol_dup(struct mempolicy *old) +{ + struct mempolicy *new = kmem_cache_alloc(policy_cache, GFP_KERNEL); + + if (!new) + return ERR_PTR(-ENOMEM); + + /* task's mempolicy is protected by alloc_lock */ + if (old == current->mempolicy) { + task_lock(current); + *new = *old; + task_unlock(current); + } else + *new = *old; + + if (current_cpuset_is_being_rebound()) { + nodemask_t mems = cpuset_mems_allowed(current); + mpol_rebind_policy(new, &mems); + } + atomic_set(&new->refcnt, 1); + return new; +} + +/* Slow path of a mempolicy comparison */ +bool __mpol_equal(struct mempolicy *a, struct mempolicy *b) +{ + if (!a || !b) + return false; + if (a->mode != b->mode) + return false; + if (a->flags != b->flags) + return false; + if (a->home_node != b->home_node) + return false; + if (mpol_store_user_nodemask(a)) + if (!nodes_equal(a->w.user_nodemask, b->w.user_nodemask)) + return false; + + switch (a->mode) { + case MPOL_BIND: + case MPOL_INTERLEAVE: + case MPOL_PREFERRED: + case MPOL_PREFERRED_MANY: + return !!nodes_equal(a->nodes, b->nodes); + case MPOL_LOCAL: + return true; + default: + BUG(); + return false; + } +} + +/* + * 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 rwlock, which should be held + * for any accesses to the tree. + */ + +/* + * lookup first element intersecting start-end. Caller holds sp->lock for + * reading or for writing + */ +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 for + * writing. + */ +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); + pr_debug("inserting %lx-%lx: %d\n", new->start, new->end, + new->policy ? new->policy->mode : 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; + read_lock(&sp->lock); + sn = sp_lookup(sp, idx, idx+1); + if (sn) { + mpol_get(sn->policy); + pol = sn->policy; + } + read_unlock(&sp->lock); + return pol; +} + +static void sp_free(struct sp_node *n) +{ + mpol_put(n->policy); + kmem_cache_free(sn_cache, n); +} + +/** + * 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. Policy determination "mimics" alloc_page_vma(). + * Called from fault path where we know the vma and faulting address. + * + * Return: NUMA_NO_NODE if the page is in a node that is valid for this + * policy, or a suitable node ID to allocate a replacement page from. + */ +int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr) +{ + struct mempolicy *pol; + struct zoneref *z; + int curnid = page_to_nid(page); + unsigned long pgoff; + int thiscpu = raw_smp_processor_id(); + int thisnid = cpu_to_node(thiscpu); + int polnid = NUMA_NO_NODE; + int ret = NUMA_NO_NODE; + + pol = get_vma_policy(vma, addr); + if (!(pol->flags & MPOL_F_MOF)) + goto out; + + switch (pol->mode) { + case MPOL_INTERLEAVE: + pgoff = vma->vm_pgoff; + pgoff += (addr - vma->vm_start) >> PAGE_SHIFT; + polnid = offset_il_node(pol, pgoff); + break; + + case MPOL_PREFERRED: + if (node_isset(curnid, pol->nodes)) + goto out; + polnid = first_node(pol->nodes); + break; + + case MPOL_LOCAL: + polnid = numa_node_id(); + break; + + case MPOL_BIND: + /* Optimize placement among multiple nodes via NUMA balancing */ + if (pol->flags & MPOL_F_MORON) { + if (node_isset(thisnid, pol->nodes)) + break; + goto out; + } + fallthrough; + + case MPOL_PREFERRED_MANY: + /* + * 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->nodes)) + goto out; + z = first_zones_zonelist( + node_zonelist(numa_node_id(), GFP_HIGHUSER), + gfp_zone(GFP_HIGHUSER), + &pol->nodes); + polnid = zone_to_nid(z->zone); + break; + + default: + BUG(); + } + + /* Migrate the page towards the node whose CPU is referencing it */ + if (pol->flags & MPOL_F_MORON) { + polnid = thisnid; + + if (!should_numa_migrate_memory(current, page, curnid, thiscpu)) + goto out; + } + + if (curnid != polnid) + ret = polnid; +out: + mpol_cond_put(pol); + + return ret; +} + +/* + * Drop the (possibly final) reference to task->mempolicy. It needs to be + * dropped after task->mempolicy is set to NULL so that any allocation done as + * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed + * policy. + */ +void mpol_put_task_policy(struct task_struct *task) +{ + struct mempolicy *pol; + + task_lock(task); + pol = task->mempolicy; + task->mempolicy = NULL; + task_unlock(task); + mpol_put(pol); +} + +static void sp_delete(struct shared_policy *sp, struct sp_node *n) +{ + pr_debug("deleting %lx-l%lx\n", n->start, n->end); + rb_erase(&n->nd, &sp->root); + sp_free(n); +} + +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; +} + +static struct sp_node *sp_alloc(unsigned long start, unsigned long end, + struct mempolicy *pol) +{ + struct sp_node *n; + struct mempolicy *newpol; + + n = kmem_cache_alloc(sn_cache, GFP_KERNEL); + if (!n) + return NULL; + + newpol = mpol_dup(pol); + if (IS_ERR(newpol)) { + kmem_cache_free(sn_cache, n); + return NULL; + } + newpol->flags |= MPOL_F_SHARED; + sp_node_init(n, start, end, newpol); + + 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; + struct sp_node *n_new = NULL; + struct mempolicy *mpol_new = NULL; + int ret = 0; + +restart: + write_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 (!n_new) + goto alloc_new; + + *mpol_new = *n->policy; + atomic_set(&mpol_new->refcnt, 1); + sp_node_init(n_new, end, n->end, mpol_new); + n->end = start; + sp_insert(sp, n_new); + n_new = NULL; + mpol_new = NULL; + break; + } else + n->end = start; + } + if (!next) + break; + n = rb_entry(next, struct sp_node, nd); + } + if (new) + sp_insert(sp, new); + write_unlock(&sp->lock); + ret = 0; + +err_out: + if (mpol_new) + mpol_put(mpol_new); + if (n_new) + kmem_cache_free(sn_cache, n_new); + + return ret; + +alloc_new: + write_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; + atomic_set(&mpol_new->refcnt, 1); + goto restart; +} + +/** + * 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. + * This is called at get_inode() calls and we can use GFP_KERNEL. + */ +void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol) +{ + int ret; + + sp->root = RB_ROOT; /* empty tree == default mempolicy */ + rwlock_init(&sp->lock); + + if (mpol) { + struct vm_area_struct pvma; + struct mempolicy *new; + NODEMASK_SCRATCH(scratch); + + if (!scratch) + goto put_mpol; + /* contextualize the tmpfs mount point mempolicy */ + new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask); + if (IS_ERR(new)) + goto free_scratch; /* no valid nodemask intersection */ + + task_lock(current); + ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch); + task_unlock(current); + if (ret) + goto put_new; + + /* Create pseudo-vma that contains just the policy */ + vma_init(&pvma, NULL); + pvma.vm_end = TASK_SIZE; /* policy covers entire file */ + mpol_set_shared_policy(sp, &pvma, new); /* adds ref */ + +put_new: + mpol_put(new); /* drop initial ref */ +free_scratch: + NODEMASK_SCRATCH_FREE(scratch); +put_mpol: + mpol_put(mpol); /* drop our incoming ref on sb mpol */ + } +} + +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); + + pr_debug("set_shared_policy %lx sz %lu %d %d %lx\n", + vma->vm_pgoff, + sz, npol ? npol->mode : -1, + npol ? npol->flags : -1, + npol ? nodes_addr(npol->nodes)[0] : NUMA_NO_NODE); + + 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) + sp_free(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; + write_lock(&p->lock); + next = rb_first(&p->root); + while (next) { + n = rb_entry(next, struct sp_node, nd); + next = rb_next(&n->nd); + sp_delete(p, n); + } + write_unlock(&p->lock); +} + +#ifdef CONFIG_NUMA_BALANCING +static int __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; + + /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */ + if (numabalancing_override) + set_numabalancing_state(numabalancing_override == 1); + + if (num_online_nodes() > 1 && !numabalancing_override) { + pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n", + numabalancing_default ? "Enabling" : "Disabling"); + set_numabalancing_state(numabalancing_default); + } +} + +static int __init setup_numabalancing(char *str) +{ + int ret = 0; + if (!str) + goto out; + + if (!strcmp(str, "enable")) { + numabalancing_override = 1; + ret = 1; + } else if (!strcmp(str, "disable")) { + numabalancing_override = -1; + ret = 1; + } +out: + if (!ret) + pr_warn("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 */ + +/* assumes fs == KERNEL_DS */ +void __init numa_policy_init(void) +{ + nodemask_t interleave_nodes; + unsigned long largest = 0; + int nid, prefer = 0; + + policy_cache = kmem_cache_create("numa_policy", + sizeof(struct mempolicy), + 0, SLAB_PANIC, NULL); + + sn_cache = kmem_cache_create("shared_policy_node", + sizeof(struct sp_node), + 0, SLAB_PANIC, NULL); + + for_each_node(nid) { + preferred_node_policy[nid] = (struct mempolicy) { + .refcnt = ATOMIC_INIT(1), + .mode = MPOL_PREFERRED, + .flags = MPOL_F_MOF | MPOL_F_MORON, + .nodes = nodemask_of_node(nid), + }; + } + + /* + * 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); + for_each_node_state(nid, N_MEMORY) { + 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); + + if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes)) + pr_err("%s: interleaving failed\n", __func__); + + check_numabalancing_enable(); +} + +/* Reset policy of current process to default */ +void numa_default_policy(void) +{ + do_set_mempolicy(MPOL_DEFAULT, 0, NULL); +} + +/* + * Parse and format mempolicy from/to strings + */ + +static const char * const policy_modes[] = +{ + [MPOL_DEFAULT] = "default", + [MPOL_PREFERRED] = "prefer", + [MPOL_BIND] = "bind", + [MPOL_INTERLEAVE] = "interleave", + [MPOL_LOCAL] = "local", + [MPOL_PREFERRED_MANY] = "prefer (many)", +}; + + +#ifdef CONFIG_TMPFS +/** + * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option. + * @str: string containing mempolicy to parse + * @mpol: pointer to struct mempolicy pointer, returned on success. + * + * Format of input: + * <mode>[=<flags>][:<nodelist>] + * + * Return: %0 on success, else %1 + */ +int mpol_parse_str(char *str, struct mempolicy **mpol) +{ + struct mempolicy *new = NULL; + unsigned short mode_flags; + nodemask_t nodes; + char *nodelist = strchr(str, ':'); + char *flags = strchr(str, '='); + int err = 1, mode; + + if (flags) + *flags++ = '\0'; /* terminate mode string */ + + if (nodelist) { + /* NUL-terminate mode or flags string */ + *nodelist++ = '\0'; + if (nodelist_parse(nodelist, nodes)) + goto out; + if (!nodes_subset(nodes, node_states[N_MEMORY])) + goto out; + } else + nodes_clear(nodes); + + mode = match_string(policy_modes, MPOL_MAX, str); + if (mode < 0) + goto out; + + switch (mode) { + case MPOL_PREFERRED: + /* + * Insist on a nodelist of one node only, although later + * we use first_node(nodes) to grab a single node, so here + * nodelist (or nodes) cannot be empty. + */ + if (nodelist) { + char *rest = nodelist; + while (isdigit(*rest)) + rest++; + if (*rest) + goto out; + if (nodes_empty(nodes)) + goto out; + } + break; + case MPOL_INTERLEAVE: + /* + * Default to online nodes with memory if no nodelist + */ + if (!nodelist) + nodes = node_states[N_MEMORY]; + break; + case MPOL_LOCAL: + /* + * Don't allow a nodelist; mpol_new() checks flags + */ + if (nodelist) + goto out; + break; + case MPOL_DEFAULT: + /* + * Insist on a empty nodelist + */ + if (!nodelist) + err = 0; + goto out; + case MPOL_PREFERRED_MANY: + case MPOL_BIND: + /* + * Insist on a nodelist + */ + if (!nodelist) + goto out; + } + + mode_flags = 0; + if (flags) { + /* + * Currently, we only support two mutually exclusive + * mode flags. + */ + if (!strcmp(flags, "static")) + mode_flags |= MPOL_F_STATIC_NODES; + else if (!strcmp(flags, "relative")) + mode_flags |= MPOL_F_RELATIVE_NODES; + else + goto out; + } + + new = mpol_new(mode, mode_flags, &nodes); + if (IS_ERR(new)) + goto out; + + /* + * 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->nodes = nodes; + } else if (nodelist) { + nodes_clear(new->nodes); + node_set(first_node(nodes), new->nodes); + } else { + new->mode = MPOL_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; + + err = 0; + +out: + /* Restore string for error message */ + if (nodelist) + *--nodelist = ':'; + if (flags) + *--flags = '='; + if (!err) + *mpol = new; + return err; +} +#endif /* CONFIG_TMPFS */ + +/** + * 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 + * + * 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. + */ +void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) +{ + char *p = buffer; + nodemask_t nodes = NODE_MASK_NONE; + unsigned short mode = MPOL_DEFAULT; + unsigned short flags = 0; + + if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) { + mode = pol->mode; + flags = pol->flags; + } + + switch (mode) { + case MPOL_DEFAULT: + case MPOL_LOCAL: + break; + case MPOL_PREFERRED: + case MPOL_PREFERRED_MANY: + case MPOL_BIND: + case MPOL_INTERLEAVE: + nodes = pol->nodes; + break; + default: + WARN_ON_ONCE(1); + snprintf(p, maxlen, "unknown"); + return; + } + + p += snprintf(p, maxlen, "%s", policy_modes[mode]); + + if (flags & MPOL_MODE_FLAGS) { + p += snprintf(p, buffer + maxlen - p, "="); + + /* + * Currently, the only defined flags are mutually exclusive + */ + if (flags & MPOL_F_STATIC_NODES) + p += snprintf(p, buffer + maxlen - p, "static"); + else if (flags & MPOL_F_RELATIVE_NODES) + p += snprintf(p, buffer + maxlen - p, "relative"); + } + + if (!nodes_empty(nodes)) + p += scnprintf(p, buffer + maxlen - p, ":%*pbl", + nodemask_pr_args(&nodes)); +} |