/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2013 EMC Corp. * Copyright (c) 2011 Jeffrey Roberson * Copyright (c) 2008 Mayur Shardul * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * */ /* * Path-compressed radix trie implementation. * * The implementation takes into account the following rationale: * - Size of the nodes should be as small as possible but still big enough * to avoid a large maximum depth for the trie. This is a balance * between the necessity to not wire too much physical memory for the nodes * and the necessity to avoid too much cache pollution during the trie * operations. * - There is not a huge bias toward the number of lookup operations over * the number of insert and remove operations. This basically implies * that optimizations supposedly helping one operation but hurting the * other might be carefully evaluated. * - On average not many nodes are expected to be fully populated, hence * level compression may just complicate things. */ #include #include "opt_ddb.h" #include #include #include #include #include #include /* smr.h depends on struct thread. */ #include #include #ifdef DDB #include #endif #if PCTRIE_WIDTH == 3 typedef uint8_t pn_popmap_t; #elif PCTRIE_WIDTH == 4 typedef uint16_t pn_popmap_t; #elif PCTRIE_WIDTH == 5 typedef uint32_t pn_popmap_t; #else #error Unsupported width #endif _Static_assert(sizeof(pn_popmap_t) <= sizeof(int), "pn_popmap_t too wide"); struct pctrie_node; typedef SMR_POINTER(struct pctrie_node *) smr_pctnode_t; struct pctrie_node { uint64_t pn_owner; /* Owner of record. */ pn_popmap_t pn_popmap; /* Valid children. */ uint8_t pn_clev; /* Level * WIDTH. */ smr_pctnode_t pn_parent; /* Parent node. */ smr_pctnode_t pn_child[PCTRIE_COUNT]; /* Child nodes. */ }; /* * Map index to an array position for the children of node, */ static __inline int pctrie_slot(struct pctrie_node *node, uint64_t index) { return ((index >> node->pn_clev) & (PCTRIE_COUNT - 1)); } /* * Returns true if index does not belong to the specified node. Otherwise, * sets slot value, and returns false. */ static __inline bool pctrie_keybarr(struct pctrie_node *node, uint64_t index, int *slot) { index = (index - node->pn_owner) >> node->pn_clev; if (index >= PCTRIE_COUNT) return (true); *slot = index; return (false); } enum pctrie_access { PCTRIE_SMR, PCTRIE_LOCKED, PCTRIE_UNSERIALIZED }; /* * Fetch a node pointer from a slot. */ static __inline struct pctrie_node * pctrie_node_load(smr_pctnode_t *p, smr_t smr, enum pctrie_access access) { switch (access) { case PCTRIE_UNSERIALIZED: return (smr_unserialized_load(p, true)); case PCTRIE_LOCKED: return (smr_serialized_load(p, true)); case PCTRIE_SMR: return (smr_entered_load(p, smr)); } __assert_unreachable(); } static __inline void pctrie_node_store(smr_pctnode_t *p, void *v, enum pctrie_access access) { switch (access) { case PCTRIE_UNSERIALIZED: smr_unserialized_store(p, v, true); break; case PCTRIE_LOCKED: smr_serialized_store(p, v, true); break; case PCTRIE_SMR: panic("%s: Not supported in SMR section.", __func__); break; default: __assert_unreachable(); break; } } /* * Get the root address, cast to proper type for load/store. */ static __inline smr_pctnode_t * pctrie_root(struct pctrie *ptree) { return ((smr_pctnode_t *)&ptree->pt_root); } /* * Get the root node for a tree. */ static __inline struct pctrie_node * pctrie_root_load(struct pctrie *ptree, smr_t smr, enum pctrie_access access) { return (pctrie_node_load(pctrie_root(ptree), smr, access)); } /* * Get the child of a node. */ static __inline smr_pctnode_t * pctrie_child(struct pctrie *ptree, struct pctrie_node *node, uint64_t index) { return (node == NULL ? pctrie_root(ptree) : &node->pn_child[pctrie_slot(node, index)]); } /* * Returns TRUE if the specified node is a leaf and FALSE otherwise. */ static __inline bool pctrie_isleaf(struct pctrie_node *node) { return (((uintptr_t)node & PCTRIE_ISLEAF) != 0); } /* * Returns val with leaf bit set. */ static __inline void * pctrie_toleaf(uint64_t *val) { return ((void *)((uintptr_t)val | PCTRIE_ISLEAF)); } /* * Returns the associated val extracted from node. */ static __inline uint64_t * pctrie_toval(struct pctrie_node *node) { return ((uint64_t *)((uintptr_t)node & ~PCTRIE_FLAGS)); } /* * Returns the associated pointer extracted from node and field offset. */ static __inline void * pctrie_toptr(struct pctrie_node *node, int keyoff) { return ((void *)(((uintptr_t)node & ~PCTRIE_FLAGS) - keyoff)); } /* * Make 'parent' a parent of 'child'. */ static __inline void pctrie_setparent(struct pctrie_node *child, struct pctrie_node *parent) { pctrie_node_store(&child->pn_parent, parent, PCTRIE_UNSERIALIZED); } /* * Return the parent of 'node'. */ static __inline struct pctrie_node * pctrie_parent(struct pctrie_node *node) { return (pctrie_node_load(&node->pn_parent, NULL, PCTRIE_UNSERIALIZED)); } /* * Make 'child' a child of 'node'. */ static __inline void pctrie_addnode(struct pctrie_node *node, uint64_t index, struct pctrie_node *child, enum pctrie_access access) { int slot; slot = pctrie_slot(node, index); pctrie_node_store(&node->pn_child[slot], child, access); node->pn_popmap ^= 1 << slot; KASSERT((node->pn_popmap & (1 << slot)) != 0, ("%s: bad popmap slot %d in node %p", __func__, slot, node)); } /* * pctrie node zone initializer. */ int pctrie_zone_init(void *mem, int size __unused, int flags __unused) { struct pctrie_node *node; node = mem; node->pn_popmap = 0; for (int i = 0; i < nitems(node->pn_child); i++) pctrie_node_store(&node->pn_child[i], PCTRIE_NULL, PCTRIE_UNSERIALIZED); return (0); } size_t pctrie_node_size(void) { return (sizeof(struct pctrie_node)); } /* * Return the value associated with the node, if the node is a leaf that matches * the index; otherwise NULL. */ static __always_inline uint64_t * pctrie_match_value(struct pctrie_node *node, uint64_t index) { uint64_t *m; if (!pctrie_isleaf(node) || (m = pctrie_toval(node)) == NULL || *m != index) m = NULL; return (m); } /* * Returns the last node examined in the search for the index, and sets the * parent of that node. */ static __always_inline struct pctrie_node * _pctrie_lookup_node(struct pctrie *ptree, struct pctrie_node *node, uint64_t index, struct pctrie_node **parent_out, smr_t smr, enum pctrie_access access) { struct pctrie_node *parent; int slot; parent = node; if (parent == NULL) node = pctrie_root_load(ptree, smr, access); /* * Climb the search path to find the lowest node from which to start the * search for a value matching 'index'. */ while (parent != NULL) { KASSERT(access == PCTRIE_SMR || !powerof2(parent->pn_popmap), ("%s: freed node in iter path", __func__)); node = parent; if (!pctrie_keybarr(node, index, &slot)) break; parent = pctrie_parent(node); } /* Seek a node that matches index. */ while (!pctrie_isleaf(node) && !pctrie_keybarr(node, index, &slot)) { parent = node; KASSERT(access == PCTRIE_SMR || !powerof2(parent->pn_popmap), ("%s: freed node in iter path", __func__)); node = pctrie_node_load(&node->pn_child[slot], smr, access); } *parent_out = parent; return (node); } /* * Returns the value stored at the index, assuming access is externally * synchronized by a lock. * * If the index is not present, NULL is returned. */ uint64_t * pctrie_lookup(struct pctrie *ptree, uint64_t index) { struct pctrie_node *node, *parent; node = _pctrie_lookup_node(ptree, NULL, index, &parent, NULL, PCTRIE_LOCKED); return (pctrie_match_value(node, index)); } /* * Returns the value stored at the index without requiring an external lock. * * If the index is not present, NULL is returned. */ uint64_t * pctrie_lookup_unlocked(struct pctrie *ptree, uint64_t index, smr_t smr) { struct pctrie_node *node, *parent; uint64_t *res; smr_enter(smr); node = _pctrie_lookup_node(ptree, NULL, index, &parent, smr, PCTRIE_SMR); res = pctrie_match_value(node, index); smr_exit(smr); return (res); } /* * Returns the value stored at a given index value, possibly NULL, assuming * access is externally synchronized by a lock. */ uint64_t * pctrie_iter_lookup(struct pctrie_iter *it, uint64_t index) { struct pctrie_node *node; node = _pctrie_lookup_node(it->ptree, it->node, index, &it->node, NULL, PCTRIE_LOCKED); it->index = index; return (pctrie_match_value(node, index)); } /* * Look for where to insert the key-value pair into the trie. Complete the * insertion if it replaces a null leaf. Return the insertion location if the * insertion needs to be completed by the caller; otherwise return NULL. * * If the key is already present in the trie, populate *found_out as if by * pctrie_lookup(). */ static __always_inline void * _pctrie_insert_lookup(struct pctrie *ptree, struct pctrie_node *parent, uint64_t *val, struct pctrie_node **parent_out, uint64_t **found_out) { struct pctrie_node *node; node = _pctrie_lookup_node(ptree, parent, *val, parent_out, NULL, PCTRIE_LOCKED); *found_out = NULL; if (node == PCTRIE_NULL) { if (*parent_out == NULL) pctrie_node_store(pctrie_root(ptree), pctrie_toleaf(val), PCTRIE_LOCKED); else pctrie_addnode(*parent_out, *val, pctrie_toleaf(val), PCTRIE_LOCKED); return (NULL); } if (__predict_false(pctrie_match_value(node, *val) != NULL)) { *found_out = pctrie_toval(node); return (NULL); } /* * 'node' must be replaced in the tree with a new branch node, with * children 'node' and 'val'. Return the place that points to 'node' * now, and will point to to the new branching node later. */ return (pctrie_child(ptree, *parent_out, *val)); } /* * Wrap _pctrie_insert_lookup to implement a strict insertion. Panic * if the key already exists, and do not look for neighboring entries. */ void * pctrie_insert_lookup_strict(struct pctrie *ptree, uint64_t *val, struct pctrie_node **parent_out) { void *parentp; uint64_t *found; parentp = _pctrie_insert_lookup(ptree, NULL, val, parent_out, &found); if (__predict_false(found != NULL)) panic("%s: key %jx is already present", __func__, (uintmax_t)*val); return (parentp); } /* * Wrap _pctrie_insert_lookup to implement find-or-insert. Do not look * for neighboring entries. */ void * pctrie_insert_lookup(struct pctrie *ptree, uint64_t *val, struct pctrie_node **parent_out, uint64_t **found_out) { return (_pctrie_insert_lookup(ptree, NULL, val, parent_out, found_out)); } /* * Insert the val in the trie, starting search with iterator. Return a pointer * to indicate where a new node must be allocated to complete insertion. * Assumes access is externally synchronized by a lock. */ void * pctrie_iter_insert_lookup(struct pctrie_iter *it, uint64_t *val) { void *res; uint64_t *found; it->index = *val; res = _pctrie_insert_lookup(it->ptree, it->node, val, &it->node, &found); if (__predict_false(found != NULL)) panic("%s: key %jx is already present", __func__, (uintmax_t)it->index); return (res); } /* * Inserts newly allocated node 'child' into trie at location 'parentp', with * parent 'parent' and two children, 'val' and whatever non-NULL node or leaf * was at 'parentp' to begin with. */ void pctrie_insert_node(uint64_t *val, struct pctrie_node *parent, void *parentp, struct pctrie_node *child) { struct pctrie_node *node; uint64_t index, newind; /* * Clear the last child pointer of the newly allocated child. We want * to clear it after the final section has exited so lookup can not * return false negatives. It is done here because it will be * cache-cold in the dtor callback. */ if (child->pn_popmap != 0) { pctrie_node_store(&child->pn_child[ffs(child->pn_popmap) - 1], PCTRIE_NULL, PCTRIE_UNSERIALIZED); child->pn_popmap = 0; } /* * Recover the values of the two children of the new child node. If * 'node' is not a leaf, this stores into 'newind' the 'owner' field, * which must be first in the node. */ index = *val; node = pctrie_node_load(parentp, NULL, PCTRIE_UNSERIALIZED); pctrie_setparent(child, parent); if (!pctrie_isleaf(node)) pctrie_setparent(node, child); newind = *pctrie_toval(node); /* * From the highest-order bit where the indexes differ, * compute the highest level in the trie where they differ. Then, * compute the least index of this subtrie. */ _Static_assert(sizeof(long long) >= sizeof(uint64_t), "uint64 too wide"); _Static_assert(sizeof(uint64_t) * NBBY <= (1 << (sizeof(child->pn_clev) * NBBY)), "pn_clev too narrow"); child->pn_clev = rounddown(ilog2(index ^ newind), PCTRIE_WIDTH); child->pn_owner = PCTRIE_COUNT; child->pn_owner = index & -(child->pn_owner << child->pn_clev); /* These writes are not yet visible due to ordering. */ pctrie_addnode(child, index, pctrie_toleaf(val), PCTRIE_UNSERIALIZED); pctrie_addnode(child, newind, node, PCTRIE_UNSERIALIZED); /* Synchronize to make the above visible. */ pctrie_node_store(parentp, child, PCTRIE_LOCKED); } /* * Returns the value stored at a fixed offset from the current index value, * possibly NULL. */ uint64_t * pctrie_iter_stride(struct pctrie_iter *it, int stride) { uint64_t index = it->index + stride; /* Detect stride overflow. */ if ((stride > 0) != (index > it->index)) return (NULL); /* Detect crossing limit */ if ((index < it->limit) != (it->index < it->limit)) return (NULL); return (pctrie_iter_lookup(it, index)); } /* * Returns the value stored at one more than the current index value, possibly * NULL, assuming access is externally synchronized by a lock. */ uint64_t * pctrie_iter_next(struct pctrie_iter *it) { return (pctrie_iter_stride(it, 1)); } /* * Returns the value stored at one less than the current index value, possibly * NULL, assuming access is externally synchronized by a lock. */ uint64_t * pctrie_iter_prev(struct pctrie_iter *it) { return (pctrie_iter_stride(it, -1)); } /* * Returns the number of contiguous, non-NULL entries read into the value[] * array, starting at index. */ static __always_inline int _pctrie_lookup_range(struct pctrie *ptree, struct pctrie_node *node, uint64_t index, uint64_t *value[], int count, struct pctrie_node **parent_out, smr_t smr, enum pctrie_access access) { struct pctrie_node *parent; uint64_t *val; int base, end, i; parent = node; for (i = 0; i < count;) { node = _pctrie_lookup_node(ptree, parent, index + i, &parent, smr, access); if ((val = pctrie_match_value(node, index + i)) == NULL) break; value[i++] = val; base = (index + i) % PCTRIE_COUNT; if (base == 0 || parent == NULL || parent->pn_clev != 0) continue; /* * For PCTRIE_SMR, compute an upper bound on the number of * children of this parent left to examine. For PCTRIE_LOCKED, * compute the number of non-NULL children from base up to the * first NULL child, if any, using the fact that pn_popmap has * bits set for only the non-NULL children. * * The pn_popmap field is accessed only when a lock is held. * To use it for PCTRIE_SMR here would require that we know that * race conditions cannot occur if the tree is modified while * accessed here. Guarantees about the visibility of changes to * child pointers, enforced by memory barriers on the writing of * pointers, are not present for the pn_popmap field, so that * the popmap bit for a child page may, for an instant, * misrepresent the nullness of the child page because an * operation modifying the pctrie is in progress. */ end = (access == PCTRIE_SMR) ? PCTRIE_COUNT - base : ffs((parent->pn_popmap >> base) + 1) - 1; end = MIN(count, i + end); while (i < end) { node = pctrie_node_load(&parent->pn_child[base++], smr, access); val = pctrie_toval(node); if (access == PCTRIE_SMR && val == NULL) break; value[i++] = val; KASSERT(val != NULL, ("%s: null child written to range", __func__)); } if (access == PCTRIE_SMR) { if (i < end) break; } else { if (base < PCTRIE_COUNT) break; } } if (parent_out != NULL) *parent_out = parent; return (i); } /* * Returns the number of contiguous, non-NULL entries read into the value[] * array, starting at index, assuming access is externally synchronized by a * lock. */ int pctrie_lookup_range(struct pctrie *ptree, uint64_t index, uint64_t *value[], int count) { return (_pctrie_lookup_range(ptree, NULL, index, value, count, NULL, NULL, PCTRIE_LOCKED)); } /* * Returns the number of contiguous, non-NULL entries read into the value[] * array, starting at index, without requiring an external lock. These entries * *may* never have been in the pctrie all at one time, but for a series of * times t0, t1, t2, ..., with ti <= t(i+1), value[i] was in the trie at time * ti. */ int pctrie_lookup_range_unlocked(struct pctrie *ptree, uint64_t index, uint64_t *value[], int count, smr_t smr) { int res; smr_enter(smr); res = _pctrie_lookup_range(ptree, NULL, index, value, count, NULL, smr, PCTRIE_SMR); smr_exit(smr); return (res); } /* * Returns the number of contiguous, non-NULL entries read into the value[] * array, starting at index, assuming access is externally synchronized by a * lock. Uses an iterator. */ int pctrie_iter_lookup_range(struct pctrie_iter *it, uint64_t index, uint64_t *value[], int count) { return (_pctrie_lookup_range(it->ptree, it->node, index, value, count, &it->node, NULL, PCTRIE_LOCKED)); } /* * Find first leaf >= index, and fill iter with the path to the parent of that * leaf. Return NULL if there is no such leaf less than limit. */ static __inline uint64_t * _pctrie_lookup_ge(struct pctrie *ptree, struct pctrie_node *node, uint64_t index, struct pctrie_node **parent_out, uint64_t limit) { struct pctrie_node *parent; uint64_t *m; int slot; /* Seek a node that matches index. */ node = _pctrie_lookup_node(ptree, node, index, &parent, NULL, PCTRIE_LOCKED); /* * If no such node was found, and instead this path leads only to nodes * < index, back up to find a subtrie with the least value > index. */ if (node == PCTRIE_NULL || *pctrie_toval(node) < index) { /* Climb the path to find a node with a descendant > index. */ node = NULL; while (parent != NULL) { slot = pctrie_slot(parent, index) + 1; if ((parent->pn_popmap >> slot) != 0) break; node = parent; parent = pctrie_parent(node); } if (parent == NULL) { if (parent_out != NULL) *parent_out = node; return (NULL); } /* Step to the least child with a descendant > index. */ slot += ffs(parent->pn_popmap >> slot) - 1; node = pctrie_node_load(&parent->pn_child[slot], NULL, PCTRIE_LOCKED); } /* Descend to the least leaf of the subtrie. */ while (!pctrie_isleaf(node)) { if (limit != 0 && node->pn_owner >= limit) return (NULL); slot = ffs(node->pn_popmap) - 1; parent = node; node = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); } if (parent_out != NULL) *parent_out = parent; m = pctrie_toval(node); if (limit != 0 && *m >= limit) return (NULL); return (m); } uint64_t * pctrie_lookup_ge(struct pctrie *ptree, uint64_t index) { return (_pctrie_lookup_ge(ptree, NULL, index, NULL, 0)); } /* * Find first leaf >= index, and fill iter with the path to the parent of that * leaf. Return NULL if there is no such leaf less than limit. */ uint64_t * pctrie_iter_lookup_ge(struct pctrie_iter *it, uint64_t index) { uint64_t *m; m = _pctrie_lookup_ge(it->ptree, it->node, index, &it->node, it->limit); if (m != NULL) it->index = *m; return (m); } /* * Find the first leaf with value at least 'jump' greater than the previous * leaf. Return NULL if that value is >= limit. */ uint64_t * pctrie_iter_jump_ge(struct pctrie_iter *it, int64_t jump) { uint64_t index = it->index + jump; /* Detect jump overflow. */ if ((jump > 0) != (index > it->index)) return (NULL); if (it->limit != 0 && index >= it->limit) return (NULL); return (pctrie_iter_lookup_ge(it, index)); } /* * Find first leaf <= index, and fill iter with the path to the parent of that * leaf. Return NULL if there is no such leaf greater than limit. */ static __inline uint64_t * _pctrie_lookup_le(struct pctrie *ptree, struct pctrie_node *node, uint64_t index, struct pctrie_node **parent_out, uint64_t limit) { struct pctrie_node *parent; uint64_t *m; int slot; /* Seek a node that matches index. */ node = _pctrie_lookup_node(ptree, node, index, &parent, NULL, PCTRIE_LOCKED); /* * If no such node was found, and instead this path leads only to nodes * > index, back up to find a subtrie with the greatest value < index. */ if (node == PCTRIE_NULL || *pctrie_toval(node) > index) { /* Climb the path to find a node with a descendant < index. */ node = NULL; while (parent != NULL) { slot = pctrie_slot(parent, index); if ((parent->pn_popmap & ((1 << slot) - 1)) != 0) break; node = parent; parent = pctrie_parent(node); } if (parent == NULL) { if (parent_out != NULL) *parent_out = node; return (NULL); } /* Step to the greatest child with a descendant < index. */ slot = ilog2(parent->pn_popmap & ((1 << slot) - 1)); node = pctrie_node_load(&parent->pn_child[slot], NULL, PCTRIE_LOCKED); } /* Descend to the greatest leaf of the subtrie. */ while (!pctrie_isleaf(node)) { if (limit != 0 && limit >= node->pn_owner + ((uint64_t)PCTRIE_COUNT << node->pn_clev) - 1) return (NULL); slot = ilog2(node->pn_popmap); parent = node; node = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); } if (parent_out != NULL) *parent_out = parent; m = pctrie_toval(node); if (limit != 0 && *m <= limit) return (NULL); return (m); } uint64_t * pctrie_lookup_le(struct pctrie *ptree, uint64_t index) { return (_pctrie_lookup_le(ptree, NULL, index, NULL, 0)); } uint64_t * pctrie_subtree_lookup_lt(struct pctrie *ptree, struct pctrie_node *node, uint64_t index) { if (index == 0) return (NULL); return (_pctrie_lookup_le(ptree, node, index - 1, NULL, 0)); } /* * Find first leaf <= index, and fill iter with the path to the parent of that * leaf. Return NULL if there is no such leaf greater than limit. */ uint64_t * pctrie_iter_lookup_le(struct pctrie_iter *it, uint64_t index) { uint64_t *m; m = _pctrie_lookup_le(it->ptree, it->node, index, &it->node, it->limit); if (m != NULL) it->index = *m; return (m); } /* * Find the first leaf with value at most 'jump' less than the previous * leaf. Return NULL if that value is <= limit. */ uint64_t * pctrie_iter_jump_le(struct pctrie_iter *it, int64_t jump) { uint64_t index = it->index - jump; /* Detect jump overflow. */ if ((jump > 0) != (index < it->index)) return (NULL); if (it->limit != 0 && index <= it->limit) return (NULL); return (pctrie_iter_lookup_le(it, index)); } /* * Remove the non-NULL child identified by 'index' from the set of children of * 'node'. If doing so causes 'node' to have only one child, purge it from the * pctrie and save it in *freenode for later disposal. */ static bool pctrie_remove(struct pctrie *ptree, struct pctrie_node *node, uint64_t index) { smr_pctnode_t *parentp; struct pctrie_node *child; int slot; parentp = pctrie_child(ptree, node, index); if (node == NULL) { pctrie_node_store(parentp, PCTRIE_NULL, PCTRIE_LOCKED); return (false); } slot = pctrie_slot(node, index); KASSERT((node->pn_popmap & (1 << slot)) != 0, ("%s: bad popmap slot %d in node %p", __func__, slot, node)); node->pn_popmap ^= 1 << slot; if (!powerof2(node->pn_popmap)) { pctrie_node_store(parentp, PCTRIE_NULL, PCTRIE_LOCKED); return (false); } pctrie_node_store(parentp, PCTRIE_NULL, PCTRIE_UNSERIALIZED); KASSERT(node->pn_popmap != 0, ("%s: bad popmap all zeroes", __func__)); slot = ffs(node->pn_popmap) - 1; child = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); KASSERT(child != PCTRIE_NULL, ("%s: bad popmap slot %d in node %p", __func__, slot, node)); node = pctrie_parent(node); if (!pctrie_isleaf(child)) pctrie_setparent(child, node); parentp = pctrie_child(ptree, node, index); pctrie_node_store(parentp, child, PCTRIE_LOCKED); return (true); } /* * Remove the specified index from the tree, and return the value stored at * that index. If the index is not present, return NULL. */ uint64_t * pctrie_remove_lookup(struct pctrie *ptree, uint64_t index, struct pctrie_node **freenode) { struct pctrie_node *node, *parent; uint64_t *m; node = _pctrie_lookup_node(ptree, NULL, index, &parent, NULL, PCTRIE_LOCKED); m = pctrie_match_value(node, index); if (m != NULL && pctrie_remove(ptree, parent, index)) *freenode = parent; else *freenode = NULL; return (m); } /* * Remove from the trie the leaf last chosen by the iterator, and * adjust the path if it's last member is to be freed. */ void pctrie_iter_remove(struct pctrie_iter *it, struct pctrie_node **freenode) { KASSERT(NULL != pctrie_match_value(pctrie_node_load(pctrie_child( it->ptree, it->node, it->index), NULL, PCTRIE_LOCKED), it->index), ("%s: removing value %jx not at iter", __func__, (uintmax_t)it->index)); if (pctrie_remove(it->ptree, it->node, it->index)) { *freenode = it->node; it->node = pctrie_parent(it->node); } else *freenode = NULL; } /* * Return the current leaf, assuming access is externally synchronized by a * lock. */ uint64_t * pctrie_iter_value(struct pctrie_iter *it) { struct pctrie_node *node; node = pctrie_node_load(pctrie_child(it->ptree, it->node, it->index), NULL, PCTRIE_LOCKED); return (pctrie_toval(node)); } /* * Walk the subtrie rooted at *pnode in order, invoking callback on leaves, * until an interior node is stripped of all children, and returned for * deallocation, with *pnode left pointing to the parent of that node. */ static __always_inline struct pctrie_node * pctrie_reclaim_prune(struct pctrie_node **pnode, struct pctrie_node *parent, pctrie_cb_t callback, int keyoff, void *arg) { struct pctrie_node *child, *node; int slot; node = *pnode; while (node->pn_popmap != 0) { slot = ffs(node->pn_popmap) - 1; node->pn_popmap ^= 1 << slot; child = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_UNSERIALIZED); pctrie_node_store(&node->pn_child[slot], PCTRIE_NULL, PCTRIE_UNSERIALIZED); if (pctrie_isleaf(child)) { if (callback != NULL) callback(pctrie_toptr(child, keyoff), arg); continue; } /* Climb one level down the trie. */ parent = node; node = child; } *pnode = parent; return (node); } /* * Recover the node parent from its first child and continue pruning. */ static __always_inline struct pctrie_node * pctrie_reclaim_resume_compound(struct pctrie_node **pnode, pctrie_cb_t callback, int keyoff, void *arg) { if (*pnode == NULL) return (NULL); /* Climb one level up the trie. */ return (pctrie_reclaim_prune(pnode, pctrie_parent(*pnode), callback, keyoff, arg)); } /* * Find the trie root, and start pruning with a NULL parent. */ static __always_inline struct pctrie_node * pctrie_reclaim_begin_compound(struct pctrie_node **pnode, struct pctrie *ptree, pctrie_cb_t callback, int keyoff, void *arg) { struct pctrie_node *node; node = pctrie_root_load(ptree, NULL, PCTRIE_UNSERIALIZED); pctrie_node_store(pctrie_root(ptree), PCTRIE_NULL, PCTRIE_UNSERIALIZED); if (pctrie_isleaf(node)) { if (callback != NULL && node != PCTRIE_NULL) callback(pctrie_toptr(node, keyoff), arg); return (NULL); } *pnode = node; return (pctrie_reclaim_prune(pnode, NULL, callback, keyoff, arg)); } struct pctrie_node * pctrie_reclaim_resume(struct pctrie_node **pnode) { return (pctrie_reclaim_resume_compound(pnode, NULL, 0, NULL)); } struct pctrie_node * pctrie_reclaim_begin(struct pctrie_node **pnode, struct pctrie *ptree) { return (pctrie_reclaim_begin_compound(pnode, ptree, NULL, 0, NULL)); } struct pctrie_node * pctrie_reclaim_resume_cb(struct pctrie_node **pnode, pctrie_cb_t callback, int keyoff, void *arg) { return (pctrie_reclaim_resume_compound(pnode, callback, keyoff, arg)); } struct pctrie_node * pctrie_reclaim_begin_cb(struct pctrie_node **pnode, struct pctrie *ptree, pctrie_cb_t callback, int keyoff, void *arg) { return (pctrie_reclaim_begin_compound(pnode, ptree, callback, keyoff, arg)); } /* * Replace an existing value in the trie with another one. * Panics if there is not an old value in the trie at the new value's index. */ uint64_t * pctrie_replace(struct pctrie *ptree, uint64_t *newval) { struct pctrie_node *node, *parent; uint64_t *m; node = _pctrie_lookup_node(ptree, NULL, *newval, &parent, NULL, PCTRIE_LOCKED); m = pctrie_match_value(node, *newval); if (m == NULL) panic("%s: original replacing value not found", __func__); pctrie_node_store(pctrie_child(ptree, parent, *newval), pctrie_toleaf(newval), PCTRIE_LOCKED); return (m); } #ifdef DDB /* * Show details about the given node. */ DB_SHOW_COMMAND(pctrienode, db_show_pctrienode) { struct pctrie_node *node, *tmp; int slot; pn_popmap_t popmap; if (!have_addr) return; node = (struct pctrie_node *)addr; db_printf("node %p, owner %jx, children popmap %04x, level %u:\n", (void *)node, (uintmax_t)node->pn_owner, node->pn_popmap, node->pn_clev / PCTRIE_WIDTH); for (popmap = node->pn_popmap; popmap != 0; popmap ^= 1 << slot) { slot = ffs(popmap) - 1; tmp = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_UNSERIALIZED); db_printf("slot: %d, val: %p, value: %p, clev: %d\n", slot, (void *)tmp, pctrie_isleaf(tmp) ? pctrie_toval(tmp) : NULL, node->pn_clev / PCTRIE_WIDTH); } } #endif /* DDB */