diff --git a/sys/kern/subr_pctrie.c b/sys/kern/subr_pctrie.c index 76f4ee17a8ca..4017f98c207d 100644 --- a/sys/kern/subr_pctrie.c +++ b/sys/kern/subr_pctrie.c @@ -1,755 +1,926 @@ /*- * 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 #define PCTRIE_MASK (PCTRIE_COUNT - 1) #define PCTRIE_LIMIT (howmany(sizeof(uint64_t) * NBBY, PCTRIE_WIDTH) - 1) #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_child[PCTRIE_COUNT]; /* Child nodes. */ }; enum pctrie_access { PCTRIE_SMR, PCTRIE_LOCKED, PCTRIE_UNSERIALIZED }; static __inline void pctrie_node_store(smr_pctnode_t *p, void *val, enum pctrie_access access); /* * 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_MASK); } /* * 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); } /* * Check radix node. */ static __inline void pctrie_node_put(struct pctrie_node *node) { #ifdef INVARIANTS int slot; KASSERT(powerof2(node->pn_popmap), ("pctrie_node_put: node %p has too many children %04x", node, node->pn_popmap)); for (slot = 0; slot < PCTRIE_COUNT; slot++) { if ((node->pn_popmap & (1 << slot)) != 0) continue; KASSERT(smr_unserialized_load(&node->pn_child[slot], true) == PCTRIE_NULL, ("pctrie_node_put: node %p has a child", node)); } #endif } /* * 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 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((smr_pctnode_t *)&ptree->pt_root, smr, access)); } /* * Set the root node for a tree. */ static __inline void pctrie_root_store(struct pctrie *ptree, struct pctrie_node *node, enum pctrie_access access) { pctrie_node_store((smr_pctnode_t *)&ptree->pt_root, node, access); } /* * 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)); } /* * 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)); } +enum pctrie_insert_neighbor_mode { + PCTRIE_INSERT_NEIGHBOR_NONE, + PCTRIE_INSERT_NEIGHBOR_LT, + PCTRIE_INSERT_NEIGHBOR_GT, +}; + /* - * Looks for where to insert the key-value pair into the trie. Completes the - * insertion if it replaces a null leaf; otherwise, returns insertion location - * to caller. Panics if the key already exists. + * 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(). + * + * With mode PCTRIE_INSERT_NEIGHBOR_GT or PCTRIE_INSERT_NEIGHBOR_LT, set + * *neighbor_out to the lowest level node we encounter during the insert lookup + * that is a parent of the next greater or lesser entry. The value is not + * defined if the key was already present in the trie. + * + * Note that mode is expected to be a compile-time constant, and this procedure + * is expected to be inlined into callers with extraneous code optimized out. */ -void * -pctrie_insert_lookup(struct pctrie *ptree, uint64_t *val) +static __always_inline void * +pctrie_insert_lookup_compound(struct pctrie *ptree, uint64_t *val, + uint64_t **found_out, struct pctrie_node **neighbor_out, + enum pctrie_insert_neighbor_mode mode) { uint64_t index; struct pctrie_node *node, *parent; int slot; index = *val; /* * The owner of record for root is not really important because it * will never be used. */ node = pctrie_root_load(ptree, NULL, PCTRIE_LOCKED); parent = NULL; for (;;) { if (pctrie_isleaf(node)) { if (node == PCTRIE_NULL) { if (parent == NULL) ptree->pt_root = pctrie_toleaf(val); else pctrie_addnode(parent, index, pctrie_toleaf(val), PCTRIE_LOCKED); return (NULL); } - if (*pctrie_toval(node) == index) - panic("%s: key %jx is already present", - __func__, (uintmax_t)index); + if (*pctrie_toval(node) == index) { + *found_out = pctrie_toval(node); + return (NULL); + } break; } if (pctrie_keybarr(node, index, &slot)) break; + /* + * Descend. If we're tracking the next neighbor and this node + * contains a neighboring entry in the right direction, record + * it. + */ + if (mode == PCTRIE_INSERT_NEIGHBOR_LT) { + if ((node->pn_popmap & ((1 << slot) - 1)) != 0) + *neighbor_out = node; + } else if (mode == PCTRIE_INSERT_NEIGHBOR_GT) { + if ((node->pn_popmap >> slot) > 1) + *neighbor_out = node; + } parent = node; node = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); } + /* + * The caller will split this node. If we're tracking the next + * neighbor, record the old node if the old entry is in the right + * direction. + */ + if (mode == PCTRIE_INSERT_NEIGHBOR_LT) { + if (*pctrie_toval(node) < index) + *neighbor_out = node; + } else if (mode == PCTRIE_INSERT_NEIGHBOR_GT) { + if (*pctrie_toval(node) > index) + *neighbor_out = node; + } + /* * '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 ((parent != NULL) ? &parent->pn_child[slot]: (smr_pctnode_t *)&ptree->pt_root); } +/* + * Wrap pctrie_insert_lookup_compound 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) +{ + void *parentp; + uint64_t *found; + + found = NULL; + parentp = pctrie_insert_lookup_compound(ptree, val, &found, NULL, + PCTRIE_INSERT_NEIGHBOR_NONE); + if (__predict_false(found != NULL)) + panic("%s: key %jx is already present", __func__, + (uintmax_t)*val); + return (parentp); +} + +/* + * Wrap pctrie_insert_lookup_compound to implement find-or-insert. Do not look + * for neighboring entries. + */ +void * +pctrie_insert_lookup(struct pctrie *ptree, uint64_t *val, + uint64_t **found_out) +{ + *found_out = NULL; + return (pctrie_insert_lookup_compound(ptree, val, found_out, NULL, + PCTRIE_INSERT_NEIGHBOR_NONE)); +} + +/* + * Wrap pctrie_insert_lookup_compound to implement find or insert and find next + * greater entry. Find a subtree that contains the next entry greater than the + * newly-inserted or to-be-inserted entry. + */ +void * +pctrie_insert_lookup_gt(struct pctrie *ptree, uint64_t *val, + uint64_t **found_out, struct pctrie_node **neighbor_out) +{ + *found_out = NULL; + *neighbor_out = NULL; + return (pctrie_insert_lookup_compound(ptree, val, found_out, + neighbor_out, PCTRIE_INSERT_NEIGHBOR_GT)); +} + +/* + * Wrap pctrie_insert_lookup_compound to implement find or insert and find next + * lesser entry. Find a subtree that contains the next entry less than the + * newly-inserted or to-be-inserted entry. + */ +void * +pctrie_insert_lookup_lt(struct pctrie *ptree, uint64_t *val, + uint64_t **found_out, struct pctrie_node **neighbor_out) +{ + *found_out = NULL; + *neighbor_out = NULL; + return (pctrie_insert_lookup_compound(ptree, val, found_out, + neighbor_out, PCTRIE_INSERT_NEIGHBOR_LT)); +} + /* * Uses new node to insert key-value pair into the trie at given location. */ void pctrie_insert_node(void *parentp, struct pctrie_node *parent, uint64_t *val) { struct pctrie_node *node; uint64_t index, newind; /* * Clear the last child pointer of the newly allocated parent. 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 (parent->pn_popmap != 0) { pctrie_node_store(&parent->pn_child[ffs(parent->pn_popmap) - 1], PCTRIE_NULL, PCTRIE_UNSERIALIZED); parent->pn_popmap = 0; } /* * Recover the values of the two children of the new parent 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); 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(parent->pn_clev) * NBBY)), "pn_clev too narrow"); parent->pn_clev = rounddown(ilog2(index ^ newind), PCTRIE_WIDTH); parent->pn_owner = PCTRIE_COUNT; parent->pn_owner = index & -(parent->pn_owner << parent->pn_clev); /* These writes are not yet visible due to ordering. */ pctrie_addnode(parent, index, pctrie_toleaf(val), PCTRIE_UNSERIALIZED); pctrie_addnode(parent, newind, node, PCTRIE_UNSERIALIZED); /* Synchronize to make the above visible. */ pctrie_node_store(parentp, parent, PCTRIE_LOCKED); } /* * Returns the value stored at the index. If the index is not present, * NULL is returned. */ static __always_inline uint64_t * _pctrie_lookup(struct pctrie *ptree, uint64_t index, smr_t smr, enum pctrie_access access) { struct pctrie_node *node; uint64_t *m; int slot; node = pctrie_root_load(ptree, smr, access); for (;;) { if (pctrie_isleaf(node)) { if ((m = pctrie_toval(node)) != NULL && *m == index) return (m); break; } if (pctrie_keybarr(node, index, &slot)) break; node = pctrie_node_load(&node->pn_child[slot], smr, access); } return (NULL); } /* * 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) { return (_pctrie_lookup(ptree, index, NULL, PCTRIE_LOCKED)); } /* * 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) { uint64_t *res; smr_enter(smr); res = _pctrie_lookup(ptree, index, smr, PCTRIE_SMR); smr_exit(smr); return (res); } /* * Returns the value with the least index that is greater than or equal to the * specified index, or NULL if there are no such values. * * Requires that access be externally synchronized by a lock. */ -uint64_t * -pctrie_lookup_ge(struct pctrie *ptree, uint64_t index) +static __inline uint64_t * +pctrie_lookup_ge_node(struct pctrie_node *node, uint64_t index) { - struct pctrie_node *node, *succ; + struct pctrie_node *succ; uint64_t *m; int slot; /* * Descend the trie as if performing an ordinary lookup for the * specified value. However, unlike an ordinary lookup, as we descend * the trie, we use "succ" to remember the last branching-off point, * that is, the interior node under which the least value that is both * outside our current path down the trie and greater than the specified * index resides. (The node's popmap makes it fast and easy to * recognize a branching-off point.) If our ordinary lookup fails to * yield a value that is greater than or equal to the specified index, * then we will exit this loop and perform a lookup starting from * "succ". If "succ" is not NULL, then that lookup is guaranteed to * succeed. */ - node = pctrie_root_load(ptree, NULL, PCTRIE_LOCKED); succ = NULL; for (;;) { if (pctrie_isleaf(node)) { if ((m = pctrie_toval(node)) != NULL && *m >= index) return (m); break; } if (pctrie_keybarr(node, index, &slot)) { /* * If all values in this subtree are > index, then the * least value in this subtree is the answer. */ if (node->pn_owner > index) succ = node; break; } /* * Just in case the next search step leads to a subtree of all * values < index, check popmap to see if a next bigger step, to * a subtree of all pages with values > index, is available. If * so, remember to restart the search here. */ if ((node->pn_popmap >> slot) > 1) succ = node; node = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); } /* * Restart the search from the last place visited in the subtree that * included some values > index, if there was such a place. */ if (succ == NULL) return (NULL); if (succ != node) { /* * Take a step to the next bigger sibling of the node chosen * last time. In that subtree, all values > index. */ slot = pctrie_slot(succ, index) + 1; KASSERT((succ->pn_popmap >> slot) != 0, ("%s: no popmap siblings past slot %d in node %p", __func__, slot, succ)); slot += ffs(succ->pn_popmap >> slot) - 1; succ = pctrie_node_load(&succ->pn_child[slot], NULL, PCTRIE_LOCKED); } /* * Find the value in the subtree rooted at "succ" with the least index. */ while (!pctrie_isleaf(succ)) { KASSERT(succ->pn_popmap != 0, ("%s: no popmap children in node %p", __func__, succ)); slot = ffs(succ->pn_popmap) - 1; succ = pctrie_node_load(&succ->pn_child[slot], NULL, PCTRIE_LOCKED); } return (pctrie_toval(succ)); } +uint64_t * +pctrie_lookup_ge(struct pctrie *ptree, uint64_t index) +{ + return (pctrie_lookup_ge_node( + pctrie_root_load(ptree, NULL, PCTRIE_LOCKED), index)); +} + +uint64_t * +pctrie_subtree_lookup_gt(struct pctrie_node *node, uint64_t index) +{ + if (node == NULL || index + 1 == 0) + return (NULL); + return (pctrie_lookup_ge_node(node, index + 1)); +} + +#ifdef INVARIANTS +void +pctrie_subtree_lookup_gt_assert(struct pctrie_node *node, uint64_t index, + struct pctrie *ptree, uint64_t *res) +{ + uint64_t *expected; + + if (index + 1 == 0) + expected = NULL; + else + expected = pctrie_lookup_ge(ptree, index + 1); + KASSERT(res == expected, + ("pctrie subtree lookup gt result different from root lookup: " + "ptree %p, index %ju, subtree %p, found %p, expected %p", ptree, + (uintmax_t)index, node, res, expected)); +} +#endif + /* * Returns the value with the greatest index that is less than or equal to the * specified index, or NULL if there are no such values. * * Requires that access be externally synchronized by a lock. */ -uint64_t * -pctrie_lookup_le(struct pctrie *ptree, uint64_t index) +static __inline uint64_t * +pctrie_lookup_le_node(struct pctrie_node *node, uint64_t index) { - struct pctrie_node *node, *pred; + struct pctrie_node *pred; uint64_t *m; int slot; /* - * Mirror the implementation of pctrie_lookup_ge, described above. + * Mirror the implementation of pctrie_lookup_ge_node, described above. */ - node = pctrie_root_load(ptree, NULL, PCTRIE_LOCKED); pred = NULL; for (;;) { if (pctrie_isleaf(node)) { if ((m = pctrie_toval(node)) != NULL && *m <= index) return (m); break; } if (pctrie_keybarr(node, index, &slot)) { if (node->pn_owner < index) pred = node; break; } if ((node->pn_popmap & ((1 << slot) - 1)) != 0) pred = node; node = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); } if (pred == NULL) return (NULL); if (pred != node) { slot = pctrie_slot(pred, index); KASSERT((pred->pn_popmap & ((1 << slot) - 1)) != 0, ("%s: no popmap siblings before slot %d in node %p", __func__, slot, pred)); slot = ilog2(pred->pn_popmap & ((1 << slot) - 1)); pred = pctrie_node_load(&pred->pn_child[slot], NULL, PCTRIE_LOCKED); } while (!pctrie_isleaf(pred)) { KASSERT(pred->pn_popmap != 0, ("%s: no popmap children in node %p", __func__, pred)); slot = ilog2(pred->pn_popmap); pred = pctrie_node_load(&pred->pn_child[slot], NULL, PCTRIE_LOCKED); } return (pctrie_toval(pred)); } +uint64_t * +pctrie_lookup_le(struct pctrie *ptree, uint64_t index) +{ + return (pctrie_lookup_le_node( + pctrie_root_load(ptree, NULL, PCTRIE_LOCKED), index)); +} + +uint64_t * +pctrie_subtree_lookup_lt(struct pctrie_node *node, uint64_t index) +{ + if (node == NULL || index == 0) + return (NULL); + return (pctrie_lookup_le_node(node, index - 1)); +} + +#ifdef INVARIANTS +void +pctrie_subtree_lookup_lt_assert(struct pctrie_node *node, uint64_t index, + struct pctrie *ptree, uint64_t *res) +{ + uint64_t *expected; + + if (index == 0) + expected = NULL; + else + expected = pctrie_lookup_le(ptree, index - 1); + KASSERT(res == expected, + ("pctrie subtree lookup lt result different from root lookup: " + "ptree %p, index %ju, subtree %p, found %p, expected %p", ptree, + (uintmax_t)index, node, res, expected)); +} +#endif + /* * 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 *child, *node, *parent; uint64_t *m; int slot; *freenode = node = NULL; child = pctrie_root_load(ptree, NULL, PCTRIE_LOCKED); for (;;) { if (pctrie_isleaf(child)) break; parent = node; node = child; slot = pctrie_slot(node, index); child = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); } if ((m = pctrie_toval(child)) == NULL || *m != index) return (NULL); if (node == NULL) { pctrie_root_store(ptree, PCTRIE_NULL, PCTRIE_LOCKED); return (m); } KASSERT((node->pn_popmap & (1 << slot)) != 0, ("%s: bad popmap slot %d in node %p", __func__, slot, node)); node->pn_popmap ^= 1 << slot; pctrie_node_store(&node->pn_child[slot], PCTRIE_NULL, PCTRIE_LOCKED); if (!powerof2(node->pn_popmap)) return (m); 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)); if (parent == NULL) pctrie_root_store(ptree, child, PCTRIE_LOCKED); else { slot = pctrie_slot(parent, index); KASSERT(node == pctrie_node_load(&parent->pn_child[slot], NULL, PCTRIE_LOCKED), ("%s: invalid child value", __func__)); pctrie_node_store(&parent->pn_child[slot], child, PCTRIE_LOCKED); } /* * The child is still valid and we can not zero the * pointer until all SMR references are gone. */ pctrie_node_put(node); *freenode = node; return (m); } /* * Prune all the leaves of 'node' before its first non-leaf child, make child * zero of 'node' point up to 'parent', make 'node' into 'parent' and that * non-leaf child into 'node'. Repeat until a node has been stripped of all * children, and mark it for freeing, returning its parent. */ static struct pctrie_node * pctrie_reclaim_prune(struct pctrie_node **pnode, struct pctrie_node *parent) { 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)) continue; /* Climb one level down the trie. */ pctrie_node_store(&node->pn_child[0], parent, PCTRIE_UNSERIALIZED); parent = node; node = child; } *pnode = parent; return (node); } /* * Recover the node parent from its first child and continue pruning. */ struct pctrie_node * pctrie_reclaim_resume(struct pctrie_node **pnode) { struct pctrie_node *parent, *node; node = *pnode; if (node == NULL) return (NULL); /* Climb one level up the trie. */ parent = pctrie_node_load(&node->pn_child[0], NULL, PCTRIE_UNSERIALIZED); pctrie_node_store(&node->pn_child[0], PCTRIE_NULL, PCTRIE_UNSERIALIZED); return (pctrie_reclaim_prune(pnode, parent)); } /* * Find the trie root, and start pruning with a NULL parent. */ struct pctrie_node * pctrie_reclaim_begin(struct pctrie_node **pnode, struct pctrie *ptree) { struct pctrie_node *node; node = pctrie_root_load(ptree, NULL, PCTRIE_UNSERIALIZED); pctrie_root_store(ptree, PCTRIE_NULL, PCTRIE_UNSERIALIZED); if (pctrie_isleaf(node)) return (NULL); *pnode = node; return (pctrie_reclaim_prune(pnode, NULL)); } /* * 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 *leaf, *parent, *node; uint64_t *m; uint64_t index; int slot; leaf = pctrie_toleaf(newval); index = *newval; node = pctrie_root_load(ptree, NULL, PCTRIE_LOCKED); parent = NULL; for (;;) { if (pctrie_isleaf(node)) { if ((m = pctrie_toval(node)) != NULL && *m == index) { if (parent == NULL) ptree->pt_root = leaf; else pctrie_node_store( &parent->pn_child[slot], leaf, PCTRIE_LOCKED); return (m); } break; } if (pctrie_keybarr(node, index, &slot)) break; parent = node; node = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); } panic("%s: original replacing value not found", __func__); } #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 */ diff --git a/sys/sys/pctrie.h b/sys/sys/pctrie.h index 38b297899592..06b9fca79528 100644 --- a/sys/sys/pctrie.h +++ b/sys/sys/pctrie.h @@ -1,214 +1,321 @@ /*- * 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. */ #ifndef _SYS_PCTRIE_H_ #define _SYS_PCTRIE_H_ #include #include #ifdef _KERNEL #define PCTRIE_DEFINE_SMR(name, type, field, allocfn, freefn, smr) \ PCTRIE_DEFINE(name, type, field, allocfn, freefn) \ \ static __inline struct type * \ name##_PCTRIE_LOOKUP_UNLOCKED(struct pctrie *ptree, uint64_t key) \ { \ \ return name##_PCTRIE_VAL2PTR(pctrie_lookup_unlocked(ptree, \ key, (smr))); \ } \ +#ifdef INVARIANTS +void pctrie_subtree_lookup_gt_assert(struct pctrie_node *node, + uint64_t key, struct pctrie *ptree, uint64_t *res); +void pctrie_subtree_lookup_lt_assert(struct pctrie_node *node, + uint64_t key, struct pctrie *ptree, uint64_t *res); +#else +#define pctrie_subtree_lookup_gt_assert(node, key, ptree, res) +#define pctrie_subtree_lookup_lt_assert(node, key, ptree, res) +#endif + #define PCTRIE_DEFINE(name, type, field, allocfn, freefn) \ \ CTASSERT(sizeof(((struct type *)0)->field) == sizeof(uint64_t)); \ /* \ * XXX This assert protects flag bits, it does not enforce natural \ * alignment. 32bit architectures do not naturally align 64bit fields. \ */ \ CTASSERT((__offsetof(struct type, field) & (sizeof(uint32_t) - 1)) == 0); \ \ static __inline struct type * \ name##_PCTRIE_VAL2PTR(uint64_t *val) \ { \ \ if (val == NULL) \ return (NULL); \ return (struct type *) \ ((uintptr_t)val - __offsetof(struct type, field)); \ } \ \ static __inline uint64_t * \ name##_PCTRIE_PTR2VAL(struct type *ptr) \ { \ \ return &ptr->field; \ } \ \ -static __inline int \ +static __inline __unused int \ name##_PCTRIE_INSERT(struct pctrie *ptree, struct type *ptr) \ { \ struct pctrie_node *parent; \ void *parentp; \ uint64_t *val = name##_PCTRIE_PTR2VAL(ptr); \ \ - parentp = pctrie_insert_lookup(ptree, val); \ + parentp = pctrie_insert_lookup_strict(ptree, val); \ if (parentp == NULL) \ return (0); \ parent = allocfn(ptree); \ if (__predict_false(parent == NULL)) \ return (ENOMEM); \ pctrie_insert_node(parentp, parent, val); \ return (0); \ } \ \ +static __inline __unused int \ +name##_PCTRIE_FIND_OR_INSERT(struct pctrie *ptree, struct type *ptr, \ + struct type **found_out_opt) \ +{ \ + struct pctrie_node *parent; \ + void *parentp; \ + uint64_t *val = name##_PCTRIE_PTR2VAL(ptr); \ + uint64_t *found; \ + \ + parentp = pctrie_insert_lookup(ptree, val, &found); \ + if (found != NULL) { \ + if (found_out_opt != NULL) \ + *found_out_opt = name##_PCTRIE_VAL2PTR(found); \ + return (EEXIST); \ + } \ + if (parentp == NULL) \ + return (0); \ + parent = allocfn(ptree); \ + if (__predict_false(parent == NULL)) \ + return (ENOMEM); \ + pctrie_insert_node(parentp, parent, val); \ + return (0); \ +} \ + \ +static __inline __unused int \ +name##_PCTRIE_INSERT_LOOKUP_GE(struct pctrie *ptree, struct type *ptr, \ + struct type **found_out) \ +{ \ + struct pctrie_node *parent, *neighbor; \ + void *parentp; \ + uint64_t *val = name##_PCTRIE_PTR2VAL(ptr); \ + uint64_t *found; \ + \ + parentp = pctrie_insert_lookup_gt(ptree, val, &found, \ + &neighbor); \ + if (__predict_false(found != NULL)) { \ + *found_out = name##_PCTRIE_VAL2PTR(found); \ + return (EEXIST); \ + } \ + if (parentp != NULL) { \ + parent = allocfn(ptree); \ + if (__predict_false(parent == NULL)) { \ + *found_out = NULL; \ + return (ENOMEM); \ + } \ + if (neighbor == parentp) \ + neighbor = parent; \ + pctrie_insert_node(parentp, parent, val); \ + } \ + found = pctrie_subtree_lookup_gt(neighbor, *val); \ + *found_out = name##_PCTRIE_VAL2PTR(found); \ + pctrie_subtree_lookup_gt_assert(neighbor, *val, ptree, found); \ + return (0); \ +} \ + \ +static __inline __unused int \ +name##_PCTRIE_INSERT_LOOKUP_LE(struct pctrie *ptree, struct type *ptr, \ + struct type **found_out) \ +{ \ + struct pctrie_node *parent, *neighbor; \ + void *parentp; \ + uint64_t *val = name##_PCTRIE_PTR2VAL(ptr); \ + uint64_t *found; \ + \ + parentp = pctrie_insert_lookup_lt(ptree, val, &found, \ + &neighbor); \ + if (__predict_false(found != NULL)) { \ + *found_out = name##_PCTRIE_VAL2PTR(found); \ + return (EEXIST); \ + } \ + if (parentp != NULL) { \ + parent = allocfn(ptree); \ + if (__predict_false(parent == NULL)) { \ + *found_out = NULL; \ + return (ENOMEM); \ + } \ + if (neighbor == parentp) \ + neighbor = parent; \ + pctrie_insert_node(parentp, parent, val); \ + } \ + found = pctrie_subtree_lookup_lt(neighbor, *val); \ + *found_out = name##_PCTRIE_VAL2PTR(found); \ + pctrie_subtree_lookup_lt_assert(neighbor, *val, ptree, found); \ + return (0); \ +} \ + \ static __inline __unused struct type * \ name##_PCTRIE_LOOKUP(struct pctrie *ptree, uint64_t key) \ { \ \ return name##_PCTRIE_VAL2PTR(pctrie_lookup(ptree, key)); \ } \ \ static __inline __unused struct type * \ name##_PCTRIE_LOOKUP_LE(struct pctrie *ptree, uint64_t key) \ { \ \ return name##_PCTRIE_VAL2PTR(pctrie_lookup_le(ptree, key)); \ } \ \ static __inline __unused struct type * \ name##_PCTRIE_LOOKUP_GE(struct pctrie *ptree, uint64_t key) \ { \ \ return name##_PCTRIE_VAL2PTR(pctrie_lookup_ge(ptree, key)); \ } \ \ static __inline __unused void \ name##_PCTRIE_RECLAIM(struct pctrie *ptree) \ { \ struct pctrie_node *freenode, *node; \ \ for (freenode = pctrie_reclaim_begin(&node, ptree); \ freenode != NULL; \ freenode = pctrie_reclaim_resume(&node)) \ freefn(ptree, freenode); \ } \ \ static __inline __unused struct type * \ name##_PCTRIE_REPLACE(struct pctrie *ptree, struct type *ptr) \ { \ \ return name##_PCTRIE_VAL2PTR( \ pctrie_replace(ptree, name##_PCTRIE_PTR2VAL(ptr))); \ } \ \ static __inline __unused void \ name##_PCTRIE_REMOVE(struct pctrie *ptree, uint64_t key) \ { \ uint64_t *val; \ struct pctrie_node *freenode; \ \ val = pctrie_remove_lookup(ptree, key, &freenode); \ if (val == NULL) \ panic("%s: key not found", __func__); \ if (freenode != NULL) \ freefn(ptree, freenode); \ } \ \ static __inline __unused struct type * \ name##_PCTRIE_REMOVE_LOOKUP(struct pctrie *ptree, uint64_t key) \ { \ uint64_t *val; \ struct pctrie_node *freenode; \ \ val = pctrie_remove_lookup(ptree, key, &freenode); \ if (freenode != NULL) \ freefn(ptree, freenode); \ return name##_PCTRIE_VAL2PTR(val); \ } -void *pctrie_insert_lookup(struct pctrie *ptree, uint64_t *val); +void *pctrie_insert_lookup(struct pctrie *ptree, uint64_t *val, + uint64_t **found_out); +void *pctrie_insert_lookup_gt(struct pctrie *ptree, uint64_t *val, + uint64_t **found_out, struct pctrie_node **neighbor_out); +void *pctrie_insert_lookup_lt(struct pctrie *ptree, uint64_t *val, + uint64_t **found_out, struct pctrie_node **neighbor_out); +void *pctrie_insert_lookup_strict(struct pctrie *ptree, + uint64_t *val); void pctrie_insert_node(void *parentp, struct pctrie_node *parent, uint64_t *val); uint64_t *pctrie_lookup(struct pctrie *ptree, uint64_t key); uint64_t *pctrie_lookup_ge(struct pctrie *ptree, uint64_t key); uint64_t *pctrie_lookup_le(struct pctrie *ptree, uint64_t key); uint64_t *pctrie_lookup_unlocked(struct pctrie *ptree, uint64_t key, smr_t smr); struct pctrie_node *pctrie_reclaim_begin(struct pctrie_node **pnode, struct pctrie *ptree); struct pctrie_node *pctrie_reclaim_resume(struct pctrie_node **pnode); uint64_t *pctrie_remove_lookup(struct pctrie *ptree, uint64_t index, struct pctrie_node **killnode); uint64_t *pctrie_replace(struct pctrie *ptree, uint64_t *newval); +uint64_t *pctrie_subtree_lookup_gt(struct pctrie_node *node, + uint64_t key); +uint64_t *pctrie_subtree_lookup_lt(struct pctrie_node *node, + uint64_t key); size_t pctrie_node_size(void); int pctrie_zone_init(void *mem, int size, int flags); /* * Each search path in the trie terminates at a leaf, which is a pointer to a * value marked with a set 1-bit. A leaf may be associated with a null pointer * to indicate no value there. */ #define PCTRIE_ISLEAF 0x1 #define PCTRIE_NULL (struct pctrie_node *)PCTRIE_ISLEAF static __inline void pctrie_init(struct pctrie *ptree) { ptree->pt_root = PCTRIE_NULL; } static __inline bool pctrie_is_empty(struct pctrie *ptree) { return (ptree->pt_root == PCTRIE_NULL); } /* Set of all flag bits stored in node pointers. */ #define PCTRIE_FLAGS (PCTRIE_ISLEAF) /* Minimum align parameter for uma_zcreate. */ #define PCTRIE_PAD PCTRIE_FLAGS /* * These widths should allow the pointers to a node's children to fit within * a single cache line. The extra levels from a narrow width should not be * a problem thanks to path compression. */ #ifdef __LP64__ #define PCTRIE_WIDTH 4 #else #define PCTRIE_WIDTH 3 #endif #define PCTRIE_COUNT (1 << PCTRIE_WIDTH) #endif /* _KERNEL */ #endif /* !_SYS_PCTRIE_H_ */