diff --git a/sys/kern/subr_pctrie.c b/sys/kern/subr_pctrie.c index cf09903556ec..ae8408a6e1ef 100644 --- a/sys/kern/subr_pctrie.c +++ b/sys/kern/subr_pctrie.c @@ -1,810 +1,795 @@ /*- * 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 __FBSDID("$FreeBSD$"); #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"); /* Flag bits stored in node pointers. */ #define PCTRIE_ISLEAF 0x1 #define PCTRIE_FLAGS 0x1 #define PCTRIE_PAD PCTRIE_FLAGS /* Returns one unit associated with specified level. */ #define PCTRIE_UNITLEVEL(lev) \ ((uint64_t)1 << ((lev) * PCTRIE_WIDTH)) 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; /* Current level. */ 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); /* * Return the position in the array for a given level. */ static __inline int pctrie_slot(uint64_t index, uint16_t level) { return ((index >> (level * PCTRIE_WIDTH)) & PCTRIE_MASK); } /* Computes the key (index) with the low-order 'level' radix-digits zeroed. */ static __inline uint64_t pctrie_trimkey(uint64_t index, uint16_t level) { return (index & -PCTRIE_UNITLEVEL(level)); } /* * Allocate a node. Pre-allocation should ensure that the request * will always be satisfied. */ static struct pctrie_node * pctrie_node_get(struct pctrie *ptree, pctrie_alloc_t allocfn, uint64_t index, uint16_t clevel) { struct pctrie_node *node; node = allocfn(ptree); if (node == NULL) return (NULL); /* * We want to clear the last child pointer 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 (node->pn_popmap != 0) { pctrie_node_store(&node->pn_child[ffs(node->pn_popmap) - 1], NULL, PCTRIE_UNSERIALIZED); node->pn_popmap = 0; } node->pn_owner = pctrie_trimkey(index, clevel + 1); node->pn_clev = clevel; return (node); } /* * Free radix node. */ static __inline void pctrie_node_put(struct pctrie *ptree, struct pctrie_node *node, pctrie_free_t freefn) { #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) == NULL, ("pctrie_node_put: node %p has a child", node)); } #endif freefn(ptree, node); } /* * 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)); } /* - * Adds the val as a child of the provided node. + * Make 'child' a child of 'node'. */ static __inline void -pctrie_addval(struct pctrie_node *node, uint64_t index, uint16_t clev, - uint64_t *val, enum pctrie_access access) +pctrie_addnode(struct pctrie_node *node, uint64_t index, uint16_t clev, + struct pctrie_node *child, enum pctrie_access access) { int slot; slot = pctrie_slot(index, clev); - pctrie_node_store(&node->pn_child[slot], - pctrie_toleaf(val), access); + 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)); } /* * Returns the level where two keys differ. * It cannot accept 2 equal keys. */ static __inline uint16_t pctrie_keydiff(uint64_t index1, uint64_t index2) { KASSERT(index1 != index2, ("%s: passing the same key value %jx", __func__, (uintmax_t)index1)); CTASSERT(sizeof(long long) >= sizeof(uint64_t)); /* * From the highest-order bit where the indexes differ, * compute the highest level in the trie where they differ. */ return ((flsll(index1 ^ index2) - 1) / PCTRIE_WIDTH); } /* * Returns TRUE if it can be determined that key does not belong to the * specified node. Otherwise, returns FALSE. */ static __inline bool pctrie_keybarr(struct pctrie_node *node, uint64_t idx) { if (node->pn_clev < PCTRIE_LIMIT) { idx = pctrie_trimkey(idx, node->pn_clev + 1); return (idx != node->pn_owner); } return (false); } /* * Internal helper for pctrie_reclaim_allnodes(). * This function is recursive. */ static void pctrie_reclaim_allnodes_int(struct pctrie *ptree, struct pctrie_node *node, pctrie_free_t freefn) { struct pctrie_node *child; int slot; while (node->pn_popmap != 0) { slot = ffs(node->pn_popmap) - 1; child = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_UNSERIALIZED); KASSERT(child != NULL, ("%s: bad popmap slot %d in node %p", __func__, slot, node)); if (!pctrie_isleaf(child)) pctrie_reclaim_allnodes_int(ptree, child, freefn); node->pn_popmap ^= 1 << slot; pctrie_node_store(&node->pn_child[slot], NULL, PCTRIE_UNSERIALIZED); } pctrie_node_put(ptree, node, freefn); } /* * 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; memset(node->pn_child, 0, sizeof(node->pn_child)); return (0); } size_t pctrie_node_size(void) { return (sizeof(struct pctrie_node)); } /* * Inserts the key-value pair into the trie. * Panics if the key already exists. */ int pctrie_insert(struct pctrie *ptree, uint64_t *val, pctrie_alloc_t allocfn) { uint64_t index, newind; - struct pctrie_node *node, *tmp; + struct pctrie_node *leaf, *node, *tmp; smr_pctnode_t *parentp; - uint64_t *m; int slot; uint16_t clev; index = *val; + leaf = pctrie_toleaf(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); if (node == NULL) { - ptree->pt_root = (uintptr_t)pctrie_toleaf(val); + ptree->pt_root = (uintptr_t)leaf; return (0); } - parentp = (smr_pctnode_t *)&ptree->pt_root; - for (;;) { + for (parentp = (smr_pctnode_t *)&ptree->pt_root;; node = tmp) { if (pctrie_isleaf(node)) { - m = pctrie_toval(node); - if (*m == index) + newind = *pctrie_toval(node); + if (newind == index) panic("%s: key %jx is already present", __func__, (uintmax_t)index); - clev = pctrie_keydiff(*m, index); - tmp = pctrie_node_get(ptree, allocfn, index, clev); - if (tmp == NULL) - return (ENOMEM); - /* These writes are not yet visible due to ordering. */ - pctrie_addval(tmp, index, clev, val, - PCTRIE_UNSERIALIZED); - pctrie_addval(tmp, *m, clev, m, PCTRIE_UNSERIALIZED); - /* Synchronize to make leaf visible. */ - pctrie_node_store(parentp, tmp, PCTRIE_LOCKED); - return (0); - } else if (pctrie_keybarr(node, index)) break; + } else if (pctrie_keybarr(node, index)) { + newind = node->pn_owner; + break; + } slot = pctrie_slot(index, node->pn_clev); parentp = &node->pn_child[slot]; tmp = pctrie_node_load(parentp, NULL, PCTRIE_LOCKED); if (tmp == NULL) { - pctrie_addval(node, index, node->pn_clev, val, + pctrie_addnode(node, index, node->pn_clev, leaf, PCTRIE_LOCKED); return (0); } - node = tmp; } /* * A new node is needed because the right insertion level is reached. * Setup the new intermediate node and add the 2 children: the - * new object and the older edge. + * new object and the older edge or object. */ - newind = node->pn_owner; clev = pctrie_keydiff(newind, index); tmp = pctrie_node_get(ptree, allocfn, index, clev); if (tmp == NULL) return (ENOMEM); - slot = pctrie_slot(newind, clev); /* These writes are not yet visible due to ordering. */ - pctrie_addval(tmp, index, clev, val, PCTRIE_UNSERIALIZED); - pctrie_node_store(&tmp->pn_child[slot], node, PCTRIE_UNSERIALIZED); - tmp->pn_popmap ^= 1 << slot; + pctrie_addnode(tmp, index, clev, leaf, PCTRIE_UNSERIALIZED); + pctrie_addnode(tmp, newind, clev, node, PCTRIE_UNSERIALIZED); /* Synchronize to make the above visible. */ pctrie_node_store(parentp, tmp, PCTRIE_LOCKED); - return (0); } /* * 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); while (node != NULL) { if (pctrie_isleaf(node)) { m = pctrie_toval(node); if (*m == index) return (m); break; } if (pctrie_keybarr(node, index)) break; slot = pctrie_slot(index, node->pn_clev); 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); } /* * Look up the nearest entry at a position bigger than or equal to index, * assuming access is externally synchronized by a lock. */ uint64_t * pctrie_lookup_ge(struct pctrie *ptree, uint64_t index) { struct pctrie_node *stack[PCTRIE_LIMIT]; uint64_t *m; struct pctrie_node *child, *node; #ifdef INVARIANTS int loops = 0; #endif unsigned tos; int slot; node = pctrie_root_load(ptree, NULL, PCTRIE_LOCKED); if (node == NULL) return (NULL); else if (pctrie_isleaf(node)) { m = pctrie_toval(node); if (*m >= index) return (m); else return (NULL); } tos = 0; for (;;) { /* * If the keys differ before the current bisection node, * then the search key might rollback to the earliest * available bisection node or to the smallest key * in the current node (if the owner is greater than the * search key). */ if (pctrie_keybarr(node, index)) { if (index > node->pn_owner) { ascend: KASSERT(++loops < 1000, ("pctrie_lookup_ge: too many loops")); /* * Pop nodes from the stack until either the * stack is empty or a node that could have a * matching descendant is found. */ do { if (tos == 0) return (NULL); node = stack[--tos]; } while (pctrie_slot(index, node->pn_clev) == (PCTRIE_COUNT - 1)); /* * The following computation cannot overflow * because index's slot at the current level * is less than PCTRIE_COUNT - 1. */ index = pctrie_trimkey(index, node->pn_clev); index += PCTRIE_UNITLEVEL(node->pn_clev); } else index = node->pn_owner; KASSERT(!pctrie_keybarr(node, index), ("pctrie_lookup_ge: keybarr failed")); } slot = pctrie_slot(index, node->pn_clev); child = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); if (pctrie_isleaf(child)) { m = pctrie_toval(child); if (*m >= index) return (m); } else if (child != NULL) goto descend; /* Find the first set bit beyond the first slot+1 bits. */ slot = ffs(node->pn_popmap & (-2 << slot)) - 1; if (slot < 0) { /* * A value or edge greater than the search slot is not * found in the current node; ascend to the next * higher-level node. */ goto ascend; } child = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); KASSERT(child != NULL, ("%s: bad popmap slot %d in node %p", __func__, slot, node)); if (pctrie_isleaf(child)) return (pctrie_toval(child)); index = pctrie_trimkey(index, node->pn_clev + 1) + slot * PCTRIE_UNITLEVEL(node->pn_clev); descend: KASSERT(node->pn_clev > 0, ("pctrie_lookup_ge: pushing leaf's parent")); KASSERT(tos < PCTRIE_LIMIT, ("pctrie_lookup_ge: stack overflow")); stack[tos++] = node; node = child; } } /* * Look up the nearest entry at a position less than or equal to index, * assuming access is externally synchronized by a lock. */ uint64_t * pctrie_lookup_le(struct pctrie *ptree, uint64_t index) { struct pctrie_node *stack[PCTRIE_LIMIT]; uint64_t *m; struct pctrie_node *child, *node; #ifdef INVARIANTS int loops = 0; #endif unsigned tos; int slot; node = pctrie_root_load(ptree, NULL, PCTRIE_LOCKED); if (node == NULL) return (NULL); else if (pctrie_isleaf(node)) { m = pctrie_toval(node); if (*m <= index) return (m); else return (NULL); } tos = 0; for (;;) { /* * If the keys differ before the current bisection node, * then the search key might rollback to the earliest * available bisection node or to the largest key * in the current node (if the owner is smaller than the * search key). */ if (pctrie_keybarr(node, index)) { if (index > node->pn_owner) { index = node->pn_owner + PCTRIE_COUNT * PCTRIE_UNITLEVEL(node->pn_clev); } else { ascend: KASSERT(++loops < 1000, ("pctrie_lookup_le: too many loops")); /* * Pop nodes from the stack until either the * stack is empty or a node that could have a * matching descendant is found. */ do { if (tos == 0) return (NULL); node = stack[--tos]; } while (pctrie_slot(index, node->pn_clev) == 0); /* * The following computation cannot overflow * because index's slot at the current level * is greater than 0. */ index = pctrie_trimkey(index, node->pn_clev); } index--; KASSERT(!pctrie_keybarr(node, index), ("pctrie_lookup_le: keybarr failed")); } slot = pctrie_slot(index, node->pn_clev); child = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); if (pctrie_isleaf(child)) { m = pctrie_toval(child); if (*m <= index) return (m); } else if (child != NULL) goto descend; /* Find the last set bit among the first slot bits. */ slot = fls(node->pn_popmap & ((1 << slot) - 1)) - 1; if (slot < 0) { /* * A value or edge smaller than the search slot is not * found in the current node; ascend to the next * higher-level node. */ goto ascend; } child = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); if (pctrie_isleaf(child)) return (pctrie_toval(child)); index = pctrie_trimkey(index, node->pn_clev + 1) + (slot + 1) * PCTRIE_UNITLEVEL(node->pn_clev) - 1; descend: KASSERT(node->pn_clev > 0, ("pctrie_lookup_le: pushing leaf's parent")); KASSERT(tos < PCTRIE_LIMIT, ("pctrie_lookup_le: stack overflow")); stack[tos++] = node; node = child; } } /* * Remove the specified index from the tree. * Panics if the key is not present. */ void pctrie_remove(struct pctrie *ptree, uint64_t index, pctrie_free_t freefn) { struct pctrie_node *node, *parent, *tmp; uint64_t *m; int slot; node = pctrie_root_load(ptree, NULL, PCTRIE_LOCKED); if (pctrie_isleaf(node)) { m = pctrie_toval(node); if (*m != index) panic("%s: invalid key found", __func__); pctrie_root_store(ptree, NULL, PCTRIE_LOCKED); return; } parent = NULL; for (;;) { if (node == NULL) panic("pctrie_remove: impossible to locate the key"); slot = pctrie_slot(index, node->pn_clev); tmp = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); if (pctrie_isleaf(tmp)) { m = pctrie_toval(tmp); if (*m != index) panic("%s: invalid key found", __func__); 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], NULL, PCTRIE_LOCKED); if (!powerof2(node->pn_popmap)) break; KASSERT(node->pn_popmap != 0, ("%s: bad popmap all zeroes", __func__)); slot = ffs(node->pn_popmap) - 1; tmp = pctrie_node_load(&node->pn_child[slot], NULL, PCTRIE_LOCKED); KASSERT(tmp != NULL, ("%s: bad popmap slot %d in node %p", __func__, slot, node)); if (parent == NULL) pctrie_root_store(ptree, tmp, PCTRIE_LOCKED); else { slot = pctrie_slot(index, parent->pn_clev); KASSERT(pctrie_node_load( &parent->pn_child[slot], NULL, PCTRIE_LOCKED) == node, ("%s: invalid child value", __func__)); pctrie_node_store(&parent->pn_child[slot], tmp, PCTRIE_LOCKED); } /* * The child is still valid and we can not zero the * pointer until all SMR references are gone. */ pctrie_node_put(ptree, node, freefn); break; } parent = node; node = tmp; } } /* * Remove and free all the nodes from the tree. * This function is recursive but there is a tight control on it as the * maximum depth of the tree is fixed. */ void pctrie_reclaim_allnodes(struct pctrie *ptree, pctrie_free_t freefn) { struct pctrie_node *root; root = pctrie_root_load(ptree, NULL, PCTRIE_LOCKED); if (root == NULL) return; pctrie_root_store(ptree, NULL, PCTRIE_UNSERIALIZED); if (!pctrie_isleaf(root)) pctrie_reclaim_allnodes_int(ptree, root, freefn); } #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); 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); } } #endif /* DDB */ diff --git a/sys/vm/vm_radix.c b/sys/vm/vm_radix.c index d2cd2c2536fd..f6bdda70539b 100644 --- a/sys/vm/vm_radix.c +++ b/sys/vm/vm_radix.c @@ -1,887 +1,873 @@ /*- * 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 following code is not generalized into a general purpose library * because there are way too many parameters embedded that should really * be decided by the library consumers. At the same time, consumers * of this code must achieve highest possible performance. * * 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 __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #endif /* * 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 VM_RADIX_WIDTH 4 #else #define VM_RADIX_WIDTH 3 #endif #define VM_RADIX_COUNT (1 << VM_RADIX_WIDTH) #define VM_RADIX_MASK (VM_RADIX_COUNT - 1) #define VM_RADIX_LIMIT \ (howmany(sizeof(vm_pindex_t) * NBBY, VM_RADIX_WIDTH) - 1) #if VM_RADIX_WIDTH == 3 typedef uint8_t rn_popmap_t; #elif VM_RADIX_WIDTH == 4 typedef uint16_t rn_popmap_t; #elif VM_RADIX_WIDTH == 5 typedef uint32_t rn_popmap_t; #else #error Unsupported width #endif _Static_assert(sizeof(rn_popmap_t) <= sizeof(int), "rn_popmap_t too wide"); /* Flag bits stored in node pointers. */ #define VM_RADIX_ISLEAF 0x1 #define VM_RADIX_FLAGS 0x1 #define VM_RADIX_PAD VM_RADIX_FLAGS /* Returns one unit associated with specified level. */ #define VM_RADIX_UNITLEVEL(lev) \ ((vm_pindex_t)1 << ((lev) * VM_RADIX_WIDTH)) enum vm_radix_access { SMR, LOCKED, UNSERIALIZED }; struct vm_radix_node; typedef SMR_POINTER(struct vm_radix_node *) smrnode_t; struct vm_radix_node { vm_pindex_t rn_owner; /* Owner of record. */ rn_popmap_t rn_popmap; /* Valid children. */ uint8_t rn_clev; /* Current level. */ smrnode_t rn_child[VM_RADIX_COUNT]; /* Child nodes. */ }; static uma_zone_t vm_radix_node_zone; static smr_t vm_radix_smr; static void vm_radix_node_store(smrnode_t *p, struct vm_radix_node *v, enum vm_radix_access access); /* * Return the position in the array for a given level. */ static __inline int vm_radix_slot(vm_pindex_t index, uint16_t level) { return ((index >> (level * VM_RADIX_WIDTH)) & VM_RADIX_MASK); } /* Computes the key (index) with the low-order 'level' radix-digits zeroed. */ static __inline vm_pindex_t vm_radix_trimkey(vm_pindex_t index, uint16_t level) { return (index & -VM_RADIX_UNITLEVEL(level)); } /* * Allocate a radix node. */ static struct vm_radix_node * vm_radix_node_get(vm_pindex_t index, uint16_t clevel) { struct vm_radix_node *rnode; rnode = uma_zalloc_smr(vm_radix_node_zone, M_NOWAIT); if (rnode == NULL) return (NULL); /* * We want to clear the last child pointer 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 (rnode->rn_popmap != 0) { vm_radix_node_store(&rnode->rn_child[ffs(rnode->rn_popmap) - 1], NULL, UNSERIALIZED); rnode->rn_popmap = 0; } rnode->rn_owner = vm_radix_trimkey(index, clevel + 1); rnode->rn_clev = clevel; return (rnode); } /* * Free radix node. */ static __inline void vm_radix_node_put(struct vm_radix_node *rnode) { #ifdef INVARIANTS int slot; KASSERT(powerof2(rnode->rn_popmap), ("vm_radix_node_put: rnode %p has too many children %04x", rnode, rnode->rn_popmap)); for (slot = 0; slot < VM_RADIX_COUNT; slot++) { if ((rnode->rn_popmap & (1 << slot)) != 0) continue; KASSERT(smr_unserialized_load(&rnode->rn_child[slot], true) == NULL, ("vm_radix_node_put: rnode %p has a child", rnode)); } #endif uma_zfree_smr(vm_radix_node_zone, rnode); } /* * Fetch a node pointer from a slot in another node. */ static __inline struct vm_radix_node * vm_radix_node_load(smrnode_t *p, enum vm_radix_access access) { switch (access) { case UNSERIALIZED: return (smr_unserialized_load(p, true)); case LOCKED: return (smr_serialized_load(p, true)); case SMR: return (smr_entered_load(p, vm_radix_smr)); } __assert_unreachable(); } static __inline void vm_radix_node_store(smrnode_t *p, struct vm_radix_node *v, enum vm_radix_access access) { switch (access) { case UNSERIALIZED: smr_unserialized_store(p, v, true); break; case LOCKED: smr_serialized_store(p, v, true); break; case SMR: panic("vm_radix_node_store: Not supported in smr section."); } } /* * Get the root node for a radix tree. */ static __inline struct vm_radix_node * vm_radix_root_load(struct vm_radix *rtree, enum vm_radix_access access) { return (vm_radix_node_load((smrnode_t *)&rtree->rt_root, access)); } /* * Set the root node for a radix tree. */ static __inline void vm_radix_root_store(struct vm_radix *rtree, struct vm_radix_node *rnode, enum vm_radix_access access) { vm_radix_node_store((smrnode_t *)&rtree->rt_root, rnode, access); } /* * Returns TRUE if the specified radix node is a leaf and FALSE otherwise. */ static __inline bool vm_radix_isleaf(struct vm_radix_node *rnode) { return (((uintptr_t)rnode & VM_RADIX_ISLEAF) != 0); } /* * Returns page cast to radix node with leaf bit set. */ static __inline struct vm_radix_node * vm_radix_toleaf(vm_page_t page) { return ((struct vm_radix_node *)((uintptr_t)page | VM_RADIX_ISLEAF)); } /* * Returns the associated page extracted from rnode. */ static __inline vm_page_t vm_radix_topage(struct vm_radix_node *rnode) { return ((vm_page_t)((uintptr_t)rnode & ~VM_RADIX_FLAGS)); } /* - * Adds the page as a child of the provided node. + * Make 'child' a child of 'rnode'. */ static __inline void -vm_radix_addpage(struct vm_radix_node *rnode, vm_pindex_t index, uint16_t clev, - vm_page_t page, enum vm_radix_access access) +vm_radix_addnode(struct vm_radix_node *rnode, vm_pindex_t index, uint16_t clev, + struct vm_radix_node *child, enum vm_radix_access access) { int slot; slot = vm_radix_slot(index, clev); - vm_radix_node_store(&rnode->rn_child[slot], - vm_radix_toleaf(page), access); + vm_radix_node_store(&rnode->rn_child[slot], child, access); rnode->rn_popmap ^= 1 << slot; KASSERT((rnode->rn_popmap & (1 << slot)) != 0, ("%s: bad popmap slot %d in rnode %p", __func__, slot, rnode)); } /* * Returns the level where two keys differ. * It cannot accept 2 equal keys. */ static __inline uint16_t vm_radix_keydiff(vm_pindex_t index1, vm_pindex_t index2) { KASSERT(index1 != index2, ("%s: passing the same key value %jx", __func__, (uintmax_t)index1)); CTASSERT(sizeof(long long) >= sizeof(vm_pindex_t)); /* * From the highest-order bit where the indexes differ, * compute the highest level in the trie where they differ. */ return ((flsll(index1 ^ index2) - 1) / VM_RADIX_WIDTH); } /* * Returns TRUE if it can be determined that key does not belong to the * specified rnode. Otherwise, returns FALSE. */ static __inline bool vm_radix_keybarr(struct vm_radix_node *rnode, vm_pindex_t idx) { if (rnode->rn_clev < VM_RADIX_LIMIT) { idx = vm_radix_trimkey(idx, rnode->rn_clev + 1); return (idx != rnode->rn_owner); } return (false); } /* * Internal helper for vm_radix_reclaim_allnodes(). * This function is recursive. */ static void vm_radix_reclaim_allnodes_int(struct vm_radix_node *rnode) { struct vm_radix_node *child; int slot; while (rnode->rn_popmap != 0) { slot = ffs(rnode->rn_popmap) - 1; child = vm_radix_node_load(&rnode->rn_child[slot], UNSERIALIZED); KASSERT(child != NULL, ("%s: bad popmap slot %d in rnode %p", __func__, slot, rnode)); if (!vm_radix_isleaf(child)) vm_radix_reclaim_allnodes_int(child); rnode->rn_popmap ^= 1 << slot; vm_radix_node_store(&rnode->rn_child[slot], NULL, UNSERIALIZED); } vm_radix_node_put(rnode); } #ifndef UMA_MD_SMALL_ALLOC void vm_radix_reserve_kva(void); /* * Reserve the KVA necessary to satisfy the node allocation. * This is mandatory in architectures not supporting direct * mapping as they will need otherwise to carve into the kernel maps for * every node allocation, resulting into deadlocks for consumers already * working with kernel maps. */ void vm_radix_reserve_kva(void) { /* * Calculate the number of reserved nodes, discounting the pages that * are needed to store them. */ if (!uma_zone_reserve_kva(vm_radix_node_zone, ((vm_paddr_t)vm_cnt.v_page_count * PAGE_SIZE) / (PAGE_SIZE + sizeof(struct vm_radix_node)))) panic("%s: unable to reserve KVA", __func__); } #endif /* * Initialize the UMA slab zone. */ void vm_radix_zinit(void) { vm_radix_node_zone = uma_zcreate("RADIX NODE", sizeof(struct vm_radix_node), NULL, NULL, NULL, NULL, VM_RADIX_PAD, UMA_ZONE_VM | UMA_ZONE_SMR | UMA_ZONE_ZINIT); vm_radix_smr = uma_zone_get_smr(vm_radix_node_zone); } /* * Inserts the key-value pair into the trie. * Panics if the key already exists. */ int vm_radix_insert(struct vm_radix *rtree, vm_page_t page) { vm_pindex_t index, newind; - struct vm_radix_node *rnode, *tmp; + struct vm_radix_node *leaf, *rnode, *tmp; smrnode_t *parentp; - vm_page_t m; int slot; uint16_t clev; index = page->pindex; + leaf = vm_radix_toleaf(page); /* * The owner of record for root is not really important because it * will never be used. */ rnode = vm_radix_root_load(rtree, LOCKED); if (rnode == NULL) { - rtree->rt_root = (uintptr_t)vm_radix_toleaf(page); + rtree->rt_root = (uintptr_t)leaf; return (0); } - parentp = (smrnode_t *)&rtree->rt_root; - for (;;) { + for (parentp = (smrnode_t *)&rtree->rt_root;; rnode = tmp) { if (vm_radix_isleaf(rnode)) { - m = vm_radix_topage(rnode); - if (m->pindex == index) + newind = vm_radix_topage(rnode)->pindex; + if (newind == index) panic("%s: key %jx is already present", __func__, (uintmax_t)index); - clev = vm_radix_keydiff(m->pindex, index); - tmp = vm_radix_node_get(index, clev); - if (tmp == NULL) - return (ENOMEM); - /* These writes are not yet visible due to ordering. */ - vm_radix_addpage(tmp, index, clev, page, UNSERIALIZED); - vm_radix_addpage(tmp, m->pindex, clev, m, UNSERIALIZED); - /* Synchronize to make leaf visible. */ - vm_radix_node_store(parentp, tmp, LOCKED); - return (0); - } else if (vm_radix_keybarr(rnode, index)) break; + } else if (vm_radix_keybarr(rnode, index)) { + newind = rnode->rn_owner; + break; + } slot = vm_radix_slot(index, rnode->rn_clev); parentp = &rnode->rn_child[slot]; tmp = vm_radix_node_load(parentp, LOCKED); if (tmp == NULL) { - vm_radix_addpage(rnode, index, rnode->rn_clev, page, + vm_radix_addnode(rnode, index, rnode->rn_clev, leaf, LOCKED); return (0); } - rnode = tmp; } /* * A new node is needed because the right insertion level is reached. * Setup the new intermediate node and add the 2 children: the - * new object and the older edge. + * new object and the older edge or object. */ - newind = rnode->rn_owner; clev = vm_radix_keydiff(newind, index); tmp = vm_radix_node_get(index, clev); if (tmp == NULL) return (ENOMEM); - slot = vm_radix_slot(newind, clev); /* These writes are not yet visible due to ordering. */ - vm_radix_addpage(tmp, index, clev, page, UNSERIALIZED); - vm_radix_node_store(&tmp->rn_child[slot], rnode, UNSERIALIZED); - tmp->rn_popmap ^= 1 << slot; + vm_radix_addnode(tmp, index, clev, leaf, UNSERIALIZED); + vm_radix_addnode(tmp, newind, clev, rnode, UNSERIALIZED); /* Serializing write to make the above visible. */ vm_radix_node_store(parentp, tmp, LOCKED); - return (0); } /* * Returns the value stored at the index. If the index is not present, * NULL is returned. */ static __always_inline vm_page_t _vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index, enum vm_radix_access access) { struct vm_radix_node *rnode; vm_page_t m; int slot; rnode = vm_radix_root_load(rtree, access); while (rnode != NULL) { if (vm_radix_isleaf(rnode)) { m = vm_radix_topage(rnode); if (m->pindex == index) return (m); break; } if (vm_radix_keybarr(rnode, index)) break; slot = vm_radix_slot(index, rnode->rn_clev); rnode = vm_radix_node_load(&rnode->rn_child[slot], access); } return (NULL); } /* * Returns the value stored at the index assuming there is an external lock. * * If the index is not present, NULL is returned. */ vm_page_t vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index) { return _vm_radix_lookup(rtree, index, LOCKED); } /* * Returns the value stored at the index without requiring an external lock. * * If the index is not present, NULL is returned. */ vm_page_t vm_radix_lookup_unlocked(struct vm_radix *rtree, vm_pindex_t index) { vm_page_t m; smr_enter(vm_radix_smr); m = _vm_radix_lookup(rtree, index, SMR); smr_exit(vm_radix_smr); return (m); } /* * Look up the nearest entry at a position greater than or equal to index. */ vm_page_t vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index) { struct vm_radix_node *stack[VM_RADIX_LIMIT]; vm_page_t m; struct vm_radix_node *child, *rnode; #ifdef INVARIANTS int loops = 0; #endif int slot, tos; rnode = vm_radix_root_load(rtree, LOCKED); if (rnode == NULL) return (NULL); else if (vm_radix_isleaf(rnode)) { m = vm_radix_topage(rnode); if (m->pindex >= index) return (m); else return (NULL); } tos = 0; for (;;) { /* * If the keys differ before the current bisection node, * then the search key might rollback to the earliest * available bisection node or to the smallest key * in the current node (if the owner is greater than the * search key). */ if (vm_radix_keybarr(rnode, index)) { if (index > rnode->rn_owner) { ascend: KASSERT(++loops < 1000, ("vm_radix_lookup_ge: too many loops")); /* * Pop nodes from the stack until either the * stack is empty or a node that could have a * matching descendant is found. */ do { if (tos == 0) return (NULL); rnode = stack[--tos]; } while (vm_radix_slot(index, rnode->rn_clev) == (VM_RADIX_COUNT - 1)); /* * The following computation cannot overflow * because index's slot at the current level * is less than VM_RADIX_COUNT - 1. */ index = vm_radix_trimkey(index, rnode->rn_clev); index += VM_RADIX_UNITLEVEL(rnode->rn_clev); } else index = rnode->rn_owner; KASSERT(!vm_radix_keybarr(rnode, index), ("vm_radix_lookup_ge: keybarr failed")); } slot = vm_radix_slot(index, rnode->rn_clev); child = vm_radix_node_load(&rnode->rn_child[slot], LOCKED); if (vm_radix_isleaf(child)) { m = vm_radix_topage(child); if (m->pindex >= index) return (m); } else if (child != NULL) goto descend; /* Find the first set bit beyond the first slot+1 bits. */ slot = ffs(rnode->rn_popmap & (-2 << slot)) - 1; if (slot < 0) { /* * A page or edge greater than the search slot is not * found in the current node; ascend to the next * higher-level node. */ goto ascend; } child = vm_radix_node_load(&rnode->rn_child[slot], LOCKED); KASSERT(child != NULL, ("%s: bad popmap slot %d in rnode %p", __func__, slot, rnode)); if (vm_radix_isleaf(child)) return (vm_radix_topage(child)); index = vm_radix_trimkey(index, rnode->rn_clev + 1) + slot * VM_RADIX_UNITLEVEL(rnode->rn_clev); descend: KASSERT(rnode->rn_clev > 0, ("vm_radix_lookup_ge: pushing leaf's parent")); KASSERT(tos < VM_RADIX_LIMIT, ("vm_radix_lookup_ge: stack overflow")); stack[tos++] = rnode; rnode = child; } } /* * Look up the nearest entry at a position less than or equal to index. */ vm_page_t vm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index) { struct vm_radix_node *stack[VM_RADIX_LIMIT]; vm_page_t m; struct vm_radix_node *child, *rnode; #ifdef INVARIANTS int loops = 0; #endif int slot, tos; rnode = vm_radix_root_load(rtree, LOCKED); if (rnode == NULL) return (NULL); else if (vm_radix_isleaf(rnode)) { m = vm_radix_topage(rnode); if (m->pindex <= index) return (m); else return (NULL); } tos = 0; for (;;) { /* * If the keys differ before the current bisection node, * then the search key might rollback to the earliest * available bisection node or to the largest key * in the current node (if the owner is smaller than the * search key). */ if (vm_radix_keybarr(rnode, index)) { if (index > rnode->rn_owner) { index = rnode->rn_owner + VM_RADIX_COUNT * VM_RADIX_UNITLEVEL(rnode->rn_clev); } else { ascend: KASSERT(++loops < 1000, ("vm_radix_lookup_le: too many loops")); /* * Pop nodes from the stack until either the * stack is empty or a node that could have a * matching descendant is found. */ do { if (tos == 0) return (NULL); rnode = stack[--tos]; } while (vm_radix_slot(index, rnode->rn_clev) == 0); /* * The following computation cannot overflow * because index's slot at the current level * is greater than 0. */ index = vm_radix_trimkey(index, rnode->rn_clev); } index--; KASSERT(!vm_radix_keybarr(rnode, index), ("vm_radix_lookup_le: keybarr failed")); } slot = vm_radix_slot(index, rnode->rn_clev); child = vm_radix_node_load(&rnode->rn_child[slot], LOCKED); if (vm_radix_isleaf(child)) { m = vm_radix_topage(child); if (m->pindex <= index) return (m); } else if (child != NULL) goto descend; /* Find the last set bit among the first slot bits. */ slot = fls(rnode->rn_popmap & ((1 << slot) - 1)) - 1; if (slot < 0) { /* * A page or edge smaller than the search slot is not * found in the current node; ascend to the next * higher-level node. */ goto ascend; } child = vm_radix_node_load(&rnode->rn_child[slot], LOCKED); KASSERT(child != NULL, ("%s: bad popmap slot %d in rnode %p", __func__, slot, rnode)); if (vm_radix_isleaf(child)) return (vm_radix_topage(child)); index = vm_radix_trimkey(index, rnode->rn_clev + 1) + (slot + 1) * VM_RADIX_UNITLEVEL(rnode->rn_clev) - 1; descend: KASSERT(rnode->rn_clev > 0, ("vm_radix_lookup_le: pushing leaf's parent")); KASSERT(tos < VM_RADIX_LIMIT, ("vm_radix_lookup_le: stack overflow")); stack[tos++] = rnode; rnode = child; } } /* * Remove the specified index from the trie, and return the value stored at * that index. If the index is not present, return NULL. */ vm_page_t vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index) { struct vm_radix_node *rnode, *parent, *tmp; vm_page_t m; int slot; rnode = vm_radix_root_load(rtree, LOCKED); if (vm_radix_isleaf(rnode)) { m = vm_radix_topage(rnode); if (m->pindex != index) return (NULL); vm_radix_root_store(rtree, NULL, LOCKED); return (m); } parent = NULL; for (;;) { if (rnode == NULL) return (NULL); slot = vm_radix_slot(index, rnode->rn_clev); tmp = vm_radix_node_load(&rnode->rn_child[slot], LOCKED); if (vm_radix_isleaf(tmp)) { m = vm_radix_topage(tmp); if (m->pindex != index) return (NULL); KASSERT((rnode->rn_popmap & (1 << slot)) != 0, ("%s: bad popmap slot %d in rnode %p", __func__, slot, rnode)); rnode->rn_popmap ^= 1 << slot; vm_radix_node_store( &rnode->rn_child[slot], NULL, LOCKED); if (!powerof2(rnode->rn_popmap)) return (m); KASSERT(rnode->rn_popmap != 0, ("%s: bad popmap all zeroes", __func__)); slot = ffs(rnode->rn_popmap) - 1; tmp = vm_radix_node_load(&rnode->rn_child[slot], LOCKED); KASSERT(tmp != NULL, ("%s: bad popmap slot %d in rnode %p", __func__, slot, rnode)); if (parent == NULL) vm_radix_root_store(rtree, tmp, LOCKED); else { slot = vm_radix_slot(index, parent->rn_clev); KASSERT(vm_radix_node_load( &parent->rn_child[slot], LOCKED) == rnode, ("%s: invalid child value", __func__)); vm_radix_node_store(&parent->rn_child[slot], tmp, LOCKED); } /* * The child is still valid and we can not zero the * pointer until all smr references are gone. */ vm_radix_node_put(rnode); return (m); } parent = rnode; rnode = tmp; } } /* * Remove and free all the nodes from the radix tree. * This function is recursive but there is a tight control on it as the * maximum depth of the tree is fixed. */ void vm_radix_reclaim_allnodes(struct vm_radix *rtree) { struct vm_radix_node *root; root = vm_radix_root_load(rtree, LOCKED); if (root == NULL) return; vm_radix_root_store(rtree, NULL, UNSERIALIZED); if (!vm_radix_isleaf(root)) vm_radix_reclaim_allnodes_int(root); } /* * Replace an existing page in the trie with another one. * Panics if there is not an old page in the trie at the new page's index. */ vm_page_t vm_radix_replace(struct vm_radix *rtree, vm_page_t newpage) { struct vm_radix_node *rnode, *tmp; vm_page_t m; vm_pindex_t index; int slot; index = newpage->pindex; rnode = vm_radix_root_load(rtree, LOCKED); if (rnode == NULL) panic("%s: replacing page on an empty trie", __func__); if (vm_radix_isleaf(rnode)) { m = vm_radix_topage(rnode); if (m->pindex != index) panic("%s: original replacing root key not found", __func__); rtree->rt_root = (uintptr_t)vm_radix_toleaf(newpage); return (m); } for (;;) { slot = vm_radix_slot(index, rnode->rn_clev); tmp = vm_radix_node_load(&rnode->rn_child[slot], LOCKED); if (vm_radix_isleaf(tmp)) { m = vm_radix_topage(tmp); if (m->pindex != index) break; vm_radix_node_store(&rnode->rn_child[slot], vm_radix_toleaf(newpage), LOCKED); return (m); } else if (tmp == NULL || vm_radix_keybarr(tmp, index)) break; rnode = tmp; } panic("%s: original replacing page not found", __func__); } void vm_radix_wait(void) { uma_zwait(vm_radix_node_zone); } #ifdef DDB /* * Show details about the given radix node. */ DB_SHOW_COMMAND(radixnode, db_show_radixnode) { struct vm_radix_node *rnode, *tmp; int slot; rn_popmap_t popmap; if (!have_addr) return; rnode = (struct vm_radix_node *)addr; db_printf("radixnode %p, owner %jx, children popmap %04x, level %u:\n", (void *)rnode, (uintmax_t)rnode->rn_owner, rnode->rn_popmap, rnode->rn_clev); for (popmap = rnode->rn_popmap; popmap != 0; popmap ^= 1 << slot) { slot = ffs(popmap) - 1; tmp = vm_radix_node_load(&rnode->rn_child[slot], UNSERIALIZED); db_printf("slot: %d, val: %p, page: %p, clev: %d\n", slot, (void *)tmp, vm_radix_isleaf(tmp) ? vm_radix_topage(tmp) : NULL, rnode->rn_clev); } } #endif /* DDB */