795 lines
22 KiB
C
795 lines
22 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2013 EMC Corp.
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* Copyright (c) 2011 Jeffrey Roberson <jeff@freebsd.org>
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* Copyright (c) 2008 Mayur Shardul <mayur.shardul@gmail.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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/*
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* Path-compressed radix trie implementation.
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* The following code is not generalized into a general purpose library
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* because there are way too many parameters embedded that should really
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* be decided by the library consumers. At the same time, consumers
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* of this code must achieve highest possible performance.
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*
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* The implementation takes into account the following rationale:
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* - Size of the nodes should be as small as possible but still big enough
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* to avoid a large maximum depth for the trie. This is a balance
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* between the necessity to not wire too much physical memory for the nodes
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* and the necessity to avoid too much cache pollution during the trie
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* operations.
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* - There is not a huge bias toward the number of lookup operations over
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* the number of insert and remove operations. This basically implies
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* that optimizations supposedly helping one operation but hurting the
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* other might be carefully evaluated.
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* - On average not many nodes are expected to be fully populated, hence
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* level compression may just complicate things.
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*/
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#include <sys/cdefs.h>
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#include "opt_ddb.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/libkern.h>
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#include <sys/proc.h>
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#include <sys/vmmeter.h>
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#include <sys/smr.h>
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#include <sys/smr_types.h>
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#include <vm/uma.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_radix.h>
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#ifdef DDB
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#include <ddb/ddb.h>
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#endif
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/*
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* These widths should allow the pointers to a node's children to fit within
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* a single cache line. The extra levels from a narrow width should not be
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* a problem thanks to path compression.
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*/
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#ifdef __LP64__
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#define VM_RADIX_WIDTH 4
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#else
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#define VM_RADIX_WIDTH 3
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#endif
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#define VM_RADIX_COUNT (1 << VM_RADIX_WIDTH)
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#define VM_RADIX_MASK (VM_RADIX_COUNT - 1)
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#define VM_RADIX_LIMIT \
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(howmany(sizeof(vm_pindex_t) * NBBY, VM_RADIX_WIDTH) - 1)
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#if VM_RADIX_WIDTH == 3
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typedef uint8_t rn_popmap_t;
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#elif VM_RADIX_WIDTH == 4
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typedef uint16_t rn_popmap_t;
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#elif VM_RADIX_WIDTH == 5
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typedef uint32_t rn_popmap_t;
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#else
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#error Unsupported width
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#endif
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_Static_assert(sizeof(rn_popmap_t) <= sizeof(int),
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"rn_popmap_t too wide");
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/* Set of all flag bits stored in node pointers. */
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#define VM_RADIX_FLAGS (VM_RADIX_ISLEAF)
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#define VM_RADIX_PAD VM_RADIX_FLAGS
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enum vm_radix_access { SMR, LOCKED, UNSERIALIZED };
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struct vm_radix_node;
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typedef SMR_POINTER(struct vm_radix_node *) smrnode_t;
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struct vm_radix_node {
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vm_pindex_t rn_owner; /* Owner of record. */
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rn_popmap_t rn_popmap; /* Valid children. */
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uint8_t rn_clev; /* Level * WIDTH. */
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smrnode_t rn_child[VM_RADIX_COUNT]; /* Child nodes. */
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};
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static uma_zone_t vm_radix_node_zone;
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static smr_t vm_radix_smr;
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static void vm_radix_node_store(smrnode_t *p, struct vm_radix_node *v,
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enum vm_radix_access access);
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/*
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* Map index to an array position for the children of rnode,
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*/
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static __inline int
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vm_radix_slot(struct vm_radix_node *rnode, vm_pindex_t index)
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{
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return ((index >> rnode->rn_clev) & VM_RADIX_MASK);
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}
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/*
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* Returns true if index does not belong to the specified rnode. Otherwise,
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* sets slot value, and returns false.
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*/
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static __inline bool
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vm_radix_keybarr(struct vm_radix_node *rnode, vm_pindex_t index, int *slot)
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{
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index = (index - rnode->rn_owner) >> rnode->rn_clev;
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if (index >= VM_RADIX_COUNT)
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return (true);
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*slot = index;
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return (false);
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}
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/*
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* Allocate a radix node.
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*/
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static struct vm_radix_node *
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vm_radix_node_get(vm_pindex_t index, vm_pindex_t newind)
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{
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struct vm_radix_node *rnode;
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rnode = uma_zalloc_smr(vm_radix_node_zone, M_NOWAIT);
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if (rnode == NULL)
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return (NULL);
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/*
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* We want to clear the last child pointer after the final section
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* has exited so lookup can not return false negatives. It is done
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* here because it will be cache-cold in the dtor callback.
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*/
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if (rnode->rn_popmap != 0) {
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vm_radix_node_store(&rnode->rn_child[ffs(rnode->rn_popmap) - 1],
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VM_RADIX_NULL, UNSERIALIZED);
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rnode->rn_popmap = 0;
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}
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/*
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* From the highest-order bit where the indexes differ,
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* compute the highest level in the trie where they differ. Then,
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* compute the least index of this subtrie.
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*/
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KASSERT(index != newind, ("%s: passing the same key value %jx",
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__func__, (uintmax_t)index));
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_Static_assert(sizeof(long long) >= sizeof(vm_pindex_t),
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"vm_pindex_t too wide");
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_Static_assert(sizeof(vm_pindex_t) * NBBY <=
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(1 << (sizeof(rnode->rn_clev) * NBBY)), "rn_clev too narrow");
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rnode->rn_clev = rounddown(flsll(index ^ newind) - 1, VM_RADIX_WIDTH);
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rnode->rn_owner = VM_RADIX_COUNT;
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rnode->rn_owner = index & -(rnode->rn_owner << rnode->rn_clev);
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return (rnode);
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}
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/*
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* Free radix node.
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*/
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static __inline void
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vm_radix_node_put(struct vm_radix_node *rnode)
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{
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#ifdef INVARIANTS
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int slot;
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KASSERT(powerof2(rnode->rn_popmap),
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("vm_radix_node_put: rnode %p has too many children %04x", rnode,
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rnode->rn_popmap));
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for (slot = 0; slot < VM_RADIX_COUNT; slot++) {
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if ((rnode->rn_popmap & (1 << slot)) != 0)
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continue;
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KASSERT(smr_unserialized_load(&rnode->rn_child[slot], true) ==
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VM_RADIX_NULL,
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("vm_radix_node_put: rnode %p has a child", rnode));
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}
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#endif
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uma_zfree_smr(vm_radix_node_zone, rnode);
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}
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/*
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* Fetch a node pointer from a slot in another node.
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*/
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static __inline struct vm_radix_node *
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vm_radix_node_load(smrnode_t *p, enum vm_radix_access access)
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{
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switch (access) {
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case UNSERIALIZED:
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return (smr_unserialized_load(p, true));
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case LOCKED:
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return (smr_serialized_load(p, true));
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case SMR:
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return (smr_entered_load(p, vm_radix_smr));
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}
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__assert_unreachable();
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}
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static __inline void
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vm_radix_node_store(smrnode_t *p, struct vm_radix_node *v,
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enum vm_radix_access access)
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{
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switch (access) {
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case UNSERIALIZED:
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smr_unserialized_store(p, v, true);
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break;
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case LOCKED:
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smr_serialized_store(p, v, true);
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break;
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case SMR:
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panic("vm_radix_node_store: Not supported in smr section.");
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}
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}
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/*
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* Get the root node for a radix tree.
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*/
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static __inline struct vm_radix_node *
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vm_radix_root_load(struct vm_radix *rtree, enum vm_radix_access access)
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{
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return (vm_radix_node_load((smrnode_t *)&rtree->rt_root, access));
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}
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/*
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* Set the root node for a radix tree.
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*/
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static __inline void
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vm_radix_root_store(struct vm_radix *rtree, struct vm_radix_node *rnode,
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enum vm_radix_access access)
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{
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vm_radix_node_store((smrnode_t *)&rtree->rt_root, rnode, access);
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}
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/*
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* Returns TRUE if the specified radix node is a leaf and FALSE otherwise.
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*/
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static __inline bool
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vm_radix_isleaf(struct vm_radix_node *rnode)
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{
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return (((uintptr_t)rnode & VM_RADIX_ISLEAF) != 0);
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}
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/*
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* Returns page cast to radix node with leaf bit set.
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*/
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static __inline struct vm_radix_node *
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vm_radix_toleaf(vm_page_t page)
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{
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return ((struct vm_radix_node *)((uintptr_t)page | VM_RADIX_ISLEAF));
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}
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/*
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* Returns the associated page extracted from rnode.
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*/
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static __inline vm_page_t
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vm_radix_topage(struct vm_radix_node *rnode)
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{
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return ((vm_page_t)((uintptr_t)rnode & ~VM_RADIX_FLAGS));
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}
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/*
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* Make 'child' a child of 'rnode'.
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*/
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static __inline void
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vm_radix_addnode(struct vm_radix_node *rnode, vm_pindex_t index,
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struct vm_radix_node *child, enum vm_radix_access access)
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{
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int slot;
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slot = vm_radix_slot(rnode, index);
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vm_radix_node_store(&rnode->rn_child[slot], child, access);
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rnode->rn_popmap ^= 1 << slot;
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KASSERT((rnode->rn_popmap & (1 << slot)) != 0,
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("%s: bad popmap slot %d in rnode %p", __func__, slot, rnode));
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}
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/*
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* Internal helper for vm_radix_reclaim_allnodes().
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* This function is recursive.
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*/
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static void
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vm_radix_reclaim_allnodes_int(struct vm_radix_node *rnode)
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{
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struct vm_radix_node *child;
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int slot;
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while (rnode->rn_popmap != 0) {
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slot = ffs(rnode->rn_popmap) - 1;
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child = vm_radix_node_load(&rnode->rn_child[slot],
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UNSERIALIZED);
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KASSERT(child != VM_RADIX_NULL,
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("%s: bad popmap slot %d in rnode %p",
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__func__, slot, rnode));
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if (!vm_radix_isleaf(child))
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vm_radix_reclaim_allnodes_int(child);
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rnode->rn_popmap ^= 1 << slot;
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vm_radix_node_store(&rnode->rn_child[slot], VM_RADIX_NULL,
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UNSERIALIZED);
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}
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vm_radix_node_put(rnode);
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}
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/*
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* radix node zone initializer.
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*/
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static int
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vm_radix_zone_init(void *mem, int size, int flags)
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{
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struct vm_radix_node *rnode;
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rnode = mem;
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rnode->rn_popmap = 0;
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for (int i = 0; i < nitems(rnode->rn_child); i++)
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vm_radix_node_store(&rnode->rn_child[i], VM_RADIX_NULL,
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UNSERIALIZED);
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return (0);
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}
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#ifndef UMA_MD_SMALL_ALLOC
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void vm_radix_reserve_kva(void);
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/*
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* Reserve the KVA necessary to satisfy the node allocation.
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* This is mandatory in architectures not supporting direct
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* mapping as they will need otherwise to carve into the kernel maps for
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* every node allocation, resulting into deadlocks for consumers already
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* working with kernel maps.
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*/
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void
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vm_radix_reserve_kva(void)
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{
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/*
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* Calculate the number of reserved nodes, discounting the pages that
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* are needed to store them.
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*/
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if (!uma_zone_reserve_kva(vm_radix_node_zone,
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((vm_paddr_t)vm_cnt.v_page_count * PAGE_SIZE) / (PAGE_SIZE +
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sizeof(struct vm_radix_node))))
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panic("%s: unable to reserve KVA", __func__);
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}
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#endif
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/*
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* Initialize the UMA slab zone.
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*/
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void
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vm_radix_zinit(void)
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{
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vm_radix_node_zone = uma_zcreate("RADIX NODE",
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sizeof(struct vm_radix_node), NULL, NULL, vm_radix_zone_init, NULL,
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VM_RADIX_PAD, UMA_ZONE_VM | UMA_ZONE_SMR);
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vm_radix_smr = uma_zone_get_smr(vm_radix_node_zone);
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}
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/*
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* Inserts the key-value pair into the trie.
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* Panics if the key already exists.
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*/
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int
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vm_radix_insert(struct vm_radix *rtree, vm_page_t page)
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{
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vm_pindex_t index, newind;
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struct vm_radix_node *leaf, *parent, *rnode;
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smrnode_t *parentp;
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int slot;
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index = page->pindex;
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leaf = vm_radix_toleaf(page);
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/*
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* The owner of record for root is not really important because it
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* will never be used.
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*/
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rnode = vm_radix_root_load(rtree, LOCKED);
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parent = NULL;
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for (;;) {
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if (vm_radix_isleaf(rnode)) {
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if (rnode == VM_RADIX_NULL) {
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if (parent == NULL)
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rtree->rt_root = leaf;
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else
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vm_radix_addnode(parent, index, leaf,
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LOCKED);
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return (0);
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}
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newind = vm_radix_topage(rnode)->pindex;
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if (newind == index)
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panic("%s: key %jx is already present",
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__func__, (uintmax_t)index);
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break;
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}
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if (vm_radix_keybarr(rnode, index, &slot)) {
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newind = rnode->rn_owner;
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break;
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}
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parent = rnode;
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rnode = vm_radix_node_load(&rnode->rn_child[slot], LOCKED);
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}
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/*
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* A new node is needed because the right insertion level is reached.
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* Setup the new intermediate node and add the 2 children: the
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* new object and the older edge or object.
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*/
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parentp = (parent != NULL) ? &parent->rn_child[slot]:
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(smrnode_t *)&rtree->rt_root;
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parent = vm_radix_node_get(index, newind);
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if (parent == NULL)
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return (ENOMEM);
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/* These writes are not yet visible due to ordering. */
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vm_radix_addnode(parent, index, leaf, UNSERIALIZED);
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vm_radix_addnode(parent, newind, rnode, UNSERIALIZED);
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/* Serializing write to make the above visible. */
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vm_radix_node_store(parentp, parent, LOCKED);
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return (0);
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}
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/*
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* Returns the value stored at the index. If the index is not present,
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* NULL is returned.
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*/
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static __always_inline vm_page_t
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_vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index,
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enum vm_radix_access access)
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{
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struct vm_radix_node *rnode;
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vm_page_t m;
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int slot;
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rnode = vm_radix_root_load(rtree, access);
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for (;;) {
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if (vm_radix_isleaf(rnode)) {
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if ((m = vm_radix_topage(rnode)) != NULL &&
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m->pindex == index)
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return (m);
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break;
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}
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if (vm_radix_keybarr(rnode, index, &slot))
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break;
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rnode = vm_radix_node_load(&rnode->rn_child[slot], access);
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}
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return (NULL);
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}
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/*
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* Returns the value stored at the index assuming there is an external lock.
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*
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* If the index is not present, NULL is returned.
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*/
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vm_page_t
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vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index)
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{
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return _vm_radix_lookup(rtree, index, LOCKED);
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}
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/*
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* Returns the value stored at the index without requiring an external lock.
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*
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* If the index is not present, NULL is returned.
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|
*/
|
|
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);
|
|
}
|
|
|
|
/*
|
|
* Returns the page with the least pindex that is greater than or equal to the
|
|
* specified pindex, or NULL if there are no such pages.
|
|
*
|
|
* Requires that access be externally synchronized by a lock.
|
|
*/
|
|
vm_page_t
|
|
vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index)
|
|
{
|
|
struct vm_radix_node *rnode, *succ;
|
|
vm_page_t m;
|
|
int slot;
|
|
|
|
/*
|
|
* Descend the trie as if performing an ordinary lookup for the page
|
|
* with the specified pindex. 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 page with the least
|
|
* pindex that is both outside our current path down the trie and more
|
|
* than the specified pindex resides. (The node's popmap makes it fast
|
|
* and easy to recognize a branching-off point.) If our ordinary lookup
|
|
* fails to yield a page with a pindex that is greater than or equal to
|
|
* the specified pindex, 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.
|
|
*/
|
|
rnode = vm_radix_root_load(rtree, LOCKED);
|
|
succ = NULL;
|
|
for (;;) {
|
|
if (vm_radix_isleaf(rnode)) {
|
|
if ((m = vm_radix_topage(rnode)) != NULL &&
|
|
m->pindex >= index)
|
|
return (m);
|
|
break;
|
|
}
|
|
if (vm_radix_keybarr(rnode, index, &slot)) {
|
|
/*
|
|
* If all pages in this subtree have pindex > index,
|
|
* then the page in this subtree with the least pindex
|
|
* is the answer.
|
|
*/
|
|
if (rnode->rn_owner > index)
|
|
succ = rnode;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Just in case the next search step leads to a subtree of all
|
|
* pages with pindex < index, check popmap to see if a next
|
|
* bigger step, to a subtree of all pages with pindex > index,
|
|
* is available. If so, remember to restart the search here.
|
|
*/
|
|
if ((rnode->rn_popmap >> slot) > 1)
|
|
succ = rnode;
|
|
rnode = vm_radix_node_load(&rnode->rn_child[slot], LOCKED);
|
|
}
|
|
|
|
/*
|
|
* Restart the search from the last place visited in the subtree that
|
|
* included some pages with pindex > index, if there was such a place.
|
|
*/
|
|
if (succ == NULL)
|
|
return (NULL);
|
|
if (succ != rnode) {
|
|
/*
|
|
* Take a step to the next bigger sibling of the node chosen
|
|
* last time. In that subtree, all pages have pindex > index.
|
|
*/
|
|
slot = vm_radix_slot(succ, index) + 1;
|
|
KASSERT((succ->rn_popmap >> slot) != 0,
|
|
("%s: no popmap siblings past slot %d in node %p",
|
|
__func__, slot, succ));
|
|
slot += ffs(succ->rn_popmap >> slot) - 1;
|
|
succ = vm_radix_node_load(&succ->rn_child[slot], LOCKED);
|
|
}
|
|
|
|
/*
|
|
* Find the page in the subtree rooted at "succ" with the least pindex.
|
|
*/
|
|
while (!vm_radix_isleaf(succ)) {
|
|
KASSERT(succ->rn_popmap != 0,
|
|
("%s: no popmap children in node %p", __func__, succ));
|
|
slot = ffs(succ->rn_popmap) - 1;
|
|
succ = vm_radix_node_load(&succ->rn_child[slot], LOCKED);
|
|
}
|
|
return (vm_radix_topage(succ));
|
|
}
|
|
|
|
/*
|
|
* Returns the page with the greatest pindex that is less than or equal to the
|
|
* specified pindex, or NULL if there are no such pages.
|
|
*
|
|
* Requires that access be externally synchronized by a lock.
|
|
*/
|
|
vm_page_t
|
|
vm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index)
|
|
{
|
|
struct vm_radix_node *pred, *rnode;
|
|
vm_page_t m;
|
|
int slot;
|
|
|
|
/*
|
|
* Mirror the implementation of vm_radix_lookup_ge, described above.
|
|
*/
|
|
rnode = vm_radix_root_load(rtree, LOCKED);
|
|
pred = NULL;
|
|
for (;;) {
|
|
if (vm_radix_isleaf(rnode)) {
|
|
if ((m = vm_radix_topage(rnode)) != NULL &&
|
|
m->pindex <= index)
|
|
return (m);
|
|
break;
|
|
}
|
|
if (vm_radix_keybarr(rnode, index, &slot)) {
|
|
if (rnode->rn_owner < index)
|
|
pred = rnode;
|
|
break;
|
|
}
|
|
if ((rnode->rn_popmap & ((1 << slot) - 1)) != 0)
|
|
pred = rnode;
|
|
rnode = vm_radix_node_load(&rnode->rn_child[slot], LOCKED);
|
|
}
|
|
if (pred == NULL)
|
|
return (NULL);
|
|
if (pred != rnode) {
|
|
slot = vm_radix_slot(pred, index);
|
|
KASSERT((pred->rn_popmap & ((1 << slot) - 1)) != 0,
|
|
("%s: no popmap siblings before slot %d in node %p",
|
|
__func__, slot, pred));
|
|
slot = fls(pred->rn_popmap & ((1 << slot) - 1)) - 1;
|
|
pred = vm_radix_node_load(&pred->rn_child[slot], LOCKED);
|
|
}
|
|
while (!vm_radix_isleaf(pred)) {
|
|
KASSERT(pred->rn_popmap != 0,
|
|
("%s: no popmap children in node %p", __func__, pred));
|
|
slot = fls(pred->rn_popmap) - 1;
|
|
pred = vm_radix_node_load(&pred->rn_child[slot], LOCKED);
|
|
}
|
|
return (vm_radix_topage(pred));
|
|
}
|
|
|
|
/*
|
|
* 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 *child, *parent, *rnode;
|
|
vm_page_t m;
|
|
int slot;
|
|
|
|
rnode = NULL;
|
|
child = vm_radix_root_load(rtree, LOCKED);
|
|
for (;;) {
|
|
if (vm_radix_isleaf(child))
|
|
break;
|
|
parent = rnode;
|
|
rnode = child;
|
|
slot = vm_radix_slot(rnode, index);
|
|
child = vm_radix_node_load(&rnode->rn_child[slot], LOCKED);
|
|
}
|
|
if ((m = vm_radix_topage(child)) == NULL || m->pindex != index)
|
|
return (NULL);
|
|
if (rnode == NULL) {
|
|
vm_radix_root_store(rtree, VM_RADIX_NULL, LOCKED);
|
|
return (m);
|
|
}
|
|
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], VM_RADIX_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;
|
|
child = vm_radix_node_load(&rnode->rn_child[slot], LOCKED);
|
|
KASSERT(child != VM_RADIX_NULL,
|
|
("%s: bad popmap slot %d in rnode %p", __func__, slot, rnode));
|
|
if (parent == NULL)
|
|
vm_radix_root_store(rtree, child, LOCKED);
|
|
else {
|
|
slot = vm_radix_slot(parent, index);
|
|
KASSERT(rnode ==
|
|
vm_radix_node_load(&parent->rn_child[slot], LOCKED),
|
|
("%s: invalid child value", __func__));
|
|
vm_radix_node_store(&parent->rn_child[slot], child, 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);
|
|
}
|
|
|
|
/*
|
|
* 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 == VM_RADIX_NULL)
|
|
return;
|
|
vm_radix_root_store(rtree, VM_RADIX_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 *leaf, *parent, *rnode;
|
|
vm_page_t m;
|
|
vm_pindex_t index;
|
|
int slot;
|
|
|
|
leaf = vm_radix_toleaf(newpage);
|
|
index = newpage->pindex;
|
|
rnode = vm_radix_root_load(rtree, LOCKED);
|
|
parent = NULL;
|
|
for (;;) {
|
|
if (vm_radix_isleaf(rnode)) {
|
|
if ((m = vm_radix_topage(rnode)) != NULL &&
|
|
m->pindex == index) {
|
|
if (parent == NULL)
|
|
rtree->rt_root = leaf;
|
|
else
|
|
vm_radix_node_store(
|
|
&parent->rn_child[slot], leaf,
|
|
LOCKED);
|
|
return (m);
|
|
}
|
|
break;
|
|
}
|
|
if (vm_radix_keybarr(rnode, index, &slot))
|
|
break;
|
|
parent = rnode;
|
|
rnode = vm_radix_node_load(&rnode->rn_child[slot], LOCKED);
|
|
}
|
|
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 / VM_RADIX_WIDTH);
|
|
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 / VM_RADIX_WIDTH);
|
|
}
|
|
}
|
|
#endif /* DDB */
|