freebsd-dev/sys/vm/vm_radix.c
Alan Cox 96f1a84272 Replace the remaining uses of vm_radix_node_page() by vm_radix_isleaf() and
vm_radix_topage().  This transformation eliminates some unnecessary
conditional branches from the inner loops of vm_radix_insert(),
vm_radix_lookup{,_ge,_le}(), and vm_radix_remove().

Simplify the control flow of vm_radix_lookup_{ge,le}().

Reviewed by:	attilio (an earlier version)
Tested by:	pho
Sponsored by:	EMC / Isilon Storage Division
2013-04-03 06:37:25 +00:00

788 lines
21 KiB
C

/*
* Copyright (c) 2013 EMC Corp.
* Copyright (c) 2011 Jeffrey Roberson <jeff@freebsd.org>
* Copyright (c) 2008 Mayur Shardul <mayur.shardul@gmail.com>
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/vmmeter.h>
#include <vm/uma.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_page.h>
#include <vm/vm_radix.h>
#ifdef DDB
#include <ddb/ddb.h>
#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)
/* 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 << ((VM_RADIX_LIMIT - (lev)) * VM_RADIX_WIDTH))
struct vm_radix_node {
void *rn_child[VM_RADIX_COUNT]; /* Child nodes. */
vm_pindex_t rn_owner; /* Owner of record. */
uint16_t rn_count; /* Valid children. */
uint16_t rn_clev; /* Current level. */
};
static uma_zone_t vm_radix_node_zone;
/*
* Allocate a radix node. Pre-allocation should ensure that the request
* will always be satisfied.
*/
static __inline struct vm_radix_node *
vm_radix_node_get(vm_pindex_t owner, uint16_t count, uint16_t clevel)
{
struct vm_radix_node *rnode;
rnode = uma_zalloc(vm_radix_node_zone, M_NOWAIT);
/*
* The required number of nodes should already be pre-allocated
* by vm_radix_prealloc(). However, UMA can hold a few nodes
* in per-CPU buckets, which will not be accessible by the
* current CPU. Thus, the allocation could return NULL when
* the pre-allocated pool is close to exhaustion. Anyway,
* in practice this should never occur because a new node
* is not always required for insert. Thus, the pre-allocated
* pool should have some extra pages that prevent this from
* becoming a problem.
*/
if (rnode == NULL)
panic("%s: uma_zalloc() returned NULL for a new node",
__func__);
rnode->rn_owner = owner;
rnode->rn_count = count;
rnode->rn_clev = clevel;
return (rnode);
}
/*
* Free radix node.
*/
static __inline void
vm_radix_node_put(struct vm_radix_node *rnode)
{
uma_zfree(vm_radix_node_zone, rnode);
}
/*
* 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 >> ((VM_RADIX_LIMIT - level) * VM_RADIX_WIDTH)) &
VM_RADIX_MASK);
}
/* Trims the key after the specified level. */
static __inline vm_pindex_t
vm_radix_trimkey(vm_pindex_t index, uint16_t level)
{
vm_pindex_t ret;
ret = index;
if (level < VM_RADIX_LIMIT) {
ret >>= (VM_RADIX_LIMIT - level) * VM_RADIX_WIDTH;
ret <<= (VM_RADIX_LIMIT - level) * VM_RADIX_WIDTH;
}
return (ret);
}
/*
* Get the root node for a radix tree.
*/
static __inline struct vm_radix_node *
vm_radix_getroot(struct vm_radix *rtree)
{
return ((struct vm_radix_node *)(rtree->rt_root & ~VM_RADIX_FLAGS));
}
/*
* Set the root node for a radix tree.
*/
static __inline void
vm_radix_setroot(struct vm_radix *rtree, struct vm_radix_node *rnode)
{
rtree->rt_root = (uintptr_t)rnode;
}
/*
* Returns TRUE if the specified radix node is a leaf and FALSE otherwise.
*/
static __inline boolean_t
vm_radix_isleaf(struct vm_radix_node *rnode)
{
return (((uintptr_t)rnode & VM_RADIX_ISLEAF) != 0);
}
/*
* 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.
*/
static __inline void
vm_radix_addpage(struct vm_radix_node *rnode, vm_pindex_t index, uint16_t clev,
vm_page_t page)
{
int slot;
slot = vm_radix_slot(index, clev);
rnode->rn_child[slot] = (void *)((uintptr_t)page | VM_RADIX_ISLEAF);
}
/*
* Returns the slot 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)
{
uint16_t clev;
KASSERT(index1 != index2, ("%s: passing the same key value %jx",
__func__, (uintmax_t)index1));
index1 ^= index2;
for (clev = 0; clev <= VM_RADIX_LIMIT ; clev++)
if (vm_radix_slot(index1, clev))
return (clev);
panic("%s: cannot reach this point", __func__);
return (0);
}
/*
* Returns TRUE if it can be determined that key does not belong to the
* specified rnode. Otherwise, returns FALSE.
*/
static __inline boolean_t
vm_radix_keybarr(struct vm_radix_node *rnode, vm_pindex_t idx)
{
if (rnode->rn_clev > 0) {
idx = vm_radix_trimkey(idx, rnode->rn_clev - 1);
idx -= rnode->rn_owner;
if (idx != 0)
return (TRUE);
}
return (FALSE);
}
/*
* Adjusts the idx key to the first upper level available, based on a valid
* initial level and map of available levels.
* Returns a value bigger than 0 to signal that there are not valid levels
* available.
*/
static __inline int
vm_radix_addlev(vm_pindex_t *idx, boolean_t *levels, uint16_t ilev)
{
vm_pindex_t wrapidx;
for (; levels[ilev] == FALSE ||
vm_radix_slot(*idx, ilev) == (VM_RADIX_COUNT - 1); ilev--)
if (ilev == 0)
break;
KASSERT(ilev > 0 || levels[0],
("%s: levels back-scanning problem", __func__));
if (ilev == 0 && vm_radix_slot(*idx, ilev) == (VM_RADIX_COUNT - 1))
return (1);
wrapidx = *idx;
*idx = vm_radix_trimkey(*idx, ilev);
*idx += VM_RADIX_UNITLEVEL(ilev);
return (*idx < wrapidx);
}
/*
* Adjusts the idx key to the first lower level available, based on a valid
* initial level and map of available levels.
* Returns a value bigger than 0 to signal that there are not valid levels
* available.
*/
static __inline int
vm_radix_declev(vm_pindex_t *idx, boolean_t *levels, uint16_t ilev)
{
vm_pindex_t wrapidx;
for (; levels[ilev] == FALSE ||
vm_radix_slot(*idx, ilev) == 0; ilev--)
if (ilev == 0)
break;
KASSERT(ilev > 0 || levels[0],
("%s: levels back-scanning problem", __func__));
if (ilev == 0 && vm_radix_slot(*idx, ilev) == 0)
return (1);
wrapidx = *idx;
*idx = vm_radix_trimkey(*idx, ilev);
*idx |= VM_RADIX_UNITLEVEL(ilev) - 1;
*idx -= VM_RADIX_UNITLEVEL(ilev);
return (*idx > wrapidx);
}
/*
* Internal helper for vm_radix_reclaim_allnodes().
* This function is recursive.
*/
static void
vm_radix_reclaim_allnodes_int(struct vm_radix_node *rnode)
{
int slot;
KASSERT(rnode->rn_count <= VM_RADIX_COUNT,
("vm_radix_reclaim_allnodes_int: bad count in rnode %p", rnode));
for (slot = 0; rnode->rn_count != 0; slot++) {
if (rnode->rn_child[slot] == NULL)
continue;
if (!vm_radix_isleaf(rnode->rn_child[slot]))
vm_radix_reclaim_allnodes_int(rnode->rn_child[slot]);
rnode->rn_child[slot] = NULL;
rnode->rn_count--;
}
vm_radix_node_put(rnode);
}
#ifdef INVARIANTS
/*
* Radix node zone destructor.
*/
static void
vm_radix_node_zone_dtor(void *mem, int size __unused, void *arg __unused)
{
struct vm_radix_node *rnode;
int slot;
rnode = mem;
KASSERT(rnode->rn_count == 0,
("vm_radix_node_put: rnode %p has %d children", rnode,
rnode->rn_count));
for (slot = 0; slot < VM_RADIX_COUNT; slot++)
KASSERT(rnode->rn_child[slot] == NULL,
("vm_radix_node_put: rnode %p has a child", rnode));
}
#endif
/*
* Radix node zone initializer.
*/
static int
vm_radix_node_zone_init(void *mem, int size __unused, int flags __unused)
{
struct vm_radix_node *rnode;
rnode = mem;
memset(rnode->rn_child, 0, sizeof(rnode->rn_child));
return (0);
}
/*
* Pre-allocate intermediate nodes from the UMA slab zone.
*/
static void
vm_radix_prealloc(void *arg __unused)
{
if (!uma_zone_reserve_kva(vm_radix_node_zone, cnt.v_page_count))
panic("%s: unable to create new zone", __func__);
uma_prealloc(vm_radix_node_zone, cnt.v_page_count);
}
SYSINIT(vm_radix_prealloc, SI_SUB_KMEM, SI_ORDER_SECOND, vm_radix_prealloc,
NULL);
/*
* Initialize the UMA slab zone.
* Until vm_radix_prealloc() is called, the zone will be served by the
* UMA boot-time pre-allocated pool of pages.
*/
void
vm_radix_init(void)
{
vm_radix_node_zone = uma_zcreate("RADIX NODE",
sizeof(struct vm_radix_node), NULL,
#ifdef INVARIANTS
vm_radix_node_zone_dtor,
#else
NULL,
#endif
vm_radix_node_zone_init, NULL, VM_RADIX_PAD, UMA_ZONE_VM |
UMA_ZONE_NOFREE);
}
/*
* Inserts the key-value pair into the trie.
* Panics if the key already exists.
*/
void
vm_radix_insert(struct vm_radix *rtree, vm_page_t page)
{
vm_pindex_t index, newind;
struct vm_radix_node *rnode, *tmp, *tmp2;
vm_page_t m;
int slot;
uint16_t clev;
index = page->pindex;
/*
* The owner of record for root is not really important because it
* will never be used.
*/
rnode = vm_radix_getroot(rtree);
if (rnode == NULL) {
rnode = vm_radix_node_get(0, 1, 0);
vm_radix_setroot(rtree, rnode);
vm_radix_addpage(rnode, index, 0, page);
return;
}
do {
slot = vm_radix_slot(index, rnode->rn_clev);
if (vm_radix_isleaf(rnode->rn_child[slot])) {
m = vm_radix_topage(rnode->rn_child[slot]);
if (m->pindex == index)
panic("%s: key %jx is already present",
__func__, (uintmax_t)index);
clev = vm_radix_keydiff(m->pindex, index);
tmp = vm_radix_node_get(vm_radix_trimkey(index,
clev - 1), 2, clev);
rnode->rn_child[slot] = tmp;
vm_radix_addpage(tmp, index, clev, page);
vm_radix_addpage(tmp, m->pindex, clev, m);
return;
}
if (rnode->rn_child[slot] == NULL) {
rnode->rn_count++;
vm_radix_addpage(rnode, index, rnode->rn_clev, page);
return;
}
rnode = rnode->rn_child[slot];
} while (!vm_radix_keybarr(rnode, index));
/*
* Scan the trie from the top and find the parent to insert
* the new object.
*/
newind = rnode->rn_owner;
clev = vm_radix_keydiff(newind, index);
slot = VM_RADIX_COUNT;
for (rnode = vm_radix_getroot(rtree); ; rnode = tmp) {
KASSERT(rnode != NULL, ("%s: edge cannot be NULL in the scan",
__func__));
KASSERT(clev >= rnode->rn_clev,
("%s: unexpected trie depth: clev: %d, rnode->rn_clev: %d",
__func__, clev, rnode->rn_clev));
slot = vm_radix_slot(index, rnode->rn_clev);
tmp = rnode->rn_child[slot];
KASSERT(tmp != NULL && !vm_radix_isleaf(tmp),
("%s: unexpected lookup interruption", __func__));
if (tmp->rn_clev > clev)
break;
}
KASSERT(rnode != NULL && tmp != NULL && slot < VM_RADIX_COUNT,
("%s: invalid scan parameters rnode: %p, tmp: %p, slot: %d",
__func__, (void *)rnode, (void *)tmp, slot));
/*
* 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.
*/
tmp2 = vm_radix_node_get(vm_radix_trimkey(index, clev - 1), 2,
clev);
rnode->rn_child[slot] = tmp2;
vm_radix_addpage(tmp2, index, clev, page);
slot = vm_radix_slot(newind, clev);
tmp2->rn_child[slot] = tmp;
}
/*
* Returns the value stored at the index. If the index is not present,
* NULL is returned.
*/
vm_page_t
vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index)
{
struct vm_radix_node *rnode;
vm_page_t m;
int slot;
rnode = vm_radix_getroot(rtree);
while (rnode != NULL) {
if (vm_radix_keybarr(rnode, index))
return (NULL);
slot = vm_radix_slot(index, rnode->rn_clev);
rnode = rnode->rn_child[slot];
if (vm_radix_isleaf(rnode)) {
m = vm_radix_topage(rnode);
if (m->pindex == index)
return (m);
else
return (NULL);
}
}
return (NULL);
}
/*
* Look up the nearest entry at a position bigger than or equal to index.
*/
vm_page_t
vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index)
{
vm_pindex_t inc;
vm_page_t m;
struct vm_radix_node *child, *rnode;
int slot;
uint16_t difflev;
boolean_t maplevels[VM_RADIX_LIMIT + 1];
#ifdef INVARIANTS
int loops = 0;
#endif
restart:
KASSERT(++loops < 1000, ("%s: too many loops", __func__));
for (difflev = 0; difflev < (VM_RADIX_LIMIT + 1); difflev++)
maplevels[difflev] = FALSE;
rnode = vm_radix_getroot(rtree);
while (rnode != NULL) {
maplevels[rnode->rn_clev] = TRUE;
/*
* If the keys differ before the current bisection node
* the search key might rollback to the earliest
* available bisection node, or to the smaller value
* in the current domain (if the owner is bigger than the
* search key).
* The maplevels array records any node has been seen
* at a given level. This aids the search for a valid
* bisection node.
*/
if (vm_radix_keybarr(rnode, index)) {
difflev = vm_radix_keydiff(index, rnode->rn_owner);
if (index > rnode->rn_owner) {
if (vm_radix_addlev(&index, maplevels,
difflev) > 0)
break;
} else
index = vm_radix_trimkey(rnode->rn_owner,
difflev);
goto restart;
}
slot = vm_radix_slot(index, rnode->rn_clev);
child = rnode->rn_child[slot];
if (vm_radix_isleaf(child)) {
m = vm_radix_topage(child);
if (m->pindex >= index)
return (m);
} else if (child != NULL)
goto descend;
/*
* Look for an available edge or page within the current
* bisection node.
*/
if (slot < (VM_RADIX_COUNT - 1)) {
inc = VM_RADIX_UNITLEVEL(rnode->rn_clev);
index = vm_radix_trimkey(index, rnode->rn_clev);
do {
index += inc;
slot++;
child = rnode->rn_child[slot];
if (vm_radix_isleaf(child)) {
m = vm_radix_topage(child);
if (m->pindex >= index)
return (m);
} else if (child != NULL)
goto descend;
} while (slot < (VM_RADIX_COUNT - 1));
}
KASSERT(child == NULL || vm_radix_isleaf(child),
("vm_radix_lookup_ge: child is radix node"));
/*
* If a valid page or edge bigger than the search slot is
* found in the traversal, skip to the next higher-level key.
*/
if (rnode->rn_clev == 0 || vm_radix_addlev(&index, maplevels,
rnode->rn_clev - 1) > 0)
break;
goto restart;
descend:
rnode = child;
}
return (NULL);
}
/*
* 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)
{
vm_pindex_t inc;
vm_page_t m;
struct vm_radix_node *child, *rnode;
int slot;
uint16_t difflev;
boolean_t maplevels[VM_RADIX_LIMIT + 1];
#ifdef INVARIANTS
int loops = 0;
#endif
restart:
KASSERT(++loops < 1000, ("%s: too many loops", __func__));
for (difflev = 0; difflev < (VM_RADIX_LIMIT + 1); difflev++)
maplevels[difflev] = FALSE;
rnode = vm_radix_getroot(rtree);
while (rnode != NULL) {
maplevels[rnode->rn_clev] = TRUE;
/*
* If the keys differ before the current bisection node
* the search key might rollback to the earliest
* available bisection node, or to the higher value
* in the current domain (if the owner is smaller than the
* search key).
* The maplevels array records any node has been seen
* at a given level. This aids the search for a valid
* bisection node.
*/
if (vm_radix_keybarr(rnode, index)) {
difflev = vm_radix_keydiff(index, rnode->rn_owner);
if (index > rnode->rn_owner) {
index = vm_radix_trimkey(rnode->rn_owner,
difflev);
index |= VM_RADIX_UNITLEVEL(difflev) - 1;
} else if (vm_radix_declev(&index, maplevels,
difflev) > 0)
break;
goto restart;
}
slot = vm_radix_slot(index, rnode->rn_clev);
child = rnode->rn_child[slot];
if (vm_radix_isleaf(child)) {
m = vm_radix_topage(child);
if (m->pindex <= index)
return (m);
} else if (child != NULL)
goto descend;
/*
* Look for an available edge or page within the current
* bisection node.
*/
if (slot > 0) {
inc = VM_RADIX_UNITLEVEL(rnode->rn_clev);
index = vm_radix_trimkey(index, rnode->rn_clev);
index |= inc - 1;
do {
index -= inc;
slot--;
child = rnode->rn_child[slot];
if (vm_radix_isleaf(child)) {
m = vm_radix_topage(child);
if (m->pindex <= index)
return (m);
} else if (child != NULL)
goto descend;
} while (slot > 0);
}
KASSERT(child == NULL || vm_radix_isleaf(child),
("vm_radix_lookup_le: child is radix node"));
/*
* If a valid page or edge smaller than the search slot is
* found in the traversal, skip to the next higher-level key.
*/
if (rnode->rn_clev == 0 || vm_radix_declev(&index, maplevels,
rnode->rn_clev - 1) > 0)
break;
goto restart;
descend:
rnode = child;
}
return (NULL);
}
/*
* Remove the specified index from the tree.
* Panics if the key is not present.
*/
void
vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index)
{
struct vm_radix_node *rnode, *parent;
vm_page_t m;
int i, slot;
parent = NULL;
rnode = vm_radix_getroot(rtree);
for (;;) {
if (rnode == NULL)
panic("vm_radix_remove: impossible to locate the key");
slot = vm_radix_slot(index, rnode->rn_clev);
if (vm_radix_isleaf(rnode->rn_child[slot])) {
m = vm_radix_topage(rnode->rn_child[slot]);
if (m->pindex != index)
panic("%s: invalid key found", __func__);
rnode->rn_child[slot] = NULL;
rnode->rn_count--;
if (rnode->rn_count > 1)
break;
if (parent == NULL) {
if (rnode->rn_count == 0) {
vm_radix_node_put(rnode);
vm_radix_setroot(rtree, NULL);
}
break;
}
for (i = 0; i < VM_RADIX_COUNT; i++)
if (rnode->rn_child[i] != NULL)
break;
KASSERT(i != VM_RADIX_COUNT,
("%s: invalid node configuration", __func__));
slot = vm_radix_slot(index, parent->rn_clev);
KASSERT(parent->rn_child[slot] == rnode,
("%s: invalid child value", __func__));
parent->rn_child[slot] = rnode->rn_child[i];
rnode->rn_count--;
rnode->rn_child[i] = NULL;
vm_radix_node_put(rnode);
break;
}
parent = rnode;
rnode = rnode->rn_child[slot];
}
}
/*
* 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_getroot(rtree);
if (root == NULL)
return;
vm_radix_setroot(rtree, NULL);
vm_radix_reclaim_allnodes_int(root);
}
#ifdef DDB
/*
* Show details about the given radix node.
*/
DB_SHOW_COMMAND(radixnode, db_show_radixnode)
{
struct vm_radix_node *rnode;
int i;
if (!have_addr)
return;
rnode = (struct vm_radix_node *)addr;
db_printf("radixnode %p, owner %jx, children count %u, level %u:\n",
(void *)rnode, (uintmax_t)rnode->rn_owner, rnode->rn_count,
rnode->rn_clev);
for (i = 0; i < VM_RADIX_COUNT; i++)
if (rnode->rn_child[i] != NULL)
db_printf("slot: %d, val: %p, page: %p, clev: %d\n",
i, (void *)rnode->rn_child[i],
vm_radix_isleaf(rnode->rn_child[i]) ?
vm_radix_topage(rnode->rn_child[i]) : NULL,
rnode->rn_clev);
}
#endif /* DDB */