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To reduce the amount of arithmetic performed in the various radix tree

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functions, reverse the numbering scheme for the levels.  The highest
numbered level in the tree now appears near the root instead of the leaves.

Sponsored by:	EMC / Isilon Storage Division
This commit is contained in:
Alan Cox 2013-05-11 18:01:41 +00:00
parent 048c95417d
commit 9f2e600890
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=250520
1 changed files with 12 additions and 13 deletions
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25
sys/vm/vm_radix.c
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@ -91,7 +91,7 @@ __FBSDID("$FreeBSD$");
/* Returns one unit associated with specified level. */
#define VM_RADIX_UNITLEVEL(lev) \
((vm_pindex_t)1 << ((VM_RADIX_LIMIT - (lev)) * VM_RADIX_WIDTH))
((vm_pindex_t)1 << ((lev) * VM_RADIX_WIDTH))
struct vm_radix_node {
vm_pindex_t rn_owner; /* Owner of record. */
@ -150,8 +150,7 @@ 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);
return ((index >> (level * VM_RADIX_WIDTH)) & VM_RADIX_MASK);
}
/* Trims the key after the specified level. */
@ -161,9 +160,9 @@ 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;
if (level > 0) {
ret >>= level * VM_RADIX_WIDTH;
ret <<= level * VM_RADIX_WIDTH;
}
return (ret);
}
@ -234,7 +233,7 @@ vm_radix_keydiff(vm_pindex_t index1, vm_pindex_t index2)
__func__, (uintmax_t)index1));
index1 ^= index2;
for (clev = 0;; clev++)
for (clev = VM_RADIX_LIMIT;; clev--)
if (vm_radix_slot(index1, clev) != 0)
return (clev);
}
@ -247,8 +246,8 @@ 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);
if (rnode->rn_clev < VM_RADIX_LIMIT) {
idx = vm_radix_trimkey(idx, rnode->rn_clev + 1);
return (idx != rnode->rn_owner);
}
return (FALSE);
@ -384,7 +383,7 @@ vm_radix_insert(struct vm_radix *rtree, vm_page_t page)
__func__, (uintmax_t)index);
clev = vm_radix_keydiff(m->pindex, index);
tmp = vm_radix_node_get(vm_radix_trimkey(index,
clev - 1), 2, clev);
clev + 1), 2, clev);
*parentp = tmp;
vm_radix_addpage(tmp, index, clev, page);
vm_radix_addpage(tmp, m->pindex, clev, m);
@ -408,7 +407,7 @@ vm_radix_insert(struct vm_radix *rtree, vm_page_t page)
*/
newind = rnode->rn_owner;
clev = vm_radix_keydiff(newind, index);
tmp = vm_radix_node_get(vm_radix_trimkey(index, clev - 1), 2,
tmp = vm_radix_node_get(vm_radix_trimkey(index, clev + 1), 2,
clev);
*parentp = tmp;
vm_radix_addpage(tmp, index, clev, page);
@ -545,7 +544,7 @@ vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index)
*/
goto ascend;
descend:
KASSERT(rnode->rn_clev < VM_RADIX_LIMIT,
KASSERT(rnode->rn_clev > 0,
("vm_radix_lookup_ge: pushing leaf's parent"));
KASSERT(tos < VM_RADIX_LIMIT,
("vm_radix_lookup_ge: stack overflow"));
@ -658,7 +657,7 @@ vm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index)
*/
goto ascend;
descend:
KASSERT(rnode->rn_clev < VM_RADIX_LIMIT,
KASSERT(rnode->rn_clev > 0,
("vm_radix_lookup_le: pushing leaf's parent"));
KASSERT(tos < VM_RADIX_LIMIT,
("vm_radix_lookup_le: stack overflow"));