Author: alc
Date: Sat May 11 18:01:41 2013
New Revision: 250520
URL: http://svnweb.freebsd.org/changeset/base/250520
Log:
To reduce the amount of arithmetic performed in the various radix tree
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
Modified:
head/sys/vm/vm_radix.c
Modified: head/sys/vm/vm_radix.c
==============================================================================
--- head/sys/vm/vm_radix.c Sat May 11 17:58:26 2013 (r250519)
+++ head/sys/vm/vm_radix.c Sat May 11 18:01:41 2013 (r250520)
@@ -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, uint
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_
__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,
__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,
*/
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 @@ ascend:
*/
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 @@ ascend:
*/
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"));
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