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Avoid some lookup restarts in vm_radix_lookup_{ge,le}().

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Sponsored by:	EMC / Isilon Storage Division
This commit is contained in:
Alan Cox 2013-04-27 16:44:59 +00:00
parent 3cb14a8923
commit 40076ebc5c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=249986
1 changed files with 24 additions and 22 deletions
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46
sys/vm/vm_radix.c
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@ -527,26 +527,26 @@ vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index)
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
* 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 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) {
difflev = vm_radix_keydiff(index,
rnode->rn_owner);
if (vm_radix_addlev(&index, maplevels,
difflev) > 0)
break;
rnode = vm_radix_getroot(rtree);
goto restart;
} else
index = vm_radix_trimkey(rnode->rn_owner,
difflev);
rnode = vm_radix_getroot(rtree);
goto restart;
index = rnode->rn_owner;
}
slot = vm_radix_slot(index, rnode->rn_clev);
child = rnode->rn_child[slot];
@ -628,26 +628,28 @@ vm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index)
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
* 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).
* 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;
rnode = vm_radix_getroot(rtree);
goto restart;
index = rnode->rn_owner + VM_RADIX_COUNT *
VM_RADIX_UNITLEVEL(rnode->rn_clev) - 1;
} else {
difflev = vm_radix_keydiff(index,
rnode->rn_owner);
if (vm_radix_declev(&index, maplevels,
difflev) > 0)
break;
rnode = vm_radix_getroot(rtree);
goto restart;
}
}
slot = vm_radix_slot(index, rnode->rn_clev);
child = rnode->rn_child[slot];