d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

vm_pager_object_lookup: small performance optimization

Browse Source 
do not needlessly lock an object if its handle doesn't match

Reviewed by:	kib, alc
MFC after:	1 week
This commit is contained in:
Andriy Gapon 2012-05-23 12:51:49 +00:00
parent 807aad636f
commit b6062382be
1 changed files with 7 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
sys/vm/vm_pager.c
View File

@ -271,14 +271,15 @@ vm_pager_object_lookup(struct pagerlst *pg_list, void *handle)
vm_object_t object;
TAILQ_FOREACH(object, pg_list, pager_object_list) {
VM_OBJECT_LOCK(object);
if (object->handle == handle &&
(object->flags & OBJ_DEAD) == 0) {
vm_object_reference_locked(object);
if (object->handle == handle) {
VM_OBJECT_LOCK(object);
if ((object->flags & OBJ_DEAD) == 0) {
vm_object_reference_locked(object);
VM_OBJECT_UNLOCK(object);
break;
}
VM_OBJECT_UNLOCK(object);
break;
}
VM_OBJECT_UNLOCK(object);
}
return (object);
}