svn commit: r235829 - head/sys/vm
Andriy Gapon
avg at FreeBSD.org
Wed May 23 12:51:50 UTC 2012
Author: avg
Date: Wed May 23 12:51:49 2012
New Revision: 235829
URL: http://svn.freebsd.org/changeset/base/235829
Log:
vm_pager_object_lookup: small performance optimization
do not needlessly lock an object if its handle doesn't match
Reviewed by: kib, alc
MFC after: 1 week
Modified:
head/sys/vm/vm_pager.c
Modified: head/sys/vm/vm_pager.c
==============================================================================
--- head/sys/vm/vm_pager.c Wed May 23 11:26:28 2012 (r235828)
+++ head/sys/vm/vm_pager.c Wed May 23 12:51:49 2012 (r235829)
@@ -271,14 +271,15 @@ vm_pager_object_lookup(struct pagerlst *
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);
}
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