svn commit: r250748 - head/sys/vm
Alan Cox
alc at FreeBSD.org
Fri May 17 19:02:37 UTC 2013
Author: alc
Date: Fri May 17 19:02:36 2013
New Revision: 250748
URL: http://svnweb.freebsd.org/changeset/base/250748
Log:
Relax the object locking in vm_fault_prefault(). A read lock suffices.
Reviewed by: attilio
Sponsored by: EMC / Isilon Storage Division
Modified:
head/sys/vm/vm_fault.c
Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c Fri May 17 18:59:00 2013 (r250747)
+++ head/sys/vm/vm_fault.c Fri May 17 19:02:36 2013 (r250748)
@@ -1044,28 +1044,28 @@ vm_fault_prefault(pmap_t pmap, vm_offset
pindex = ((addr - entry->start) + entry->offset) >> PAGE_SHIFT;
lobject = object;
- VM_OBJECT_WLOCK(lobject);
+ VM_OBJECT_RLOCK(lobject);
while ((m = vm_page_lookup(lobject, pindex)) == NULL &&
lobject->type == OBJT_DEFAULT &&
(backing_object = lobject->backing_object) != NULL) {
KASSERT((lobject->backing_object_offset & PAGE_MASK) ==
0, ("vm_fault_prefault: unaligned object offset"));
pindex += lobject->backing_object_offset >> PAGE_SHIFT;
- VM_OBJECT_WLOCK(backing_object);
- VM_OBJECT_WUNLOCK(lobject);
+ VM_OBJECT_RLOCK(backing_object);
+ VM_OBJECT_RUNLOCK(lobject);
lobject = backing_object;
}
/*
* give-up when a page is not in memory
*/
if (m == NULL) {
- VM_OBJECT_WUNLOCK(lobject);
+ VM_OBJECT_RUNLOCK(lobject);
break;
}
if (m->valid == VM_PAGE_BITS_ALL &&
(m->flags & PG_FICTITIOUS) == 0)
pmap_enter_quick(pmap, addr, m, entry->protection);
- VM_OBJECT_WUNLOCK(lobject);
+ VM_OBJECT_RUNLOCK(lobject);
}
}
More information about the svn-src-all
mailing list