The code unnecessarily created an object with no handle up-front, which

has the negative effect of disabling some map optimizations.  This
patch defers the creation of the object until it needs to be at fault time.
Submitted by:	Alan Cox <alc@cs.rice.edu>
This commit is contained in:
dyson 1996-12-28 22:40:44 +00:00
parent 317725f464
commit 33d995d870

View File

@ -38,7 +38,7 @@
* from: Utah $Hdr: vm_mmap.c 1.6 91/10/21$
*
* @(#)vm_mmap.c 8.4 (Berkeley) 1/12/94
* $Id: vm_mmap.c,v 1.54 1996/12/14 17:54:17 dyson Exp $
* $Id: vm_mmap.c,v 1.55 1996/12/22 23:17:09 joerg Exp $
*/
/*
@ -905,9 +905,14 @@ vm_mmap(map, addr, size, prot, maxprot, flags, handle, foff)
type = OBJT_VNODE;
}
}
object = vm_pager_allocate(type, handle, OFF_TO_IDX(objsize), prot, foff);
if (object == NULL)
return (type == OBJT_DEVICE ? EINVAL : ENOMEM);
if (handle == NULL) {
object = NULL;
} else {
object = vm_pager_allocate(type, handle, OFF_TO_IDX(objsize), prot, foff);
if (object == NULL)
return (type == OBJT_DEVICE ? EINVAL : ENOMEM);
}
/*
* Force device mappings to be shared.
@ -939,7 +944,7 @@ vm_mmap(map, addr, size, prot, maxprot, flags, handle, foff)
/*
* "Pre-fault" resident pages.
*/
if ((type == OBJT_VNODE) && (map->pmap != NULL)) {
if ((type == OBJT_VNODE) && (map->pmap != NULL) && (object != NULL)) {
pmap_object_init_pt(map->pmap, *addr,
object, (vm_pindex_t) OFF_TO_IDX(foff), size, 1);
}