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

Remove a bogus optimization in the mmap code. It is superfluous,

Browse Source 
and at best is the same speed as the unoptimized code.  At worst, it
slows down trivial programs.
This commit is contained in:
John Dyson 1996-10-24 02:56:23 +00:00
parent c864a7c0a9
commit fcae040bc0
1 changed files with 5 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
sys/vm/vm_mmap.c
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 1.50 1996/09/19 10:12:41 davidg Exp $
* $Id: vm_mmap.c,v 1.51 1996/10/13 07:16:50 phk Exp $
*/
/*
@ -843,7 +843,7 @@ vm_mmap(map, addr, size, prot, maxprot, flags, handle, foff)
vm_ooffset_t foff;
{
boolean_t fitit;
vm_object_t object, object2;
vm_object_t object;
struct vnode *vp = NULL;
objtype_t type;
int rv = KERN_SUCCESS;
@ -915,28 +915,12 @@ vm_mmap(map, addr, size, prot, maxprot, flags, handle, foff)
flags |= MAP_SHARED;
}
object2 = NULL;
docow = 0;
if ((flags & (MAP_ANON|MAP_SHARED)) == 0) {
docow = MAP_COPY_ON_WRITE;
if (objsize < size) {
object2 = vm_object_allocate( OBJT_DEFAULT,
OFF_TO_IDX(size - (foff & ~PAGE_MASK)));
object2->backing_object = object;
object2->backing_object_offset = foff;
TAILQ_INSERT_TAIL(&object->shadow_head,
object2, shadow_list);
++object->shadow_count;
} else {
docow |= MAP_COPY_NEEDED;
}
docow = MAP_COPY_ON_WRITE | MAP_COPY_NEEDED;
}
if (object2)
rv = vm_map_find(map, object2, 0, addr, size, fitit,
prot, maxprot, docow);
else
rv = vm_map_find(map, object, foff, addr, size, fitit,
rv = vm_map_find(map, object, foff, addr, size, fitit,
prot, maxprot, docow);
@ -946,10 +930,7 @@ vm_mmap(map, addr, size, prot, maxprot, flags, handle, foff)
* object if it's an unnamed anonymous mapping
* or named anonymous without other references.
*/
if (object2)
vm_object_deallocate(object2);
else
vm_object_deallocate(object);
vm_object_deallocate(object);
goto out;
}