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Introduce vm_object_prefer(), which interrogates the PMAP layer in search

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for an optimal virtual address for a given object.
This commit is contained in:
pk 1994-12-10 11:46:25 +00:00
parent c09156bf8b
commit d114baba9a
2 changed files with 43 additions and 2 deletions
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41
sys/vm/vm_object.c
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@ -1,4 +1,4 @@
/* $NetBSD: vm_object.c,v 1.27 1994/10/30 19:11:18 cgd Exp $ */
/* $NetBSD: vm_object.c,v 1.28 1994/12/10 11:46:25 pk Exp $ */
/*
* Copyright (c) 1991, 1993
@ -1402,6 +1402,45 @@ vm_object_coalesce(prev_object, next_object,
return(TRUE);
}
/*
* vm_object_prefer:
*
* Return optimal virtual address for new mapping of this object.
*
* The object must *not* be locked.
*/
void
vm_object_prefer(object, offset, addr)
register vm_object_t object;
register vm_offset_t offset;
register vm_offset_t *addr;
{
register vm_page_t p;
register vm_offset_t paddr;
if (object == NULL)
return;
#ifdef PMAP_PREFER
vm_object_lock(object);
/*
* Look for the first page that the pmap layer has something
* to say about. Since an object maps a contiguous range of
* virutal addresses, this will determine the preferred origin
* of the proposed mapping.
*/
for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) {
if (p->flags & (PG_FAKE | PG_FICTITIOUS))
continue;
paddr = PMAP_PREFER(VM_PAGE_TO_PHYS(p), *addr+p->offset-offset);
if (paddr == (vm_offset_t)-1)
continue;
*addr = paddr - (p->offset - offset);
break;
}
vm_object_unlock(object);
#endif
}
/*
* vm_object_print: [ debug ]
*/

4
sys/vm/vm_object.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: vm_object.h,v 1.13 1994/06/29 06:48:23 cgd Exp $ */
/* $NetBSD: vm_object.h,v 1.14 1994/12/10 11:46:31 pk Exp $ */
/*
* Copyright (c) 1991, 1993
@ -163,6 +163,8 @@ void vm_object_pmap_copy __P((vm_object_t,
vm_offset_t, vm_offset_t));
void vm_object_pmap_remove __P((vm_object_t,
vm_offset_t, vm_offset_t));
void vm_object_prefer __P((vm_object_t,
vm_offset_t, vm_offset_t *));
void vm_object_print __P((vm_object_t, boolean_t));
void _vm_object_print __P((vm_object_t, boolean_t,
void (*)(const char *, ...)));