95e5e988e0
original BSD code. The association between the vnode and the vm_object no longer includes reference counts. The major difference is that vm_object's are no longer freed gratuitiously from the vnode, and so once an object is created for the vnode, it will last as long as the vnode does. When a vnode object reference count is incremented, then the underlying vnode reference count is incremented also. The two "objects" are now more intimately related, and so the interactions are now much less complex. When vnodes are now normally placed onto the free queue with an object still attached. The rundown of the object happens at vnode rundown time, and happens with exactly the same filesystem semantics of the original VFS code. There is absolutely no need for vnode_pager_uncache and other travesties like that anymore. A side-effect of these changes is that SMP locking should be much simpler, the I/O copyin/copyout optimizations work, NFS should be more ponderable, and further work on layered filesystems should be less frustrating, because of the totally coherent management of the vnode objects and vnodes. Please be careful with your system while running this code, but I would greatly appreciate feedback as soon a reasonably possible.
185 lines
7.1 KiB
C
185 lines
7.1 KiB
C
/*
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* The Mach Operating System project at Carnegie-Mellon University.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)vm_object.h 8.3 (Berkeley) 1/12/94
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*
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*
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* Copyright (c) 1987, 1990 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Authors: Avadis Tevanian, Jr., Michael Wayne Young
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*
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* $Id: vm_object.h,v 1.40 1997/12/29 00:24:55 dyson Exp $
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*/
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/*
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* Virtual memory object module definitions.
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*/
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#ifndef _VM_OBJECT_
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#define _VM_OBJECT_
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#include <sys/queue.h>
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enum obj_type { OBJT_DEFAULT, OBJT_SWAP, OBJT_VNODE, OBJT_DEVICE };
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typedef enum obj_type objtype_t;
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/*
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* Types defined:
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*
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* vm_object_t Virtual memory object.
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*/
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struct vm_object {
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TAILQ_ENTRY(vm_object) object_list; /* list of all objects */
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TAILQ_HEAD(, vm_object) shadow_head; /* objects that this is a shadow for */
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TAILQ_ENTRY(vm_object) shadow_list; /* chain of shadow objects */
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TAILQ_HEAD(, vm_page) memq; /* list of resident pages */
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objtype_t type; /* type of pager */
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vm_size_t size; /* Object size */
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int ref_count; /* How many refs?? */
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int shadow_count; /* how many objects that this is a shadow for */
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int pg_color; /* color of first page in obj */
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u_short flags; /* see below */
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u_short paging_in_progress; /* Paging (in or out) so don't collapse or destroy */
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u_short behavior; /* see below */
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int resident_page_count; /* number of resident pages */
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vm_ooffset_t paging_offset; /* Offset into paging space */
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struct vm_object *backing_object; /* object that I'm a shadow of */
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vm_ooffset_t backing_object_offset;/* Offset in backing object */
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vm_offset_t last_read; /* last read in object -- detect seq behavior */
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vm_page_t page_hint; /* hint for last looked-up or allocated page */
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TAILQ_ENTRY(vm_object) pager_object_list; /* list of all objects of this pager type */
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void *handle;
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union {
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struct {
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off_t vnp_size; /* Current size of file */
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} vnp;
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struct {
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TAILQ_HEAD(, vm_page) devp_pglist; /* list of pages allocated */
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} devp;
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struct {
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int swp_nblocks;
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int swp_allocsize;
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struct swblock *swp_blocks;
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short swp_poip;
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} swp;
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} un_pager;
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};
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/*
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* Flags
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*/
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#define OBJ_ACTIVE 0x0004 /* active objects */
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#define OBJ_DEAD 0x0008 /* dead objects (during rundown) */
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#define OBJ_PIPWNT 0x0040 /* paging in progress wanted */
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#define OBJ_WRITEABLE 0x0080 /* object has been made writable */
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#define OBJ_MIGHTBEDIRTY 0x0100 /* object might be dirty */
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#define OBJ_CLEANING 0x0200
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#define OBJ_OPT 0x1000 /* I/O optimization */
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#define OBJ_NORMAL 0x0 /* default behavior */
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#define OBJ_SEQUENTIAL 0x1 /* expect sequential accesses */
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#define OBJ_RANDOM 0x2 /* expect random accesses */
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#define IDX_TO_OFF(idx) (((vm_ooffset_t)(idx)) << PAGE_SHIFT)
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#define OFF_TO_IDX(off) ((vm_pindex_t)(((vm_ooffset_t)(off)) >> PAGE_SHIFT))
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#ifdef KERNEL
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TAILQ_HEAD(object_q, vm_object);
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extern struct object_q vm_object_list; /* list of allocated objects */
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/* lock for object list and count */
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extern vm_object_t kernel_object; /* the single kernel object */
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extern vm_object_t kmem_object;
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#endif /* KERNEL */
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#ifdef KERNEL
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static __inline void
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vm_object_pip_wakeup(vm_object_t object)
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{
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object->paging_in_progress--;
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if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
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object->flags &= ~OBJ_PIPWNT;
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wakeup(object);
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}
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}
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vm_object_t vm_object_allocate __P((objtype_t, vm_size_t));
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void _vm_object_allocate __P((objtype_t, vm_size_t, vm_object_t));
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boolean_t vm_object_coalesce __P((vm_object_t, vm_pindex_t, vm_size_t, vm_size_t));
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void vm_object_collapse __P((vm_object_t));
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void vm_object_copy __P((vm_object_t, vm_pindex_t, vm_object_t *, vm_pindex_t *, boolean_t *));
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void vm_object_deallocate __P((vm_object_t));
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void vm_object_terminate __P((vm_object_t));
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void vm_object_vndeallocate __P((vm_object_t));
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void vm_object_init __P((void));
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void vm_object_page_clean __P((vm_object_t, vm_pindex_t, vm_pindex_t, boolean_t));
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void vm_object_page_remove __P((vm_object_t, vm_pindex_t, vm_pindex_t, boolean_t));
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void vm_object_pmap_copy __P((vm_object_t, vm_pindex_t, vm_pindex_t));
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void vm_object_pmap_copy_1 __P((vm_object_t, vm_pindex_t, vm_pindex_t));
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void vm_object_pmap_remove __P((vm_object_t, vm_pindex_t, vm_pindex_t));
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void vm_object_reference __P((vm_object_t));
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void vm_object_shadow __P((vm_object_t *, vm_ooffset_t *, vm_size_t));
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void vm_object_madvise __P((vm_object_t, vm_pindex_t, int, int));
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void vm_object_init2 __P((void));
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#endif /* KERNEL */
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#endif /* _VM_OBJECT_ */
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