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eaf13dd73a
MUST be PG_BUSY. It is bogus to free a page that isn't busy, because it is in a state of being "unavailable" when being freed. The additional advantage is that the page_remove code has a better cross-check that the page should be busy and unavailable for other use. There were some minor problems with the collapse code, and this plugs those subtile "holes." Also, the vfs_bio code wasn't checking correctly for PG_BUSY pages. I am going to develop a more consistant scheme for grabbing pages, busy or otherwise. For now, we are stuck with the current morass.
189 lines
7.3 KiB
C
189 lines
7.3 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 1.43 1998/01/22 17:30:40 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, OBJT_DEAD };
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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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int generation; /* generation ID */
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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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int cache_count; /* number of cached pages */
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int wire_count; /* number of wired 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_dispose __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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