1385 lines
34 KiB
C
1385 lines
34 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.c 8.5 (Berkeley) 3/22/94
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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.c,v 1.58 1995/12/07 12:48:21 davidg Exp $
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*/
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/*
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* Virtual memory object module.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/proc.h> /* for curproc, pageproc */
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#include <sys/malloc.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/vmmeter.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_prot.h>
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#include <vm/lock.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pageout.h>
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#include <vm/vm_pager.h>
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#include <vm/swap_pager.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_extern.h>
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#ifdef DDB
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extern void vm_object_check __P((void));
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#endif
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static void _vm_object_allocate __P((objtype_t, vm_size_t, vm_object_t));
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#ifdef DDB
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static int _vm_object_in_map __P((vm_map_t map, vm_object_t object,
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vm_map_entry_t entry));
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static int vm_object_in_map __P((vm_object_t object));
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#endif
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static vm_page_t
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vm_object_page_lookup __P((vm_object_t object,
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vm_offset_t offset));
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static void vm_object_qcollapse __P((vm_object_t object));
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/*
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* Virtual memory objects maintain the actual data
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* associated with allocated virtual memory. A given
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* page of memory exists within exactly one object.
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*
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* An object is only deallocated when all "references"
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* are given up. Only one "reference" to a given
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* region of an object should be writeable.
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*
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* Associated with each object is a list of all resident
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* memory pages belonging to that object; this list is
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* maintained by the "vm_page" module, and locked by the object's
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* lock.
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*
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* Each object also records a "pager" routine which is
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* used to retrieve (and store) pages to the proper backing
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* storage. In addition, objects may be backed by other
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* objects from which they were virtual-copied.
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*
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* The only items within the object structure which are
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* modified after time of creation are:
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* reference count locked by object's lock
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* pager routine locked by object's lock
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*
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*/
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int vm_object_cache_max;
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struct object_q vm_object_cached_list;
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int vm_object_cached;
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struct object_q vm_object_list;
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long vm_object_count;
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vm_object_t kernel_object;
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vm_object_t kmem_object;
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struct vm_object kernel_object_store;
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struct vm_object kmem_object_store;
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extern int vm_pageout_page_count;
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long object_collapses;
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long object_bypasses;
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static void
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_vm_object_allocate(type, size, object)
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objtype_t type;
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vm_size_t size;
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register vm_object_t object;
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{
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TAILQ_INIT(&object->memq);
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TAILQ_INIT(&object->shadow_head);
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object->type = type;
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object->size = size;
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object->ref_count = 1;
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object->flags = 0;
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object->paging_in_progress = 0;
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object->resident_page_count = 0;
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object->handle = NULL;
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object->paging_offset = (vm_ooffset_t) 0;
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object->backing_object = NULL;
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object->backing_object_offset = (vm_ooffset_t) 0;
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object->last_read = 0;
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TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
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vm_object_count++;
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}
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/*
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* vm_object_init:
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*
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* Initialize the VM objects module.
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*/
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void
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vm_object_init()
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{
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TAILQ_INIT(&vm_object_cached_list);
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TAILQ_INIT(&vm_object_list);
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vm_object_count = 0;
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vm_object_cache_max = 84;
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if (cnt.v_page_count > 1000)
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vm_object_cache_max += (cnt.v_page_count - 1000) / 4;
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kernel_object = &kernel_object_store;
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_vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
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kernel_object);
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kmem_object = &kmem_object_store;
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_vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
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kmem_object);
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}
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/*
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* vm_object_allocate:
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*
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* Returns a new object with the given size.
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*/
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vm_object_t
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vm_object_allocate(type, size)
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objtype_t type;
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vm_size_t size;
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{
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register vm_object_t result;
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result = (vm_object_t)
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malloc((u_long) sizeof *result, M_VMOBJ, M_WAITOK);
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_vm_object_allocate(type, size, result);
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return (result);
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}
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/*
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* vm_object_reference:
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*
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* Gets another reference to the given object.
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*/
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inline void
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vm_object_reference(object)
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register vm_object_t object;
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{
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if (object == NULL)
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return;
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if (object->ref_count == 0) {
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if ((object->flags & OBJ_CANPERSIST) == 0)
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panic("vm_object_reference: non-persistent object with 0 ref_count");
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TAILQ_REMOVE(&vm_object_cached_list, object, cached_list);
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vm_object_cached--;
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}
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object->ref_count++;
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}
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/*
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* vm_object_deallocate:
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*
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* Release a reference to the specified object,
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* gained either through a vm_object_allocate
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* or a vm_object_reference call. When all references
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* are gone, storage associated with this object
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* may be relinquished.
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*
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* No object may be locked.
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*/
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void
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vm_object_deallocate(object)
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vm_object_t object;
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{
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vm_object_t temp;
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while (object != NULL) {
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if (object->ref_count == 0)
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panic("vm_object_deallocate: object deallocated too many times");
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/*
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* Lose the reference
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*/
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object->ref_count--;
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if (object->ref_count != 0) {
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if ((object->ref_count == 1) &&
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(object->handle == NULL) &&
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(object->type == OBJT_DEFAULT ||
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object->type == OBJT_SWAP)) {
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vm_object_t robject;
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robject = object->shadow_head.tqh_first;
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if ((robject != NULL) &&
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(robject->handle == NULL) &&
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(robject->type == OBJT_DEFAULT ||
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robject->type == OBJT_SWAP)) {
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int s;
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robject->ref_count += 2;
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object->ref_count += 2;
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do {
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s = splhigh();
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while (robject->paging_in_progress) {
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robject->flags |= OBJ_PIPWNT;
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tsleep(robject, PVM, "objde1", 0);
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}
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while (object->paging_in_progress) {
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object->flags |= OBJ_PIPWNT;
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tsleep(object, PVM, "objde2", 0);
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}
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splx(s);
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} while( object->paging_in_progress || robject->paging_in_progress);
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object->ref_count -= 2;
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robject->ref_count -= 2;
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if( robject->ref_count == 0) {
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robject->ref_count += 1;
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object = robject;
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continue;
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}
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vm_object_collapse(robject);
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return;
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}
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}
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/*
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* If there are still references, then we are done.
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*/
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return;
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}
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if (object->type == OBJT_VNODE) {
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struct vnode *vp = object->handle;
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vp->v_flag &= ~VTEXT;
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}
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/*
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* See if this object can persist and has some resident
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* pages. If so, enter it in the cache.
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*/
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if (object->flags & OBJ_CANPERSIST) {
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if (object->resident_page_count != 0) {
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vm_object_page_clean(object, 0, 0 ,TRUE, TRUE);
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TAILQ_INSERT_TAIL(&vm_object_cached_list, object,
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cached_list);
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vm_object_cached++;
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vm_object_cache_trim();
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return;
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} else {
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object->flags &= ~OBJ_CANPERSIST;
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}
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}
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/*
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* Make sure no one uses us.
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*/
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object->flags |= OBJ_DEAD;
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temp = object->backing_object;
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if (temp)
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TAILQ_REMOVE(&temp->shadow_head, object, shadow_list);
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vm_object_terminate(object);
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/* unlocks and deallocates object */
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object = temp;
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}
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}
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/*
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* vm_object_terminate actually destroys the specified object, freeing
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* up all previously used resources.
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*
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* The object must be locked.
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*/
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void
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vm_object_terminate(object)
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register vm_object_t object;
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{
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register vm_page_t p;
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int s;
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/*
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* wait for the pageout daemon to be done with the object
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*/
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s = splhigh();
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while (object->paging_in_progress) {
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object->flags |= OBJ_PIPWNT;
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tsleep(object, PVM, "objtrm", 0);
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}
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splx(s);
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if (object->paging_in_progress != 0)
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panic("vm_object_deallocate: pageout in progress");
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/*
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* Clean and free the pages, as appropriate. All references to the
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* object are gone, so we don't need to lock it.
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*/
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if (object->type == OBJT_VNODE) {
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struct vnode *vp = object->handle;
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VOP_LOCK(vp);
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vm_object_page_clean(object, 0, 0, TRUE, FALSE);
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vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0);
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VOP_UNLOCK(vp);
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}
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/*
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* Now free the pages. For internal objects, this also removes them
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* from paging queues.
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*/
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while ((p = object->memq.tqh_first) != NULL) {
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if (p->flags & PG_BUSY)
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printf("vm_object_terminate: freeing busy page\n");
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PAGE_WAKEUP(p);
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vm_page_free(p);
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cnt.v_pfree++;
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}
|
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|
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/*
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* Let the pager know object is dead.
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*/
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vm_pager_deallocate(object);
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TAILQ_REMOVE(&vm_object_list, object, object_list);
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vm_object_count--;
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|
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wakeup(object);
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/*
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* Free the space for the object.
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*/
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free((caddr_t) object, M_VMOBJ);
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}
|
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|
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/*
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* vm_object_page_clean
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*
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* Clean all dirty pages in the specified range of object.
|
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* Leaves page on whatever queue it is currently on.
|
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*
|
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* Odd semantics: if start == end, we clean everything.
|
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*
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* The object must be locked.
|
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*/
|
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|
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void
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vm_object_page_clean(object, start, end, syncio, lockflag)
|
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vm_object_t object;
|
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vm_pindex_t start;
|
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vm_pindex_t end;
|
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boolean_t syncio;
|
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boolean_t lockflag;
|
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{
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register vm_page_t p;
|
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register vm_offset_t tstart, tend;
|
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int s;
|
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struct vnode *vp;
|
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int runlen;
|
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vm_page_t ma[vm_pageout_page_count];
|
|
|
|
if (object->type != OBJT_VNODE ||
|
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(object->flags & OBJ_MIGHTBEDIRTY) == 0)
|
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return;
|
|
|
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vp = object->handle;
|
|
|
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if (lockflag)
|
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VOP_LOCK(vp);
|
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object->flags |= OBJ_CLEANING;
|
|
|
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tstart = start;
|
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if (end == 0) {
|
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tend = object->size;
|
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} else {
|
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tend = end;
|
|
}
|
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if ((tstart == 0) && (tend == object->size)) {
|
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object->flags &= ~(OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
|
|
}
|
|
|
|
runlen = 0;
|
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for(;tstart < tend; tstart += 1) {
|
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relookup:
|
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p = vm_page_lookup(object, tstart);
|
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if (!p) {
|
|
if (runlen > 0) {
|
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vm_pageout_flush(ma, runlen, syncio);
|
|
runlen = 0;
|
|
}
|
|
continue;
|
|
}
|
|
if ((p->valid == 0) || (p->flags & PG_CACHE)) {
|
|
if (runlen > 0) {
|
|
vm_pageout_flush(ma, runlen, syncio);
|
|
runlen = 0;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
vm_page_protect(p, VM_PROT_READ);
|
|
|
|
s = splhigh();
|
|
while ((p->flags & PG_BUSY) || p->busy) {
|
|
if (runlen > 0) {
|
|
splx(s);
|
|
vm_pageout_flush(ma, runlen, syncio);
|
|
runlen = 0;
|
|
goto relookup;
|
|
}
|
|
p->flags |= PG_WANTED|PG_REFERENCED;
|
|
tsleep(p, PVM, "vpcwai", 0);
|
|
splx(s);
|
|
goto relookup;
|
|
}
|
|
splx(s);
|
|
|
|
if (p->dirty == 0)
|
|
vm_page_test_dirty(p);
|
|
|
|
if ((p->valid & p->dirty) != 0) {
|
|
ma[runlen] = p;
|
|
p->flags |= PG_BUSY;
|
|
runlen++;
|
|
if (runlen >= vm_pageout_page_count) {
|
|
vm_pageout_flush(ma, runlen, syncio);
|
|
runlen = 0;
|
|
}
|
|
} else if (runlen > 0) {
|
|
vm_pageout_flush(ma, runlen, syncio);
|
|
runlen = 0;
|
|
}
|
|
|
|
}
|
|
if (runlen > 0) {
|
|
vm_pageout_flush(ma, runlen, syncio);
|
|
}
|
|
|
|
VOP_FSYNC(vp, NULL, syncio, curproc);
|
|
|
|
if (lockflag)
|
|
VOP_UNLOCK(vp);
|
|
object->flags &= ~OBJ_CLEANING;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* vm_object_deactivate_pages
|
|
*
|
|
* Deactivate all pages in the specified object. (Keep its pages
|
|
* in memory even though it is no longer referenced.)
|
|
*
|
|
* The object must be locked.
|
|
*/
|
|
void
|
|
vm_object_deactivate_pages(object)
|
|
register vm_object_t object;
|
|
{
|
|
register vm_page_t p, next;
|
|
|
|
for (p = object->memq.tqh_first; p != NULL; p = next) {
|
|
next = p->listq.tqe_next;
|
|
vm_page_deactivate(p);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Trim the object cache to size.
|
|
*/
|
|
void
|
|
vm_object_cache_trim()
|
|
{
|
|
register vm_object_t object;
|
|
|
|
while (vm_object_cached > vm_object_cache_max) {
|
|
object = vm_object_cached_list.tqh_first;
|
|
|
|
vm_object_reference(object);
|
|
pager_cache(object, FALSE);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* vm_object_pmap_copy:
|
|
*
|
|
* Makes all physical pages in the specified
|
|
* object range copy-on-write. No writeable
|
|
* references to these pages should remain.
|
|
*
|
|
* The object must *not* be locked.
|
|
*/
|
|
void
|
|
vm_object_pmap_copy(object, start, end)
|
|
register vm_object_t object;
|
|
register vm_pindex_t start;
|
|
register vm_pindex_t end;
|
|
{
|
|
register vm_page_t p;
|
|
|
|
if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0)
|
|
return;
|
|
|
|
for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) {
|
|
vm_page_protect(p, VM_PROT_READ);
|
|
}
|
|
|
|
object->flags &= ~OBJ_WRITEABLE;
|
|
}
|
|
|
|
/*
|
|
* vm_object_pmap_remove:
|
|
*
|
|
* Removes all physical pages in the specified
|
|
* object range from all physical maps.
|
|
*
|
|
* The object must *not* be locked.
|
|
*/
|
|
void
|
|
vm_object_pmap_remove(object, start, end)
|
|
register vm_object_t object;
|
|
register vm_pindex_t start;
|
|
register vm_pindex_t end;
|
|
{
|
|
register vm_page_t p;
|
|
if (object == NULL)
|
|
return;
|
|
for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) {
|
|
vm_page_protect(p, VM_PROT_NONE);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_object_copy:
|
|
*
|
|
* Create a new object which is a copy of an existing
|
|
* object, and mark all of the pages in the existing
|
|
* object 'copy-on-write'. The new object has one reference.
|
|
* Returns the new object.
|
|
*
|
|
* May defer the copy until later if the object is not backed
|
|
* up by a non-default pager.
|
|
*/
|
|
void
|
|
vm_object_copy(src_object, src_offset,
|
|
dst_object, dst_offset, src_needs_copy)
|
|
register vm_object_t src_object;
|
|
vm_pindex_t src_offset;
|
|
vm_object_t *dst_object;/* OUT */
|
|
vm_pindex_t *dst_offset;/* OUT */
|
|
boolean_t *src_needs_copy; /* OUT */
|
|
{
|
|
if (src_object == NULL) {
|
|
/*
|
|
* Nothing to copy
|
|
*/
|
|
*dst_object = NULL;
|
|
*dst_offset = 0;
|
|
*src_needs_copy = FALSE;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Try to collapse the object before copying it.
|
|
*/
|
|
if (src_object->handle == NULL &&
|
|
(src_object->type == OBJT_DEFAULT ||
|
|
src_object->type == OBJT_SWAP))
|
|
vm_object_collapse(src_object);
|
|
|
|
|
|
/*
|
|
* Make another reference to the object
|
|
*/
|
|
src_object->ref_count++;
|
|
|
|
*dst_object = src_object;
|
|
*dst_offset = src_offset;
|
|
|
|
/*
|
|
* Must make a shadow when write is desired
|
|
*/
|
|
*src_needs_copy = TRUE;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* vm_object_shadow:
|
|
*
|
|
* Create a new object which is backed by the
|
|
* specified existing object range. The source
|
|
* object reference is deallocated.
|
|
*
|
|
* The new object and offset into that object
|
|
* are returned in the source parameters.
|
|
*/
|
|
|
|
void
|
|
vm_object_shadow(object, offset, length)
|
|
vm_object_t *object; /* IN/OUT */
|
|
vm_ooffset_t *offset; /* IN/OUT */
|
|
vm_size_t length;
|
|
{
|
|
register vm_object_t source;
|
|
register vm_object_t result;
|
|
|
|
source = *object;
|
|
|
|
/*
|
|
* Allocate a new object with the given length
|
|
*/
|
|
|
|
if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL)
|
|
panic("vm_object_shadow: no object for shadowing");
|
|
|
|
/*
|
|
* The new object shadows the source object, adding a reference to it.
|
|
* Our caller changes his reference to point to the new object,
|
|
* removing a reference to the source object. Net result: no change
|
|
* of reference count.
|
|
*/
|
|
result->backing_object = source;
|
|
if (source)
|
|
TAILQ_INSERT_TAIL(&result->backing_object->shadow_head, result, shadow_list);
|
|
|
|
/*
|
|
* Store the offset into the source object, and fix up the offset into
|
|
* the new object.
|
|
*/
|
|
|
|
result->backing_object_offset = *offset;
|
|
|
|
/*
|
|
* Return the new things
|
|
*/
|
|
|
|
*offset = 0;
|
|
*object = result;
|
|
}
|
|
|
|
|
|
/*
|
|
* this version of collapse allows the operation to occur earlier and
|
|
* when paging_in_progress is true for an object... This is not a complete
|
|
* operation, but should plug 99.9% of the rest of the leaks.
|
|
*/
|
|
static void
|
|
vm_object_qcollapse(object)
|
|
register vm_object_t object;
|
|
{
|
|
register vm_object_t backing_object;
|
|
register vm_pindex_t backing_offset_index, paging_offset_index;
|
|
vm_pindex_t backing_object_paging_offset_index;
|
|
vm_pindex_t new_pindex;
|
|
register vm_page_t p, pp;
|
|
register vm_size_t size;
|
|
|
|
backing_object = object->backing_object;
|
|
if (backing_object->ref_count != 1)
|
|
return;
|
|
|
|
backing_object->ref_count += 2;
|
|
|
|
backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
|
|
backing_object_paging_offset_index = OFF_TO_IDX(backing_object->paging_offset);
|
|
paging_offset_index = OFF_TO_IDX(object->paging_offset);
|
|
size = object->size;
|
|
p = backing_object->memq.tqh_first;
|
|
while (p) {
|
|
vm_page_t next;
|
|
|
|
next = p->listq.tqe_next;
|
|
if ((p->flags & (PG_BUSY | PG_FICTITIOUS | PG_CACHE)) ||
|
|
!p->valid || p->hold_count || p->wire_count || p->busy) {
|
|
p = next;
|
|
continue;
|
|
}
|
|
vm_page_protect(p, VM_PROT_NONE);
|
|
new_pindex = p->pindex - backing_offset_index;
|
|
if (p->pindex < backing_offset_index ||
|
|
new_pindex >= size) {
|
|
if (backing_object->type == OBJT_SWAP)
|
|
swap_pager_freespace(backing_object,
|
|
backing_object_paging_offset_index+p->pindex,
|
|
1);
|
|
vm_page_free(p);
|
|
} else {
|
|
pp = vm_page_lookup(object, new_pindex);
|
|
if (pp != NULL || (object->type == OBJT_SWAP && vm_pager_has_page(object,
|
|
paging_offset_index + new_pindex, NULL, NULL))) {
|
|
if (backing_object->type == OBJT_SWAP)
|
|
swap_pager_freespace(backing_object,
|
|
backing_object_paging_offset_index + p->pindex, 1);
|
|
vm_page_free(p);
|
|
} else {
|
|
if (backing_object->type == OBJT_SWAP)
|
|
swap_pager_freespace(backing_object,
|
|
backing_object_paging_offset_index + p->pindex, 1);
|
|
vm_page_rename(p, object, new_pindex);
|
|
p->dirty = VM_PAGE_BITS_ALL;
|
|
}
|
|
}
|
|
p = next;
|
|
}
|
|
backing_object->ref_count -= 2;
|
|
}
|
|
|
|
/*
|
|
* vm_object_collapse:
|
|
*
|
|
* Collapse an object with the object backing it.
|
|
* Pages in the backing object are moved into the
|
|
* parent, and the backing object is deallocated.
|
|
*/
|
|
void
|
|
vm_object_collapse(object)
|
|
vm_object_t object;
|
|
|
|
{
|
|
vm_object_t backing_object;
|
|
vm_ooffset_t backing_offset;
|
|
vm_size_t size;
|
|
vm_pindex_t new_pindex, backing_offset_index;
|
|
vm_page_t p, pp;
|
|
|
|
while (TRUE) {
|
|
/*
|
|
* Verify that the conditions are right for collapse:
|
|
*
|
|
* The object exists and no pages in it are currently being paged
|
|
* out.
|
|
*/
|
|
if (object == NULL)
|
|
return;
|
|
|
|
/*
|
|
* Make sure there is a backing object.
|
|
*/
|
|
if ((backing_object = object->backing_object) == NULL)
|
|
return;
|
|
|
|
/*
|
|
* we check the backing object first, because it is most likely
|
|
* not collapsable.
|
|
*/
|
|
if (backing_object->handle != NULL ||
|
|
(backing_object->type != OBJT_DEFAULT &&
|
|
backing_object->type != OBJT_SWAP) ||
|
|
(backing_object->flags & OBJ_DEAD) ||
|
|
object->handle != NULL ||
|
|
(object->type != OBJT_DEFAULT &&
|
|
object->type != OBJT_SWAP) ||
|
|
(object->flags & OBJ_DEAD)) {
|
|
return;
|
|
}
|
|
|
|
if (object->paging_in_progress != 0 ||
|
|
backing_object->paging_in_progress != 0) {
|
|
vm_object_qcollapse(object);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* We know that we can either collapse the backing object (if
|
|
* the parent is the only reference to it) or (perhaps) remove
|
|
* the parent's reference to it.
|
|
*/
|
|
|
|
backing_offset = object->backing_object_offset;
|
|
backing_offset_index = OFF_TO_IDX(backing_offset);
|
|
size = object->size;
|
|
|
|
/*
|
|
* If there is exactly one reference to the backing object, we
|
|
* can collapse it into the parent.
|
|
*/
|
|
|
|
if (backing_object->ref_count == 1) {
|
|
|
|
backing_object->flags |= OBJ_DEAD;
|
|
/*
|
|
* We can collapse the backing object.
|
|
*
|
|
* Move all in-memory pages from backing_object to the
|
|
* parent. Pages that have been paged out will be
|
|
* overwritten by any of the parent's pages that
|
|
* shadow them.
|
|
*/
|
|
|
|
while ((p = backing_object->memq.tqh_first) != 0) {
|
|
|
|
new_pindex = p->pindex - backing_offset_index;
|
|
|
|
/*
|
|
* If the parent has a page here, or if this
|
|
* page falls outside the parent, dispose of
|
|
* it.
|
|
*
|
|
* Otherwise, move it as planned.
|
|
*/
|
|
|
|
if (p->pindex < backing_offset_index ||
|
|
new_pindex >= size) {
|
|
vm_page_protect(p, VM_PROT_NONE);
|
|
PAGE_WAKEUP(p);
|
|
vm_page_free(p);
|
|
} else {
|
|
pp = vm_page_lookup(object, new_pindex);
|
|
if (pp != NULL || (object->type == OBJT_SWAP && vm_pager_has_page(object,
|
|
OFF_TO_IDX(object->paging_offset) + new_pindex, NULL, NULL))) {
|
|
vm_page_protect(p, VM_PROT_NONE);
|
|
PAGE_WAKEUP(p);
|
|
vm_page_free(p);
|
|
} else {
|
|
vm_page_rename(p, object, new_pindex);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Move the pager from backing_object to object.
|
|
*/
|
|
|
|
if (backing_object->type == OBJT_SWAP) {
|
|
backing_object->paging_in_progress++;
|
|
if (object->type == OBJT_SWAP) {
|
|
object->paging_in_progress++;
|
|
/*
|
|
* copy shadow object pages into ours
|
|
* and destroy unneeded pages in
|
|
* shadow object.
|
|
*/
|
|
swap_pager_copy(
|
|
backing_object,
|
|
OFF_TO_IDX(backing_object->paging_offset),
|
|
object,
|
|
OFF_TO_IDX(object->paging_offset),
|
|
OFF_TO_IDX(object->backing_object_offset));
|
|
vm_object_pip_wakeup(object);
|
|
} else {
|
|
object->paging_in_progress++;
|
|
/*
|
|
* move the shadow backing_object's pager data to
|
|
* "object" and convert "object" type to OBJT_SWAP.
|
|
*/
|
|
object->type = OBJT_SWAP;
|
|
object->un_pager.swp.swp_nblocks =
|
|
backing_object->un_pager.swp.swp_nblocks;
|
|
object->un_pager.swp.swp_allocsize =
|
|
backing_object->un_pager.swp.swp_allocsize;
|
|
object->un_pager.swp.swp_blocks =
|
|
backing_object->un_pager.swp.swp_blocks;
|
|
object->un_pager.swp.swp_poip = /* XXX */
|
|
backing_object->un_pager.swp.swp_poip;
|
|
object->paging_offset = backing_object->paging_offset + backing_offset;
|
|
TAILQ_INSERT_TAIL(&swap_pager_un_object_list, object, pager_object_list);
|
|
|
|
/*
|
|
* Convert backing object from OBJT_SWAP to
|
|
* OBJT_DEFAULT. XXX - only the TAILQ_REMOVE is
|
|
* actually necessary.
|
|
*/
|
|
backing_object->type = OBJT_DEFAULT;
|
|
TAILQ_REMOVE(&swap_pager_un_object_list, backing_object, pager_object_list);
|
|
/*
|
|
* free unnecessary blocks
|
|
*/
|
|
swap_pager_freespace(object, 0,
|
|
OFF_TO_IDX(object->paging_offset));
|
|
vm_object_pip_wakeup(object);
|
|
}
|
|
|
|
vm_object_pip_wakeup(backing_object);
|
|
}
|
|
/*
|
|
* Object now shadows whatever backing_object did.
|
|
* Note that the reference to backing_object->backing_object
|
|
* moves from within backing_object to within object.
|
|
*/
|
|
|
|
TAILQ_REMOVE(&object->backing_object->shadow_head, object,
|
|
shadow_list);
|
|
if (backing_object->backing_object)
|
|
TAILQ_REMOVE(&backing_object->backing_object->shadow_head,
|
|
backing_object, shadow_list);
|
|
object->backing_object = backing_object->backing_object;
|
|
if (object->backing_object)
|
|
TAILQ_INSERT_TAIL(&object->backing_object->shadow_head,
|
|
object, shadow_list);
|
|
|
|
object->backing_object_offset += backing_object->backing_object_offset;
|
|
/*
|
|
* Discard backing_object.
|
|
*
|
|
* Since the backing object has no pages, no pager left,
|
|
* and no object references within it, all that is
|
|
* necessary is to dispose of it.
|
|
*/
|
|
|
|
TAILQ_REMOVE(&vm_object_list, backing_object,
|
|
object_list);
|
|
vm_object_count--;
|
|
|
|
free((caddr_t) backing_object, M_VMOBJ);
|
|
|
|
object_collapses++;
|
|
} else {
|
|
/*
|
|
* If all of the pages in the backing object are
|
|
* shadowed by the parent object, the parent object no
|
|
* longer has to shadow the backing object; it can
|
|
* shadow the next one in the chain.
|
|
*
|
|
* The backing object must not be paged out - we'd have
|
|
* to check all of the paged-out pages, as well.
|
|
*/
|
|
|
|
if (backing_object->type != OBJT_DEFAULT) {
|
|
return;
|
|
}
|
|
/*
|
|
* Should have a check for a 'small' number of pages
|
|
* here.
|
|
*/
|
|
|
|
for (p = backing_object->memq.tqh_first; p; p = p->listq.tqe_next) {
|
|
new_pindex = p->pindex - backing_offset_index;
|
|
|
|
/*
|
|
* If the parent has a page here, or if this
|
|
* page falls outside the parent, keep going.
|
|
*
|
|
* Otherwise, the backing_object must be left in
|
|
* the chain.
|
|
*/
|
|
|
|
if (p->pindex >= backing_offset_index &&
|
|
new_pindex <= size) {
|
|
|
|
pp = vm_page_lookup(object, new_pindex);
|
|
|
|
if ((pp == NULL || pp->valid == 0) &&
|
|
!vm_pager_has_page(object, OFF_TO_IDX(object->paging_offset) + new_pindex, NULL, NULL)) {
|
|
/*
|
|
* Page still needed. Can't go any
|
|
* further.
|
|
*/
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Make the parent shadow the next object in the
|
|
* chain. Deallocating backing_object will not remove
|
|
* it, since its reference count is at least 2.
|
|
*/
|
|
|
|
TAILQ_REMOVE(&object->backing_object->shadow_head,
|
|
object, shadow_list);
|
|
vm_object_reference(object->backing_object = backing_object->backing_object);
|
|
if (object->backing_object)
|
|
TAILQ_INSERT_TAIL(&object->backing_object->shadow_head,
|
|
object, shadow_list);
|
|
object->backing_object_offset += backing_object->backing_object_offset;
|
|
|
|
/*
|
|
* Drop the reference count on backing_object. Since
|
|
* its ref_count was at least 2, it will not vanish;
|
|
* so we don't need to call vm_object_deallocate.
|
|
*/
|
|
if (backing_object->ref_count == 1)
|
|
printf("should have called obj deallocate\n");
|
|
backing_object->ref_count--;
|
|
|
|
object_bypasses++;
|
|
|
|
}
|
|
|
|
/*
|
|
* Try again with this object's new backing object.
|
|
*/
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_object_page_remove: [internal]
|
|
*
|
|
* Removes all physical pages in the specified
|
|
* object range from the object's list of pages.
|
|
*
|
|
* The object must be locked.
|
|
*/
|
|
void
|
|
vm_object_page_remove(object, start, end, clean_only)
|
|
register vm_object_t object;
|
|
register vm_pindex_t start;
|
|
register vm_pindex_t end;
|
|
boolean_t clean_only;
|
|
{
|
|
register vm_page_t p, next;
|
|
unsigned int size;
|
|
int s;
|
|
|
|
if (object == NULL)
|
|
return;
|
|
|
|
object->paging_in_progress++;
|
|
again:
|
|
size = end - start;
|
|
if (size > 4 || size >= object->size / 4) {
|
|
for (p = object->memq.tqh_first; p != NULL; p = next) {
|
|
next = p->listq.tqe_next;
|
|
if ((start <= p->pindex) && (p->pindex < end)) {
|
|
s = splhigh();
|
|
if (p->bmapped) {
|
|
splx(s);
|
|
continue;
|
|
}
|
|
if ((p->flags & PG_BUSY) || p->busy) {
|
|
p->flags |= PG_WANTED;
|
|
tsleep(p, PVM, "vmopar", 0);
|
|
splx(s);
|
|
goto again;
|
|
}
|
|
splx(s);
|
|
if (clean_only) {
|
|
vm_page_test_dirty(p);
|
|
if (p->valid & p->dirty)
|
|
continue;
|
|
}
|
|
vm_page_protect(p, VM_PROT_NONE);
|
|
PAGE_WAKEUP(p);
|
|
vm_page_free(p);
|
|
}
|
|
}
|
|
} else {
|
|
while (size > 0) {
|
|
while ((p = vm_page_lookup(object, start)) != 0) {
|
|
s = splhigh();
|
|
if (p->bmapped) {
|
|
splx(s);
|
|
break;
|
|
}
|
|
if ((p->flags & PG_BUSY) || p->busy) {
|
|
p->flags |= PG_WANTED;
|
|
tsleep(p, PVM, "vmopar", 0);
|
|
splx(s);
|
|
goto again;
|
|
}
|
|
splx(s);
|
|
if (clean_only) {
|
|
vm_page_test_dirty(p);
|
|
if (p->valid & p->dirty)
|
|
continue;
|
|
}
|
|
vm_page_protect(p, VM_PROT_NONE);
|
|
PAGE_WAKEUP(p);
|
|
vm_page_free(p);
|
|
}
|
|
start += 1;
|
|
size -= 1;
|
|
}
|
|
}
|
|
vm_object_pip_wakeup(object);
|
|
}
|
|
|
|
/*
|
|
* Routine: vm_object_coalesce
|
|
* Function: Coalesces two objects backing up adjoining
|
|
* regions of memory into a single object.
|
|
*
|
|
* returns TRUE if objects were combined.
|
|
*
|
|
* NOTE: Only works at the moment if the second object is NULL -
|
|
* if it's not, which object do we lock first?
|
|
*
|
|
* Parameters:
|
|
* prev_object First object to coalesce
|
|
* prev_offset Offset into prev_object
|
|
* next_object Second object into coalesce
|
|
* next_offset Offset into next_object
|
|
*
|
|
* prev_size Size of reference to prev_object
|
|
* next_size Size of reference to next_object
|
|
*
|
|
* Conditions:
|
|
* The object must *not* be locked.
|
|
*/
|
|
boolean_t
|
|
vm_object_coalesce(prev_object, prev_pindex, prev_size, next_size)
|
|
register vm_object_t prev_object;
|
|
vm_pindex_t prev_pindex;
|
|
vm_size_t prev_size, next_size;
|
|
{
|
|
vm_size_t newsize;
|
|
|
|
if (prev_object == NULL) {
|
|
return (TRUE);
|
|
}
|
|
|
|
/*
|
|
* Try to collapse the object first
|
|
*/
|
|
vm_object_collapse(prev_object);
|
|
|
|
/*
|
|
* Can't coalesce if: . more than one reference . paged out . shadows
|
|
* another object . has a copy elsewhere (any of which mean that the
|
|
* pages not mapped to prev_entry may be in use anyway)
|
|
*/
|
|
|
|
if (prev_object->ref_count > 1 ||
|
|
prev_object->type != OBJT_DEFAULT ||
|
|
prev_object->backing_object != NULL) {
|
|
return (FALSE);
|
|
}
|
|
|
|
prev_size >>= PAGE_SHIFT;
|
|
next_size >>= PAGE_SHIFT;
|
|
/*
|
|
* Remove any pages that may still be in the object from a previous
|
|
* deallocation.
|
|
*/
|
|
|
|
vm_object_page_remove(prev_object,
|
|
prev_pindex + prev_size,
|
|
prev_pindex + prev_size + next_size, FALSE);
|
|
|
|
/*
|
|
* Extend the object if necessary.
|
|
*/
|
|
newsize = prev_pindex + prev_size + next_size;
|
|
if (newsize > prev_object->size)
|
|
prev_object->size = newsize;
|
|
|
|
return (TRUE);
|
|
}
|
|
|
|
#ifdef DDB
|
|
|
|
static int
|
|
_vm_object_in_map(map, object, entry)
|
|
vm_map_t map;
|
|
vm_object_t object;
|
|
vm_map_entry_t entry;
|
|
{
|
|
vm_map_t tmpm;
|
|
vm_map_entry_t tmpe;
|
|
vm_object_t obj;
|
|
int entcount;
|
|
|
|
if (map == 0)
|
|
return 0;
|
|
|
|
if (entry == 0) {
|
|
tmpe = map->header.next;
|
|
entcount = map->nentries;
|
|
while (entcount-- && (tmpe != &map->header)) {
|
|
if( _vm_object_in_map(map, object, tmpe)) {
|
|
return 1;
|
|
}
|
|
tmpe = tmpe->next;
|
|
}
|
|
} else if (entry->is_sub_map || entry->is_a_map) {
|
|
tmpm = entry->object.share_map;
|
|
tmpe = tmpm->header.next;
|
|
entcount = tmpm->nentries;
|
|
while (entcount-- && tmpe != &tmpm->header) {
|
|
if( _vm_object_in_map(tmpm, object, tmpe)) {
|
|
return 1;
|
|
}
|
|
tmpe = tmpe->next;
|
|
}
|
|
} else if (obj = entry->object.vm_object) {
|
|
for(; obj; obj=obj->backing_object)
|
|
if( obj == object) {
|
|
return 1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
vm_object_in_map( object)
|
|
vm_object_t object;
|
|
{
|
|
struct proc *p;
|
|
for (p = (struct proc *) allproc; p != NULL; p = p->p_next) {
|
|
if( !p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
|
|
continue;
|
|
/*
|
|
if (p->p_stat != SRUN && p->p_stat != SSLEEP) {
|
|
continue;
|
|
}
|
|
*/
|
|
if( _vm_object_in_map(&p->p_vmspace->vm_map, object, 0))
|
|
return 1;
|
|
}
|
|
if( _vm_object_in_map( kernel_map, object, 0))
|
|
return 1;
|
|
if( _vm_object_in_map( kmem_map, object, 0))
|
|
return 1;
|
|
if( _vm_object_in_map( pager_map, object, 0))
|
|
return 1;
|
|
if( _vm_object_in_map( buffer_map, object, 0))
|
|
return 1;
|
|
if( _vm_object_in_map( io_map, object, 0))
|
|
return 1;
|
|
if( _vm_object_in_map( phys_map, object, 0))
|
|
return 1;
|
|
if( _vm_object_in_map( mb_map, object, 0))
|
|
return 1;
|
|
if( _vm_object_in_map( u_map, object, 0))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
|
|
void
|
|
vm_object_check() {
|
|
vm_object_t object;
|
|
|
|
/*
|
|
* make sure that internal objs are in a map somewhere
|
|
* and none have zero ref counts.
|
|
*/
|
|
for (object = vm_object_list.tqh_first;
|
|
object != NULL;
|
|
object = object->object_list.tqe_next) {
|
|
if (object->handle == NULL &&
|
|
(object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
|
|
if (object->ref_count == 0) {
|
|
printf("vmochk: internal obj has zero ref count: %d\n",
|
|
object->size);
|
|
}
|
|
if (!vm_object_in_map(object)) {
|
|
printf("vmochk: internal obj is not in a map: "
|
|
"ref: %d, size: %d: 0x%x, backing_object: 0x%x\n",
|
|
object->ref_count, object->size,
|
|
object->size, object->backing_object);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_object_print: [ debug ]
|
|
*/
|
|
void
|
|
vm_object_print(iobject, full, dummy3, dummy4)
|
|
/* db_expr_t */ int iobject;
|
|
boolean_t full;
|
|
/* db_expr_t */ int dummy3;
|
|
char *dummy4;
|
|
{
|
|
vm_object_t object = (vm_object_t)iobject; /* XXX */
|
|
register vm_page_t p;
|
|
|
|
register int count;
|
|
|
|
if (object == NULL)
|
|
return;
|
|
|
|
iprintf("Object 0x%x: size=0x%x, res=%d, ref=%d, ",
|
|
(int) object, (int) object->size,
|
|
object->resident_page_count, object->ref_count);
|
|
printf("offset=0x%x, backing_object=(0x%x)+0x%x\n",
|
|
(int) object->paging_offset,
|
|
(int) object->backing_object, (int) object->backing_object_offset);
|
|
printf("cache: next=%p, prev=%p\n",
|
|
object->cached_list.tqe_next, object->cached_list.tqe_prev);
|
|
|
|
if (!full)
|
|
return;
|
|
|
|
indent += 2;
|
|
count = 0;
|
|
for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) {
|
|
if (count == 0)
|
|
iprintf("memory:=");
|
|
else if (count == 6) {
|
|
printf("\n");
|
|
iprintf(" ...");
|
|
count = 0;
|
|
} else
|
|
printf(",");
|
|
count++;
|
|
|
|
printf("(off=0x%lx,page=0x%lx)",
|
|
(u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p));
|
|
}
|
|
if (count != 0)
|
|
printf("\n");
|
|
indent -= 2;
|
|
}
|
|
#endif /* DDB */
|