09e0c6ccdd
scheme. Additionally, add the capability for checking for unexpected kernel page faults. The maximum amount of kva space for buffers hasn't been decreased from where it is, but it will now be possible to do so. This scheme manages the kva space similar to the buffers themselves. If there isn't enough kva space because of usage or fragementation, buffers will be reclaimed until a buffer allocation is successful. This scheme should be very resistant to fragmentation problems until/if the LFS code is fixed and uses the bogus buffer locking scheme -- but a 'fixed' LFS is not likely to use such a scheme. Now there should be NO problem allocating buffers up to MAXPHYS.
373 lines
8.9 KiB
C
373 lines
8.9 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_pager.c 8.6 (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_pager.c,v 1.24 1996/09/08 20:44:49 dyson Exp $
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*/
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/*
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* Paging space routine stubs. Emulates a matchmaker-like interface
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* for builtin pagers.
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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/proc.h>
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#include <sys/malloc.h>
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#include <sys/buf.h>
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#include <sys/ucred.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/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_pager.h>
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#include <vm/vm_extern.h>
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extern struct pagerops defaultpagerops;
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extern struct pagerops swappagerops;
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extern struct pagerops vnodepagerops;
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extern struct pagerops devicepagerops;
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static struct pagerops *pagertab[] = {
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&defaultpagerops, /* OBJT_DEFAULT */
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&swappagerops, /* OBJT_SWAP */
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&vnodepagerops, /* OBJT_VNODE */
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&devicepagerops, /* OBJT_DEVICE */
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};
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static int npagers = sizeof(pagertab) / sizeof(pagertab[0]);
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/*
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* Kernel address space for mapping pages.
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* Used by pagers where KVAs are needed for IO.
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*
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* XXX needs to be large enough to support the number of pending async
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* cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size
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* (MAXPHYS == 64k) if you want to get the most efficiency.
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*/
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#define PAGER_MAP_SIZE (8 * 1024 * 1024)
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int pager_map_size = PAGER_MAP_SIZE;
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vm_map_t pager_map;
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static int bswneeded;
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static vm_offset_t swapbkva; /* swap buffers kva */
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void
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vm_pager_init()
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{
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struct pagerops **pgops;
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/*
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* Initialize known pagers
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*/
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for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
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if (pgops && ((*pgops)->pgo_init != NULL))
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(*(*pgops)->pgo_init) ();
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}
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void
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vm_pager_bufferinit()
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{
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struct buf *bp;
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int i;
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bp = swbuf;
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/*
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* Now set up swap and physical I/O buffer headers.
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*/
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for (i = 0; i < nswbuf - 1; i++, bp++) {
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TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist);
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bp->b_rcred = bp->b_wcred = NOCRED;
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bp->b_vnbufs.le_next = NOLIST;
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}
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bp->b_rcred = bp->b_wcred = NOCRED;
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bp->b_vnbufs.le_next = NOLIST;
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swapbkva = kmem_alloc_pageable(pager_map, nswbuf * MAXPHYS);
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if (!swapbkva)
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panic("Not enough pager_map VM space for physical buffers");
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}
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/*
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* Allocate an instance of a pager of the given type.
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* Size, protection and offset parameters are passed in for pagers that
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* need to perform page-level validation (e.g. the device pager).
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*/
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vm_object_t
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vm_pager_allocate(type, handle, size, prot, off)
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objtype_t type;
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void *handle;
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vm_size_t size;
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vm_prot_t prot;
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vm_ooffset_t off;
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{
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struct pagerops *ops;
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ops = pagertab[type];
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if (ops)
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return ((*ops->pgo_alloc) (handle, size, prot, off));
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return (NULL);
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}
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void
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vm_pager_deallocate(object)
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vm_object_t object;
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{
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(*pagertab[object->type]->pgo_dealloc) (object);
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}
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int
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vm_pager_get_pages(object, m, count, reqpage)
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vm_object_t object;
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vm_page_t *m;
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int count;
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int reqpage;
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{
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return ((*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage));
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}
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int
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vm_pager_put_pages(object, m, count, sync, rtvals)
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vm_object_t object;
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vm_page_t *m;
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int count;
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boolean_t sync;
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int *rtvals;
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{
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return ((*pagertab[object->type]->pgo_putpages)(object, m, count, sync, rtvals));
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}
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boolean_t
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vm_pager_has_page(object, offset, before, after)
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vm_object_t object;
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vm_pindex_t offset;
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int *before;
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int *after;
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{
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return ((*pagertab[object->type]->pgo_haspage) (object, offset, before, after));
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}
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/*
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* Called by pageout daemon before going back to sleep.
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* Gives pagers a chance to clean up any completed async pageing operations.
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*/
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void
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vm_pager_sync()
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{
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struct pagerops **pgops;
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for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
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if (pgops && ((*pgops)->pgo_sync != NULL))
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(*(*pgops)->pgo_sync) ();
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}
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vm_offset_t
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vm_pager_map_page(m)
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vm_page_t m;
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{
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vm_offset_t kva;
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kva = kmem_alloc_wait(pager_map, PAGE_SIZE);
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pmap_kenter(kva, VM_PAGE_TO_PHYS(m));
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return (kva);
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}
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void
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vm_pager_unmap_page(kva)
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vm_offset_t kva;
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{
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pmap_kremove(kva);
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kmem_free_wakeup(pager_map, kva, PAGE_SIZE);
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}
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vm_object_t
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vm_pager_object_lookup(pg_list, handle)
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register struct pagerlst *pg_list;
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void *handle;
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{
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register vm_object_t object;
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for (object = TAILQ_FIRST(pg_list); object != NULL; object = TAILQ_NEXT(object,pager_object_list))
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if (object->handle == handle)
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return (object);
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return (NULL);
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}
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/*
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* This routine loses a reference to the object -
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* thus a reference must be gained before calling.
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*/
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int
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pager_cache(object, should_cache)
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vm_object_t object;
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boolean_t should_cache;
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{
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if (object == NULL)
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return (KERN_INVALID_ARGUMENT);
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if (should_cache)
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object->flags |= OBJ_CANPERSIST;
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else
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object->flags &= ~OBJ_CANPERSIST;
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vm_object_deallocate(object);
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return (KERN_SUCCESS);
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}
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/*
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* initialize a physical buffer
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*/
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static void
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initpbuf(struct buf *bp) {
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bzero(bp, sizeof *bp);
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bp->b_rcred = NOCRED;
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bp->b_wcred = NOCRED;
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bp->b_qindex = QUEUE_NONE;
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bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva;
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bp->b_kvabase = bp->b_data;
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bp->b_kvasize = MAXPHYS;
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bp->b_vnbufs.le_next = NOLIST;
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}
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/*
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* allocate a physical buffer
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*/
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struct buf *
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getpbuf()
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{
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int s;
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struct buf *bp;
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s = splbio();
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/* get a bp from the swap buffer header pool */
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while ((bp = TAILQ_FIRST(&bswlist)) == NULL) {
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bswneeded = 1;
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tsleep(&bswneeded, PVM, "wswbuf", 0);
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}
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TAILQ_REMOVE(&bswlist, bp, b_freelist);
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splx(s);
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initpbuf(bp);
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return bp;
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}
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/*
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* allocate a physical buffer, if one is available
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*/
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struct buf *
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trypbuf()
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{
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int s;
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struct buf *bp;
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s = splbio();
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if ((bp = TAILQ_FIRST(&bswlist)) == NULL) {
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splx(s);
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return NULL;
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}
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TAILQ_REMOVE(&bswlist, bp, b_freelist);
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splx(s);
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initpbuf(bp);
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return bp;
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}
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/*
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* release a physical buffer
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*/
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void
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relpbuf(bp)
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struct buf *bp;
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{
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int s;
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s = splbio();
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if (bp->b_rcred != NOCRED) {
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crfree(bp->b_rcred);
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bp->b_rcred = NOCRED;
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}
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if (bp->b_wcred != NOCRED) {
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crfree(bp->b_wcred);
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bp->b_wcred = NOCRED;
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}
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if (bp->b_vp)
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pbrelvp(bp);
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if (bp->b_flags & B_WANTED)
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wakeup(bp);
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TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist);
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if (bswneeded) {
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bswneeded = 0;
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wakeup(&bswneeded);
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}
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splx(s);
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}
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