3364c323e6
rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
509 lines
12 KiB
C
509 lines
12 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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* 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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/*
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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/cdefs.h>
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__FBSDID("$FreeBSD$");
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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/vnode.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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#include <sys/ucred.h>
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#include <sys/malloc.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_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pager.h>
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#include <vm/vm_extern.h>
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MALLOC_DEFINE(M_VMPGDATA, "vm_pgdata", "XXX: VM pager private data");
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int cluster_pbuf_freecnt = -1; /* unlimited to begin with */
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static int dead_pager_getpages(vm_object_t, vm_page_t *, int, int);
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static vm_object_t dead_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
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vm_ooffset_t, struct ucred *);
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static void dead_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
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static boolean_t dead_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
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static void dead_pager_dealloc(vm_object_t);
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static int
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dead_pager_getpages(obj, ma, count, req)
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vm_object_t obj;
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vm_page_t *ma;
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int count;
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int req;
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{
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return VM_PAGER_FAIL;
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}
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static vm_object_t
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dead_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
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vm_ooffset_t off, struct ucred *cred)
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{
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return NULL;
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}
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static void
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dead_pager_putpages(object, m, count, flags, 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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int flags;
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int *rtvals;
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{
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int i;
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for (i = 0; i < count; i++) {
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rtvals[i] = VM_PAGER_AGAIN;
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}
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}
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static int
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dead_pager_haspage(object, pindex, prev, next)
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vm_object_t object;
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vm_pindex_t pindex;
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int *prev;
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int *next;
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{
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if (prev)
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*prev = 0;
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if (next)
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*next = 0;
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return FALSE;
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}
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static void
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dead_pager_dealloc(object)
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vm_object_t object;
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{
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return;
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}
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static struct pagerops deadpagerops = {
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.pgo_alloc = dead_pager_alloc,
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.pgo_dealloc = dead_pager_dealloc,
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.pgo_getpages = dead_pager_getpages,
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.pgo_putpages = dead_pager_putpages,
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.pgo_haspage = dead_pager_haspage,
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};
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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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&physpagerops, /* OBJT_PHYS */
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&deadpagerops /* OBJT_DEAD */
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};
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static const 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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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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struct mtx pbuf_mtx;
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static TAILQ_HEAD(swqueue, buf) bswlist;
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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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TAILQ_INIT(&bswlist);
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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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mtx_init(&pbuf_mtx, "pbuf mutex", NULL, MTX_DEF);
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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; i++, bp++) {
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TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist);
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BUF_LOCKINIT(bp);
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LIST_INIT(&bp->b_dep);
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bp->b_rcred = bp->b_wcred = NOCRED;
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bp->b_xflags = 0;
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}
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cluster_pbuf_freecnt = nswbuf / 2;
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vnode_pbuf_freecnt = nswbuf / 2 + 1;
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swapbkva = kmem_alloc_nofault(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(objtype_t type, void *handle, vm_ooffset_t size,
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vm_prot_t prot, vm_ooffset_t off, struct ucred *cred)
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{
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vm_object_t ret;
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struct pagerops *ops;
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ops = pagertab[type];
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if (ops)
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ret = (*ops->pgo_alloc) (handle, size, prot, off, cred);
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else
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ret = NULL;
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return (ret);
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}
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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_pager_deallocate(object)
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vm_object_t object;
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{
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VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
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(*pagertab[object->type]->pgo_dealloc) (object);
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}
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/*
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* vm_pager_get_pages() - inline, see vm/vm_pager.h
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* vm_pager_put_pages() - inline, see vm/vm_pager.h
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* vm_pager_has_page() - inline, see vm/vm_pager.h
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*/
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/*
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* Search the specified pager object list for an object with the
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* specified handle. If an object with the specified handle is found,
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* increase its reference count and return it. Otherwise, return NULL.
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*
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* The pager object list must be locked.
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*/
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vm_object_t
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vm_pager_object_lookup(struct pagerlst *pg_list, void *handle)
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{
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vm_object_t object;
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TAILQ_FOREACH(object, pg_list, pager_object_list) {
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VM_OBJECT_LOCK(object);
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if (object->handle == handle &&
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(object->flags & OBJ_DEAD) == 0) {
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vm_object_reference_locked(object);
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VM_OBJECT_UNLOCK(object);
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break;
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}
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VM_OBJECT_UNLOCK(object);
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}
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return (object);
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}
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/*
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* initialize a physical buffer
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*/
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/*
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* XXX This probably belongs in vfs_bio.c
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*/
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static void
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initpbuf(struct buf *bp)
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{
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KASSERT(bp->b_bufobj == NULL, ("initpbuf with bufobj"));
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KASSERT(bp->b_vp == NULL, ("initpbuf with vp"));
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bp->b_rcred = NOCRED;
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bp->b_wcred = NOCRED;
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bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */
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bp->b_saveaddr = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva;
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bp->b_data = bp->b_saveaddr;
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bp->b_kvabase = bp->b_saveaddr;
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bp->b_kvasize = MAXPHYS;
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bp->b_xflags = 0;
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bp->b_flags = 0;
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bp->b_ioflags = 0;
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bp->b_iodone = NULL;
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bp->b_error = 0;
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BUF_LOCK(bp, LK_EXCLUSIVE, NULL);
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}
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/*
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* allocate a physical buffer
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*
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* There are a limited number (nswbuf) of physical buffers. We need
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* to make sure that no single subsystem is able to hog all of them,
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* so each subsystem implements a counter which is typically initialized
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* to 1/2 nswbuf. getpbuf() decrements this counter in allocation and
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* increments it on release, and blocks if the counter hits zero. A
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* subsystem may initialize the counter to -1 to disable the feature,
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* but it must still be sure to match up all uses of getpbuf() with
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* relpbuf() using the same variable.
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*
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* NOTE: pfreecnt can be NULL, but this 'feature' will be removed
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* relatively soon when the rest of the subsystems get smart about it. XXX
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*/
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struct buf *
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getpbuf(int *pfreecnt)
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{
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struct buf *bp;
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mtx_lock(&pbuf_mtx);
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for (;;) {
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if (pfreecnt) {
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while (*pfreecnt == 0) {
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msleep(pfreecnt, &pbuf_mtx, PVM, "wswbuf0", 0);
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}
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}
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/* get a bp from the swap buffer header pool */
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if ((bp = TAILQ_FIRST(&bswlist)) != NULL)
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break;
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bswneeded = 1;
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msleep(&bswneeded, &pbuf_mtx, PVM, "wswbuf1", 0);
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/* loop in case someone else grabbed one */
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}
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TAILQ_REMOVE(&bswlist, bp, b_freelist);
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if (pfreecnt)
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--*pfreecnt;
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mtx_unlock(&pbuf_mtx);
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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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* Note that there is no NULL hack here - all subsystems using this
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* call understand how to use pfreecnt.
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*/
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struct buf *
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trypbuf(int *pfreecnt)
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{
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struct buf *bp;
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mtx_lock(&pbuf_mtx);
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if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) {
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mtx_unlock(&pbuf_mtx);
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return NULL;
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}
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TAILQ_REMOVE(&bswlist, bp, b_freelist);
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--*pfreecnt;
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mtx_unlock(&pbuf_mtx);
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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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* NOTE: pfreecnt can be NULL, but this 'feature' will be removed
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* relatively soon when the rest of the subsystems get smart about it. XXX
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*/
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void
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relpbuf(struct buf *bp, int *pfreecnt)
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{
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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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KASSERT(bp->b_vp == NULL, ("relpbuf with vp"));
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KASSERT(bp->b_bufobj == NULL, ("relpbuf with bufobj"));
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BUF_UNLOCK(bp);
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mtx_lock(&pbuf_mtx);
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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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if (pfreecnt) {
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if (++*pfreecnt == 1)
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wakeup(pfreecnt);
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}
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mtx_unlock(&pbuf_mtx);
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}
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/*
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* Associate a p-buffer with a vnode.
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*
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* Also sets B_PAGING flag to indicate that vnode is not fully associated
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* with the buffer. i.e. the bp has not been linked into the vnode or
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* ref-counted.
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*/
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void
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pbgetvp(struct vnode *vp, struct buf *bp)
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{
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KASSERT(bp->b_vp == NULL, ("pbgetvp: not free"));
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KASSERT(bp->b_bufobj == NULL, ("pbgetvp: not free (bufobj)"));
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bp->b_vp = vp;
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bp->b_flags |= B_PAGING;
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bp->b_bufobj = &vp->v_bufobj;
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}
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/*
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* Associate a p-buffer with a vnode.
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*
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* Also sets B_PAGING flag to indicate that vnode is not fully associated
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* with the buffer. i.e. the bp has not been linked into the vnode or
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* ref-counted.
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*/
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void
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pbgetbo(struct bufobj *bo, struct buf *bp)
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{
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KASSERT(bp->b_vp == NULL, ("pbgetbo: not free (vnode)"));
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KASSERT(bp->b_bufobj == NULL, ("pbgetbo: not free (bufobj)"));
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bp->b_flags |= B_PAGING;
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bp->b_bufobj = bo;
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}
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/*
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* Disassociate a p-buffer from a vnode.
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*/
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void
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pbrelvp(struct buf *bp)
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{
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KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL"));
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KASSERT(bp->b_bufobj != NULL, ("pbrelvp: NULL bufobj"));
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/* XXX REMOVE ME */
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BO_LOCK(bp->b_bufobj);
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if (TAILQ_NEXT(bp, b_bobufs) != NULL) {
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panic(
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"relpbuf(): b_vp was probably reassignbuf()d %p %x",
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bp,
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(int)bp->b_flags
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);
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}
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BO_UNLOCK(bp->b_bufobj);
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bp->b_vp = NULL;
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bp->b_bufobj = NULL;
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bp->b_flags &= ~B_PAGING;
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}
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/*
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* Disassociate a p-buffer from a bufobj.
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*/
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void
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pbrelbo(struct buf *bp)
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{
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KASSERT(bp->b_vp == NULL, ("pbrelbo: vnode"));
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KASSERT(bp->b_bufobj != NULL, ("pbrelbo: NULL bufobj"));
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/* XXX REMOVE ME */
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BO_LOCK(bp->b_bufobj);
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if (TAILQ_NEXT(bp, b_bobufs) != NULL) {
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panic(
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"relpbuf(): b_vp was probably reassignbuf()d %p %x",
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bp,
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(int)bp->b_flags
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);
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}
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BO_UNLOCK(bp->b_bufobj);
|
|
bp->b_bufobj = NULL;
|
|
bp->b_flags &= ~B_PAGING;
|
|
}
|