2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
44 * Permission to use, copy, modify and distribute this software and
45 * its documentation is hereby granted, provided that both the copyright
46 * notice and this permission notice appear in all copies of the
47 * software, derivative works or modified versions, and any portions
48 * thereof, and that both notices appear in supporting documentation.
50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
54 * Carnegie Mellon requests users of this software to return to
56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
64 * $FreeBSD: src/sys/vm/vm_pager.c,v 1.54.2.2 2001/11/18 07:11:00 dillon Exp $
65 * $DragonFly: src/sys/vm/vm_pager.c,v 1.24 2007/11/06 03:50:01 dillon Exp $
69 * Paging space routine stubs. Emulates a matchmaker-like interface
73 #include <sys/param.h>
74 #include <sys/systm.h>
75 #include <sys/kernel.h>
76 #include <sys/vnode.h>
78 #include <sys/ucred.h>
79 #include <sys/malloc.h>
80 #include <sys/dsched.h>
82 #include <sys/thread2.h>
85 #include <vm/vm_param.h>
86 #include <vm/vm_object.h>
87 #include <vm/vm_page.h>
88 #include <vm/vm_pager.h>
89 #include <vm/vm_extern.h>
93 MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data");
95 extern struct pagerops defaultpagerops;
96 extern struct pagerops swappagerops;
97 extern struct pagerops vnodepagerops;
98 extern struct pagerops devicepagerops;
99 extern struct pagerops physpagerops;
101 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */
103 static int dead_pager_getpage (vm_object_t, vm_page_t *, int);
104 static void dead_pager_putpages (vm_object_t, vm_page_t *, int, int, int *);
105 static boolean_t dead_pager_haspage (vm_object_t, vm_pindex_t);
106 static void dead_pager_dealloc (vm_object_t);
109 dead_pager_getpage(vm_object_t obj, vm_page_t *mpp, int seqaccess)
111 return VM_PAGER_FAIL;
115 dead_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
120 for (i = 0; i < count; i++) {
121 rtvals[i] = VM_PAGER_AGAIN;
126 dead_pager_haspage(vm_object_t object, vm_pindex_t pindex)
132 dead_pager_dealloc(vm_object_t object)
134 KKASSERT(object->swblock_count == 0);
138 static struct pagerops deadpagerops = {
145 struct pagerops *pagertab[] = {
146 &defaultpagerops, /* OBJT_DEFAULT */
147 &swappagerops, /* OBJT_SWAP */
148 &vnodepagerops, /* OBJT_VNODE */
149 &devicepagerops, /* OBJT_DEVICE */
150 &physpagerops, /* OBJT_PHYS */
151 &deadpagerops /* OBJT_DEAD */
154 int npagers = sizeof(pagertab) / sizeof(pagertab[0]);
157 * Kernel address space for mapping pages.
158 * Used by pagers where KVAs are needed for IO.
160 * XXX needs to be large enough to support the number of pending async
161 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size
162 * (MAXPHYS == 64k) if you want to get the most efficiency.
164 #define PAGER_MAP_SIZE (8 * 1024 * 1024)
166 int pager_map_size = PAGER_MAP_SIZE;
167 struct vm_map pager_map;
169 static int bswneeded;
170 static vm_offset_t swapbkva; /* swap buffers kva */
171 static TAILQ_HEAD(swqueue, buf) bswlist;
172 static struct spinlock bswspin = SPINLOCK_INITIALIZER(&bswspin);
175 vm_pager_init(void *arg __unused)
178 * Initialize the swap buffer list.
180 TAILQ_INIT(&bswlist);
182 SYSINIT(vm_mem, SI_BOOT1_VM, SI_ORDER_SECOND, vm_pager_init, NULL)
185 vm_pager_bufferinit(void)
191 * Reserve KVM space for pbuf data.
193 swapbkva = kmem_alloc_pageable(&pager_map, nswbuf * MAXPHYS);
195 panic("Not enough pager_map VM space for physical buffers");
198 * Initial pbuf setup.
201 for (i = 0; i < nswbuf; ++i, ++bp) {
202 bp->b_kvabase = (caddr_t)((intptr_t)i * MAXPHYS) + swapbkva;
203 bp->b_kvasize = MAXPHYS;
204 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist);
210 * Allow the clustering code to use half of our pbufs.
212 cluster_pbuf_freecnt = nswbuf / 2;
216 vm_pager_deallocate(vm_object_t object)
218 (*pagertab[object->type]->pgo_dealloc) (object);
222 * vm_pager_get_pages() - inline, see vm/vm_pager.h
223 * vm_pager_put_pages() - inline, see vm/vm_pager.h
224 * vm_pager_has_page() - inline, see vm/vm_pager.h
225 * vm_pager_page_inserted() - inline, see vm/vm_pager.h
226 * vm_pager_page_removed() - inline, see vm/vm_pager.h
233 * Called by pageout daemon before going back to sleep.
234 * Gives pagers a chance to clean up any completed async pageing
240 struct pagerops **pgops;
242 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
243 if (pgops && ((*pgops)->pgo_sync != NULL))
244 (*(*pgops)->pgo_sync) ();
250 * Initialize a physical buffer.
253 initpbuf(struct buf *bp)
255 bp->b_qindex = 0; /* BQUEUE_NONE */
256 bp->b_data = bp->b_kvabase;
257 bp->b_flags = B_PAGING;
258 bp->b_cmd = BUF_CMD_DONE;
261 bp->b_bufsize = MAXPHYS;
263 xio_init(&bp->b_xio);
264 BUF_LOCK(bp, LK_EXCLUSIVE);
268 * Allocate a physical buffer
270 * There are a limited number (nswbuf) of physical buffers. We need
271 * to make sure that no single subsystem is able to hog all of them,
272 * so each subsystem implements a counter which is typically initialized
273 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and
274 * increments it on release, and blocks if the counter hits zero. A
275 * subsystem may initialize the counter to -1 to disable the feature,
276 * but it must still be sure to match up all uses of getpbuf() with
277 * relpbuf() using the same variable.
279 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed
280 * relatively soon when the rest of the subsystems get smart about it. XXX
285 getpbuf(int *pfreecnt)
289 spin_lock_wr(&bswspin);
293 while (*pfreecnt == 0)
294 ssleep(pfreecnt, &bswspin, 0, "wswbuf0", 0);
297 /* get a bp from the swap buffer header pool */
298 if ((bp = TAILQ_FIRST(&bswlist)) != NULL)
301 ssleep(&bswneeded, &bswspin, 0, "wswbuf1", 0);
302 /* loop in case someone else grabbed one */
304 TAILQ_REMOVE(&bswlist, bp, b_freelist);
308 spin_unlock_wr(&bswspin);
311 KKASSERT(dsched_is_clear_buf_priv(bp));
316 * Allocate a physical buffer, if one is available.
318 * Note that there is no NULL hack here - all subsystems using this
319 * call understand how to use pfreecnt.
324 trypbuf(int *pfreecnt)
328 spin_lock_wr(&bswspin);
330 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) {
331 spin_unlock_wr(&bswspin);
334 TAILQ_REMOVE(&bswlist, bp, b_freelist);
337 spin_unlock_wr(&bswspin);
345 * Release a physical buffer
347 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed
348 * relatively soon when the rest of the subsystems get smart about it. XXX
353 relpbuf(struct buf *bp, int *pfreecnt)
356 int wake_freecnt = 0;
358 KKASSERT(bp->b_flags & B_PAGING);
361 spin_lock_wr(&bswspin);
364 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist);
370 if (++*pfreecnt == 1)
374 spin_unlock_wr(&bswspin);