4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
8 * The Mach Operating System project at Carnegie-Mellon University.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94
41 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
42 * All rights reserved.
44 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
46 * Permission to use, copy, modify and distribute this software and
47 * its documentation is hereby granted, provided that both the copyright
48 * notice and this permission notice appear in all copies of the
49 * software, derivative works or modified versions, and any portions
50 * thereof, and that both notices appear in supporting documentation.
52 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
53 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
54 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
56 * Carnegie Mellon requests users of this software to return to
58 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
59 * School of Computer Science
60 * Carnegie Mellon University
61 * Pittsburgh PA 15213-3890
63 * any improvements or extensions that they make and grant Carnegie the
64 * rights to redistribute these changes.
66 * $FreeBSD: src/sys/vm/vm_pager.c,v 1.54.2.2 2001/11/18 07:11:00 dillon Exp $
67 * $DragonFly: src/sys/vm/vm_pager.c,v 1.24 2007/11/06 03:50:01 dillon Exp $
71 * Paging space routine stubs. Emulates a matchmaker-like interface
75 #include <sys/param.h>
76 #include <sys/systm.h>
77 #include <sys/kernel.h>
78 #include <sys/vnode.h>
80 #include <sys/ucred.h>
81 #include <sys/malloc.h>
82 #include <sys/dsched.h>
84 #include <sys/sysctl.h>
85 #include <sys/thread2.h>
88 #include <vm/vm_param.h>
89 #include <vm/vm_kern.h>
90 #include <vm/vm_object.h>
91 #include <vm/vm_page.h>
92 #include <vm/vm_pager.h>
93 #include <vm/vm_extern.h>
97 MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data");
99 extern struct pagerops defaultpagerops;
100 extern struct pagerops swappagerops;
101 extern struct pagerops vnodepagerops;
102 extern struct pagerops devicepagerops;
103 extern struct pagerops physpagerops;
105 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */
107 static int dead_pager_getpage (vm_object_t, vm_page_t *, int);
108 static void dead_pager_putpages (vm_object_t, vm_page_t *, int, int, int *);
109 static boolean_t dead_pager_haspage (vm_object_t, vm_pindex_t);
110 static void dead_pager_dealloc (vm_object_t);
116 dead_pager_getpage(vm_object_t obj, vm_page_t *mpp, int seqaccess)
118 return VM_PAGER_FAIL;
125 dead_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
130 for (i = 0; i < count; i++) {
131 rtvals[i] = VM_PAGER_AGAIN;
139 dead_pager_haspage(vm_object_t object, vm_pindex_t pindex)
148 dead_pager_dealloc(vm_object_t object)
150 KKASSERT(object->swblock_count == 0);
154 static struct pagerops deadpagerops = {
161 struct pagerops *pagertab[] = {
162 &defaultpagerops, /* OBJT_DEFAULT */
163 &swappagerops, /* OBJT_SWAP */
164 &vnodepagerops, /* OBJT_VNODE */
165 &devicepagerops, /* OBJT_DEVICE */
166 &physpagerops, /* OBJT_PHYS */
167 &deadpagerops /* OBJT_DEAD */
170 int npagers = sizeof(pagertab) / sizeof(pagertab[0]);
173 * Kernel address space for mapping pages.
174 * Used by pagers where KVAs are needed for IO.
176 * XXX needs to be large enough to support the number of pending async
177 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size
178 * (MAXPHYS == 64k) if you want to get the most efficiency.
180 #define PAGER_MAP_SIZE (8 * 1024 * 1024)
182 TAILQ_HEAD(swqueue, buf);
184 int pager_map_size = PAGER_MAP_SIZE;
185 struct vm_map pager_map;
187 static int bswneeded_raw;
188 static int bswneeded_kva;
189 static int nswbuf_raw;
190 static struct buf *swbuf_raw;
191 static vm_offset_t swapbkva; /* swap buffers kva */
192 static struct swqueue bswlist_raw; /* without kva */
193 static struct swqueue bswlist_kva; /* with kva */
194 static struct spinlock bswspin = SPINLOCK_INITIALIZER(&bswspin);
195 static int pbuf_raw_count;
196 static int pbuf_kva_count;
198 SYSCTL_INT(_vfs, OID_AUTO, pbuf_raw_count, CTLFLAG_RD, &pbuf_raw_count, 0, "");
199 SYSCTL_INT(_vfs, OID_AUTO, pbuf_kva_count, CTLFLAG_RD, &pbuf_kva_count, 0, "");
202 * Initialize the swap buffer list.
204 * Called from the low level boot code only.
207 vm_pager_init(void *arg __unused)
209 TAILQ_INIT(&bswlist_raw);
210 TAILQ_INIT(&bswlist_kva);
212 SYSINIT(vm_mem, SI_BOOT1_VM, SI_ORDER_SECOND, vm_pager_init, NULL)
215 * Called from the low level boot code only.
218 vm_pager_bufferinit(void)
224 * Reserve KVM space for pbuf data.
226 swapbkva = kmem_alloc_pageable(&pager_map, nswbuf * MAXPHYS);
228 panic("Not enough pager_map VM space for physical buffers");
231 * Initial pbuf setup. These pbufs have KVA reservations.
234 for (i = 0; i < nswbuf; ++i, ++bp) {
235 bp->b_kvabase = (caddr_t)((intptr_t)i * MAXPHYS) + swapbkva;
236 bp->b_kvasize = MAXPHYS;
239 TAILQ_INSERT_HEAD(&bswlist_kva, bp, b_freelist);
244 * Initial pbuf setup. These pbufs do not have KVA reservations,
245 * so we can have a lot more of them. These are typically used
246 * to massage low level buf/bio requests.
248 nswbuf_raw = nbuf * 2;
249 swbuf_raw = (void *)kmem_alloc(&kernel_map,
250 round_page(nswbuf_raw * sizeof(struct buf)));
252 for (i = 0; i < nswbuf_raw; ++i, ++bp) {
255 TAILQ_INSERT_HEAD(&bswlist_raw, bp, b_freelist);
260 * Allow the clustering code to use half of our pbufs.
262 cluster_pbuf_freecnt = nswbuf / 2;
269 vm_pager_deallocate(vm_object_t object)
271 (*pagertab[object->type]->pgo_dealloc) (object);
275 * vm_pager_get_pages() - inline, see vm/vm_pager.h
276 * vm_pager_put_pages() - inline, see vm/vm_pager.h
277 * vm_pager_has_page() - inline, see vm/vm_pager.h
278 * vm_pager_page_inserted() - inline, see vm/vm_pager.h
279 * vm_pager_page_removed() - inline, see vm/vm_pager.h
286 * Called by pageout daemon before going back to sleep.
287 * Gives pagers a chance to clean up any completed async pageing
293 struct pagerops **pgops;
295 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
296 if (pgops && ((*pgops)->pgo_sync != NULL))
297 (*(*pgops)->pgo_sync) ();
303 * Initialize a physical buffer.
308 initpbuf(struct buf *bp)
310 bp->b_qindex = 0; /* BQUEUE_NONE */
311 bp->b_data = bp->b_kvabase; /* NULL if pbuf sans kva */
312 bp->b_flags = B_PAGING;
313 bp->b_cmd = BUF_CMD_DONE;
316 bp->b_bufsize = MAXPHYS;
318 xio_init(&bp->b_xio);
319 BUF_LOCK(bp, LK_EXCLUSIVE);
323 * Allocate a physical buffer
325 * There are a limited number (nswbuf) of physical buffers. We need
326 * to make sure that no single subsystem is able to hog all of them,
327 * so each subsystem implements a counter which is typically initialized
328 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and
329 * increments it on release, and blocks if the counter hits zero. A
330 * subsystem may initialize the counter to -1 to disable the feature,
331 * but it must still be sure to match up all uses of getpbuf() with
332 * relpbuf() using the same variable.
334 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed
335 * relatively soon when the rest of the subsystems get smart about it. XXX
337 * Physical buffers can be with or without KVA space reserved. There
338 * are severe limitations on the ones with KVA reserved, and fewer
339 * limitations on the ones without. getpbuf() gets one without,
340 * getpbuf_kva() gets one with.
345 getpbuf(int *pfreecnt)
353 while (*pfreecnt == 0)
354 ssleep(pfreecnt, &bswspin, 0, "wswbuf0", 0);
357 /* get a bp from the swap buffer header pool */
358 if ((bp = TAILQ_FIRST(&bswlist_raw)) != NULL)
361 ssleep(&bswneeded_raw, &bswspin, 0, "wswbuf1", 0);
362 /* loop in case someone else grabbed one */
364 TAILQ_REMOVE(&bswlist_raw, bp, b_freelist);
369 spin_unlock(&bswspin);
372 KKASSERT(dsched_is_clear_buf_priv(bp));
378 getpbuf_kva(int *pfreecnt)
386 while (*pfreecnt == 0)
387 ssleep(pfreecnt, &bswspin, 0, "wswbuf0", 0);
390 /* get a bp from the swap buffer header pool */
391 if ((bp = TAILQ_FIRST(&bswlist_kva)) != NULL)
394 ssleep(&bswneeded_kva, &bswspin, 0, "wswbuf1", 0);
395 /* loop in case someone else grabbed one */
397 TAILQ_REMOVE(&bswlist_kva, bp, b_freelist);
402 spin_unlock(&bswspin);
405 KKASSERT(dsched_is_clear_buf_priv(bp));
411 * Allocate a physical buffer, if one is available.
413 * Note that there is no NULL hack here - all subsystems using this
414 * call understand how to use pfreecnt.
419 trypbuf(int *pfreecnt)
425 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist_raw)) == NULL) {
426 spin_unlock(&bswspin);
429 TAILQ_REMOVE(&bswlist_raw, bp, b_freelist);
433 spin_unlock(&bswspin);
441 trypbuf_kva(int *pfreecnt)
447 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist_kva)) == NULL) {
448 spin_unlock(&bswspin);
451 TAILQ_REMOVE(&bswlist_kva, bp, b_freelist);
455 spin_unlock(&bswspin);
463 * Release a physical buffer
465 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed
466 * relatively soon when the rest of the subsystems get smart about it. XXX
471 relpbuf(struct buf *bp, int *pfreecnt)
473 int wake_bsw_kva = 0;
474 int wake_bsw_raw = 0;
475 int wake_freecnt = 0;
477 KKASSERT(bp->b_flags & B_PAGING);
484 TAILQ_INSERT_HEAD(&bswlist_kva, bp, b_freelist);
487 TAILQ_INSERT_HEAD(&bswlist_raw, bp, b_freelist);
499 if (++*pfreecnt == 1)
502 spin_unlock(&bswspin);
505 wakeup(&bswneeded_kva);
507 wakeup(&bswneeded_raw);