BUF/BIO work, for removing the requirement of KVA mappings for I/O
[dragonfly.git] / sys / vm / vm_pager.c
CommitLineData
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1/*
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
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.
23 *
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
34 * SUCH DAMAGE.
35 *
36 * from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94
37 *
38 *
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
41 *
42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
43 *
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.
49 *
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.
53 *
54 * Carnegie Mellon requests users of this software to return to
55 *
56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
60 *
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
63 *
64 * $FreeBSD: src/sys/vm/vm_pager.c,v 1.54.2.2 2001/11/18 07:11:00 dillon Exp $
54f51aeb 65 * $DragonFly: src/sys/vm/vm_pager.c,v 1.11 2004/07/14 03:10:17 hmp Exp $
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66 */
67
68/*
69 * Paging space routine stubs. Emulates a matchmaker-like interface
70 * for builtin pagers.
71 */
72
73#include <sys/param.h>
74#include <sys/systm.h>
75#include <sys/kernel.h>
76#include <sys/vnode.h>
77#include <sys/buf.h>
78#include <sys/ucred.h>
79#include <sys/malloc.h>
80#include <sys/proc.h>
81
82#include <vm/vm.h>
83#include <vm/vm_param.h>
84#include <vm/vm_object.h>
85#include <vm/vm_page.h>
86#include <vm/vm_pager.h>
87#include <vm/vm_extern.h>
88
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89#include <sys/buf2.h>
90
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91MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data");
92
93extern struct pagerops defaultpagerops;
94extern struct pagerops swappagerops;
95extern struct pagerops vnodepagerops;
96extern struct pagerops devicepagerops;
97extern struct pagerops physpagerops;
98
99int cluster_pbuf_freecnt = -1; /* unlimited to begin with */
100
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101static int dead_pager_getpages (vm_object_t, vm_page_t *, int, int);
102static vm_object_t dead_pager_alloc (void *, vm_ooffset_t, vm_prot_t,
103 vm_ooffset_t);
104static void dead_pager_putpages (vm_object_t, vm_page_t *, int, int, int *);
105static boolean_t dead_pager_haspage (vm_object_t, vm_pindex_t, int *, int *);
106static void dead_pager_dealloc (vm_object_t);
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107
108static int
57e43348 109dead_pager_getpages(vm_object_t obj, vm_page_t *ma, int count, int req)
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110{
111 return VM_PAGER_FAIL;
112}
113
114static vm_object_t
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115dead_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
116 vm_ooffset_t off)
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117{
118 return NULL;
119}
120
121static void
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122dead_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
123 int *rtvals)
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124{
125 int i;
126
127 for (i = 0; i < count; i++) {
128 rtvals[i] = VM_PAGER_AGAIN;
129 }
130}
131
132static int
57e43348 133dead_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *prev, int *next)
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134{
135 if (prev)
136 *prev = 0;
137 if (next)
138 *next = 0;
139 return FALSE;
140}
141
142static void
57e43348 143dead_pager_dealloc(vm_object_t object)
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144{
145 return;
146}
147
148static struct pagerops deadpagerops = {
149 NULL,
150 dead_pager_alloc,
151 dead_pager_dealloc,
152 dead_pager_getpages,
153 dead_pager_putpages,
154 dead_pager_haspage,
155 NULL
156};
157
158struct pagerops *pagertab[] = {
159 &defaultpagerops, /* OBJT_DEFAULT */
160 &swappagerops, /* OBJT_SWAP */
161 &vnodepagerops, /* OBJT_VNODE */
162 &devicepagerops, /* OBJT_DEVICE */
163 &physpagerops, /* OBJT_PHYS */
164 &deadpagerops /* OBJT_DEAD */
165};
166
167int npagers = sizeof(pagertab) / sizeof(pagertab[0]);
168
169/*
170 * Kernel address space for mapping pages.
171 * Used by pagers where KVAs are needed for IO.
172 *
173 * XXX needs to be large enough to support the number of pending async
174 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size
175 * (MAXPHYS == 64k) if you want to get the most efficiency.
176 */
177#define PAGER_MAP_SIZE (8 * 1024 * 1024)
178
179int pager_map_size = PAGER_MAP_SIZE;
180vm_map_t pager_map;
181static int bswneeded;
182static vm_offset_t swapbkva; /* swap buffers kva */
183
184void
57e43348 185vm_pager_init(void)
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186{
187 struct pagerops **pgops;
188
189 /*
190 * Initialize known pagers
191 */
192 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
193 if (pgops && ((*pgops)->pgo_init != NULL))
194 (*(*pgops)->pgo_init) ();
195}
196
197void
57e43348 198vm_pager_bufferinit(void)
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199{
200 struct buf *bp;
201 int i;
202
203 bp = swbuf;
204 /*
205 * Now set up swap and physical I/O buffer headers.
206 */
207 for (i = 0; i < nswbuf; i++, bp++) {
208 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist);
209 BUF_LOCKINIT(bp);
210 LIST_INIT(&bp->b_dep);
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211 bp->b_xflags = 0;
212 }
213
214 cluster_pbuf_freecnt = nswbuf / 2;
215
216 swapbkva = kmem_alloc_pageable(pager_map, nswbuf * MAXPHYS);
217 if (!swapbkva)
218 panic("Not enough pager_map VM space for physical buffers");
219}
220
221/*
222 * Allocate an instance of a pager of the given type.
223 * Size, protection and offset parameters are passed in for pagers that
224 * need to perform page-level validation (e.g. the device pager).
225 */
226vm_object_t
227vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, vm_prot_t prot,
228 vm_ooffset_t off)
229{
230 struct pagerops *ops;
231
232 ops = pagertab[type];
233 if (ops)
234 return ((*ops->pgo_alloc) (handle, size, prot, off));
235 return (NULL);
236}
237
238void
57e43348 239vm_pager_deallocate(vm_object_t object)
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240{
241 (*pagertab[object->type]->pgo_dealloc) (object);
242}
243
244/*
245 * vm_pager_strategy:
246 *
247 * called with no specific spl
248 * Execute strategy routine directly to pager.
249 */
250
251void
252vm_pager_strategy(vm_object_t object, struct buf *bp)
253{
254 if (pagertab[object->type]->pgo_strategy) {
255 (*pagertab[object->type]->pgo_strategy)(object, bp);
256 } else {
257 bp->b_flags |= B_ERROR;
258 bp->b_error = ENXIO;
259 biodone(bp);
260 }
261}
262
263/*
264 * vm_pager_get_pages() - inline, see vm/vm_pager.h
265 * vm_pager_put_pages() - inline, see vm/vm_pager.h
266 * vm_pager_has_page() - inline, see vm/vm_pager.h
267 * vm_pager_page_inserted() - inline, see vm/vm_pager.h
268 * vm_pager_page_removed() - inline, see vm/vm_pager.h
269 */
270
271#if 0
272/*
273 * vm_pager_sync:
274 *
275 * Called by pageout daemon before going back to sleep.
276 * Gives pagers a chance to clean up any completed async pageing
277 * operations.
278 */
279void
57e43348 280vm_pager_sync(void)
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281{
282 struct pagerops **pgops;
283
284 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
285 if (pgops && ((*pgops)->pgo_sync != NULL))
286 (*(*pgops)->pgo_sync) ();
287}
288
289#endif
290
984263bc 291vm_object_t
57e43348 292vm_pager_object_lookup(struct pagerlst *pg_list, void *handle)
984263bc 293{
5f910b2f 294 vm_object_t object;
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295
296 for (object = TAILQ_FIRST(pg_list); object != NULL; object = TAILQ_NEXT(object,pager_object_list))
297 if (object->handle == handle)
298 return (object);
299 return (NULL);
300}
301
302/*
303 * initialize a physical buffer
304 */
305
306static void
307initpbuf(struct buf *bp)
308{
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309 bp->b_qindex = QUEUE_NONE;
310 bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva;
311 bp->b_kvabase = bp->b_data;
312 bp->b_kvasize = MAXPHYS;
313 bp->b_xflags = 0;
314 bp->b_flags = 0;
315 bp->b_error = 0;
54f51aeb 316 xio_init(&bp->b_xio);
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317 BUF_LOCK(bp, LK_EXCLUSIVE);
318}
319
320/*
321 * allocate a physical buffer
322 *
323 * There are a limited number (nswbuf) of physical buffers. We need
324 * to make sure that no single subsystem is able to hog all of them,
325 * so each subsystem implements a counter which is typically initialized
326 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and
327 * increments it on release, and blocks if the counter hits zero. A
328 * subsystem may initialize the counter to -1 to disable the feature,
329 * but it must still be sure to match up all uses of getpbuf() with
330 * relpbuf() using the same variable.
331 *
332 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed
333 * relatively soon when the rest of the subsystems get smart about it. XXX
334 */
335struct buf *
57e43348 336getpbuf(int *pfreecnt)
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337{
338 int s;
339 struct buf *bp;
340
341 s = splvm();
342
343 for (;;) {
344 if (pfreecnt) {
345 while (*pfreecnt == 0) {
377d4740 346 tsleep(pfreecnt, 0, "wswbuf0", 0);
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347 }
348 }
349
350 /* get a bp from the swap buffer header pool */
351 if ((bp = TAILQ_FIRST(&bswlist)) != NULL)
352 break;
353
354 bswneeded = 1;
377d4740 355 tsleep(&bswneeded, 0, "wswbuf1", 0);
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356 /* loop in case someone else grabbed one */
357 }
358 TAILQ_REMOVE(&bswlist, bp, b_freelist);
359 if (pfreecnt)
360 --*pfreecnt;
361 splx(s);
362
363 initpbuf(bp);
364 return bp;
365}
366
367/*
368 * allocate a physical buffer, if one is available.
369 *
370 * Note that there is no NULL hack here - all subsystems using this
371 * call understand how to use pfreecnt.
372 */
373struct buf *
57e43348 374trypbuf(int *pfreecnt)
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375{
376 int s;
377 struct buf *bp;
378
379 s = splvm();
380 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) {
381 splx(s);
382 return NULL;
383 }
384 TAILQ_REMOVE(&bswlist, bp, b_freelist);
385
386 --*pfreecnt;
387
388 splx(s);
389
390 initpbuf(bp);
391
392 return bp;
393}
394
395/*
396 * release a physical buffer
397 *
398 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed
399 * relatively soon when the rest of the subsystems get smart about it. XXX
400 */
401void
57e43348 402relpbuf(struct buf *bp, int *pfreecnt)
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403{
404 int s;
405
406 s = splvm();
407
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408 if (bp->b_vp)
409 pbrelvp(bp);
410
411 BUF_UNLOCK(bp);
412
413 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist);
414
415 if (bswneeded) {
416 bswneeded = 0;
417 wakeup(&bswneeded);
418 }
419 if (pfreecnt) {
420 if (++*pfreecnt == 1)
421 wakeup(pfreecnt);
422 }
423 splx(s);
424}
425
426/********************************************************
427 * CHAINING FUNCTIONS *
428 ********************************************************
429 *
430 * These functions support recursion of I/O operations
431 * on bp's, typically by chaining one or more 'child' bp's
432 * to the parent. Synchronous, asynchronous, and semi-synchronous
433 * chaining is possible.
434 */
435
436/*
437 * vm_pager_chain_iodone:
438 *
439 * io completion routine for child bp. Currently we fudge a bit
440 * on dealing with b_resid. Since users of these routines may issue
441 * multiple children simultaniously, sequencing of the error can be lost.
442 */
443
444static void
445vm_pager_chain_iodone(struct buf *nbp)
446{
447 struct buf *bp;
448
449 if ((bp = nbp->b_chain.parent) != NULL) {
450 if (nbp->b_flags & B_ERROR) {
451 bp->b_flags |= B_ERROR;
452 bp->b_error = nbp->b_error;
453 } else if (nbp->b_resid != 0) {
454 bp->b_flags |= B_ERROR;
455 bp->b_error = EINVAL;
456 } else {
457 bp->b_resid -= nbp->b_bcount;
458 }
459 nbp->b_chain.parent = NULL;
460 --bp->b_chain.count;
461 if (bp->b_flags & B_WANT) {
462 bp->b_flags &= ~B_WANT;
463 wakeup(bp);
464 }
465 if (!bp->b_chain.count && (bp->b_xflags & BX_AUTOCHAINDONE)) {
466 bp->b_xflags &= ~BX_AUTOCHAINDONE;
467 if (bp->b_resid != 0 && !(bp->b_flags & B_ERROR)) {
468 bp->b_flags |= B_ERROR;
469 bp->b_error = EINVAL;
470 }
471 biodone(bp);
472 }
473 }
474 nbp->b_flags |= B_DONE;
475 nbp->b_flags &= ~B_ASYNC;
476 relpbuf(nbp, NULL);
477}
478
479/*
480 * getchainbuf:
481 *
482 * Obtain a physical buffer and chain it to its parent buffer. When
483 * I/O completes, the parent buffer will be B_SIGNAL'd. Errors are
484 * automatically propogated to the parent
485 *
486 * Since these are brand new buffers, we do not have to clear B_INVAL
487 * and B_ERROR because they are already clear.
488 */
489
490struct buf *
491getchainbuf(struct buf *bp, struct vnode *vp, int flags)
492{
493 struct buf *nbp = getpbuf(NULL);
494
495 nbp->b_chain.parent = bp;
496 ++bp->b_chain.count;
497
498 if (bp->b_chain.count > 4)
499 waitchainbuf(bp, 4, 0);
500
501 nbp->b_flags = B_CALL | (bp->b_flags & B_ORDERED) | flags;
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502 nbp->b_iodone = vm_pager_chain_iodone;
503
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504 if (vp)
505 pbgetvp(vp, nbp);
506 return(nbp);
507}
508
509void
510flushchainbuf(struct buf *nbp)
511{
512 if (nbp->b_bcount) {
513 nbp->b_bufsize = nbp->b_bcount;
514 if ((nbp->b_flags & B_READ) == 0)
515 nbp->b_dirtyend = nbp->b_bcount;
516 BUF_KERNPROC(nbp);
517 VOP_STRATEGY(nbp->b_vp, nbp);
518 } else {
519 biodone(nbp);
520 }
521}
522
523void
524waitchainbuf(struct buf *bp, int count, int done)
525{
526 int s;
527
528 s = splbio();
529 while (bp->b_chain.count > count) {
530 bp->b_flags |= B_WANT;
377d4740 531 tsleep(bp, 0, "bpchain", 0);
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532 }
533 if (done) {
534 if (bp->b_resid != 0 && !(bp->b_flags & B_ERROR)) {
535 bp->b_flags |= B_ERROR;
536 bp->b_error = EINVAL;
537 }
538 biodone(bp);
539 }
540 splx(s);
541}
542
543void
544autochaindone(struct buf *bp)
545{
546 int s;
547
548 s = splbio();
549 if (bp->b_chain.count == 0)
550 biodone(bp);
551 else
552 bp->b_xflags |= BX_AUTOCHAINDONE;
553 splx(s);
554}