1 /*
2 * (MPSAFE)
3 *
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * The Mach Operating System project at Carnegie-Mellon University.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
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. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94
35 *
36 *
37 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
38 * All rights reserved.
39 *
40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
41 *
42 * Permission to use, copy, modify and distribute this software and
43 * its documentation is hereby granted, provided that both the copyright
44 * notice and this permission notice appear in all copies of the
45 * software, derivative works or modified versions, and any portions
46 * thereof, and that both notices appear in supporting documentation.
47 *
48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
51 *
52 * Carnegie Mellon requests users of this software to return to
53 *
54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
55 * School of Computer Science
56 * Carnegie Mellon University
57 * Pittsburgh PA 15213-3890
58 *
59 * any improvements or extensions that they make and grant Carnegie the
60 * rights to redistribute these changes.
61 *
62 * $FreeBSD: src/sys/vm/vm_pager.c,v 1.54.2.2 2001/11/18 07:11:00 dillon Exp $
63 */
64
65 /*
66 * Paging space routine stubs. Emulates a matchmaker-like interface
67 * for builtin pagers.
68 */
69
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/kernel.h>
73 #include <sys/vnode.h>
74 #include <sys/buf.h>
75 #include <sys/ucred.h>
76 #include <sys/dsched.h>
77 #include <sys/proc.h>
78 #include <sys/sysctl.h>
79
80 #include <vm/vm.h>
81 #include <vm/vm_param.h>
82 #include <vm/vm_kern.h>
83 #include <vm/vm_object.h>
84 #include <vm/vm_page.h>
85 #include <vm/vm_pager.h>
86 #include <vm/vm_extern.h>
87
88 #include <sys/buf2.h>
89 #include <vm/vm_page2.h>
90
91 static pgo_dealloc_t dead_pager_dealloc;
92 static pgo_getpage_t dead_pager_getpage;
93 static pgo_putpages_t dead_pager_putpages;
94 static pgo_haspage_t dead_pager_haspage;
95
96 static struct pagerops deadpagerops = {
97 .pgo_dealloc = dead_pager_dealloc,
98 .pgo_getpage = dead_pager_getpage,
99 .pgo_putpages = dead_pager_putpages,
100 .pgo_haspage = dead_pager_haspage
101 };
102
103 extern struct pagerops defaultpagerops;
104 extern struct pagerops swappagerops;
105 extern struct pagerops vnodepagerops;
106 extern struct pagerops devicepagerops;
107 extern struct pagerops physpagerops;
108
109 /*
110 * No requirements.
111 */
112 static int
dead_pager_getpage(vm_object_t obj,vm_pindex_t pindex,vm_page_t * mpp,int seqaccess)113 dead_pager_getpage(vm_object_t obj, vm_pindex_t pindex,
114 vm_page_t *mpp, int seqaccess)
115 {
116 return VM_PAGER_FAIL;
117 }
118
119 /*
120 * No requirements.
121 */
122 static void
dead_pager_putpages(vm_object_t object,vm_page_t * m,int count,int flags,int * rtvals)123 dead_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
124 int *rtvals)
125 {
126 int i;
127
128 for (i = 0; i < count; i++) {
129 rtvals[i] = VM_PAGER_AGAIN;
130 }
131 }
132
133 /*
134 * No requirements.
135 */
136 static boolean_t
dead_pager_haspage(vm_object_t object,vm_pindex_t pindex)137 dead_pager_haspage(vm_object_t object, vm_pindex_t pindex)
138 {
139 return FALSE;
140 }
141
142 /*
143 * No requirements.
144 */
145 static void
dead_pager_dealloc(vm_object_t object)146 dead_pager_dealloc(vm_object_t object)
147 {
148 KKASSERT(object->swblock_count == 0);
149 return;
150 }
151
152 struct pagerops *pagertab[] = {
153 &defaultpagerops, /* OBJT_DEFAULT */
154 &swappagerops, /* OBJT_SWAP */
155 &vnodepagerops, /* OBJT_VNODE */
156 &devicepagerops, /* OBJT_DEVICE */
157 &devicepagerops, /* OBJT_MGTDEVICE */
158 &physpagerops, /* OBJT_PHYS */
159 &deadpagerops /* OBJT_DEAD */
160 };
161
162 /*
163 * Kernel address space for mapping pages.
164 * Used by pagers where KVAs are needed for IO.
165 *
166 * XXX needs to be large enough to support the number of pending async
167 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size
168 * (MAXPHYS == 64k) if you want to get the most efficiency.
169 */
170 #define PAGER_MAP_SIZE (8 * 1024 * 1024)
171
172 #define BSWHSIZE 16
173 #define BSWHMASK (BSWHSIZE - 1)
174
175 TAILQ_HEAD(swqueue, buf);
176
177 int pager_map_size = PAGER_MAP_SIZE;
178
179 static struct vm_map pager_map_store;
180 struct vm_map *pager_map = &pager_map_store;
181
182 static vm_offset_t swapbkva_mem; /* swap buffers kva */
183 static vm_offset_t swapbkva_kva; /* swap buffers kva */
184 static struct swqueue bswlist_mem[BSWHSIZE]; /* with preallocated memory */
185 static struct swqueue bswlist_kva[BSWHSIZE]; /* with kva */
186 static struct swqueue bswlist_raw[BSWHSIZE]; /* without kva */
187 static struct spinlock bswspin_mem[BSWHSIZE];
188 static struct spinlock bswspin_kva[BSWHSIZE];
189 static struct spinlock bswspin_raw[BSWHSIZE];
190 static int pbuf_raw_count;
191 static int pbuf_kva_count;
192 static int pbuf_mem_count;
193
194 SYSCTL_INT(_vm, OID_AUTO, pbuf_raw_count, CTLFLAG_RD, &pbuf_raw_count, 0,
195 "Kernel pbuf raw reservations");
196 SYSCTL_INT(_vm, OID_AUTO, pbuf_kva_count, CTLFLAG_RD, &pbuf_kva_count, 0,
197 "Kernel pbuf kva reservations");
198 SYSCTL_INT(_vm, OID_AUTO, pbuf_mem_count, CTLFLAG_RD, &pbuf_mem_count, 0,
199 "Kernel pbuf mem reservations");
200
201 /*
202 * Initialize the swap buffer list.
203 *
204 * Called from the low level boot code only.
205 */
206 static void
vm_pager_init(void * arg __unused)207 vm_pager_init(void *arg __unused)
208 {
209 int i;
210
211 for (i = 0; i < BSWHSIZE; ++i) {
212 TAILQ_INIT(&bswlist_mem[i]);
213 TAILQ_INIT(&bswlist_kva[i]);
214 TAILQ_INIT(&bswlist_raw[i]);
215 spin_init(&bswspin_mem[i], "bswmem");
216 spin_init(&bswspin_kva[i], "bswkva");
217 spin_init(&bswspin_raw[i], "bswraw");
218 }
219 }
220 SYSINIT(vm_mem, SI_BOOT1_VM, SI_ORDER_SECOND, vm_pager_init, NULL);
221
222 /*
223 * Called from the low level boot code only.
224 */
225 static
226 void
vm_pager_bufferinit(void * dummy __unused)227 vm_pager_bufferinit(void *dummy __unused)
228 {
229 struct buf *bp;
230 long i;
231
232 /*
233 * Reserve KVM space for pbuf data.
234 */
235 swapbkva_mem = kmem_alloc_pageable(pager_map, nswbuf_mem * MAXPHYS,
236 VM_SUBSYS_BUFDATA);
237 if (!swapbkva_mem)
238 panic("Not enough pager_map VM space for physical buffers");
239 swapbkva_kva = kmem_alloc_pageable(pager_map, nswbuf_kva * MAXPHYS,
240 VM_SUBSYS_BUFDATA);
241 if (!swapbkva_kva)
242 panic("Not enough pager_map VM space for physical buffers");
243
244 /*
245 * Initial pbuf setup.
246 *
247 * mem - These pbufs have permanently allocated memory
248 * kva - These pbufs have unallocated kva reservations
249 * raw - These pbufs have no kva reservations
250 */
251
252 /*
253 * Buffers with pre-allocated kernel memory can be convenient for
254 * copyin/copyout because no SMP page invalidation or other pmap
255 * operations are needed.
256 */
257 bp = swbuf_mem;
258 for (i = 0; i < nswbuf_mem; ++i, ++bp) {
259 vm_page_t m;
260 vm_pindex_t pg;
261 int j;
262
263 bp->b_kvabase = (caddr_t)((intptr_t)i * MAXPHYS) + swapbkva_mem;
264 bp->b_kvasize = MAXPHYS;
265 bp->b_swindex = i & BSWHMASK;
266 bp->b_cpumask = smp_active_mask;
267 BUF_LOCKINIT(bp);
268 buf_dep_init(bp);
269 TAILQ_INSERT_HEAD(&bswlist_mem[i & BSWHMASK], bp, b_freelist);
270 atomic_add_int(&pbuf_mem_count, 1);
271 bp->b_data = bp->b_kvabase;
272 bp->b_bcount = MAXPHYS;
273 bp->b_xio.xio_pages = bp->b_xio.xio_internal_pages;
274
275 pg = (vm_offset_t)bp->b_kvabase >> PAGE_SHIFT;
276 vm_object_hold(kernel_object);
277 for (j = 0; j < MAXPHYS / PAGE_SIZE; ++j) {
278 m = vm_page_alloc(kernel_object, pg, VM_ALLOC_NORMAL |
279 VM_ALLOC_SYSTEM);
280 KKASSERT(m != NULL);
281 bp->b_xio.xio_internal_pages[j] = m;
282 vm_page_wire(m);
283 /* early boot, no other cpus running yet */
284 pmap_kenter_noinval(pg * PAGE_SIZE, VM_PAGE_TO_PHYS(m));
285 cpu_invlpg((void *)(pg * PAGE_SIZE));
286 vm_page_wakeup(m);
287 ++pg;
288 }
289 vm_object_drop(kernel_object);
290 bp->b_xio.xio_npages = j;
291 }
292
293 /*
294 * Buffers with pre-assigned KVA bases. The KVA has no memory pages
295 * assigned to it. Saves the caller from having to reserve KVA for
296 * the page map.
297 */
298 bp = swbuf_kva;
299 for (i = 0; i < nswbuf_kva; ++i, ++bp) {
300 bp->b_kvabase = (caddr_t)((intptr_t)i * MAXPHYS) + swapbkva_kva;
301 bp->b_kvasize = MAXPHYS;
302 bp->b_swindex = i & BSWHMASK;
303 BUF_LOCKINIT(bp);
304 buf_dep_init(bp);
305 TAILQ_INSERT_HEAD(&bswlist_kva[i & BSWHMASK], bp, b_freelist);
306 atomic_add_int(&pbuf_kva_count, 1);
307 }
308
309 /*
310 * RAW buffers with no KVA mappings.
311 *
312 * NOTE: We use KM_NOTLBSYNC here to reduce unnecessary IPIs
313 * during startup, which can really slow down emulated
314 * systems.
315 */
316 nswbuf_raw = nbuf * 2;
317 swbuf_raw = (void *)kmem_alloc3(kernel_map,
318 round_page(nswbuf_raw * sizeof(struct buf)),
319 VM_SUBSYS_BUFDATA,
320 KM_NOTLBSYNC);
321 smp_invltlb();
322 bp = swbuf_raw;
323 for (i = 0; i < nswbuf_raw; ++i, ++bp) {
324 bp->b_swindex = i & BSWHMASK;
325 BUF_LOCKINIT(bp);
326 buf_dep_init(bp);
327 TAILQ_INSERT_HEAD(&bswlist_raw[i & BSWHMASK], bp, b_freelist);
328 atomic_add_int(&pbuf_raw_count, 1);
329 }
330 }
331
332 SYSINIT(do_vmpg, SI_BOOT2_MACHDEP, SI_ORDER_FIRST, vm_pager_bufferinit, NULL);
333
334 /*
335 * No requirements.
336 */
337 void
vm_pager_deallocate(vm_object_t object)338 vm_pager_deallocate(vm_object_t object)
339 {
340 (*pagertab[object->type]->pgo_dealloc) (object);
341 }
342
343 /*
344 * vm_pager_get_pages() - inline, see vm/vm_pager.h
345 * vm_pager_put_pages() - inline, see vm/vm_pager.h
346 * vm_pager_has_page() - inline, see vm/vm_pager.h
347 * vm_pager_page_inserted() - inline, see vm/vm_pager.h
348 * vm_pager_page_removed() - inline, see vm/vm_pager.h
349 */
350
351 /*
352 * Search the specified pager object list for an object with the
353 * specified handle. If an object with the specified handle is found,
354 * increase its reference count and return it. Otherwise, return NULL.
355 *
356 * The pager object list must be locked.
357 */
358 vm_object_t
vm_pager_object_lookup(struct pagerlst * pg_list,void * handle)359 vm_pager_object_lookup(struct pagerlst *pg_list, void *handle)
360 {
361 vm_object_t object;
362
363 TAILQ_FOREACH(object, pg_list, pager_object_entry) {
364 if (object->handle == handle) {
365 VM_OBJECT_LOCK(object);
366 if ((object->flags & OBJ_DEAD) == 0) {
367 vm_object_reference_locked(object);
368 VM_OBJECT_UNLOCK(object);
369 break;
370 }
371 VM_OBJECT_UNLOCK(object);
372 }
373 }
374 return (object);
375 }
376
377 /*
378 * Initialize a physical buffer.
379 *
380 * No requirements.
381 */
382 static void
initpbuf(struct buf * bp)383 initpbuf(struct buf *bp)
384 {
385 bp->b_qindex = 0; /* BQUEUE_NONE */
386 bp->b_data = bp->b_kvabase; /* NULL if pbuf sans kva */
387 bp->b_flags = B_PAGING;
388 bp->b_cmd = BUF_CMD_DONE;
389 bp->b_error = 0;
390 bp->b_bcount = 0;
391 bp->b_bufsize = MAXPHYS;
392 initbufbio(bp);
393 xio_init(&bp->b_xio);
394 BUF_LOCK(bp, LK_EXCLUSIVE);
395 }
396
397 /*
398 * Allocate a physical buffer
399 *
400 * If (pfreecnt != NULL) then *pfreecnt will be decremented on return and
401 * the function will block while it is <= 0.
402 *
403 * Physical buffers can be with or without KVA space reserved. There
404 * are severe limitations on the ones with KVA reserved, and fewer
405 * limitations on the ones without. getpbuf() gets one without,
406 * getpbuf_kva() gets one with.
407 *
408 * No requirements.
409 */
410 struct buf *
getpbuf(int * pfreecnt)411 getpbuf(int *pfreecnt)
412 {
413 struct buf *bp;
414 int iter;
415 int loops;
416
417 for (;;) {
418 while (pfreecnt && *pfreecnt <= 0) {
419 tsleep_interlock(pfreecnt, 0);
420 if ((int)atomic_fetchadd_int(pfreecnt, 0) <= 0)
421 tsleep(pfreecnt, PINTERLOCKED, "wswbuf0", 0);
422 }
423 if (pbuf_raw_count <= 0) {
424 tsleep_interlock(&pbuf_raw_count, 0);
425 if ((int)atomic_fetchadd_int(&pbuf_raw_count, 0) <= 0)
426 tsleep(&pbuf_raw_count, PINTERLOCKED,
427 "wswbuf1", 0);
428 continue;
429 }
430 iter = mycpuid & BSWHMASK;
431 for (loops = BSWHSIZE; loops; --loops) {
432 if (TAILQ_FIRST(&bswlist_raw[iter]) == NULL) {
433 iter = (iter + 1) & BSWHMASK;
434 continue;
435 }
436 spin_lock(&bswspin_raw[iter]);
437 if ((bp = TAILQ_FIRST(&bswlist_raw[iter])) == NULL) {
438 spin_unlock(&bswspin_raw[iter]);
439 iter = (iter + 1) & BSWHMASK;
440 continue;
441 }
442 TAILQ_REMOVE(&bswlist_raw[iter], bp, b_freelist);
443 atomic_add_int(&pbuf_raw_count, -1);
444 if (pfreecnt)
445 atomic_add_int(pfreecnt, -1);
446 spin_unlock(&bswspin_raw[iter]);
447 initpbuf(bp);
448
449 return bp;
450 }
451 }
452 /* not reached */
453 }
454
455 struct buf *
getpbuf_kva(int * pfreecnt)456 getpbuf_kva(int *pfreecnt)
457 {
458 struct buf *bp;
459 int iter;
460 int loops;
461
462 for (;;) {
463 while (pfreecnt && *pfreecnt <= 0) {
464 tsleep_interlock(pfreecnt, 0);
465 if ((int)atomic_fetchadd_int(pfreecnt, 0) <= 0)
466 tsleep(pfreecnt, PINTERLOCKED, "wswbuf2", 0);
467 }
468 if (pbuf_kva_count <= 0) {
469 tsleep_interlock(&pbuf_kva_count, 0);
470 if ((int)atomic_fetchadd_int(&pbuf_kva_count, 0) <= 0)
471 tsleep(&pbuf_kva_count, PINTERLOCKED,
472 "wswbuf3", 0);
473 continue;
474 }
475 iter = mycpuid & BSWHMASK;
476 for (loops = BSWHSIZE; loops; --loops) {
477 if (TAILQ_FIRST(&bswlist_kva[iter]) == NULL) {
478 iter = (iter + 1) & BSWHMASK;
479 continue;
480 }
481 spin_lock(&bswspin_kva[iter]);
482 if ((bp = TAILQ_FIRST(&bswlist_kva[iter])) == NULL) {
483 spin_unlock(&bswspin_kva[iter]);
484 iter = (iter + 1) & BSWHMASK;
485 continue;
486 }
487 TAILQ_REMOVE(&bswlist_kva[iter], bp, b_freelist);
488 atomic_add_int(&pbuf_kva_count, -1);
489 if (pfreecnt)
490 atomic_add_int(pfreecnt, -1);
491 spin_unlock(&bswspin_kva[iter]);
492 initpbuf(bp);
493
494 return bp;
495 }
496 }
497 /* not reached */
498 }
499
500 /*
501 * Allocate a pbuf with kernel memory already preallocated. Caller must
502 * not change the mapping.
503 */
504 struct buf *
getpbuf_mem(int * pfreecnt)505 getpbuf_mem(int *pfreecnt)
506 {
507 struct buf *bp;
508 int iter;
509 int loops;
510
511 for (;;) {
512 while (pfreecnt && *pfreecnt <= 0) {
513 tsleep_interlock(pfreecnt, 0);
514 if ((int)atomic_fetchadd_int(pfreecnt, 0) <= 0)
515 tsleep(pfreecnt, PINTERLOCKED, "wswbuf4", 0);
516 }
517 if (pbuf_mem_count <= 0) {
518 tsleep_interlock(&pbuf_mem_count, 0);
519 if ((int)atomic_fetchadd_int(&pbuf_mem_count, 0) <= 0)
520 tsleep(&pbuf_mem_count, PINTERLOCKED,
521 "wswbuf5", 0);
522 continue;
523 }
524 iter = mycpuid & BSWHMASK;
525 for (loops = BSWHSIZE; loops; --loops) {
526 if (TAILQ_FIRST(&bswlist_mem[iter]) == NULL) {
527 iter = (iter + 1) & BSWHMASK;
528 continue;
529 }
530 spin_lock(&bswspin_mem[iter]);
531 if ((bp = TAILQ_FIRST(&bswlist_mem[iter])) == NULL) {
532 spin_unlock(&bswspin_mem[iter]);
533 iter = (iter + 1) & BSWHMASK;
534 continue;
535 }
536 TAILQ_REMOVE(&bswlist_mem[iter], bp, b_freelist);
537 atomic_add_int(&pbuf_mem_count, -1);
538 if (pfreecnt)
539 atomic_add_int(pfreecnt, -1);
540 spin_unlock(&bswspin_mem[iter]);
541 initpbuf(bp);
542
543 return bp;
544 }
545 }
546 /* not reached */
547 }
548
549 /*
550 * Allocate a physical buffer, if one is available.
551 *
552 * Note that there is no NULL hack here - all subsystems using this
553 * call are required to use a non-NULL pfreecnt.
554 *
555 * No requirements.
556 */
557 struct buf *
trypbuf(int * pfreecnt)558 trypbuf(int *pfreecnt)
559 {
560 struct buf *bp;
561 int iter = mycpuid & BSWHMASK;
562 int loops;
563
564 for (loops = BSWHSIZE; loops; --loops) {
565 if (*pfreecnt <= 0 || TAILQ_FIRST(&bswlist_raw[iter]) == NULL) {
566 iter = (iter + 1) & BSWHMASK;
567 continue;
568 }
569 spin_lock(&bswspin_raw[iter]);
570 if (*pfreecnt <= 0 ||
571 (bp = TAILQ_FIRST(&bswlist_raw[iter])) == NULL) {
572 spin_unlock(&bswspin_raw[iter]);
573 iter = (iter + 1) & BSWHMASK;
574 continue;
575 }
576 TAILQ_REMOVE(&bswlist_raw[iter], bp, b_freelist);
577 atomic_add_int(&pbuf_raw_count, -1);
578 atomic_add_int(pfreecnt, -1);
579
580 spin_unlock(&bswspin_raw[iter]);
581
582 initpbuf(bp);
583
584 return bp;
585 }
586 return NULL;
587 }
588
589 struct buf *
trypbuf_kva(int * pfreecnt)590 trypbuf_kva(int *pfreecnt)
591 {
592 struct buf *bp;
593 int iter = mycpuid & BSWHMASK;
594 int loops;
595
596 for (loops = BSWHSIZE; loops; --loops) {
597 if (*pfreecnt <= 0 || TAILQ_FIRST(&bswlist_kva[iter]) == NULL) {
598 iter = (iter + 1) & BSWHMASK;
599 continue;
600 }
601 spin_lock(&bswspin_kva[iter]);
602 if (*pfreecnt <= 0 ||
603 (bp = TAILQ_FIRST(&bswlist_kva[iter])) == NULL) {
604 spin_unlock(&bswspin_kva[iter]);
605 iter = (iter + 1) & BSWHMASK;
606 continue;
607 }
608 TAILQ_REMOVE(&bswlist_kva[iter], bp, b_freelist);
609 atomic_add_int(&pbuf_kva_count, -1);
610 atomic_add_int(pfreecnt, -1);
611
612 spin_unlock(&bswspin_kva[iter]);
613
614 initpbuf(bp);
615
616 return bp;
617 }
618 return NULL;
619 }
620
621 /*
622 * Release a physical buffer
623 *
624 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed
625 * relatively soon when the rest of the subsystems get smart about it. XXX
626 *
627 * No requirements.
628 */
629 void
relpbuf(struct buf * bp,int * pfreecnt)630 relpbuf(struct buf *bp, int *pfreecnt)
631 {
632 int wake = 0;
633 int wake_free = 0;
634 int iter = bp->b_swindex;
635
636 KKASSERT(bp->b_flags & B_PAGING);
637 dsched_buf_exit(bp);
638
639 BUF_UNLOCK(bp);
640
641 if (bp >= swbuf_mem && bp < &swbuf_mem[nswbuf_mem]) {
642 KKASSERT(bp->b_kvabase);
643 spin_lock(&bswspin_mem[iter]);
644 TAILQ_INSERT_HEAD(&bswlist_mem[iter], bp, b_freelist);
645 if (atomic_fetchadd_int(&pbuf_mem_count, 1) == nswbuf_mem / 4)
646 wake = 1;
647 if (pfreecnt) {
648 if (atomic_fetchadd_int(pfreecnt, 1) == 1)
649 wake_free = 1;
650 }
651 spin_unlock(&bswspin_mem[iter]);
652 if (wake)
653 wakeup(&pbuf_mem_count);
654 } else if (bp >= swbuf_kva && bp < &swbuf_kva[nswbuf_kva]) {
655 KKASSERT(bp->b_kvabase);
656 CPUMASK_ASSZERO(bp->b_cpumask);
657 spin_lock(&bswspin_kva[iter]);
658 TAILQ_INSERT_HEAD(&bswlist_kva[iter], bp, b_freelist);
659 if (atomic_fetchadd_int(&pbuf_kva_count, 1) == nswbuf_kva / 4)
660 wake = 1;
661 if (pfreecnt) {
662 if (atomic_fetchadd_int(pfreecnt, 1) == 1)
663 wake_free = 1;
664 }
665 spin_unlock(&bswspin_kva[iter]);
666 if (wake)
667 wakeup(&pbuf_kva_count);
668 } else {
669 KKASSERT(bp->b_kvabase == NULL);
670 KKASSERT(bp >= swbuf_raw && bp < &swbuf_raw[nswbuf_raw]);
671 CPUMASK_ASSZERO(bp->b_cpumask);
672 spin_lock(&bswspin_raw[iter]);
673 TAILQ_INSERT_HEAD(&bswlist_raw[iter], bp, b_freelist);
674 if (atomic_fetchadd_int(&pbuf_raw_count, 1) == nswbuf_raw / 4)
675 wake = 1;
676 if (pfreecnt) {
677 if (atomic_fetchadd_int(pfreecnt, 1) == 1)
678 wake_free = 1;
679 }
680 spin_unlock(&bswspin_raw[iter]);
681 if (wake)
682 wakeup(&pbuf_raw_count);
683 }
684 if (wake_free)
685 wakeup(pfreecnt);
686 }
687
688 void
pbuf_adjcount(int * pfreecnt,int n)689 pbuf_adjcount(int *pfreecnt, int n)
690 {
691 if (n) {
692 atomic_add_int(pfreecnt, n);
693 wakeup(pfreecnt);
694 }
695 }
696