1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include "namespace.h"
33 #include <sys/param.h>
34 #include <sys/queue.h>
35 #include <sys/stat.h>
36
37 #include <errno.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 #include "un-namespace.h"
43
44 #include <db.h>
45
46 #define __MPOOLINTERFACE_PRIVATE
47 #include <mpool.h>
48
49 static BKT *mpool_bkt(MPOOL *);
50 static BKT *mpool_look(MPOOL *, pgno_t);
51 static int mpool_write(MPOOL *, BKT *);
52
53 /*
54 * mpool_open --
55 * Initialize a memory pool.
56 */
57 /* ARGSUSED */
58 MPOOL *
mpool_open(void * key,int fd,pgno_t pagesize,pgno_t maxcache)59 mpool_open(void *key, int fd, pgno_t pagesize, pgno_t maxcache)
60 {
61 struct stat sb;
62 MPOOL *mp;
63 int entry;
64
65 /*
66 * Get information about the file.
67 *
68 * XXX
69 * We don't currently handle pipes, although we should.
70 */
71 if (_fstat(fd, &sb))
72 return (NULL);
73 if (!S_ISREG(sb.st_mode)) {
74 errno = ESPIPE;
75 return (NULL);
76 }
77
78 /* Allocate and initialize the MPOOL cookie. */
79 if ((mp = (MPOOL *)calloc(1, sizeof(MPOOL))) == NULL)
80 return (NULL);
81 TAILQ_INIT(&mp->lqh);
82 for (entry = 0; entry < HASHSIZE; ++entry)
83 TAILQ_INIT(&mp->hqh[entry]);
84 mp->maxcache = maxcache;
85 mp->npages = sb.st_size / pagesize;
86 mp->pagesize = pagesize;
87 mp->fd = fd;
88 return (mp);
89 }
90
91 /*
92 * mpool_filter --
93 * Initialize input/output filters.
94 */
95 void
mpool_filter(MPOOL * mp,void (* pgin)(void *,pgno_t,void *),void (* pgout)(void *,pgno_t,void *),void * pgcookie)96 mpool_filter(MPOOL *mp, void (*pgin) (void *, pgno_t, void *),
97 void (*pgout) (void *, pgno_t, void *), void *pgcookie)
98 {
99 mp->pgin = pgin;
100 mp->pgout = pgout;
101 mp->pgcookie = pgcookie;
102 }
103
104 /*
105 * mpool_new --
106 * Get a new page of memory.
107 */
108 void *
mpool_new(MPOOL * mp,pgno_t * pgnoaddr,u_int flags)109 mpool_new(MPOOL *mp, pgno_t *pgnoaddr, u_int flags)
110 {
111 struct _hqh *head;
112 BKT *bp;
113
114 if (mp->npages == MAX_PAGE_NUMBER) {
115 (void)fprintf(stderr, "mpool_new: page allocation overflow.\n");
116 abort();
117 }
118 #ifdef STATISTICS
119 ++mp->pagenew;
120 #endif
121 /*
122 * Get a BKT from the cache. Assign a new page number, attach
123 * it to the head of the hash chain, the tail of the lru chain,
124 * and return.
125 */
126 if ((bp = mpool_bkt(mp)) == NULL)
127 return (NULL);
128 if (flags == MPOOL_PAGE_REQUEST) {
129 mp->npages++;
130 bp->pgno = *pgnoaddr;
131 } else
132 bp->pgno = *pgnoaddr = mp->npages++;
133
134 bp->flags = MPOOL_PINNED | MPOOL_INUSE;
135
136 head = &mp->hqh[HASHKEY(bp->pgno)];
137 TAILQ_INSERT_HEAD(head, bp, hq);
138 TAILQ_INSERT_TAIL(&mp->lqh, bp, q);
139 return (bp->page);
140 }
141
142 int
mpool_delete(MPOOL * mp,void * page)143 mpool_delete(MPOOL *mp, void *page)
144 {
145 struct _hqh *head;
146 BKT *bp;
147
148 bp = (BKT *)((char *)page - sizeof(BKT));
149
150 #ifdef DEBUG
151 if (!(bp->flags & MPOOL_PINNED)) {
152 (void)fprintf(stderr,
153 "mpool_delete: page %d not pinned\n", bp->pgno);
154 abort();
155 }
156 #endif
157
158 /* Remove from the hash and lru queues. */
159 head = &mp->hqh[HASHKEY(bp->pgno)];
160 TAILQ_REMOVE(head, bp, hq);
161 TAILQ_REMOVE(&mp->lqh, bp, q);
162
163 free(bp);
164 mp->curcache--;
165 return (RET_SUCCESS);
166 }
167
168 /*
169 * mpool_get
170 * Get a page.
171 */
172 /* ARGSUSED */
173 void *
mpool_get(MPOOL * mp,pgno_t pgno,u_int flags)174 mpool_get(MPOOL *mp, pgno_t pgno,
175 u_int flags) /* XXX not used? */
176 {
177 struct _hqh *head;
178 BKT *bp;
179 off_t off;
180 int nr;
181
182 #ifdef STATISTICS
183 ++mp->pageget;
184 #endif
185
186 /* Check for a page that is cached. */
187 if ((bp = mpool_look(mp, pgno)) != NULL) {
188 #ifdef DEBUG
189 if (!(flags & MPOOL_IGNOREPIN) && bp->flags & MPOOL_PINNED) {
190 (void)fprintf(stderr,
191 "mpool_get: page %d already pinned\n", bp->pgno);
192 abort();
193 }
194 #endif
195 /*
196 * Move the page to the head of the hash chain and the tail
197 * of the lru chain.
198 */
199 head = &mp->hqh[HASHKEY(bp->pgno)];
200 TAILQ_REMOVE(head, bp, hq);
201 TAILQ_INSERT_HEAD(head, bp, hq);
202 TAILQ_REMOVE(&mp->lqh, bp, q);
203 TAILQ_INSERT_TAIL(&mp->lqh, bp, q);
204
205 /* Return a pinned page. */
206 bp->flags |= MPOOL_PINNED;
207 return (bp->page);
208 }
209
210 /* Get a page from the cache. */
211 if ((bp = mpool_bkt(mp)) == NULL)
212 return (NULL);
213
214 /* Read in the contents. */
215 off = mp->pagesize * pgno;
216 if ((nr = pread(mp->fd, bp->page, mp->pagesize, off)) != (ssize_t)mp->pagesize) {
217 switch (nr) {
218 case -1:
219 /* errno is set for us by pread(). */
220 free(bp);
221 mp->curcache--;
222 return (NULL);
223 case 0:
224 /*
225 * A zero-length read means you need to create a
226 * new page.
227 */
228 memset(bp->page, 0, mp->pagesize);
229 break;
230 default:
231 /* A partial read is definitely bad. */
232 free(bp);
233 mp->curcache--;
234 errno = EINVAL;
235 return (NULL);
236 }
237 }
238 #ifdef STATISTICS
239 ++mp->pageread;
240 #endif
241
242 /* Set the page number, pin the page. */
243 bp->pgno = pgno;
244 if (!(flags & MPOOL_IGNOREPIN))
245 bp->flags = MPOOL_PINNED;
246 bp->flags |= MPOOL_INUSE;
247
248 /*
249 * Add the page to the head of the hash chain and the tail
250 * of the lru chain.
251 */
252 head = &mp->hqh[HASHKEY(bp->pgno)];
253 TAILQ_INSERT_HEAD(head, bp, hq);
254 TAILQ_INSERT_TAIL(&mp->lqh, bp, q);
255
256 /* Run through the user's filter. */
257 if (mp->pgin != NULL)
258 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page);
259
260 return (bp->page);
261 }
262
263 /*
264 * mpool_put
265 * Return a page.
266 */
267 /* ARGSUSED */
268 int
mpool_put(MPOOL * mp,void * page,u_int flags)269 mpool_put(MPOOL *mp, void *page, u_int flags)
270 {
271 BKT *bp;
272
273 #ifdef STATISTICS
274 ++mp->pageput;
275 #endif
276 bp = (BKT *)((char *)page - sizeof(BKT));
277 #ifdef DEBUG
278 if (!(bp->flags & MPOOL_PINNED)) {
279 (void)fprintf(stderr,
280 "mpool_put: page %d not pinned\n", bp->pgno);
281 abort();
282 }
283 #endif
284 bp->flags &= ~MPOOL_PINNED;
285 if (flags & MPOOL_DIRTY)
286 bp->flags |= flags & MPOOL_DIRTY;
287 return (RET_SUCCESS);
288 }
289
290 /*
291 * mpool_close
292 * Close the buffer pool.
293 */
294 int
mpool_close(MPOOL * mp)295 mpool_close(MPOOL *mp)
296 {
297 BKT *bp;
298
299 /* Free up any space allocated to the lru pages. */
300 while (!TAILQ_EMPTY(&mp->lqh)) {
301 bp = TAILQ_FIRST(&mp->lqh);
302 TAILQ_REMOVE(&mp->lqh, bp, q);
303 free(bp);
304 }
305
306 /* Free the MPOOL cookie. */
307 free(mp);
308 return (RET_SUCCESS);
309 }
310
311 /*
312 * mpool_sync
313 * Sync the pool to disk.
314 */
315 int
mpool_sync(MPOOL * mp)316 mpool_sync(MPOOL *mp)
317 {
318 BKT *bp;
319
320 /* Walk the lru chain, flushing any dirty pages to disk. */
321 TAILQ_FOREACH(bp, &mp->lqh, q)
322 if (bp->flags & MPOOL_DIRTY &&
323 mpool_write(mp, bp) == RET_ERROR)
324 return (RET_ERROR);
325
326 /* Sync the file descriptor. */
327 return (_fsync(mp->fd) ? RET_ERROR : RET_SUCCESS);
328 }
329
330 /*
331 * mpool_bkt
332 * Get a page from the cache (or create one).
333 */
334 static BKT *
mpool_bkt(MPOOL * mp)335 mpool_bkt(MPOOL *mp)
336 {
337 struct _hqh *head;
338 BKT *bp;
339
340 /* If under the max cached, always create a new page. */
341 if (mp->curcache < mp->maxcache)
342 goto new;
343
344 /*
345 * If the cache is max'd out, walk the lru list for a buffer we
346 * can flush. If we find one, write it (if necessary) and take it
347 * off any lists. If we don't find anything we grow the cache anyway.
348 * The cache never shrinks.
349 */
350 TAILQ_FOREACH(bp, &mp->lqh, q)
351 if (!(bp->flags & MPOOL_PINNED)) {
352 /* Flush if dirty. */
353 if (bp->flags & MPOOL_DIRTY &&
354 mpool_write(mp, bp) == RET_ERROR)
355 return (NULL);
356 #ifdef STATISTICS
357 ++mp->pageflush;
358 #endif
359 /* Remove from the hash and lru queues. */
360 head = &mp->hqh[HASHKEY(bp->pgno)];
361 TAILQ_REMOVE(head, bp, hq);
362 TAILQ_REMOVE(&mp->lqh, bp, q);
363 #ifdef DEBUG
364 { void *spage;
365 spage = bp->page;
366 memset(bp, 0xff, sizeof(BKT) + mp->pagesize);
367 bp->page = spage;
368 }
369 #endif
370 bp->flags = 0;
371 return (bp);
372 }
373
374 new: if ((bp = (BKT *)calloc(1, sizeof(BKT) + mp->pagesize)) == NULL)
375 return (NULL);
376 #ifdef STATISTICS
377 ++mp->pagealloc;
378 #endif
379 bp->page = (char *)bp + sizeof(BKT);
380 bp->flags = 0;
381 ++mp->curcache;
382 return (bp);
383 }
384
385 /*
386 * mpool_write
387 * Write a page to disk.
388 */
389 static int
mpool_write(MPOOL * mp,BKT * bp)390 mpool_write(MPOOL *mp, BKT *bp)
391 {
392 off_t off;
393
394 #ifdef STATISTICS
395 ++mp->pagewrite;
396 #endif
397
398 /* Run through the user's filter. */
399 if (mp->pgout)
400 (mp->pgout)(mp->pgcookie, bp->pgno, bp->page);
401
402 off = mp->pagesize * bp->pgno;
403 if (pwrite(mp->fd, bp->page, mp->pagesize, off) != (ssize_t)mp->pagesize)
404 return (RET_ERROR);
405
406 /*
407 * Re-run through the input filter since this page may soon be
408 * accessed via the cache, and whatever the user's output filter
409 * did may screw things up if we don't let the input filter
410 * restore the in-core copy.
411 */
412 if (mp->pgin)
413 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page);
414
415 bp->flags &= ~MPOOL_DIRTY;
416 return (RET_SUCCESS);
417 }
418
419 /*
420 * mpool_look
421 * Lookup a page in the cache.
422 */
423 static BKT *
mpool_look(MPOOL * mp,pgno_t pgno)424 mpool_look(MPOOL *mp, pgno_t pgno)
425 {
426 struct _hqh *head;
427 BKT *bp;
428
429 head = &mp->hqh[HASHKEY(pgno)];
430 TAILQ_FOREACH(bp, head, hq)
431 if ((bp->pgno == pgno) &&
432 ((bp->flags & MPOOL_INUSE) == MPOOL_INUSE)) {
433 #ifdef STATISTICS
434 ++mp->cachehit;
435 #endif
436 return (bp);
437 }
438 #ifdef STATISTICS
439 ++mp->cachemiss;
440 #endif
441 return (NULL);
442 }
443
444 #ifdef STATISTICS
445 /*
446 * mpool_stat
447 * Print out cache statistics.
448 */
449 void
mpool_stat(MPOOL * mp)450 mpool_stat(MPOOL *mp)
451 {
452 BKT *bp;
453 int cnt;
454 char *sep;
455
456 (void)fprintf(stderr, "%lu pages in the file\n", mp->npages);
457 (void)fprintf(stderr,
458 "page size %lu, cacheing %lu pages of %lu page max cache\n",
459 mp->pagesize, mp->curcache, mp->maxcache);
460 (void)fprintf(stderr, "%lu page puts, %lu page gets, %lu page new\n",
461 mp->pageput, mp->pageget, mp->pagenew);
462 (void)fprintf(stderr, "%lu page allocs, %lu page flushes\n",
463 mp->pagealloc, mp->pageflush);
464 if (mp->cachehit + mp->cachemiss)
465 (void)fprintf(stderr,
466 "%.0f%% cache hit rate (%lu hits, %lu misses)\n",
467 ((double)mp->cachehit / (mp->cachehit + mp->cachemiss))
468 * 100, mp->cachehit, mp->cachemiss);
469 (void)fprintf(stderr, "%lu page reads, %lu page writes\n",
470 mp->pageread, mp->pagewrite);
471
472 sep = "";
473 cnt = 0;
474 TAILQ_FOREACH(bp, &mp->lqh, q) {
475 (void)fprintf(stderr, "%s%d", sep, bp->pgno);
476 if (bp->flags & MPOOL_DIRTY)
477 (void)fprintf(stderr, "d");
478 if (bp->flags & MPOOL_PINNED)
479 (void)fprintf(stderr, "P");
480 if (++cnt == 10) {
481 sep = "\n";
482 cnt = 0;
483 } else
484 sep = ", ";
485
486 }
487 (void)fprintf(stderr, "\n");
488 }
489 #endif
490