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 #if defined(LIBC_SCCS) && !defined(lint) 33 static char sccsid[] = "@(#)mpool.c 8.7 (Berkeley) 11/2/95"; 34 #endif /* LIBC_SCCS and not lint */ 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include "namespace.h" 39 #include <sys/param.h> 40 #include <sys/queue.h> 41 #include <sys/stat.h> 42 43 #include <errno.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <unistd.h> 48 #include "un-namespace.h" 49 50 #include <db.h> 51 52 #define __MPOOLINTERFACE_PRIVATE 53 #include <mpool.h> 54 55 static BKT *mpool_bkt(MPOOL *); 56 static BKT *mpool_look(MPOOL *, pgno_t); 57 static int mpool_write(MPOOL *, BKT *); 58 59 /* 60 * mpool_open -- 61 * Initialize a memory pool. 62 */ 63 /* ARGSUSED */ 64 MPOOL * 65 mpool_open(void *key, int fd, pgno_t pagesize, pgno_t maxcache) 66 { 67 struct stat sb; 68 MPOOL *mp; 69 int entry; 70 71 /* 72 * Get information about the file. 73 * 74 * XXX 75 * We don't currently handle pipes, although we should. 76 */ 77 if (_fstat(fd, &sb)) 78 return (NULL); 79 if (!S_ISREG(sb.st_mode)) { 80 errno = ESPIPE; 81 return (NULL); 82 } 83 84 /* Allocate and initialize the MPOOL cookie. */ 85 if ((mp = (MPOOL *)calloc(1, sizeof(MPOOL))) == NULL) 86 return (NULL); 87 TAILQ_INIT(&mp->lqh); 88 for (entry = 0; entry < HASHSIZE; ++entry) 89 TAILQ_INIT(&mp->hqh[entry]); 90 mp->maxcache = maxcache; 91 mp->npages = sb.st_size / pagesize; 92 mp->pagesize = pagesize; 93 mp->fd = fd; 94 return (mp); 95 } 96 97 /* 98 * mpool_filter -- 99 * Initialize input/output filters. 100 */ 101 void 102 mpool_filter(MPOOL *mp, void (*pgin) (void *, pgno_t, void *), 103 void (*pgout) (void *, pgno_t, void *), void *pgcookie) 104 { 105 mp->pgin = pgin; 106 mp->pgout = pgout; 107 mp->pgcookie = pgcookie; 108 } 109 110 /* 111 * mpool_new -- 112 * Get a new page of memory. 113 */ 114 void * 115 mpool_new(MPOOL *mp, pgno_t *pgnoaddr, u_int flags) 116 { 117 struct _hqh *head; 118 BKT *bp; 119 120 if (mp->npages == MAX_PAGE_NUMBER) { 121 (void)fprintf(stderr, "mpool_new: page allocation overflow.\n"); 122 abort(); 123 } 124 #ifdef STATISTICS 125 ++mp->pagenew; 126 #endif 127 /* 128 * Get a BKT from the cache. Assign a new page number, attach 129 * it to the head of the hash chain, the tail of the lru chain, 130 * and return. 131 */ 132 if ((bp = mpool_bkt(mp)) == NULL) 133 return (NULL); 134 if (flags == MPOOL_PAGE_REQUEST) { 135 mp->npages++; 136 bp->pgno = *pgnoaddr; 137 } else 138 bp->pgno = *pgnoaddr = mp->npages++; 139 140 bp->flags = MPOOL_PINNED | MPOOL_INUSE; 141 142 head = &mp->hqh[HASHKEY(bp->pgno)]; 143 TAILQ_INSERT_HEAD(head, bp, hq); 144 TAILQ_INSERT_TAIL(&mp->lqh, bp, q); 145 return (bp->page); 146 } 147 148 int 149 mpool_delete(MPOOL *mp, void *page) 150 { 151 struct _hqh *head; 152 BKT *bp; 153 154 bp = (BKT *)((char *)page - sizeof(BKT)); 155 156 #ifdef DEBUG 157 if (!(bp->flags & MPOOL_PINNED)) { 158 (void)fprintf(stderr, 159 "mpool_delete: page %d not pinned\n", bp->pgno); 160 abort(); 161 } 162 #endif 163 164 /* Remove from the hash and lru queues. */ 165 head = &mp->hqh[HASHKEY(bp->pgno)]; 166 TAILQ_REMOVE(head, bp, hq); 167 TAILQ_REMOVE(&mp->lqh, bp, q); 168 169 free(bp); 170 mp->curcache--; 171 return (RET_SUCCESS); 172 } 173 174 /* 175 * mpool_get 176 * Get a page. 177 */ 178 /* ARGSUSED */ 179 void * 180 mpool_get(MPOOL *mp, pgno_t pgno, 181 u_int flags) /* XXX not used? */ 182 { 183 struct _hqh *head; 184 BKT *bp; 185 off_t off; 186 int nr; 187 188 #ifdef STATISTICS 189 ++mp->pageget; 190 #endif 191 192 /* Check for a page that is cached. */ 193 if ((bp = mpool_look(mp, pgno)) != NULL) { 194 #ifdef DEBUG 195 if (!(flags & MPOOL_IGNOREPIN) && bp->flags & MPOOL_PINNED) { 196 (void)fprintf(stderr, 197 "mpool_get: page %d already pinned\n", bp->pgno); 198 abort(); 199 } 200 #endif 201 /* 202 * Move the page to the head of the hash chain and the tail 203 * of the lru chain. 204 */ 205 head = &mp->hqh[HASHKEY(bp->pgno)]; 206 TAILQ_REMOVE(head, bp, hq); 207 TAILQ_INSERT_HEAD(head, bp, hq); 208 TAILQ_REMOVE(&mp->lqh, bp, q); 209 TAILQ_INSERT_TAIL(&mp->lqh, bp, q); 210 211 /* Return a pinned page. */ 212 bp->flags |= MPOOL_PINNED; 213 return (bp->page); 214 } 215 216 /* Get a page from the cache. */ 217 if ((bp = mpool_bkt(mp)) == NULL) 218 return (NULL); 219 220 /* Read in the contents. */ 221 off = mp->pagesize * pgno; 222 if ((nr = pread(mp->fd, bp->page, mp->pagesize, off)) != (ssize_t)mp->pagesize) { 223 switch (nr) { 224 case -1: 225 /* errno is set for us by pread(). */ 226 free(bp); 227 mp->curcache--; 228 return (NULL); 229 case 0: 230 /* 231 * A zero-length read means you need to create a 232 * new page. 233 */ 234 memset(bp->page, 0, mp->pagesize); 235 break; 236 default: 237 /* A partial read is definitely bad. */ 238 free(bp); 239 mp->curcache--; 240 errno = EINVAL; 241 return (NULL); 242 } 243 } 244 #ifdef STATISTICS 245 ++mp->pageread; 246 #endif 247 248 /* Set the page number, pin the page. */ 249 bp->pgno = pgno; 250 if (!(flags & MPOOL_IGNOREPIN)) 251 bp->flags = MPOOL_PINNED; 252 bp->flags |= MPOOL_INUSE; 253 254 /* 255 * Add the page to the head of the hash chain and the tail 256 * of the lru chain. 257 */ 258 head = &mp->hqh[HASHKEY(bp->pgno)]; 259 TAILQ_INSERT_HEAD(head, bp, hq); 260 TAILQ_INSERT_TAIL(&mp->lqh, bp, q); 261 262 /* Run through the user's filter. */ 263 if (mp->pgin != NULL) 264 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page); 265 266 return (bp->page); 267 } 268 269 /* 270 * mpool_put 271 * Return a page. 272 */ 273 /* ARGSUSED */ 274 int 275 mpool_put(MPOOL *mp, void *page, u_int flags) 276 { 277 BKT *bp; 278 279 #ifdef STATISTICS 280 ++mp->pageput; 281 #endif 282 bp = (BKT *)((char *)page - sizeof(BKT)); 283 #ifdef DEBUG 284 if (!(bp->flags & MPOOL_PINNED)) { 285 (void)fprintf(stderr, 286 "mpool_put: page %d not pinned\n", bp->pgno); 287 abort(); 288 } 289 #endif 290 bp->flags &= ~MPOOL_PINNED; 291 if (flags & MPOOL_DIRTY) 292 bp->flags |= flags & MPOOL_DIRTY; 293 return (RET_SUCCESS); 294 } 295 296 /* 297 * mpool_close 298 * Close the buffer pool. 299 */ 300 int 301 mpool_close(MPOOL *mp) 302 { 303 BKT *bp; 304 305 /* Free up any space allocated to the lru pages. */ 306 while (!TAILQ_EMPTY(&mp->lqh)) { 307 bp = TAILQ_FIRST(&mp->lqh); 308 TAILQ_REMOVE(&mp->lqh, bp, q); 309 free(bp); 310 } 311 312 /* Free the MPOOL cookie. */ 313 free(mp); 314 return (RET_SUCCESS); 315 } 316 317 /* 318 * mpool_sync 319 * Sync the pool to disk. 320 */ 321 int 322 mpool_sync(MPOOL *mp) 323 { 324 BKT *bp; 325 326 /* Walk the lru chain, flushing any dirty pages to disk. */ 327 TAILQ_FOREACH(bp, &mp->lqh, q) 328 if (bp->flags & MPOOL_DIRTY && 329 mpool_write(mp, bp) == RET_ERROR) 330 return (RET_ERROR); 331 332 /* Sync the file descriptor. */ 333 return (_fsync(mp->fd) ? RET_ERROR : RET_SUCCESS); 334 } 335 336 /* 337 * mpool_bkt 338 * Get a page from the cache (or create one). 339 */ 340 static BKT * 341 mpool_bkt(MPOOL *mp) 342 { 343 struct _hqh *head; 344 BKT *bp; 345 346 /* If under the max cached, always create a new page. */ 347 if (mp->curcache < mp->maxcache) 348 goto new; 349 350 /* 351 * If the cache is max'd out, walk the lru list for a buffer we 352 * can flush. If we find one, write it (if necessary) and take it 353 * off any lists. If we don't find anything we grow the cache anyway. 354 * The cache never shrinks. 355 */ 356 TAILQ_FOREACH(bp, &mp->lqh, q) 357 if (!(bp->flags & MPOOL_PINNED)) { 358 /* Flush if dirty. */ 359 if (bp->flags & MPOOL_DIRTY && 360 mpool_write(mp, bp) == RET_ERROR) 361 return (NULL); 362 #ifdef STATISTICS 363 ++mp->pageflush; 364 #endif 365 /* Remove from the hash and lru queues. */ 366 head = &mp->hqh[HASHKEY(bp->pgno)]; 367 TAILQ_REMOVE(head, bp, hq); 368 TAILQ_REMOVE(&mp->lqh, bp, q); 369 #ifdef DEBUG 370 { void *spage; 371 spage = bp->page; 372 memset(bp, 0xff, sizeof(BKT) + mp->pagesize); 373 bp->page = spage; 374 } 375 #endif 376 bp->flags = 0; 377 return (bp); 378 } 379 380 new: if ((bp = (BKT *)calloc(1, sizeof(BKT) + mp->pagesize)) == NULL) 381 return (NULL); 382 #ifdef STATISTICS 383 ++mp->pagealloc; 384 #endif 385 bp->page = (char *)bp + sizeof(BKT); 386 bp->flags = 0; 387 ++mp->curcache; 388 return (bp); 389 } 390 391 /* 392 * mpool_write 393 * Write a page to disk. 394 */ 395 static int 396 mpool_write(MPOOL *mp, BKT *bp) 397 { 398 off_t off; 399 400 #ifdef STATISTICS 401 ++mp->pagewrite; 402 #endif 403 404 /* Run through the user's filter. */ 405 if (mp->pgout) 406 (mp->pgout)(mp->pgcookie, bp->pgno, bp->page); 407 408 off = mp->pagesize * bp->pgno; 409 if (pwrite(mp->fd, bp->page, mp->pagesize, off) != (ssize_t)mp->pagesize) 410 return (RET_ERROR); 411 412 /* 413 * Re-run through the input filter since this page may soon be 414 * accessed via the cache, and whatever the user's output filter 415 * did may screw things up if we don't let the input filter 416 * restore the in-core copy. 417 */ 418 if (mp->pgin) 419 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page); 420 421 bp->flags &= ~MPOOL_DIRTY; 422 return (RET_SUCCESS); 423 } 424 425 /* 426 * mpool_look 427 * Lookup a page in the cache. 428 */ 429 static BKT * 430 mpool_look(MPOOL *mp, pgno_t pgno) 431 { 432 struct _hqh *head; 433 BKT *bp; 434 435 head = &mp->hqh[HASHKEY(pgno)]; 436 TAILQ_FOREACH(bp, head, hq) 437 if ((bp->pgno == pgno) && 438 ((bp->flags & MPOOL_INUSE) == MPOOL_INUSE)) { 439 #ifdef STATISTICS 440 ++mp->cachehit; 441 #endif 442 return (bp); 443 } 444 #ifdef STATISTICS 445 ++mp->cachemiss; 446 #endif 447 return (NULL); 448 } 449 450 #ifdef STATISTICS 451 /* 452 * mpool_stat 453 * Print out cache statistics. 454 */ 455 void 456 mpool_stat(MPOOL *mp) 457 { 458 BKT *bp; 459 int cnt; 460 char *sep; 461 462 (void)fprintf(stderr, "%lu pages in the file\n", mp->npages); 463 (void)fprintf(stderr, 464 "page size %lu, cacheing %lu pages of %lu page max cache\n", 465 mp->pagesize, mp->curcache, mp->maxcache); 466 (void)fprintf(stderr, "%lu page puts, %lu page gets, %lu page new\n", 467 mp->pageput, mp->pageget, mp->pagenew); 468 (void)fprintf(stderr, "%lu page allocs, %lu page flushes\n", 469 mp->pagealloc, mp->pageflush); 470 if (mp->cachehit + mp->cachemiss) 471 (void)fprintf(stderr, 472 "%.0f%% cache hit rate (%lu hits, %lu misses)\n", 473 ((double)mp->cachehit / (mp->cachehit + mp->cachemiss)) 474 * 100, mp->cachehit, mp->cachemiss); 475 (void)fprintf(stderr, "%lu page reads, %lu page writes\n", 476 mp->pageread, mp->pagewrite); 477 478 sep = ""; 479 cnt = 0; 480 TAILQ_FOREACH(bp, &mp->lqh, q) { 481 (void)fprintf(stderr, "%s%d", sep, bp->pgno); 482 if (bp->flags & MPOOL_DIRTY) 483 (void)fprintf(stderr, "d"); 484 if (bp->flags & MPOOL_PINNED) 485 (void)fprintf(stderr, "P"); 486 if (++cnt == 10) { 487 sep = "\n"; 488 cnt = 0; 489 } else 490 sep = ", "; 491 492 } 493 (void)fprintf(stderr, "\n"); 494 } 495 #endif 496