mpool.c revision 1.20
1 /* $NetBSD: mpool.c,v 1.20 2013/11/22 16:25:51 christos Exp $ */ 2 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 HAVE_NBTOOL_CONFIG_H 33 #include "nbtool_config.h" 34 #endif 35 36 #include <sys/cdefs.h> 37 __RCSID("$NetBSD: mpool.c,v 1.20 2013/11/22 16:25:51 christos Exp $"); 38 39 #include "namespace.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 49 #include <db.h> 50 51 #define __MPOOLINTERFACE_PRIVATE 52 #include <mpool.h> 53 54 #ifdef __weak_alias 55 __weak_alias(mpool_close,_mpool_close) 56 __weak_alias(mpool_filter,_mpool_filter) 57 __weak_alias(mpool_get,_mpool_get) 58 __weak_alias(mpool_new,_mpool_new) 59 __weak_alias(mpool_open,_mpool_open) 60 __weak_alias(mpool_put,_mpool_put) 61 __weak_alias(mpool_sync,_mpool_sync) 62 #endif 63 64 static BKT *mpool_bkt(MPOOL *); 65 static BKT *mpool_look(MPOOL *, pgno_t); 66 static int mpool_write(MPOOL *, BKT *); 67 68 /* 69 * mpool_open -- 70 * Initialize a memory pool. 71 */ 72 /*ARGSUSED*/ 73 MPOOL * 74 mpool_open(void *key, int fd, pgno_t pagesize, pgno_t maxcache) 75 { 76 struct stat sb; 77 MPOOL *mp; 78 int entry; 79 80 /* 81 * Get information about the file. 82 * 83 * XXX 84 * We don't currently handle pipes, although we should. 85 */ 86 if (fstat(fd, &sb)) 87 return (NULL); 88 if (!S_ISREG(sb.st_mode)) { 89 errno = ESPIPE; 90 return (NULL); 91 } 92 93 /* Allocate and initialize the MPOOL cookie. */ 94 if ((mp = (MPOOL *)calloc(1, sizeof(MPOOL))) == NULL) 95 return (NULL); 96 TAILQ_INIT(&mp->lqh); 97 for (entry = 0; entry < HASHSIZE; ++entry) 98 TAILQ_INIT(&mp->hqh[entry]); 99 mp->maxcache = maxcache; 100 mp->npages = (pgno_t)(sb.st_size / pagesize); 101 mp->pagesize = pagesize; 102 mp->fd = fd; 103 return (mp); 104 } 105 106 /* 107 * mpool_filter -- 108 * Initialize input/output filters. 109 */ 110 void 111 mpool_filter(MPOOL *mp, void (*pgin)(void *, pgno_t, void *), 112 void (*pgout)(void *, pgno_t, void *), void *pgcookie) 113 { 114 mp->pgin = pgin; 115 mp->pgout = pgout; 116 mp->pgcookie = pgcookie; 117 } 118 119 /* 120 * mpool_new -- 121 * Get a new page of memory. 122 */ 123 void * 124 mpool_new( MPOOL *mp, pgno_t *pgnoaddr) 125 { 126 struct _hqh *head; 127 BKT *bp; 128 129 if (mp->npages == MAX_PAGE_NUMBER) { 130 (void)fprintf(stderr, "mpool_new: page allocation overflow.\n"); 131 abort(); 132 } 133 #ifdef STATISTICS 134 ++mp->pagenew; 135 #endif 136 /* 137 * Get a BKT from the cache. Assign a new page number, attach 138 * it to the head of the hash chain, the tail of the lru chain, 139 * and return. 140 */ 141 if ((bp = mpool_bkt(mp)) == NULL) 142 return (NULL); 143 *pgnoaddr = bp->pgno = mp->npages++; 144 bp->flags = MPOOL_PINNED; 145 146 head = &mp->hqh[HASHKEY(bp->pgno)]; 147 TAILQ_INSERT_HEAD(head, bp, hq); 148 TAILQ_INSERT_TAIL(&mp->lqh, bp, q); 149 return (bp->page); 150 } 151 152 /* 153 * mpool_get 154 * Get a page. 155 */ 156 /*ARGSUSED*/ 157 void * 158 mpool_get(MPOOL *mp, pgno_t pgno, u_int flags) 159 { 160 struct _hqh *head; 161 BKT *bp; 162 off_t off; 163 ssize_t nr; 164 165 /* Check for attempt to retrieve a non-existent page. */ 166 if (pgno >= mp->npages) { 167 errno = EINVAL; 168 return (NULL); 169 } 170 171 #ifdef STATISTICS 172 ++mp->pageget; 173 #endif 174 175 /* Check for a page that is cached. */ 176 if ((bp = mpool_look(mp, pgno)) != NULL) { 177 #ifdef DEBUG 178 if (bp->flags & MPOOL_PINNED) { 179 (void)fprintf(stderr, 180 "mpool_get: page %d already pinned\n", bp->pgno); 181 abort(); 182 } 183 #endif 184 /* 185 * Move the page to the head of the hash chain and the tail 186 * of the lru chain. 187 */ 188 head = &mp->hqh[HASHKEY(bp->pgno)]; 189 TAILQ_REMOVE(head, bp, hq); 190 TAILQ_INSERT_HEAD(head, bp, hq); 191 TAILQ_REMOVE(&mp->lqh, bp, q); 192 TAILQ_INSERT_TAIL(&mp->lqh, bp, q); 193 194 /* Return a pinned page. */ 195 bp->flags |= MPOOL_PINNED; 196 return (bp->page); 197 } 198 199 /* Get a page from the cache. */ 200 if ((bp = mpool_bkt(mp)) == NULL) 201 return (NULL); 202 203 /* Read in the contents. */ 204 #ifdef STATISTICS 205 ++mp->pageread; 206 #endif 207 off = mp->pagesize * pgno; 208 if ((nr = pread(mp->fd, bp->page, (size_t)mp->pagesize, off)) != (int)mp->pagesize) { 209 if (nr >= 0) 210 errno = EFTYPE; 211 return (NULL); 212 } 213 214 /* Set the page number, pin the page. */ 215 bp->pgno = pgno; 216 bp->flags = MPOOL_PINNED; 217 218 /* 219 * Add the page to the head of the hash chain and the tail 220 * of the lru chain. 221 */ 222 head = &mp->hqh[HASHKEY(bp->pgno)]; 223 TAILQ_INSERT_HEAD(head, bp, hq); 224 TAILQ_INSERT_TAIL(&mp->lqh, bp, q); 225 226 /* Run through the user's filter. */ 227 if (mp->pgin != NULL) 228 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page); 229 230 return (bp->page); 231 } 232 233 /* 234 * mpool_put 235 * Return a page. 236 */ 237 /*ARGSUSED*/ 238 int 239 mpool_put(MPOOL *mp, void *page, u_int flags) 240 { 241 BKT *bp; 242 243 #ifdef STATISTICS 244 ++mp->pageput; 245 #endif 246 bp = (BKT *)(void *)((char *)page - sizeof(BKT)); 247 #ifdef DEBUG 248 if (!(bp->flags & MPOOL_PINNED)) { 249 (void)fprintf(stderr, 250 "mpool_put: page %d not pinned\n", bp->pgno); 251 abort(); 252 } 253 #endif 254 bp->flags &= ~MPOOL_PINNED; 255 bp->flags |= flags & MPOOL_DIRTY; 256 return (RET_SUCCESS); 257 } 258 259 /* 260 * mpool_close 261 * Close the buffer pool. 262 */ 263 int 264 mpool_close(MPOOL *mp) 265 { 266 BKT *bp; 267 268 /* Free up any space allocated to the lru pages. */ 269 while (!TAILQ_EMPTY(&mp->lqh)) { 270 bp = TAILQ_FIRST(&mp->lqh); 271 TAILQ_REMOVE(&mp->lqh, bp, q); 272 free(bp); 273 } 274 275 /* Free the MPOOL cookie. */ 276 free(mp); 277 return (RET_SUCCESS); 278 } 279 280 /* 281 * mpool_sync 282 * Sync the pool to disk. 283 */ 284 int 285 mpool_sync(MPOOL *mp) 286 { 287 BKT *bp; 288 289 /* Walk the lru chain, flushing any dirty pages to disk. */ 290 TAILQ_FOREACH(bp, &mp->lqh, q) 291 if (bp->flags & MPOOL_DIRTY && 292 mpool_write(mp, bp) == RET_ERROR) 293 return (RET_ERROR); 294 295 /* Sync the file descriptor. */ 296 return (fsync(mp->fd) ? RET_ERROR : RET_SUCCESS); 297 } 298 299 /* 300 * mpool_bkt 301 * Get a page from the cache (or create one). 302 */ 303 static BKT * 304 mpool_bkt(MPOOL *mp) 305 { 306 struct _hqh *head; 307 BKT *bp; 308 309 /* If under the max cached, always create a new page. */ 310 if (mp->curcache < mp->maxcache) 311 goto new; 312 313 /* 314 * If the cache is max'd out, walk the lru list for a buffer we 315 * can flush. If we find one, write it (if necessary) and take it 316 * off any lists. If we don't find anything we grow the cache anyway. 317 * The cache never shrinks. 318 */ 319 TAILQ_FOREACH(bp, &mp->lqh, q) 320 if (!(bp->flags & MPOOL_PINNED)) { 321 /* Flush if dirty. */ 322 if (bp->flags & MPOOL_DIRTY && 323 mpool_write(mp, bp) == RET_ERROR) 324 return (NULL); 325 #ifdef STATISTICS 326 ++mp->pageflush; 327 #endif 328 /* Remove from the hash and lru queues. */ 329 head = &mp->hqh[HASHKEY(bp->pgno)]; 330 TAILQ_REMOVE(head, bp, hq); 331 TAILQ_REMOVE(&mp->lqh, bp, q); 332 #ifdef DEBUG 333 { 334 void *spage = bp->page; 335 (void)memset(bp, 0xff, 336 (size_t)(sizeof(BKT) + mp->pagesize)); 337 bp->page = spage; 338 } 339 #endif 340 return (bp); 341 } 342 343 new: if ((bp = calloc(1, (size_t)(sizeof(BKT) + mp->pagesize))) == NULL) 344 return (NULL); 345 #ifdef STATISTICS 346 ++mp->pagealloc; 347 #endif 348 #if defined(DEBUG) || defined(PURIFY) 349 (void)memset(bp, 0xff, (size_t)(sizeof(BKT) + mp->pagesize)); 350 #endif 351 bp->page = (char *)(void *)bp + sizeof(BKT); 352 ++mp->curcache; 353 return (bp); 354 } 355 356 /* 357 * mpool_write 358 * Write a page to disk. 359 */ 360 static int 361 mpool_write(MPOOL *mp, BKT *bp) 362 { 363 off_t off; 364 365 #ifdef STATISTICS 366 ++mp->pagewrite; 367 #endif 368 369 /* Run through the user's filter. */ 370 if (mp->pgout) 371 (mp->pgout)(mp->pgcookie, bp->pgno, bp->page); 372 373 off = mp->pagesize * bp->pgno; 374 if (pwrite(mp->fd, bp->page, (size_t)mp->pagesize, off) != (int)mp->pagesize) 375 return (RET_ERROR); 376 377 /* 378 * Re-run through the input filter since this page may soon be 379 * accessed via the cache, and whatever the user's output filter 380 * did may screw things up if we don't let the input filter 381 * restore the in-core copy. 382 */ 383 if (mp->pgin) 384 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page); 385 386 bp->flags &= ~MPOOL_DIRTY; 387 return (RET_SUCCESS); 388 } 389 390 /* 391 * mpool_look 392 * Lookup a page in the cache. 393 */ 394 static BKT * 395 mpool_look(MPOOL *mp, pgno_t pgno) 396 { 397 struct _hqh *head; 398 BKT *bp; 399 400 head = &mp->hqh[HASHKEY(pgno)]; 401 TAILQ_FOREACH(bp, head, hq) 402 if (bp->pgno == pgno) { 403 #ifdef STATISTICS 404 ++mp->cachehit; 405 #endif 406 return (bp); 407 } 408 #ifdef STATISTICS 409 ++mp->cachemiss; 410 #endif 411 return (NULL); 412 } 413 414 #ifdef STATISTICS 415 /* 416 * mpool_stat 417 * Print out cache statistics. 418 */ 419 void 420 mpool_stat(mp) 421 MPOOL *mp; 422 { 423 BKT *bp; 424 int cnt; 425 const char *sep; 426 427 (void)fprintf(stderr, "%lu pages in the file\n", (u_long)mp->npages); 428 (void)fprintf(stderr, 429 "page size %lu, cacheing %lu pages of %lu page max cache\n", 430 (u_long)mp->pagesize, (u_long)mp->curcache, (u_long)mp->maxcache); 431 (void)fprintf(stderr, "%lu page puts, %lu page gets, %lu page new\n", 432 mp->pageput, mp->pageget, mp->pagenew); 433 (void)fprintf(stderr, "%lu page allocs, %lu page flushes\n", 434 mp->pagealloc, mp->pageflush); 435 if (mp->cachehit + mp->cachemiss) 436 (void)fprintf(stderr, 437 "%.0f%% cache hit rate (%lu hits, %lu misses)\n", 438 ((double)mp->cachehit / (mp->cachehit + mp->cachemiss)) 439 * 100, mp->cachehit, mp->cachemiss); 440 (void)fprintf(stderr, "%lu page reads, %lu page writes\n", 441 mp->pageread, mp->pagewrite); 442 443 sep = ""; 444 cnt = 0; 445 TAILQ_FOREACH(bp, &mp->lqh, q) { 446 (void)fprintf(stderr, "%s%d", sep, bp->pgno); 447 if (bp->flags & MPOOL_DIRTY) 448 (void)fprintf(stderr, "d"); 449 if (bp->flags & MPOOL_PINNED) 450 (void)fprintf(stderr, "P"); 451 if (++cnt == 10) { 452 sep = "\n"; 453 cnt = 0; 454 } else 455 sep = ", "; 456 457 } 458 (void)fprintf(stderr, "\n"); 459 } 460 #endif 461
Indexes created Mon Sep 22 21:09:42 GMT 2025