1 /*- 2 * Copyright (c) 1990, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char sccsid[] = "@(#)mpool.c 8.5 (Berkeley) 7/26/94"; 32 #endif /* LIBC_SCCS and not lint */ 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include "namespace.h" 37 #include <sys/param.h> 38 #include <sys/queue.h> 39 #include <sys/stat.h> 40 41 #include <errno.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <unistd.h> 46 #include "un-namespace.h" 47 48 #include <db.h> 49 50 #define __MPOOLINTERFACE_PRIVATE 51 #include <mpool.h> 52 53 static BKT *mpool_bkt(MPOOL *); 54 static BKT *mpool_look(MPOOL *, pgno_t); 55 static int mpool_write(MPOOL *, BKT *); 56 57 /* 58 * mpool_open -- 59 * Initialize a memory pool. 60 */ 61 /* ARGSUSED */ 62 MPOOL * 63 mpool_open(void *key, int fd, pgno_t pagesize, pgno_t maxcache) 64 { 65 struct stat sb; 66 MPOOL *mp; 67 int entry; 68 69 /* 70 * Get information about the file. 71 * 72 * XXX 73 * We don't currently handle pipes, although we should. 74 */ 75 if (_fstat(fd, &sb)) 76 return (NULL); 77 if (!S_ISREG(sb.st_mode)) { 78 errno = ESPIPE; 79 return (NULL); 80 } 81 82 /* Allocate and initialize the MPOOL cookie. */ 83 if ((mp = (MPOOL *)calloc(1, sizeof(MPOOL))) == NULL) 84 return (NULL); 85 TAILQ_INIT(&mp->lqh); 86 for (entry = 0; entry < HASHSIZE; ++entry) 87 TAILQ_INIT(&mp->hqh[entry]); 88 mp->maxcache = maxcache; 89 mp->npages = sb.st_size / pagesize; 90 mp->pagesize = pagesize; 91 mp->fd = fd; 92 return (mp); 93 } 94 95 /* 96 * mpool_filter -- 97 * Initialize input/output filters. 98 */ 99 void 100 mpool_filter(MPOOL *mp, void (*pgin) (void *, pgno_t, void *), 101 void (*pgout) (void *, pgno_t, void *), void *pgcookie) 102 { 103 mp->pgin = pgin; 104 mp->pgout = pgout; 105 mp->pgcookie = pgcookie; 106 } 107 108 /* 109 * mpool_new -- 110 * Get a new page of memory. 111 */ 112 void * 113 mpool_new(mp, pgnoaddr) 114 MPOOL *mp; 115 pgno_t *pgnoaddr; 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 *pgnoaddr = bp->pgno = mp->npages++; 135 bp->flags = MPOOL_PINNED; 136 137 head = &mp->hqh[HASHKEY(bp->pgno)]; 138 TAILQ_INSERT_HEAD(head, bp, hq); 139 TAILQ_INSERT_TAIL(&mp->lqh, bp, q); 140 return (bp->page); 141 } 142 143 /* 144 * mpool_get 145 * Get a page. 146 */ 147 /* ARGSUSED */ 148 void * 149 mpool_get(MPOOL *mp, pgno_t pgno, 150 u_int flags) /* XXX not used? */ 151 { 152 struct _hqh *head; 153 BKT *bp; 154 off_t off; 155 int nr; 156 157 /* Check for attempt to retrieve a non-existent page. */ 158 if (pgno >= mp->npages) { 159 errno = EINVAL; 160 return (NULL); 161 } 162 163 #ifdef STATISTICS 164 ++mp->pageget; 165 #endif 166 167 /* Check for a page that is cached. */ 168 if ((bp = mpool_look(mp, pgno)) != NULL) { 169 #ifdef DEBUG 170 if (bp->flags & MPOOL_PINNED) { 171 (void)fprintf(stderr, 172 "mpool_get: page %d already pinned\n", bp->pgno); 173 abort(); 174 } 175 #endif 176 /* 177 * Move the page to the head of the hash chain and the tail 178 * of the lru chain. 179 */ 180 head = &mp->hqh[HASHKEY(bp->pgno)]; 181 TAILQ_REMOVE(head, bp, hq); 182 TAILQ_INSERT_HEAD(head, bp, hq); 183 TAILQ_REMOVE(&mp->lqh, bp, q); 184 TAILQ_INSERT_TAIL(&mp->lqh, bp, q); 185 186 /* Return a pinned page. */ 187 bp->flags |= MPOOL_PINNED; 188 return (bp->page); 189 } 190 191 /* Get a page from the cache. */ 192 if ((bp = mpool_bkt(mp)) == NULL) 193 return (NULL); 194 195 /* Read in the contents. */ 196 #ifdef STATISTICS 197 ++mp->pageread; 198 #endif 199 off = mp->pagesize * pgno; 200 nr = pread(mp->fd, bp->page, mp->pagesize, off); 201 if (nr != mp->pagesize) { 202 if (nr >= 0) 203 errno = EFTYPE; 204 return (NULL); 205 } 206 207 /* Set the page number, pin the page. */ 208 bp->pgno = pgno; 209 bp->flags = MPOOL_PINNED; 210 211 /* 212 * Add the page to the head of the hash chain and the tail 213 * of the lru chain. 214 */ 215 head = &mp->hqh[HASHKEY(bp->pgno)]; 216 TAILQ_INSERT_HEAD(head, bp, hq); 217 TAILQ_INSERT_TAIL(&mp->lqh, bp, q); 218 219 /* Run through the user's filter. */ 220 if (mp->pgin != NULL) 221 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page); 222 223 return (bp->page); 224 } 225 226 /* 227 * mpool_put 228 * Return a page. 229 */ 230 /* ARGSUSED */ 231 int 232 mpool_put(MPOOL *mp, void *page, u_int flags) 233 { 234 BKT *bp; 235 236 #ifdef STATISTICS 237 ++mp->pageput; 238 #endif 239 bp = (BKT *)((char *)page - sizeof(BKT)); 240 #ifdef DEBUG 241 if (!(bp->flags & MPOOL_PINNED)) { 242 (void)fprintf(stderr, 243 "mpool_put: page %d not pinned\n", bp->pgno); 244 abort(); 245 } 246 #endif 247 bp->flags &= ~MPOOL_PINNED; 248 bp->flags |= flags & MPOOL_DIRTY; 249 return (RET_SUCCESS); 250 } 251 252 /* 253 * mpool_close 254 * Close the buffer pool. 255 */ 256 int 257 mpool_close(MPOOL *mp) 258 { 259 BKT *bp; 260 261 /* Free up any space allocated to the lru pages. */ 262 while (!TAILQ_EMPTY(&mp->lqh)) { 263 bp = TAILQ_FIRST(&mp->lqh); 264 TAILQ_REMOVE(&mp->lqh, bp, q); 265 free(bp); 266 } 267 268 /* Free the MPOOL cookie. */ 269 free(mp); 270 return (RET_SUCCESS); 271 } 272 273 /* 274 * mpool_sync 275 * Sync the pool to disk. 276 */ 277 int 278 mpool_sync(MPOOL *mp) 279 { 280 BKT *bp; 281 282 /* Walk the lru chain, flushing any dirty pages to disk. */ 283 TAILQ_FOREACH(bp, &mp->lqh, q) 284 if (bp->flags & MPOOL_DIRTY && 285 mpool_write(mp, bp) == RET_ERROR) 286 return (RET_ERROR); 287 288 /* Sync the file descriptor. */ 289 return (_fsync(mp->fd) ? RET_ERROR : RET_SUCCESS); 290 } 291 292 /* 293 * mpool_bkt 294 * Get a page from the cache (or create one). 295 */ 296 static BKT * 297 mpool_bkt(MPOOL *mp) 298 { 299 struct _hqh *head; 300 BKT *bp; 301 302 /* If under the max cached, always create a new page. */ 303 if (mp->curcache < mp->maxcache) 304 goto new; 305 306 /* 307 * If the cache is max'd out, walk the lru list for a buffer we 308 * can flush. If we find one, write it (if necessary) and take it 309 * off any lists. If we don't find anything we grow the cache anyway. 310 * The cache never shrinks. 311 */ 312 TAILQ_FOREACH(bp, &mp->lqh, q) 313 if (!(bp->flags & MPOOL_PINNED)) { 314 /* Flush if dirty. */ 315 if (bp->flags & MPOOL_DIRTY && 316 mpool_write(mp, bp) == RET_ERROR) 317 return (NULL); 318 #ifdef STATISTICS 319 ++mp->pageflush; 320 #endif 321 /* Remove from the hash and lru queues. */ 322 head = &mp->hqh[HASHKEY(bp->pgno)]; 323 TAILQ_REMOVE(head, bp, hq); 324 TAILQ_REMOVE(&mp->lqh, bp, q); 325 #ifdef DEBUG 326 { void *spage; 327 spage = bp->page; 328 memset(bp, 0xff, sizeof(BKT) + mp->pagesize); 329 bp->page = spage; 330 } 331 #endif 332 return (bp); 333 } 334 335 new: if ((bp = (BKT *)malloc(sizeof(BKT) + mp->pagesize)) == NULL) 336 return (NULL); 337 #ifdef STATISTICS 338 ++mp->pagealloc; 339 #endif 340 #if defined(DEBUG) || defined(PURIFY) 341 memset(bp, 0xff, sizeof(BKT) + mp->pagesize); 342 #endif 343 bp->page = (char *)bp + sizeof(BKT); 344 ++mp->curcache; 345 return (bp); 346 } 347 348 /* 349 * mpool_write 350 * Write a page to disk. 351 */ 352 static int 353 mpool_write(MPOOL *mp, BKT *bp) 354 { 355 off_t off; 356 357 #ifdef STATISTICS 358 ++mp->pagewrite; 359 #endif 360 361 /* Run through the user's filter. */ 362 if (mp->pgout) 363 (mp->pgout)(mp->pgcookie, bp->pgno, bp->page); 364 365 off = mp->pagesize * bp->pgno; 366 if (pwrite(mp->fd, bp->page, mp->pagesize, off) != mp->pagesize) 367 return (RET_ERROR); 368 369 bp->flags &= ~MPOOL_DIRTY; 370 return (RET_SUCCESS); 371 } 372 373 /* 374 * mpool_look 375 * Lookup a page in the cache. 376 */ 377 static BKT * 378 mpool_look(MPOOL *mp, pgno_t pgno) 379 { 380 struct _hqh *head; 381 BKT *bp; 382 383 head = &mp->hqh[HASHKEY(pgno)]; 384 TAILQ_FOREACH(bp, head, hq) 385 if (bp->pgno == pgno) { 386 #ifdef STATISTICS 387 ++mp->cachehit; 388 #endif 389 return (bp); 390 } 391 #ifdef STATISTICS 392 ++mp->cachemiss; 393 #endif 394 return (NULL); 395 } 396 397 #ifdef STATISTICS 398 /* 399 * mpool_stat 400 * Print out cache statistics. 401 */ 402 void 403 mpool_stat(MPOOL *mp) 404 { 405 BKT *bp; 406 int cnt; 407 char *sep; 408 409 (void)fprintf(stderr, "%lu pages in the file\n", mp->npages); 410 (void)fprintf(stderr, 411 "page size %lu, cacheing %lu pages of %lu page max cache\n", 412 mp->pagesize, mp->curcache, mp->maxcache); 413 (void)fprintf(stderr, "%lu page puts, %lu page gets, %lu page new\n", 414 mp->pageput, mp->pageget, mp->pagenew); 415 (void)fprintf(stderr, "%lu page allocs, %lu page flushes\n", 416 mp->pagealloc, mp->pageflush); 417 if (mp->cachehit + mp->cachemiss) 418 (void)fprintf(stderr, 419 "%.0f%% cache hit rate (%lu hits, %lu misses)\n", 420 ((double)mp->cachehit / (mp->cachehit + mp->cachemiss)) 421 * 100, mp->cachehit, mp->cachemiss); 422 (void)fprintf(stderr, "%lu page reads, %lu page writes\n", 423 mp->pageread, mp->pagewrite); 424 425 sep = ""; 426 cnt = 0; 427 TAILQ_FOREACH(bp, &mp->lqh, q) { 428 (void)fprintf(stderr, "%s%d", sep, bp->pgno); 429 if (bp->flags & MPOOL_DIRTY) 430 (void)fprintf(stderr, "d"); 431 if (bp->flags & MPOOL_PINNED) 432 (void)fprintf(stderr, "P"); 433 if (++cnt == 10) { 434 sep = "\n"; 435 cnt = 0; 436 } else 437 sep = ", "; 438 439 } 440 (void)fprintf(stderr, "\n"); 441 } 442 #endif 443