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) 31static 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: src/lib/libc/db/mpool/mpool.c,v 1.16 2009/03/28 04:00:46 delphij Exp $"); 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 53static BKT *mpool_bkt(MPOOL *); 54static BKT *mpool_look(MPOOL *, pgno_t); 55static int mpool_write(MPOOL *, BKT *); 56 57/* 58 * mpool_open -- 59 * Initialize a memory pool. 60 */ 61/* ARGSUSED */ 62MPOOL * 63mpool_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 */ 99void 100mpool_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 */ 112void * 113mpool_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 LIBC_ABORT("page allocation overflow"); 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 */ 148void * 149mpool_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 LIBC_ABORT("page %d already pinned", bp->pgno); 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 */ 231int 232mpool_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 LIBC_ABORT("page %d not pinned", bp->pgno); 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 */ 256int 257mpool_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 */ 277int 278mpool_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 if (mpool_write(mp, bp) == RET_ERROR) { 286 return (RET_ERROR); 287 } else { 288 /* 4874757: Re-run through the user's pgin filter. */ 289 if (mp->pgin != NULL) 290 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page); 291 } 292 } 293 } 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 */ 303static BKT * 304mpool_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 { void *spage; 334 spage = bp->page; 335 memset(bp, 0xff, sizeof(BKT) + mp->pagesize); 336 bp->page = spage; 337 } 338#endif 339 return (bp); 340 } 341 342new: if ((bp = (BKT *)calloc(1, sizeof(BKT) + mp->pagesize)) == NULL) 343 return (NULL); 344#ifdef STATISTICS 345 ++mp->pagealloc; 346#endif 347 bp->page = (char *)bp + sizeof(BKT); 348 ++mp->curcache; 349 return (bp); 350} 351 352/* 353 * mpool_write 354 * Write a page to disk. 355 */ 356static int 357mpool_write(MPOOL *mp, BKT *bp) 358{ 359 off_t off; 360 361#ifdef STATISTICS 362 ++mp->pagewrite; 363#endif 364 365 /* Run through the user's filter. */ 366 if (mp->pgout) 367 (mp->pgout)(mp->pgcookie, bp->pgno, bp->page); 368 369 off = mp->pagesize * bp->pgno; 370 if (pwrite(mp->fd, bp->page, mp->pagesize, off) != mp->pagesize) 371 return (RET_ERROR); 372 373 bp->flags &= ~MPOOL_DIRTY; 374 return (RET_SUCCESS); 375} 376 377/* 378 * mpool_look 379 * Lookup a page in the cache. 380 */ 381static BKT * 382mpool_look(MPOOL *mp, pgno_t pgno) 383{ 384 struct _hqh *head; 385 BKT *bp; 386 387 head = &mp->hqh[HASHKEY(pgno)]; 388 TAILQ_FOREACH(bp, head, hq) 389 if (bp->pgno == pgno) { 390#ifdef STATISTICS 391 ++mp->cachehit; 392#endif 393 return (bp); 394 } 395#ifdef STATISTICS 396 ++mp->cachemiss; 397#endif 398 return (NULL); 399} 400 401#ifdef STATISTICS 402/* 403 * mpool_stat 404 * Print out cache statistics. 405 */ 406void 407mpool_stat(MPOOL *mp) 408{ 409 BKT *bp; 410 int cnt; 411 char *sep; 412 413 (void)fprintf(stderr, "%lu pages in the file\n", mp->npages); 414 (void)fprintf(stderr, 415 "page size %lu, cacheing %lu pages of %lu page max cache\n", 416 mp->pagesize, mp->curcache, mp->maxcache); 417 (void)fprintf(stderr, "%lu page puts, %lu page gets, %lu page new\n", 418 mp->pageput, mp->pageget, mp->pagenew); 419 (void)fprintf(stderr, "%lu page allocs, %lu page flushes\n", 420 mp->pagealloc, mp->pageflush); 421 if (mp->cachehit + mp->cachemiss) 422 (void)fprintf(stderr, 423 "%.0f%% cache hit rate (%lu hits, %lu misses)\n", 424 ((double)mp->cachehit / (mp->cachehit + mp->cachemiss)) 425 * 100, mp->cachehit, mp->cachemiss); 426 (void)fprintf(stderr, "%lu page reads, %lu page writes\n", 427 mp->pageread, mp->pagewrite); 428 429 sep = ""; 430 cnt = 0; 431 TAILQ_FOREACH(bp, &mp->lqh, q) { 432 (void)fprintf(stderr, "%s%d", sep, bp->pgno); 433 if (bp->flags & MPOOL_DIRTY) 434 (void)fprintf(stderr, "d"); 435 if (bp->flags & MPOOL_PINNED) 436 (void)fprintf(stderr, "P"); 437 if (++cnt == 10) { 438 sep = "\n"; 439 cnt = 0; 440 } else 441 sep = ", "; 442 443 } 444 (void)fprintf(stderr, "\n"); 445} 446#endif 447