1 /* $OpenBSD: mpool.c,v 1.14 2005/08/05 13:03:00 espie Exp $ */
2
3 /*-
4 * Copyright © 2013
5 * Thorsten “mirabilos” Glaser <tg@mirbsd.org>
6 * Copyright (c) 1990, 1993, 1994
7 * The Regents of the University of California. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #include <sys/param.h>
35 #include <sys/queue.h>
36 #include <sys/stat.h>
37
38 #include <errno.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43
44 #include <db.h>
45
46 __RCSID("$MirOS: src/lib/libc/db/mpool/mpool.c,v 1.3 2013/10/31 20:06:17 tg Exp $");
47
48 #define __MPOOLINTERFACE_PRIVATE
49 #include <mpool.h>
50
51 static BKT *mpool_bkt(MPOOL *);
52 static BKT *mpool_look(MPOOL *, pgno_t);
53 static int mpool_write(MPOOL *, BKT *);
54
55 /*
56 * mpool_open --
57 * Initialize a memory pool.
58 */
59 /* ARGSUSED */
60 MPOOL *
mpool_open(void * key,int fd,pgno_t pagesize,pgno_t maxcache)61 mpool_open(void *key __attribute__((__unused__)), int fd, pgno_t pagesize,
62 pgno_t maxcache)
63 {
64 struct stat sb;
65 MPOOL *mp;
66 int entry;
67
68 /*
69 * Get information about the file.
70 *
71 * XXX
72 * We don't currently handle pipes, although we should.
73 */
74 if (fstat(fd, &sb))
75 return (NULL);
76 if (!S_ISREG(sb.st_mode)) {
77 errno = ESPIPE;
78 return (NULL);
79 }
80
81 /* Allocate and initialize the MPOOL cookie. */
82 if ((mp = (MPOOL *)calloc(1, sizeof(MPOOL))) == NULL)
83 return (NULL);
84 CIRCLEQ_INIT(&mp->lqh);
85 for (entry = 0; entry < HASHSIZE; ++entry)
86 CIRCLEQ_INIT(&mp->hqh[entry]);
87 mp->maxcache = maxcache;
88 mp->npages = sb.st_size / pagesize;
89 mp->pagesize = pagesize;
90 mp->fd = fd;
91 return (mp);
92 }
93
94 /*
95 * mpool_filter --
96 * Initialize input/output filters.
97 */
98 void
mpool_filter(MPOOL * mp,void (* pgin)(void *,pgno_t,void *),void (* pgout)(void *,pgno_t,void *),void * pgcookie)99 mpool_filter(MPOOL *mp, void (*pgin) (void *, pgno_t, void *),
100 void (*pgout) (void *, pgno_t, void *), void *pgcookie)
101 {
102 mp->pgin = pgin;
103 mp->pgout = pgout;
104 mp->pgcookie = pgcookie;
105 }
106
107 /*
108 * mpool_new --
109 * Get a new page of memory.
110 */
111 void *
mpool_new(MPOOL * mp,pgno_t * pgnoaddr,u_int flags)112 mpool_new(MPOOL *mp, pgno_t *pgnoaddr, u_int flags)
113 {
114 struct _hqh *head;
115 BKT *bp;
116
117 if (mp->npages == MAX_PAGE_NUMBER) {
118 (void)fprintf(stderr, "mpool_new: page allocation overflow.\n");
119 abort();
120 }
121 #ifdef STATISTICS
122 ++mp->pagenew;
123 #endif
124 /*
125 * Get a BKT from the cache. Assign a new page number, attach
126 * it to the head of the hash chain, the tail of the lru chain,
127 * and return.
128 */
129 if ((bp = mpool_bkt(mp)) == NULL)
130 return (NULL);
131 if (flags == MPOOL_PAGE_REQUEST) {
132 mp->npages++;
133 bp->pgno = *pgnoaddr;
134 } else
135 bp->pgno = *pgnoaddr = mp->npages++;
136
137 bp->flags = MPOOL_PINNED | MPOOL_INUSE;
138
139 head = &mp->hqh[HASHKEY(bp->pgno)];
140 CIRCLEQ_INSERT_HEAD(head, bp, hq);
141 CIRCLEQ_INSERT_TAIL(&mp->lqh, bp, q);
142 return (bp->page);
143 }
144
145 int
mpool_delete(MPOOL * mp,void * page)146 mpool_delete(MPOOL *mp, void *page)
147 {
148 struct _hqh *head;
149 BKT *bp;
150
151 bp = (BKT *)((char *)page - sizeof(BKT));
152
153 #ifdef DEBUG
154 if (!(bp->flags & MPOOL_PINNED)) {
155 (void)fprintf(stderr,
156 "mpool_delete: page %d not pinned\n", bp->pgno);
157 abort();
158 }
159 #endif
160
161 /* Remove from the hash and lru queues. */
162 head = &mp->hqh[HASHKEY(bp->pgno)];
163 CIRCLEQ_REMOVE(head, bp, hq);
164 CIRCLEQ_REMOVE(&mp->lqh, bp, q);
165
166 free(bp);
167 return (RET_SUCCESS);
168 }
169
170 /*
171 * mpool_get
172 * Get a page.
173 */
174 /* ARGSUSED */
175 void *
mpool_get(MPOOL * mp,pgno_t pgno,u_int flags)176 mpool_get(MPOOL *mp, pgno_t pgno,
177 u_int flags) /* XXX not used? */
178 {
179 struct _hqh *head;
180 BKT *bp;
181 off_t off;
182 int nr;
183
184 #ifdef STATISTICS
185 ++mp->pageget;
186 #endif
187
188 /* Check for a page that is cached. */
189 if ((bp = mpool_look(mp, pgno)) != NULL) {
190 #ifdef DEBUG
191 if (!(flags & MPOOL_IGNOREPIN) && bp->flags & MPOOL_PINNED) {
192 (void)fprintf(stderr,
193 "mpool_get: page %d already pinned\n", bp->pgno);
194 abort();
195 }
196 #endif
197 /*
198 * Move the page to the head of the hash chain and the tail
199 * of the lru chain.
200 */
201 head = &mp->hqh[HASHKEY(bp->pgno)];
202 CIRCLEQ_REMOVE(head, bp, hq);
203 CIRCLEQ_INSERT_HEAD(head, bp, hq);
204 CIRCLEQ_REMOVE(&mp->lqh, bp, q);
205 CIRCLEQ_INSERT_TAIL(&mp->lqh, bp, q);
206
207 /* Return a pinned page. */
208 bp->flags |= MPOOL_PINNED;
209 return (bp->page);
210 }
211
212 /* Get a page from the cache. */
213 if ((bp = mpool_bkt(mp)) == NULL)
214 return (NULL);
215
216 /* Read in the contents. */
217 #ifdef STATISTICS
218 ++mp->pageread;
219 #endif
220 off = mp->pagesize * pgno;
221 if ((off_t)(nr = pread(mp->fd, bp->page, mp->pagesize, off)) != mp->pagesize) {
222 switch (nr) {
223 case -1:
224 /* errno is set for us by pread(). */
225 return (NULL);
226 case 0:
227 /*
228 * A zero-length read means you need to create a
229 * new page.
230 */
231 memset(bp->page, 0, mp->pagesize);
232 default:
233 /* A partial read is definitely bad. */
234 errno = EINVAL;
235 return (NULL);
236 }
237 }
238
239 /* Set the page number, pin the page. */
240 bp->pgno = pgno;
241 if (!(flags & MPOOL_IGNOREPIN))
242 bp->flags = MPOOL_PINNED;
243 bp->flags |= MPOOL_INUSE;
244
245 /*
246 * Add the page to the head of the hash chain and the tail
247 * of the lru chain.
248 */
249 head = &mp->hqh[HASHKEY(bp->pgno)];
250 CIRCLEQ_INSERT_HEAD(head, bp, hq);
251 CIRCLEQ_INSERT_TAIL(&mp->lqh, bp, q);
252
253 /* Run through the user's filter. */
254 if (mp->pgin != NULL)
255 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page);
256
257 return (bp->page);
258 }
259
260 /*
261 * mpool_put
262 * Return a page.
263 */
264 /* ARGSUSED */
265 int
mpool_put(MPOOL * mp,void * page,u_int flags)266 mpool_put(MPOOL *mp __attribute__((__unused__)), void *page, u_int flags)
267 {
268 BKT *bp;
269
270 #ifdef STATISTICS
271 ++mp->pageput;
272 #endif
273 bp = (BKT *)((char *)page - sizeof(BKT));
274 #ifdef DEBUG
275 if (!(bp->flags & MPOOL_PINNED)) {
276 (void)fprintf(stderr,
277 "mpool_put: page %d not pinned\n", bp->pgno);
278 abort();
279 }
280 #endif
281 bp->flags &= ~MPOOL_PINNED;
282 if (flags & MPOOL_DIRTY)
283 bp->flags |= flags & MPOOL_DIRTY;
284 return (RET_SUCCESS);
285 }
286
287 /*
288 * mpool_close
289 * Close the buffer pool.
290 */
291 int
mpool_close(MPOOL * mp)292 mpool_close(MPOOL *mp)
293 {
294 BKT *bp;
295
296 /* Free up any space allocated to the lru pages. */
297 while ((bp = mp->lqh.cqh_first) != (void *)&mp->lqh) {
298 CIRCLEQ_REMOVE(&mp->lqh, mp->lqh.cqh_first, q);
299 free(bp);
300 }
301
302 /* Free the MPOOL cookie. */
303 free(mp);
304 return (RET_SUCCESS);
305 }
306
307 /*
308 * mpool_sync
309 * Sync the pool to disk.
310 */
311 int
mpool_sync(MPOOL * mp)312 mpool_sync(MPOOL *mp)
313 {
314 BKT *bp;
315
316 /* Walk the lru chain, flushing any dirty pages to disk. */
317 for (bp = mp->lqh.cqh_first;
318 bp != (void *)&mp->lqh; bp = bp->q.cqe_next)
319 if (bp->flags & MPOOL_DIRTY &&
320 mpool_write(mp, bp) == RET_ERROR)
321 return (RET_ERROR);
322
323 /* Sync the file descriptor. */
324 return (fsync(mp->fd) ? RET_ERROR : RET_SUCCESS);
325 }
326
327 /*
328 * mpool_bkt
329 * Get a page from the cache (or create one).
330 */
331 static BKT *
mpool_bkt(MPOOL * mp)332 mpool_bkt(MPOOL *mp)
333 {
334 struct _hqh *head;
335 BKT *bp;
336
337 /* If under the max cached, always create a new page. */
338 if (mp->curcache < mp->maxcache)
339 goto new;
340
341 /*
342 * If the cache is max'd out, walk the lru list for a buffer we
343 * can flush. If we find one, write it (if necessary) and take it
344 * off any lists. If we don't find anything we grow the cache anyway.
345 * The cache never shrinks.
346 */
347 for (bp = mp->lqh.cqh_first;
348 bp != (void *)&mp->lqh; bp = bp->q.cqe_next)
349 if (!(bp->flags & MPOOL_PINNED)) {
350 /* Flush if dirty. */
351 if (bp->flags & MPOOL_DIRTY &&
352 mpool_write(mp, bp) == RET_ERROR)
353 return (NULL);
354 #ifdef STATISTICS
355 ++mp->pageflush;
356 #endif
357 /* Remove from the hash and lru queues. */
358 head = &mp->hqh[HASHKEY(bp->pgno)];
359 CIRCLEQ_REMOVE(head, bp, hq);
360 CIRCLEQ_REMOVE(&mp->lqh, bp, q);
361 #ifdef DEBUG
362 { void *spage;
363 spage = bp->page;
364 memset(bp, 0xff, sizeof(BKT) + mp->pagesize);
365 bp->page = spage;
366 }
367 #endif
368 bp->flags = 0;
369 return (bp);
370 }
371
372 new: if ((bp = (BKT *)malloc(sizeof(BKT) + mp->pagesize)) == NULL)
373 return (NULL);
374 #ifdef STATISTICS
375 ++mp->pagealloc;
376 #endif
377 memset(bp, 0xff, sizeof(BKT) + mp->pagesize);
378 bp->page = (char *)bp + sizeof(BKT);
379 bp->flags = 0;
380 ++mp->curcache;
381 return (bp);
382 }
383
384 /*
385 * mpool_write
386 * Write a page to disk.
387 */
388 static int
mpool_write(MPOOL * mp,BKT * bp)389 mpool_write(MPOOL *mp, BKT *bp)
390 {
391 off_t off;
392
393 #ifdef STATISTICS
394 ++mp->pagewrite;
395 #endif
396
397 /* Run through the user's filter. */
398 if (mp->pgout)
399 (mp->pgout)(mp->pgcookie, bp->pgno, bp->page);
400
401 off = mp->pagesize * bp->pgno;
402 if ((off_t)pwrite(mp->fd, bp->page, mp->pagesize, off) != mp->pagesize)
403 return (RET_ERROR);
404
405 /*
406 * Re-run through the input filter since this page may soon be
407 * accessed via the cache, and whatever the user's output filter
408 * did may screw things up if we don't let the input filter
409 * restore the in-core copy.
410 */
411 if (mp->pgin)
412 (mp->pgin)(mp->pgcookie, bp->pgno, bp->page);
413
414 bp->flags &= ~MPOOL_DIRTY;
415 return (RET_SUCCESS);
416 }
417
418 /*
419 * mpool_look
420 * Lookup a page in the cache.
421 */
422 static BKT *
mpool_look(MPOOL * mp,pgno_t pgno)423 mpool_look(MPOOL *mp, pgno_t pgno)
424 {
425 struct _hqh *head;
426 BKT *bp;
427
428 head = &mp->hqh[HASHKEY(pgno)];
429 for (bp = head->cqh_first; bp != (void *)head; bp = bp->hq.cqe_next)
430 if ((bp->pgno == pgno) &&
431 ((bp->flags & MPOOL_INUSE) == MPOOL_INUSE)) {
432 #ifdef STATISTICS
433 ++mp->cachehit;
434 #endif
435 return (bp);
436 }
437 #ifdef STATISTICS
438 ++mp->cachemiss;
439 #endif
440 return (NULL);
441 }
442
443 #ifdef STATISTICS
444 /*
445 * mpool_stat
446 * Print out cache statistics.
447 */
448 void
mpool_stat(MPOOL * mp)449 mpool_stat(MPOOL *mp)
450 {
451 BKT *bp;
452 int cnt;
453 char *sep;
454
455 (void)fprintf(stderr, "%lu pages in the file\n", mp->npages);
456 (void)fprintf(stderr,
457 "page size %lu, cacheing %lu pages of %lu page max cache\n",
458 mp->pagesize, mp->curcache, mp->maxcache);
459 (void)fprintf(stderr, "%lu page puts, %lu page gets, %lu page new\n",
460 mp->pageput, mp->pageget, mp->pagenew);
461 (void)fprintf(stderr, "%lu page allocs, %lu page flushes\n",
462 mp->pagealloc, mp->pageflush);
463 if (mp->cachehit + mp->cachemiss)
464 (void)fprintf(stderr,
465 "%.0f%% cache hit rate (%lu hits, %lu misses)\n",
466 ((double)mp->cachehit / (mp->cachehit + mp->cachemiss))
467 * 100, mp->cachehit, mp->cachemiss);
468 (void)fprintf(stderr, "%lu page reads, %lu page writes\n",
469 mp->pageread, mp->pagewrite);
470
471 sep = "";
472 cnt = 0;
473 for (bp = mp->lqh.cqh_first;
474 bp != (void *)&mp->lqh; bp = bp->q.cqe_next) {
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