aboutsummaryrefslogtreecommitdiff
path: root/db/mpool
diff options
context:
space:
mode:
authorRoland McGrath <roland@gnu.org>1996-01-02 08:57:42 +0000
committerRoland McGrath <roland@gnu.org>1996-01-02 08:57:42 +0000
commit71733723fb421bd54467d1a27096463ed1dcc2ed (patch)
treef304556d491722c797d876911834dc4afbfa2740 /db/mpool
parentfc4026d8e43407ba2739e493878d1ce259500059 (diff)
downloadglibc-71733723fb421bd54467d1a27096463ed1dcc2ed.zip
glibc-71733723fb421bd54467d1a27096463ed1dcc2ed.tar.gz
glibc-71733723fb421bd54467d1a27096463ed1dcc2ed.tar.bz2
* hurd/hurd/signal.h (struct hurd_sigstate): New member `preempters'.cvs/libc-960102
(hurd_preempt_signals, hurd_unpreempt_signals): Decls removed. * hurd/hurd/sigpreempt.h: New file. * hurd/preempt-sig.c: Rewritten with new interface. * sysdeps/mach/hurd/jmp-unwind.c (_longjmp_unwind): Remove local signal preempters being unwound past. * db: New directory, 4.4 BSD db package incorporated from BSD db-1.85 release. * sysdeps/unix/sysv/linux/sys/param.h: Several new macros for BSD compatibility.
Diffstat (limited to 'db/mpool')
-rw-r--r--db/mpool/mpool.c463
1 files changed, 463 insertions, 0 deletions
diff --git a/db/mpool/mpool.c b/db/mpool/mpool.c
new file mode 100644
index 0000000..a61041e
--- /dev/null
+++ b/db/mpool/mpool.c
@@ -0,0 +1,463 @@
+/*-
+ * Copyright (c) 1990, 1993, 1994
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)mpool.c 8.5 (Berkeley) 7/26/94";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/param.h>
+#include <sys/queue.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <db.h>
+
+#define __MPOOLINTERFACE_PRIVATE
+#include <mpool.h>
+
+static BKT *mpool_bkt __P((MPOOL *));
+static BKT *mpool_look __P((MPOOL *, pgno_t));
+static int mpool_write __P((MPOOL *, BKT *));
+
+/*
+ * mpool_open --
+ * Initialize a memory pool.
+ */
+MPOOL *
+mpool_open(key, fd, pagesize, maxcache)
+ void *key;
+ int fd;
+ pgno_t pagesize, maxcache;
+{
+ struct stat sb;
+ MPOOL *mp;
+ int entry;
+
+ /*
+ * Get information about the file.
+ *
+ * XXX
+ * We don't currently handle pipes, although we should.
+ */
+ if (fstat(fd, &sb))
+ return (NULL);
+ if (!S_ISREG(sb.st_mode)) {
+ errno = ESPIPE;
+ return (NULL);
+ }
+
+ /* Allocate and initialize the MPOOL cookie. */
+ if ((mp = (MPOOL *)calloc(1, sizeof(MPOOL))) == NULL)
+ return (NULL);
+ CIRCLEQ_INIT(&mp->lqh);
+ for (entry = 0; entry < HASHSIZE; ++entry)
+ CIRCLEQ_INIT(&mp->hqh[entry]);
+ mp->maxcache = maxcache;
+ mp->npages = sb.st_size / pagesize;
+ mp->pagesize = pagesize;
+ mp->fd = fd;
+ return (mp);
+}
+
+/*
+ * mpool_filter --
+ * Initialize input/output filters.
+ */
+void
+mpool_filter(mp, pgin, pgout, pgcookie)
+ MPOOL *mp;
+ void (*pgin) __P((void *, pgno_t, void *));
+ void (*pgout) __P((void *, pgno_t, void *));
+ void *pgcookie;
+{
+ mp->pgin = pgin;
+ mp->pgout = pgout;
+ mp->pgcookie = pgcookie;
+}
+
+/*
+ * mpool_new --
+ * Get a new page of memory.
+ */
+void *
+mpool_new(mp, pgnoaddr)
+ MPOOL *mp;
+ pgno_t *pgnoaddr;
+{
+ struct _hqh *head;
+ BKT *bp;
+
+ if (mp->npages == MAX_PAGE_NUMBER) {
+ (void)fprintf(stderr, "mpool_new: page allocation overflow.\n");
+ abort();
+ }
+#ifdef STATISTICS
+ ++mp->pagenew;
+#endif
+ /*
+ * Get a BKT from the cache. Assign a new page number, attach
+ * it to the head of the hash chain, the tail of the lru chain,
+ * and return.
+ */
+ if ((bp = mpool_bkt(mp)) == NULL)
+ return (NULL);
+ *pgnoaddr = bp->pgno = mp->npages++;
+ bp->flags = MPOOL_PINNED;
+
+ head = &mp->hqh[HASHKEY(bp->pgno)];
+ CIRCLEQ_INSERT_HEAD(head, bp, hq);
+ CIRCLEQ_INSERT_TAIL(&mp->lqh, bp, q);
+ return (bp->page);
+}
+
+/*
+ * mpool_get
+ * Get a page.
+ */
+void *
+mpool_get(mp, pgno, flags)
+ MPOOL *mp;
+ pgno_t pgno;
+ u_int flags; /* XXX not used? */
+{
+ struct _hqh *head;
+ BKT *bp;
+ off_t off;
+ int nr;
+
+ /* Check for attempt to retrieve a non-existent page. */
+ if (pgno >= mp->npages) {
+ errno = EINVAL;
+ return (NULL);
+ }
+
+#ifdef STATISTICS
+ ++mp->pageget;
+#endif
+
+ /* Check for a page that is cached. */
+ if ((bp = mpool_look(mp, pgno)) != NULL) {
+#ifdef DEBUG
+ if (bp->flags & MPOOL_PINNED) {
+ (void)fprintf(stderr,
+ "mpool_get: page %d already pinned\n", bp->pgno);
+ abort();
+ }
+#endif
+ /*
+ * Move the page to the head of the hash chain and the tail
+ * of the lru chain.
+ */
+ head = &mp->hqh[HASHKEY(bp->pgno)];
+ CIRCLEQ_REMOVE(head, bp, hq);
+ CIRCLEQ_INSERT_HEAD(head, bp, hq);
+ CIRCLEQ_REMOVE(&mp->lqh, bp, q);
+ CIRCLEQ_INSERT_TAIL(&mp->lqh, bp, q);
+
+ /* Return a pinned page. */
+ bp->flags |= MPOOL_PINNED;
+ return (bp->page);
+ }
+
+ /* Get a page from the cache. */
+ if ((bp = mpool_bkt(mp)) == NULL)
+ return (NULL);
+
+ /* Read in the contents. */
+#ifdef STATISTICS
+ ++mp->pageread;
+#endif
+ off = mp->pagesize * pgno;
+ if (lseek(mp->fd, off, SEEK_SET) != off)
+ return (NULL);
+ if ((nr = read(mp->fd, bp->page, mp->pagesize)) != mp->pagesize) {
+ if (nr >= 0)
+ errno = EFTYPE;
+ return (NULL);
+ }
+
+ /* Set the page number, pin the page. */
+ bp->pgno = pgno;
+ bp->flags = MPOOL_PINNED;
+
+ /*
+ * Add the page to the head of the hash chain and the tail
+ * of the lru chain.
+ */
+ head = &mp->hqh[HASHKEY(bp->pgno)];
+ CIRCLEQ_INSERT_HEAD(head, bp, hq);
+ CIRCLEQ_INSERT_TAIL(&mp->lqh, bp, q);
+
+ /* Run through the user's filter. */
+ if (mp->pgin != NULL)
+ (mp->pgin)(mp->pgcookie, bp->pgno, bp->page);
+
+ return (bp->page);
+}
+
+/*
+ * mpool_put
+ * Return a page.
+ */
+int
+mpool_put(mp, page, flags)
+ MPOOL *mp;
+ void *page;
+ u_int flags;
+{
+ BKT *bp;
+
+#ifdef STATISTICS
+ ++mp->pageput;
+#endif
+ bp = (BKT *)((char *)page - sizeof(BKT));
+#ifdef DEBUG
+ if (!(bp->flags & MPOOL_PINNED)) {
+ (void)fprintf(stderr,
+ "mpool_put: page %d not pinned\n", bp->pgno);
+ abort();
+ }
+#endif
+ bp->flags &= ~MPOOL_PINNED;
+ bp->flags |= flags & MPOOL_DIRTY;
+ return (RET_SUCCESS);
+}
+
+/*
+ * mpool_close
+ * Close the buffer pool.
+ */
+int
+mpool_close(mp)
+ MPOOL *mp;
+{
+ BKT *bp;
+
+ /* Free up any space allocated to the lru pages. */
+ while ((bp = mp->lqh.cqh_first) != (void *)&mp->lqh) {
+ CIRCLEQ_REMOVE(&mp->lqh, mp->lqh.cqh_first, q);
+ free(bp);
+ }
+
+ /* Free the MPOOL cookie. */
+ free(mp);
+ return (RET_SUCCESS);
+}
+
+/*
+ * mpool_sync
+ * Sync the pool to disk.
+ */
+int
+mpool_sync(mp)
+ MPOOL *mp;
+{
+ BKT *bp;
+
+ /* Walk the lru chain, flushing any dirty pages to disk. */
+ for (bp = mp->lqh.cqh_first;
+ bp != (void *)&mp->lqh; bp = bp->q.cqe_next)
+ if (bp->flags & MPOOL_DIRTY &&
+ mpool_write(mp, bp) == RET_ERROR)
+ return (RET_ERROR);
+
+ /* Sync the file descriptor. */
+ return (fsync(mp->fd) ? RET_ERROR : RET_SUCCESS);
+}
+
+/*
+ * mpool_bkt
+ * Get a page from the cache (or create one).
+ */
+static BKT *
+mpool_bkt(mp)
+ MPOOL *mp;
+{
+ struct _hqh *head;
+ BKT *bp;
+
+ /* If under the max cached, always create a new page. */
+ if (mp->curcache < mp->maxcache)
+ goto new;
+
+ /*
+ * If the cache is max'd out, walk the lru list for a buffer we
+ * can flush. If we find one, write it (if necessary) and take it
+ * off any lists. If we don't find anything we grow the cache anyway.
+ * The cache never shrinks.
+ */
+ for (bp = mp->lqh.cqh_first;
+ bp != (void *)&mp->lqh; bp = bp->q.cqe_next)
+ if (!(bp->flags & MPOOL_PINNED)) {
+ /* Flush if dirty. */
+ if (bp->flags & MPOOL_DIRTY &&
+ mpool_write(mp, bp) == RET_ERROR)
+ return (NULL);
+#ifdef STATISTICS
+ ++mp->pageflush;
+#endif
+ /* Remove from the hash and lru queues. */
+ head = &mp->hqh[HASHKEY(bp->pgno)];
+ CIRCLEQ_REMOVE(head, bp, hq);
+ CIRCLEQ_REMOVE(&mp->lqh, bp, q);
+#ifdef DEBUG
+ { void *spage;
+ spage = bp->page;
+ memset(bp, 0xff, sizeof(BKT) + mp->pagesize);
+ bp->page = spage;
+ }
+#endif
+ return (bp);
+ }
+
+new: if ((bp = (BKT *)malloc(sizeof(BKT) + mp->pagesize)) == NULL)
+ return (NULL);
+#ifdef STATISTICS
+ ++mp->pagealloc;
+#endif
+#if defined(DEBUG) || defined(PURIFY)
+ memset(bp, 0xff, sizeof(BKT) + mp->pagesize);
+#endif
+ bp->page = (char *)bp + sizeof(BKT);
+ ++mp->curcache;
+ return (bp);
+}
+
+/*
+ * mpool_write
+ * Write a page to disk.
+ */
+static int
+mpool_write(mp, bp)
+ MPOOL *mp;
+ BKT *bp;
+{
+ off_t off;
+
+#ifdef STATISTICS
+ ++mp->pagewrite;
+#endif
+
+ /* Run through the user's filter. */
+ if (mp->pgout)
+ (mp->pgout)(mp->pgcookie, bp->pgno, bp->page);
+
+ off = mp->pagesize * bp->pgno;
+ if (lseek(mp->fd, off, SEEK_SET) != off)
+ return (RET_ERROR);
+ if (write(mp->fd, bp->page, mp->pagesize) != mp->pagesize)
+ return (RET_ERROR);
+
+ bp->flags &= ~MPOOL_DIRTY;
+ return (RET_SUCCESS);
+}
+
+/*
+ * mpool_look
+ * Lookup a page in the cache.
+ */
+static BKT *
+mpool_look(mp, pgno)
+ MPOOL *mp;
+ pgno_t pgno;
+{
+ struct _hqh *head;
+ BKT *bp;
+
+ head = &mp->hqh[HASHKEY(pgno)];
+ for (bp = head->cqh_first; bp != (void *)head; bp = bp->hq.cqe_next)
+ if (bp->pgno == pgno) {
+#ifdef STATISTICS
+ ++mp->cachehit;
+#endif
+ return (bp);
+ }
+#ifdef STATISTICS
+ ++mp->cachemiss;
+#endif
+ return (NULL);
+}
+
+#ifdef STATISTICS
+/*
+ * mpool_stat
+ * Print out cache statistics.
+ */
+void
+mpool_stat(mp)
+ MPOOL *mp;
+{
+ BKT *bp;
+ int cnt;
+ char *sep;
+
+ (void)fprintf(stderr, "%lu pages in the file\n", mp->npages);
+ (void)fprintf(stderr,
+ "page size %lu, cacheing %lu pages of %lu page max cache\n",
+ mp->pagesize, mp->curcache, mp->maxcache);
+ (void)fprintf(stderr, "%lu page puts, %lu page gets, %lu page new\n",
+ mp->pageput, mp->pageget, mp->pagenew);
+ (void)fprintf(stderr, "%lu page allocs, %lu page flushes\n",
+ mp->pagealloc, mp->pageflush);
+ if (mp->cachehit + mp->cachemiss)
+ (void)fprintf(stderr,
+ "%.0f%% cache hit rate (%lu hits, %lu misses)\n",
+ ((double)mp->cachehit / (mp->cachehit + mp->cachemiss))
+ * 100, mp->cachehit, mp->cachemiss);
+ (void)fprintf(stderr, "%lu page reads, %lu page writes\n",
+ mp->pageread, mp->pagewrite);
+
+ sep = "";
+ cnt = 0;
+ for (bp = mp->lqh.cqh_first;
+ bp != (void *)&mp->lqh; bp = bp->q.cqe_next) {
+ (void)fprintf(stderr, "%s%d", sep, bp->pgno);
+ if (bp->flags & MPOOL_DIRTY)
+ (void)fprintf(stderr, "d");
+ if (bp->flags & MPOOL_PINNED)
+ (void)fprintf(stderr, "P");
+ if (++cnt == 10) {
+ sep = "\n";
+ cnt = 0;
+ } else
+ sep = ", ";
+
+ }
+ (void)fprintf(stderr, "\n");
+}
+#endif