freebsd-dev/lib/libc/db/mpool/mpool.c
Daniel Eischen d201fe46e3 Remove _THREAD_SAFE and make libc thread-safe by default by
adding (weak definitions to) stubs for some of the pthread
functions.  If the threads library is linked in, the real
pthread functions will pulled in.

Use the following convention for system calls wrapped by the
threads library:
	__sys_foo - actual system call
	_foo - weak definition to __sys_foo
	foo - weak definition to __sys_foo

Change all libc uses of system calls wrapped by the threads
library from foo to _foo.  In order to define the prototypes
for _foo(), we introduce namespace.h and un-namespace.h
(suggested by bde).  All files that need to reference these
system calls, should include namespace.h before any standard
includes, then include un-namespace.h after the standard
includes and before any local includes.  <db.h> is an exception
and shouldn't be included in between namespace.h and
un-namespace.h  namespace.h will define foo to _foo, and
un-namespace.h will undefine foo.

Try to eliminate some of the recursive calls to MT-safe
functions in libc/stdio in preparation for adding a mutex
to FILE.  We have recursive mutexes, but would like to avoid
using them if possible.

Remove uneeded includes of <errno.h> from a few files.

Add $FreeBSD$ to a few files in order to pass commitprep.

Approved by:	-arch
2001-01-24 13:01:12 +00:00

466 lines
10 KiB
C

/*-
* 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.
*
* $FreeBSD$
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)mpool.c 8.5 (Berkeley) 7/26/94";
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#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 "un-namespace.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);
TAILQ_INIT(&mp->lqh);
for (entry = 0; entry < HASHSIZE; ++entry)
TAILQ_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)];
TAILQ_INSERT_HEAD(head, bp, hq);
TAILQ_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)];
TAILQ_REMOVE(head, bp, hq);
TAILQ_INSERT_HEAD(head, bp, hq);
TAILQ_REMOVE(&mp->lqh, bp, q);
TAILQ_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)];
TAILQ_INSERT_HEAD(head, bp, hq);
TAILQ_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 (!TAILQ_EMPTY(&mp->lqh)) {
bp = TAILQ_FIRST(&mp->lqh);
TAILQ_REMOVE(&mp->lqh, bp, 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. */
TAILQ_FOREACH(bp, &mp->lqh, q)
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.
*/
TAILQ_FOREACH(bp, &mp->lqh, q)
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)];
TAILQ_REMOVE(head, bp, hq);
TAILQ_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)];
TAILQ_FOREACH(bp, head, hq)
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;
TAILQ_FOREACH(bp, &mp->lqh, q) {
(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