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authorRodney W. Grimes <rgrimes@FreeBSD.org>1994-05-24 09:57:34 +0000
committerRodney W. Grimes <rgrimes@FreeBSD.org>1994-05-24 09:57:34 +0000
commit59deaec541ae8baaa58daf6c5a2196ea7de180c3 (patch)
tree09f0848dc45f73d9ec271a31af87eaf035d17dd2 /include/mpool.h
parent628b2ef68cdc04f2b5d5ec381ab5bc16f16bb7f6 (diff)
downloadsrc-59deaec541ae8baaa58daf6c5a2196ea7de180c3.tar.gz
src-59deaec541ae8baaa58daf6c5a2196ea7de180c3.zip
BSD 4.4 Lite Include Sources
Notes
Notes: svn path=/head/; revision=1539
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+/*-
+ * Copyright (c) 1991, 1993
+ * 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.
+ *
+ * @(#)mpool.h 8.1 (Berkeley) 6/2/93
+ */
+
+/*
+ * The memory pool scheme is a simple one. Each in memory page is referenced
+ * by a bucket which is threaded in three ways. All active pages are threaded
+ * on a hash chain (hashed by the page number) and an lru chain. Inactive
+ * pages are threaded on a free chain. Each reference to a memory pool is
+ * handed an MPOOL which is the opaque cookie passed to all of the memory
+ * routines.
+ */
+#define HASHSIZE 128
+#define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
+
+/* The BKT structures are the elements of the lists. */
+typedef struct BKT {
+ struct BKT *hnext; /* next hash bucket */
+ struct BKT *hprev; /* previous hash bucket */
+ struct BKT *cnext; /* next free/lru bucket */
+ struct BKT *cprev; /* previous free/lru bucket */
+ void *page; /* page */
+ pgno_t pgno; /* page number */
+
+#define MPOOL_DIRTY 0x01 /* page needs to be written */
+#define MPOOL_PINNED 0x02 /* page is pinned into memory */
+ unsigned long flags; /* flags */
+} BKT;
+
+/* The BKTHDR structures are the heads of the lists. */
+typedef struct BKTHDR {
+ struct BKT *hnext; /* next hash bucket */
+ struct BKT *hprev; /* previous hash bucket */
+ struct BKT *cnext; /* next free/lru bucket */
+ struct BKT *cprev; /* previous free/lru bucket */
+} BKTHDR;
+
+typedef struct MPOOL {
+ BKTHDR free; /* The free list. */
+ BKTHDR lru; /* The LRU list. */
+ BKTHDR hashtable[HASHSIZE]; /* Hashed list by page number. */
+ pgno_t curcache; /* Current number of cached pages. */
+ pgno_t maxcache; /* Max number of cached pages. */
+ pgno_t npages; /* Number of pages in the file. */
+ u_long pagesize; /* File page size. */
+ int fd; /* File descriptor. */
+ /* Page in conversion routine. */
+ void (*pgin) __P((void *, pgno_t, void *));
+ /* Page out conversion routine. */
+ void (*pgout) __P((void *, pgno_t, void *));
+ void *pgcookie; /* Cookie for page in/out routines. */
+#ifdef STATISTICS
+ unsigned long cachehit;
+ unsigned long cachemiss;
+ unsigned long pagealloc;
+ unsigned long pageflush;
+ unsigned long pageget;
+ unsigned long pagenew;
+ unsigned long pageput;
+ unsigned long pageread;
+ unsigned long pagewrite;
+#endif
+} MPOOL;
+
+#ifdef __MPOOLINTERFACE_PRIVATE
+/* Macros to insert/delete into/from hash chain. */
+#define rmhash(bp) { \
+ (bp)->hprev->hnext = (bp)->hnext; \
+ (bp)->hnext->hprev = (bp)->hprev; \
+}
+#define inshash(bp, pg) { \
+ hp = &mp->hashtable[HASHKEY(pg)]; \
+ (bp)->hnext = hp->hnext; \
+ (bp)->hprev = (struct BKT *)hp; \
+ hp->hnext->hprev = (bp); \
+ hp->hnext = (bp); \
+}
+
+/* Macros to insert/delete into/from lru and free chains. */
+#define rmchain(bp) { \
+ (bp)->cprev->cnext = (bp)->cnext; \
+ (bp)->cnext->cprev = (bp)->cprev; \
+}
+#define inschain(bp, dp) { \
+ (bp)->cnext = (dp)->cnext; \
+ (bp)->cprev = (struct BKT *)(dp); \
+ (dp)->cnext->cprev = (bp); \
+ (dp)->cnext = (bp); \
+}
+#endif
+
+__BEGIN_DECLS
+MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t));
+void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
+ void (*)(void *, pgno_t, void *), void *));
+void *mpool_new __P((MPOOL *, pgno_t *));
+void *mpool_get __P((MPOOL *, pgno_t, u_int));
+int mpool_put __P((MPOOL *, void *, u_int));
+int mpool_sync __P((MPOOL *));
+int mpool_close __P((MPOOL *));
+#ifdef STATISTICS
+void mpool_stat __P((MPOOL *));
+#endif
+__END_DECLS