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2c874db2dd
* db2/btree/bt_cursor.c: Likewise. * db2/common/db_region.db_c: Likewise. * db2/common/db_salloc.db_c: Likewise. * db2/db/db.c: Likewise. * db2/db/db_rec.c: Likewise. * db2/hash/hash.c: Likewise. * db2/hash/hash_page.c: Likewise. * db2/hash/hash_rec.c: Likewise. * db2/log/log_findckp.c: Likewise. * db2/log/log_get.c: Likewise. * db2/log/log_put.c: Likewise. * db2/mp/mp_fget.c: Likewise. * db2/mp/mp_fput.c: Likewise. * db2/mp/mp_region.c: Likewise.
309 lines
7.6 KiB
C
309 lines
7.6 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996, 1997, 1998
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* Sleepycat Software. All rights reserved.
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*/
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#include "config.h"
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#ifndef lint
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static const char sccsid[] = "@(#)mp_region.c 10.30 (Sleepycat) 5/31/98";
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#endif /* not lint */
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#ifndef NO_SYSTEM_INCLUDES
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#include <sys/types.h>
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#include <errno.h>
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#include <string.h>
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#endif
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#include "db_int.h"
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#include "shqueue.h"
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#include "db_shash.h"
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#include "mp.h"
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#include "common_ext.h"
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/*
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* __memp_ralloc --
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* Allocate some space in the mpool region.
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*
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* PUBLIC: int __memp_ralloc __P((DB_MPOOL *, size_t, size_t *, void *));
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*/
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int
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__memp_ralloc(dbmp, len, offsetp, retp)
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DB_MPOOL *dbmp;
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size_t len, *offsetp;
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void *retp;
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{
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BH *bhp, *nbhp;
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MPOOL *mp;
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MPOOLFILE *mfp;
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size_t fsize, total;
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int nomore, restart, ret, wrote;
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void *p;
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mp = dbmp->mp;
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nomore = 0;
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alloc: if ((ret = __db_shalloc(dbmp->addr, len, MUTEX_ALIGNMENT, &p)) == 0) {
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if (offsetp != NULL)
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*offsetp = R_OFFSET(dbmp, p);
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*(void **)retp = p;
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return (0);
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}
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if (nomore) {
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__db_err(dbmp->dbenv, "%s", strerror(ret));
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return (ret);
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}
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/* Look for a buffer on the free list that's the right size. */
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for (bhp =
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SH_TAILQ_FIRST(&mp->bhfq, __bh); bhp != NULL; bhp = nbhp) {
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nbhp = SH_TAILQ_NEXT(bhp, q, __bh);
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if (__db_shsizeof(bhp) == len) {
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SH_TAILQ_REMOVE(&mp->bhfq, bhp, q, __bh);
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if (offsetp != NULL)
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*offsetp = R_OFFSET(dbmp, bhp);
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*(void **)retp = bhp;
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return (0);
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}
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}
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/* Discard from the free list until we've freed enough memory. */
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total = 0;
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for (bhp =
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SH_TAILQ_FIRST(&mp->bhfq, __bh); bhp != NULL; bhp = nbhp) {
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nbhp = SH_TAILQ_NEXT(bhp, q, __bh);
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SH_TAILQ_REMOVE(&mp->bhfq, bhp, q, __bh);
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__db_shalloc_free(dbmp->addr, bhp);
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--mp->stat.st_page_clean;
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/*
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* Retry as soon as we've freed up sufficient space. If we
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* will have to coalesce memory to satisfy the request, don't
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* try until it's likely (possible?) that we'll succeed.
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*/
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total += fsize = __db_shsizeof(bhp);
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if (fsize >= len || total >= 3 * len)
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goto alloc;
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}
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retry: /* Find a buffer we can flush; pure LRU. */
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total = 0;
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for (bhp =
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SH_TAILQ_FIRST(&mp->bhq, __bh); bhp != NULL; bhp = nbhp) {
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nbhp = SH_TAILQ_NEXT(bhp, q, __bh);
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/* Ignore pinned or locked (I/O in progress) buffers. */
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if (bhp->ref != 0 || F_ISSET(bhp, BH_LOCKED))
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continue;
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/* Find the associated MPOOLFILE. */
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mfp = R_ADDR(dbmp, bhp->mf_offset);
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/*
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* Write the page if it's dirty.
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*
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* If we wrote the page, fall through and free the buffer. We
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* don't have to rewalk the list to acquire the buffer because
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* it was never available for any other process to modify it.
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* If we didn't write the page, but we discarded and reacquired
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* the region lock, restart the buffer list walk. If we neither
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* wrote the buffer nor discarded the region lock, continue down
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* the buffer list.
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*/
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if (F_ISSET(bhp, BH_DIRTY)) {
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if ((ret = __memp_bhwrite(dbmp,
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mfp, bhp, &restart, &wrote)) != 0)
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return (ret);
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/*
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* It's possible that another process wants this buffer
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* and incremented the ref count while we were writing
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* it.
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*/
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if (bhp->ref != 0)
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goto retry;
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if (wrote)
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++mp->stat.st_rw_evict;
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else {
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if (restart)
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goto retry;
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continue;
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}
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} else
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++mp->stat.st_ro_evict;
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/*
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* Check to see if the buffer is the size we're looking for.
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* If it is, simply reuse it.
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*/
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total += fsize = __db_shsizeof(bhp);
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if (fsize == len) {
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__memp_bhfree(dbmp, mfp, bhp, 0);
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if (offsetp != NULL)
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*offsetp = R_OFFSET(dbmp, bhp);
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*(void **)retp = bhp;
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return (0);
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}
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/* Free the buffer. */
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__memp_bhfree(dbmp, mfp, bhp, 1);
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/*
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* Retry as soon as we've freed up sufficient space. If we
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* have to coalesce of memory to satisfy the request, don't
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* try until it's likely (possible?) that we'll succeed.
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*/
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if (fsize >= len || total >= 3 * len)
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goto alloc;
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/* Restart the walk if we discarded the region lock. */
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if (restart)
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goto retry;
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}
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nomore = 1;
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goto alloc;
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}
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/*
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* __memp_ropen --
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* Attach to, and optionally create, the mpool region.
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*
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* PUBLIC: int __memp_ropen
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* PUBLIC: __P((DB_MPOOL *, const char *, size_t, int, int, u_int32_t));
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*/
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int
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__memp_ropen(dbmp, path, cachesize, mode, is_private, flags)
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DB_MPOOL *dbmp;
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const char *path;
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size_t cachesize;
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int mode, is_private;
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u_int32_t flags;
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{
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MPOOL *mp;
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size_t rlen;
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int defcache, ret;
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/*
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* Unlike other DB subsystems, mpool can't simply grow the region
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* because it returns pointers into the region to its clients. To
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* "grow" the region, we'd have to allocate a new region and then
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* store a region number in the structures that reference regional
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* objects. It's reasonable that we fail regardless, as clients
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* shouldn't have every page in the region pinned, so the only
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* "failure" mode should be a performance penalty because we don't
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* find a page in the cache that we'd like to have found.
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*
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* Up the user's cachesize by 25% to account for our overhead.
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*/
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defcache = 0;
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if (cachesize < DB_CACHESIZE_MIN) {
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if (cachesize == 0) {
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defcache = 1;
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cachesize = DB_CACHESIZE_DEF;
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} else
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cachesize = DB_CACHESIZE_MIN;
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}
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rlen = cachesize + cachesize / 4;
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/*
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* Map in the region.
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*
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* If it's a private mpool, use malloc, it's a lot faster than
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* instantiating a region.
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*/
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dbmp->reginfo.dbenv = dbmp->dbenv;
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dbmp->reginfo.appname = DB_APP_NONE;
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if (path == NULL)
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dbmp->reginfo.path = NULL;
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else
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if ((dbmp->reginfo.path = __db_strdup(path)) == NULL)
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return (ENOMEM);
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dbmp->reginfo.file = DB_DEFAULT_MPOOL_FILE;
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dbmp->reginfo.mode = mode;
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dbmp->reginfo.size = rlen;
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dbmp->reginfo.dbflags = flags;
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dbmp->reginfo.flags = 0;
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if (defcache)
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F_SET(&dbmp->reginfo, REGION_SIZEDEF);
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/*
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* If we're creating a temporary region, don't use any standard
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* naming.
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*/
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if (is_private) {
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dbmp->reginfo.appname = DB_APP_TMP;
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dbmp->reginfo.file = NULL;
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F_SET(&dbmp->reginfo, REGION_PRIVATE);
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}
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if ((ret = __db_rattach(&dbmp->reginfo)) != 0) {
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if (dbmp->reginfo.path != NULL)
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FREES(dbmp->reginfo.path);
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return (ret);
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}
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/*
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* The MPOOL structure is first in the region, the rest of the region
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* is free space.
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*/
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dbmp->mp = dbmp->reginfo.addr;
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dbmp->addr = (u_int8_t *)dbmp->mp + sizeof(MPOOL);
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/* Initialize a created region. */
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if (F_ISSET(&dbmp->reginfo, REGION_CREATED)) {
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mp = dbmp->mp;
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SH_TAILQ_INIT(&mp->bhq);
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SH_TAILQ_INIT(&mp->bhfq);
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SH_TAILQ_INIT(&mp->mpfq);
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__db_shalloc_init(dbmp->addr, rlen - sizeof(MPOOL));
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/*
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* Assume we want to keep the hash chains with under 10 pages
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* on each chain. We don't know the pagesize in advance, and
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* it may differ for different files. Use a pagesize of 1K for
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* the calculation -- we walk these chains a lot, they should
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* be short.
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*/
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mp->htab_buckets =
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__db_tablesize((cachesize / (1 * 1024)) / 10);
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/* Allocate hash table space and initialize it. */
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if ((ret = __db_shalloc(dbmp->addr,
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mp->htab_buckets * sizeof(DB_HASHTAB),
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0, &dbmp->htab)) != 0)
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goto err;
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__db_hashinit(dbmp->htab, mp->htab_buckets);
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mp->htab = R_OFFSET(dbmp, dbmp->htab);
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ZERO_LSN(mp->lsn);
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mp->lsn_cnt = 0;
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memset(&mp->stat, 0, sizeof(mp->stat));
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mp->stat.st_cachesize = cachesize;
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mp->flags = 0;
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}
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/* Get the local hash table address. */
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dbmp->htab = R_ADDR(dbmp, dbmp->mp->htab);
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UNLOCKREGION(dbmp);
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return (0);
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err: UNLOCKREGION(dbmp);
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(void)__db_rdetach(&dbmp->reginfo);
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if (F_ISSET(&dbmp->reginfo, REGION_CREATED))
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(void)memp_unlink(path, 1, dbmp->dbenv);
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if (dbmp->reginfo.path != NULL)
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FREES(dbmp->reginfo.path);
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return (ret);
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}
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