mp_trickle.c
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上传日期:2022-05-23
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文件大小:2k
- /*-
- * See the file LICENSE for redistribution information.
- *
- * Copyright (c) 1996-2002
- * Sleepycat Software. All rights reserved.
- */
- #include "db_config.h"
- #ifndef lint
- static const char revid[] = "$Id: mp_trickle.c,v 11.24 2002/08/06 06:13:53 bostic Exp $";
- #endif /* not lint */
- #ifndef NO_SYSTEM_INCLUDES
- #include <sys/types.h>
- #include <stdlib.h>
- #endif
- #include "db_int.h"
- #include "dbinc/db_shash.h"
- #include "dbinc/mp.h"
- /*
- * __memp_trickle --
- * Keep a specified percentage of the buffers clean.
- *
- * PUBLIC: int __memp_trickle __P((DB_ENV *, int, int *));
- */
- int
- __memp_trickle(dbenv, pct, nwrotep)
- DB_ENV *dbenv;
- int pct, *nwrotep;
- {
- DB_MPOOL *dbmp;
- MPOOL *c_mp, *mp;
- u_int32_t clean, dirty, i, total, dtmp;
- int ret, wrote;
- PANIC_CHECK(dbenv);
- ENV_REQUIRES_CONFIG(dbenv,
- dbenv->mp_handle, "memp_trickle", DB_INIT_MPOOL);
- dbmp = dbenv->mp_handle;
- mp = dbmp->reginfo[0].primary;
- if (nwrotep != NULL)
- *nwrotep = 0;
- if (pct < 1 || pct > 100)
- return (EINVAL);
- /*
- * If there are sufficient clean buffers, no buffers or no dirty
- * buffers, we're done.
- *
- * XXX
- * Using hash_page_dirty is our only choice at the moment, but it's not
- * as correct as we might like in the presence of pools having more
- * than one page size, as a free 512B buffer isn't the same as a free
- * 8KB buffer.
- *
- * Loop through the caches counting total/dirty buffers.
- */
- for (ret = 0, i = dirty = total = 0; i < mp->nreg; ++i) {
- c_mp = dbmp->reginfo[i].primary;
- total += c_mp->stat.st_pages;
- __memp_stat_hash(&dbmp->reginfo[i], c_mp, &dtmp);
- dirty += dtmp;
- }
- clean = total - dirty;
- if (clean == total || (clean * 100) / total >= (u_long)pct)
- return (0);
- if (nwrotep == NULL)
- nwrotep = &wrote;
- ret = __memp_sync_int(dbenv, NULL,
- ((total * pct) / 100) - clean, DB_SYNC_TRICKLE, nwrotep);
- mp->stat.st_page_trickle += *nwrotep;
- return (ret);
- }