Import BSDDB 4.7.25 (as of svn r89086)

common/util_cache.c

@@ -0,0 +1,47 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 2000,2008 Oracle.  All rights reserved.
+ *
+ * $Id: util_cache.c 63573 2008-05-23 21:43:21Z trent.nelson $
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+
+/*
+ * __db_util_cache --
+ *	Compute if we have enough cache.
+ *
+ * PUBLIC: int __db_util_cache __P((DB *, u_int32_t *, int *));
+ */
+int
+__db_util_cache(dbp, cachep, resizep)
+	DB *dbp;
+	u_int32_t *cachep;
+	int *resizep;
+{
+	u_int32_t pgsize;
+	int ret;
+
+	/* Get the current page size. */
+	if ((ret = dbp->get_pagesize(dbp, &pgsize)) != 0)
+		return (ret);
+
+	/*
+	 * The current cache size is in cachep.  If it's insufficient, set the
+	 * the memory referenced by resizep to 1 and set cachep to the minimum
+	 * size needed.
+	 *
+	 * Make sure our current cache is big enough.  We want at least
+	 * DB_MINPAGECACHE pages in the cache.
+	 */
+	if ((*cachep / pgsize) < DB_MINPAGECACHE) {
+		*resizep = 1;
+		*cachep = pgsize * DB_MINPAGECACHE;
+	} else
+		*resizep = 0;
+
+	return (0);
+}