1 files changed, 149 insertions, 0 deletions
diff --git a/bdb/mp/mp_trickle.c b/bdb/mp/mp_trickle.c
new file mode 100644
index 00000000000..f937805cf40
--- /dev/null
+++ b/bdb/mp/mp_trickle.c
@@ -0,0 +1,149 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996, 1997, 1998, 1999, 2000
+ *	Sleepycat Software.  All rights reserved.
+ */
+#include "db_config.h"
+
+#ifndef lint
+static const char revid[] = "$Id: mp_trickle.c,v 11.12 2000/11/30 00:58:41 ubell Exp $";
+#endif /* not lint */
+
+#ifndef NO_SYSTEM_INCLUDES
+#include <sys/types.h>
+
+#include <stdlib.h>
+#endif
+
+#ifdef  HAVE_RPC
+#include "db_server.h"
+#endif
+
+#include "db_int.h"
+#include "db_shash.h"
+#include "mp.h"
+
+#ifdef HAVE_RPC
+#include "gen_client_ext.h"
+#include "rpc_client_ext.h"
+#endif
+
+static int __memp_trick __P((DB_ENV *, int, int, int *));
+
+/*
+ * memp_trickle --
+ *	Keep a specified percentage of the buffers clean.
+ */
+int
+memp_trickle(dbenv, pct, nwrotep)
+	DB_ENV *dbenv;
+	int pct, *nwrotep;
+{
+	DB_MPOOL *dbmp;
+	MPOOL *mp;
+	u_int32_t i;
+	int ret;
+
+#ifdef HAVE_RPC
+	if (F_ISSET(dbenv, DB_ENV_RPCCLIENT))
+		return (__dbcl_memp_trickle(dbenv, pct, nwrotep));
+#endif
+
+	PANIC_CHECK(dbenv);
+	ENV_REQUIRES_CONFIG(dbenv, dbenv->mp_handle, DB_INIT_MPOOL);
+
+	dbmp = dbenv->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+
+	if (nwrotep != NULL)
+		*nwrotep = 0;
+
+	if (pct < 1 || pct > 100)
+		return (EINVAL);
+
+	R_LOCK(dbenv, dbmp->reginfo);
+
+	/* Loop through the caches... */
+	for (ret = 0, i = 0; i < mp->nreg; ++i)
+		if ((ret = __memp_trick(dbenv, i, pct, nwrotep)) != 0)
+			break;
+
+	R_UNLOCK(dbenv, dbmp->reginfo);
+	return (ret);
+}
+
+/*
+ * __memp_trick --
+ *	Trickle a single cache.
+ */
+static int
+__memp_trick(dbenv, ncache, pct, nwrotep)
+	DB_ENV *dbenv;
+	int ncache, pct, *nwrotep;
+{
+	BH *bhp;
+	DB_MPOOL *dbmp;
+	MPOOL *c_mp;
+	MPOOLFILE *mfp;
+	db_pgno_t pgno;
+	u_long total;
+	int ret, wrote;
+
+	dbmp = dbenv->mp_handle;
+	c_mp = dbmp->reginfo[ncache].primary;
+
+	/*
+	 * If there are sufficient clean buffers, or no buffers or no dirty
+	 * buffers, we're done.
+	 *
+	 * XXX
+	 * Using st_page_clean and st_page_dirty is our only choice at the
+	 * moment, but it's not as correct as we might like in the presence
+	 * of pools with more than one buffer size, as a free 512-byte buffer
+	 * isn't the same as a free 8K buffer.
+	 */
+loop:	total = c_mp->stat.st_page_clean + c_mp->stat.st_page_dirty;
+	if (total == 0 || c_mp->stat.st_page_dirty == 0 ||
+	    (c_mp->stat.st_page_clean * 100) / total >= (u_long)pct)
+		return (0);
+
+	/* Loop until we write a buffer. */
+	for (bhp = SH_TAILQ_FIRST(&c_mp->bhq, __bh);
+	    bhp != NULL; bhp = SH_TAILQ_NEXT(bhp, q, __bh)) {
+		if (bhp->ref != 0 ||
+		    !F_ISSET(bhp, BH_DIRTY) || F_ISSET(bhp, BH_LOCKED))
+			continue;
+
+		mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset);
+
+		/*
+		 * We can't write to temporary files -- see the comment in
+		 * mp_bh.c:__memp_bhwrite().
+		 */
+		if (F_ISSET(mfp, MP_TEMP))
+			continue;
+
+		pgno = bhp->pgno;
+		if ((ret = __memp_bhwrite(dbmp, mfp, bhp, NULL, &wrote)) != 0)
+			return (ret);
+
+		/*
+		 * Any process syncing the shared memory buffer pool had better
+		 * be able to write to any underlying file.  Be understanding,
+		 * but firm, on this point.
+		 */
+		if (!wrote) {
+			__db_err(dbenv, "%s: unable to flush page: %lu",
+			    __memp_fns(dbmp, mfp), (u_long)pgno);
+			return (EPERM);
+		}
+
+		++c_mp->stat.st_page_trickle;
+		if (nwrotep != NULL)
+			++*nwrotep;
+		goto loop;
+	}
+
+	return (0);
+}