The target for the maximum number of dependencies has been cut

in half because of reports that under heavy load the kernel could
exhaust its memory pool. The limit is now (desiredvnodes * 4)
rather than (desiredvnodes * 8), so it will still scale with
larger systems, just not as quickly.

Sponsored by:   DARPA & NAI Labs.

sys/ufs/ffs/ffs_softdep.c

@@ -1127,7 +1127,7 @@ softdep_initialize()
 
 	LIST_INIT(&mkdirlisthd);
 	LIST_INIT(&softdep_workitem_pending);
-	max_softdeps = desiredvnodes * 8;
+	max_softdeps = desiredvnodes * 4;
 	pagedep_hashtbl = hashinit(desiredvnodes / 5, M_PAGEDEP,
 	    &pagedep_hash);
 	sema_init(&pagedep_in_progress, "pagedep", PRIBIO, 0);