insert_community() is part of the hot path especially when people use
communities to tag internally for their filters.
Using recallocarray() there is a bit problematic since it has a much
higher overhead than any realloc verision.
Use reallocarray() and memset() instead.

In one of my IXP test setups insert_community is called 224 million times
during initial sync.
-- 
:wq Claudio

Index: rde_community.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/rde_community.c,v
diff -u -p -r1.18 rde_community.c
--- rde_community.c	4 Nov 2025 14:43:22 -0000	1.18
+++ rde_community.c	13 Nov 2025 14:28:42 -0000
@@ -227,9 +227,10 @@ insert_community(struct rde_community *c
 		struct community *new;
 		int newsize = comm->size + 8;
 
-		if ((new = recallocarray(comm->communities, comm->size,
-		    newsize, sizeof(struct community))) == NULL)
+		if ((new = reallocarray(comm->communities, newsize,
+		    sizeof(struct community))) == NULL)
 			fatal(__func__);
+		memset(&new[comm->size], 0, sizeof(struct community) * 8);
 		comm->communities = new;
 		comm->size = newsize;
 	}