nl: Increase receive buffer size to 4 pages

Assuming that the kernel does not send more than a page is no longer valid,
and enabling MSG_PEEK'ing by default to figure out the exact message buffer
requirements can have a negative influence on the performance of existing
applications. Bumping the default receive buffer space to 4 pages seems
a sane default.

Signed-off-by: Thomas Graf <tgraf@suug.ch>

lib/nl.c

@@ -597,7 +597,7 @@ int nl_recv(struct nl_sock *sk, struct sockaddr_nl *nla,
 		flags |= MSG_PEEK | MSG_TRUNC;
 
 	if (page_size == 0)
-		page_size = getpagesize();
+		page_size = getpagesize() * 4;
 
 	iov.iov_len = sk->s_bufsize ? : page_size;
 	iov.iov_base = malloc(iov.iov_len);