Otherwise the connection can be disconnected due to a timeout, because
the kernel may drop packets from a receive queue (RcvPruned in
/proc/net/netstat).

Half of buffers always stay in the socket, another half is circulated.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>