Re: [PATCH 4/4] [UDP]: memory accounting in IPv4

From: Hideo AOKI <redacted>
Date: Mon, 17 Dec 2007 21:38:47 -0500

This patch adds UDP memory usage accounting in IPv4.

Send buffer accounting is performed by IP layer, because skbuff is
allocated in the layer.

Receive buffer is charged, when the buffer successfully received.
Destructor of the buffer does uncharging and reclaiming, when the
buffer is freed. To set destructor at proper place, we use
__udp_queue_rcv_skb() instead of sock_queue_rcv_skb(). To maintain
consistency of memory accounting, socket lock is used to free receive
buffer in udp_recvmsg().

New packet will be add to backlog when the socket is used by user.

Cc: Satoshi Oshima <redacted>
signed-off-by: Takahiro Yasui <redacted>
signed-off-by: Masami Hiramatsu <redacted>
signed-off-by: Hideo Aoki <redacted>

We can't accept these changes, even once the other issues
are fixed, until IPV6 is supported as well.

It's pointless to support proper UDP memory accounting only
in IPV4 and not in IPV6 as well.