From: Daniele Lacamera <redacted>
Date: Sun, 31 Aug 2008 20:26:50 +0200

This simple patch (2.6.26) replaces the icsk_ca_priv big array with a
void pointer, reducing the default inet_connection_sock size by 60Bytes.

Each "congestion controlled" socket must allocate and free its own priv
structure if needed, from the connection init and release callbacks
inside each module.

Wouldn't this reduce memory usage for sockets that don't use ca?

Yes, but for every TCP socket there is a new memory allocation and
free.

We're trying to decrease the number of those rather than increase them
because having more of them non-trivially impacts TCP connection
rates.