David S. Miller wrote:

On Thu, 03 Mar 2005 21:44:52 +0000
Baruch Even [off-list ref] wrote:

quoted

The current linked list goes over all the packets, the linked list we 
add is for the packets that were not SACKed. The idea being that it is a 
lot faster since there are a lot less packets not SACKed compared to 
packets already SACKed (or never mentioned in SACKs).

If you have a way around this I'd be happy to hear it.

I'm sure you can find a way to steal sizeof(void *) from
"struct tcp_skb_cb" :-)

It is currently 36 bytes on both 32-bit and 64-bit platforms.
This means if you can squeeze out 4 bytes (so that it fits
in the skb->cb[] 40 byte area), you can fit a pointer in there
for the linked list stuff.

Stephen has a patch to move some of the extra congestion control data to 
their own struct, that would free some space for me :-)

I'll need to take a look at this again, the original patch actually 
increased the number of bytes for the cb from 40 to get some extra space.

Baruch