Network slowdown on lo0 introduced with svn186119/186121

Hi!

Today I built a new kernel on current and experienced a massive network 
slowdown on lo0 when doing a backup using amanda. I made some tests and it 
seems that the commits 186119 and 186121 to the svn repository are causing 
it. A kernel based on revision 186107 runs fine and all kernels starting with 
revison 186119 do not.

This slowdown seems to appear only on the loopback interface, not on my lan 
interface.

Is this a known issue? 

Regards,
Christian.