From: John Heffner <[EMAIL PROTECTED]> Date: Tue, 25 Jul 2006 09:56:38 -0400
> David Miller wrote: > > John, have a look at this code in tcp_write_timeout(): > > > > mss = min(sysctl_tcp_base_mss, > > tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low)/2); > > mss = max(mss, 68 - tp->tcp_header_len); > > > > That first line looks like it should be a max() instead > > of a min(). > > > > tcp_base_mss is the smallest MSS we should use, therefore > > we should make sure the "mss" is at least that large. > > > > It's also possible that I misread the intention of this code :) From > > what I read, it is trying to half the MSS in use and adjust the MTU > > search low point to be based upon this new value. > > No, the min() is what's intended here. The base_mss is where you want > to start searching from. So, on black hole detection, you drop > immediatly down to the base. The base is configurable, because making > it higher can make searching faster. If it's still too high for some > links, you halve it again on successive timeouts. Thanks for the clarification John. I find it interesting that black hole detection is handled different from a normal probe failure. I guess here we are dealing with a more significant failure, so we should start at the thing which is most guarenteed to work. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
