Messages in this thread |  | | Date | Tue, 13 Jun 2006 13:22:35 -0400 | From | Mark Lord <> | Subject | Re: 2.6.17: networking bug?? |
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Mark Lord wrote: > .. >> The site www.everymac.com is still not browseable until >> setting /proc/sys/net/ipv4/tcp_window_scaling===0. >> >> There's one other difference I see in the tcpdump traces. >> The first packets from each trace below show different >> values for "wscale". The old (working) kernels use "wscale 2", >> whereas 2.6.17 uses "wscale 6". In both cases, the value >> seen in /proc/sys/net/ipv4/tcp_adv_win_scale is 2. > > Okay. More progress here. The calculation of the "wscale" values > is based on the "tcp_rmem" sysctl numbers. > > The defaults for these *differ* between 2.6.16.18 and 2.6.17-rc*. > > 2.6.16: 4096 87380 174760 > 2.6.17: 4096 87380 2097152 > > If I change the tcp_rmem setting on 2.6.17 to match the old value, > then the website www.everymac.com becomes accessible again: > > echo 4096 87380 174760 > /proc/sys/net/ipv4/tcp_rmem > > Looking at diffs between 2.6.16 and 2.6.17, I see a big rework > of the tcp_rmem code in linux/net/ipv4/tcp.c > > Looks like something got broken there, or possibly the wscale > calculations have a bug that is only triggered by the new rmem values ?? >
Okay, here's the blob that broke it.
> [TCP]: Set default max buffers from memory pool size > author John Heffner <jheffner@psc.edu> > Sat, 25 Mar 2006 09:34:07 +0000 (01:34 -0800) > committer David S. Miller <davem@davemloft.net> > Sat, 25 Mar 2006 09:34:07 +0000 (01:34 -0800) > commit 7b4f4b5ebceab67ce440a61081a69f0265e17c2a > tree ac02c685ce23f2440fecbebaa5b55cd47947c03e tree > parent 2babf9daae4a3561f3264638a22ac7d0b14a6f52 commit | commitdiff > [TCP]: Set default max buffers from memory pool size > > This patch sets the maximum TCP buffer sizes (available to automatic > buffer tuning, not to setsockopt) based on the TCP memory pool size. > The maximum sndbuf and rcvbuf each will be up to 4 MB, but no more > than 1/128 of the memory pressure threshold. > > Signed-off-by: John Heffner <jheffner@psc.edu> > Signed-off-by: David S. Miller <davem@davemloft.net>
John / David: Any ideas on what's gone awry here?
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