Date: Sat, 26 Nov 2011 00:49:24 -0600 From: Kris Bauer <kristoph.bauer@gmail.com> To: Lawrence Stewart <lstewart@freebsd.org> Cc: kerbzo@gmail.com, freebsd-stable@freebsd.org, stb@lassitu.de, raul@turing.b2n.org, george+freebsd@m5p.com, FreeBSD Release Engineering Team <re@freebsd.org>, freebsd@jdc.parodius.com Subject: Re: TCP Reassembly Issues Message-ID: <CAPNZ-WqZsSjcO=dVZpOOMtB_Y_hNcj%2BpYDA4nWPXX9kY9Vj1Wg@mail.gmail.com> In-Reply-To: <4ED077BF.10205@freebsd.org> References: <CAPNZ-Wq38=F3o2hYuYF_unBj3SZQ52XhVhdcwQ8PE_vU9xc2YA@mail.gmail.com> <4ECEF6FD.5050006@freebsd.org> <4ED077BF.10205@freebsd.org>
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On Fri, Nov 25, 2011 at 11:23 PM, Lawrence Stewart <lstewart@freebsd.org>wrote: > On 11/25/11 13:01, Lawrence Stewart wrote: > >> On 11/24/11 18:02, Kris Bauer wrote: >> >>> Hello, >>> >>> I am currently experiencing an issue with FreeBSD 9.0-RC2 r227852 >>> where the >>> net.inet.tcp.reass.curesegments value is constantly increasing (and not >>> descreasing when there is nominal traffic with the box). It is causing >>> tcp >>> slowdowns as described with kern/155407: >>> >>> Exhausted net.inet.tcp.reass.maxsegments block recovering tcp session >>> (for >>> this socket and any other socket waiting for retransmited packets). After >>> exhausted net.inet.tcp.reass.maxsegments allocation new entry in >>> tcp_reass >>> failed (for this socket and any other socket waiting for retransmited >>> packets). >>> >>> I have increased the reass.maxsegments value to 16384 to temporarily >>> avoid >>> the problem, but the cursegments number keeps rising and it seems it will >>> occur again. >>> >>> Is this an issue that anyone else has seen? I can provide more >>> information >>> if need be. >>> >> >> Thanks Kris, Raul and Stefan for the reports, I'll look into this. >> > > I think I've got it - a stupid 1 line logic bug. My apologies for missing > it when I reviewed the patch which introduced the bug (patch was committed > to head as r226113, MFCed to stable/9 as r226228). > > Due to some miscommunication, the initial patch was committed to and MFCed > from head much later than it should have been in the 9.0 release cycle and > instead of being included in the BETAs, didn't make it in until 9.0-RC1 I > believe i.e. only RC1 and RC2 should be experiencing the issue. > > Could those who have reported the bug and are able to recompile their > kernel to test a patch please try the following and report back to the list: > > > http://people.freebsd.org/~lstewart/patches/misctcp/tcp_reass_plugzoneleak_10.x.r227986.patch > > The patch is against head r227986 but will apply and work correctly for > 9.0 as well. > > Cheers, > Lawrence > I have patched, recompiled, and rebooted. net.inet.tcp.reass.cursegments is no longer incrementing, and connectivity is holding steady. If anything changes over the next couple of hours, I'll be sure to report it; but all preliminary signs of the problem are gone. Thanks for all the help! Kris
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