From: Ben Greear <greearb@candelatech.com>
To: Eric Dumazet <edumazet@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
Neal Cardwell <ncardwell@google.com>,
netdev <netdev@vger.kernel.org>
Subject: Re: Debugging stuck tcp connection across localhost [snip]
Date: Wed, 12 Jan 2022 10:54:05 -0800 [thread overview]
Message-ID: <05ae90a3-4fc4-45aa-c001-fb26334332c4@candelatech.com> (raw)
In-Reply-To: <CANn89iK2iM=fM=EN3v3jfOfHRS4HKzbShLcnHt78U+OjnmeVjg@mail.gmail.com>
On 1/12/22 10:47 AM, Eric Dumazet wrote:
> On Wed, Jan 12, 2022 at 10:44 AM Ben Greear <greearb@candelatech.com> wrote:
>
>> Well, I think maybe I found the problem.
>>
>> I looked in the right place at the right time and saw that the kernel was spewing about
>> neigh entries being full. The defaults are too small for the number of interfaces
>> we are using. Our script that was supposed to set the thresholds higher had a typo
>> in it that caused it to not actually set the values.
>>
>> When the neigh entries are fully consumed, then even communication across 127.0.0.1
>> fails in somewhat mysterious ways, and I guess this can break existing connections
>> too, not just new connections.
>
> Nice to hear this is not a TCP bug ;)
For sure...it took me a long time to get brave enough to even suggest it might
be on a public list :)
That said, might be nice to always reserve a neigh entry for localhost
at least...can't be that hard to arp for it!
--Ben
--
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc http://www.candelatech.com
prev parent reply other threads:[~2022-01-12 18:54 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-06 14:59 Debugging stuck tcp connection across localhost Ben Greear
2022-01-06 15:20 ` Neal Cardwell
2022-01-06 15:39 ` Ben Greear
2022-01-06 16:16 ` Neal Cardwell
2022-01-06 19:05 ` Ben Greear
2022-01-06 20:04 ` Neal Cardwell
2022-01-06 20:20 ` Ben Greear
2022-01-06 22:26 ` Ben Greear
2022-01-10 18:10 ` Ben Greear
2022-01-10 22:16 ` David Laight
2022-01-11 10:46 ` Eric Dumazet
2022-01-11 21:35 ` Ben Greear
2022-01-12 7:41 ` Eric Dumazet
2022-01-12 14:52 ` Ben Greear
2022-01-12 17:12 ` Eric Dumazet
2022-01-12 18:01 ` Debugging stuck tcp connection across localhost [snip] Ben Greear
2022-01-12 18:44 ` Ben Greear
2022-01-12 18:47 ` Eric Dumazet
2022-01-12 18:54 ` Ben Greear [this message]
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