From: Eric Dumazet <edumazet@google.com>
To: Daniel Dao <dqminh@cloudflare.com>
Cc: netdev <netdev@vger.kernel.org>,
kernel-team <kernel-team@cloudflare.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
David Miller <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Marek Majkowski <marek@cloudflare.com>
Subject: Re: Expensive tcp_collapse with high tcp_rmem limit
Date: Thu, 6 Jan 2022 10:55:12 -0800 [thread overview]
Message-ID: <CANn89iKBqPRHFy5U+SMxT5RUPkioDFrZ5rN5WKNwfzA-TkMhwA@mail.gmail.com> (raw)
In-Reply-To: <CANn89iKTw5aZ0GvybkO=3B17HkGRmFKcqz9FqJFuo5r--=afOA@mail.gmail.com>
On Thu, Jan 6, 2022 at 10:52 AM Eric Dumazet <edumazet@google.com> wrote:
> I think that you should first look if you are under some kind of attack [1]
>
> Eventually you would still have to make room, involving expensive copies.
>
> 12% of 16MB is still a lot of memory to copy.
>
> [1] Detecting an attack signature could allow you to zap the socket
> and save ~16MB of memory per flow.
I forgot to ask, have you set tcp_min_snd_mss to a sensible value ?
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=5f3e2bf008c2221478101ee72f5cb4654b9fc363
next prev parent reply other threads:[~2022-01-06 18:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CA+wXwBRbLq6SW39qCD8GNG98YD5BJR2MFXmJV2zU1xwFjC-V0A@mail.gmail.com>
2022-01-05 13:38 ` Expensive tcp_collapse with high tcp_rmem limit Eric Dumazet
2022-01-06 12:32 ` Daniel Dao
2022-01-06 18:52 ` Eric Dumazet
2022-01-06 18:55 ` Eric Dumazet [this message]
2022-01-20 17:29 ` Daniel Dao
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