From: Lennert Buytenhek <buytenh@wantstofly.org>
To: John Heffner <jheffner@psc.edu>
Cc: Stephen Hemminger <shemminger@osdl.org>,
baruch@ev-en.org, netdev@oss.sgi.com
Subject: Re: netif_rx packet dumping
Date: Fri, 4 Mar 2005 04:31:07 +0100 [thread overview]
Message-ID: <20050304033107.GD29058@xi.wantstofly.org> (raw)
In-Reply-To: <Pine.LNX.4.58.0503032116020.28187@tesla.psc.edu>
On Thu, Mar 03, 2005 at 10:10:55PM -0500, John Heffner wrote:
> The forwarding case where you actually need congestion control, as
> opposed to absorbing bursts, is pretty gross. If you have a router
> (more likely firewall) whose bottleneck is the CPU, then you're
> operating entirely in you input queue. Yuck.
Yes. This does happen under DoS (or just if your hardware is plain
underspec'ed), and even though you can't really avoid interrupt
livelock and starving userland processes when you're using a non-NAPI
driver (which is what we're talking about here), you don't want to go
OOM as well.
Removing the backlog is a problem also for the non-forwarding case --
you don't want someone to be able to OOM your server just by flooding
it with enough packets. ("Wait, I can't drop those, those might be
legitimate ACKs!")
--L
next prev parent reply other threads:[~2005-03-04 3:31 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-03 20:38 netif_rx packet dumping Stephen Hemminger
2005-03-03 20:55 ` David S. Miller
2005-03-03 21:01 ` Stephen Hemminger
2005-03-03 21:18 ` jamal
2005-03-03 21:21 ` Stephen Hemminger
2005-03-03 21:24 ` jamal
2005-03-03 21:32 ` David S. Miller
2005-03-03 21:54 ` Stephen Hemminger
2005-03-03 22:02 ` John Heffner
2005-03-03 22:26 ` jamal
2005-03-03 23:16 ` Stephen Hemminger
2005-03-03 23:40 ` jamal
2005-03-03 23:48 ` Baruch Even
2005-03-04 3:45 ` jamal
2005-03-04 8:47 ` Baruch Even
2005-03-07 13:55 ` jamal
2005-03-08 15:56 ` Baruch Even
2005-03-08 22:02 ` jamal
2005-03-22 21:55 ` cliff white
2005-03-03 23:48 ` John Heffner
2005-03-04 1:42 ` Lennert Buytenhek
2005-03-04 3:10 ` John Heffner
2005-03-04 3:31 ` Lennert Buytenhek [this message]
2005-03-04 19:52 ` Edgar E Iglesias
2005-03-04 19:54 ` Stephen Hemminger
2005-03-04 21:41 ` Edgar E Iglesias
2005-03-04 19:49 ` Jason Lunz
2005-03-03 22:01 ` jamal
2005-03-03 21:26 ` Baruch Even
2005-03-03 21:36 ` David S. Miller
2005-03-03 21:44 ` Baruch Even
2005-03-03 21:54 ` Andi Kleen
2005-03-03 22:04 ` David S. Miller
2005-03-03 21:57 ` David S. Miller
2005-03-03 22:14 ` Baruch Even
2005-03-08 15:42 ` Baruch Even
2005-03-08 17:00 ` Andi Kleen
2005-03-08 18:01 ` Baruch Even
2005-03-08 18:09 ` David S. Miller
2005-03-08 18:18 ` Andi Kleen
2005-03-08 18:37 ` Thomas Graf
2005-03-08 18:51 ` Arnaldo Carvalho de Melo
2005-03-08 22:16 ` Andi Kleen
2005-03-08 18:27 ` Ben Greear
2005-03-09 23:57 ` Thomas Graf
2005-03-10 0:03 ` Stephen Hemminger
2005-03-10 8:33 ` Andi Kleen
2005-03-10 14:08 ` Thomas Graf
2005-03-31 16:33 ` Baruch Even
2005-03-03 22:03 ` jamal
2005-03-03 22:31 ` Baruch Even
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20050304033107.GD29058@xi.wantstofly.org \
--to=buytenh@wantstofly.org \
--cc=baruch@ev-en.org \
--cc=jheffner@psc.edu \
--cc=netdev@oss.sgi.com \
--cc=shemminger@osdl.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).