From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net-next] icmp: add a global rate limitation
Date: Mon, 22 Sep 2014 16:09:04 -0400 (EDT) [thread overview]
Message-ID: <20140922.160904.1566383839759663411.davem@davemloft.net> (raw)
In-Reply-To: <1411137520.26859.13.camel@edumazet-glaptop2.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 19 Sep 2014 07:38:40 -0700
> Current ICMP rate limiting uses inetpeer cache, which is an RBL tree
> protected by a lock, meaning that hosts can be stuck hard if all cpus
> want to check ICMP limits.
However, the replacement uses a single global spinlock for
synchronization.
...
> Note that if we really want to send millions of ICMP messages per
> second, we might extend idea and infra added in commit 04ca6973f7c1a
> ("ip: make IP identifiers less predictable") :
> add a token bucket in the ip_idents hash and no longer rely on inetpeer.
That would be preferred.
I don't really see how this patch makes things better. The code goes
through a global spinlock unconditionally, and if it passes then it
looks up the inetpeer anyways.
I need more information to be convinced that this is an improvement
and that it actually solves the stated problem. I'm sure you also
have some performance metrics to share, right? :-)
next prev parent reply other threads:[~2014-09-22 20:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-19 14:38 [PATCH net-next] icmp: add a global rate limitation Eric Dumazet
2014-09-19 14:56 ` Joe Perches
2014-09-19 15:11 ` Eric Dumazet
2014-09-22 20:09 ` David Miller [this message]
2014-09-22 20:25 ` Eric Dumazet
2014-09-23 16:48 ` David Miller
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