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From: Eric Dumazet <dada1@cosmosbay.com>
To: Vasily Averin <vvs@sw.ru>
Cc: "David S. Miller" <davem@davemloft.net>,
	Patrick McHardy <kaber@trash.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	netfilter-devel@lists.netfilter.org, rusty@rustcorp.com.au,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	devel@openvz.org
Subject: Re: [PATCH 2.6.21-rc6] [netfilter] early_drop imrovement
Date: Fri, 6 Apr 2007 10:24:33 +0200	[thread overview]
Message-ID: <20070406102433.d3a670a5.dada1@cosmosbay.com> (raw)
In-Reply-To: <4615FE1D.80206@sw.ru>

On Fri, 06 Apr 2007 12:00:29 +0400
Vasily Averin <vvs@sw.ru> wrote:

> When the number of conntracks is reached ip_conntrack_max limit, early_drop() is
> called and tries to free one of already used conntracks in one of the hash
> buckets. If it does not find any conntracks that may be freed, it
> leads to transmission errors.
> However it is not fair because of current hash bucket may be empty but the
> neighbour ones can have the number of conntracks that can be freed. With the
> following patch early_drop() will search conntracks in all hash buckets.

Have you tested your patch in a DOS situation ?
Some machines have a huge ip_conntrack_max.
A single scan of the whole table might take 1000 ms or even more.



  reply	other threads:[~2007-04-06  8:24 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-04-06  8:00 Vasily Averin
2007-04-06  8:24 ` Eric Dumazet [this message]
2007-04-06 10:26   ` Vasily Averin
2007-04-06 15:08     ` Patrick McHardy
2007-04-07 11:45       ` [PATCH nf-2.6.22] " Vasily Averin
2007-04-07 12:08         ` Eric Dumazet
2007-04-08  5:02           ` Vasily Averin
2007-05-09  6:59             ` [NETFILTER] early_drop() imrovement (v3) Vasily Averin
2007-06-25 13:53               ` Patrick McHardy
2007-06-25 14:36                 ` Jan Engelhardt
2007-06-26 13:20                 ` Vasily Averin
2007-06-26 13:27                   ` Patrick McHardy
2007-06-27  8:46                   ` [NETFILTER] early_drop() imrovement (v4) Vasily Averin
2007-06-27  8:52                     ` Patrick McHardy
2007-06-27 12:04                       ` Patrick McHardy
2007-06-27 12:29                         ` Vasily Averin
2007-06-27 12:51                           ` Patrick McHardy
2007-06-27 13:02                             ` Vasily Averin
2007-06-27 13:18                               ` Patrick McHardy
2007-06-27 13:25                                 ` Vasily Averin
2007-06-27 13:28                                   ` Patrick McHardy
  -- strict thread matches above, loose matches on Subject: below --
2007-04-06  7:48 [PATCH 2.6.21-rc6] [netfilter] early_drop imrovement Vasily Averin

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