From: Patrick McHardy <kaber@trash•net>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: Netfilter Developers <netfilter-devel@vger•kernel.org>,
netdev <netdev@vger•kernel.org>
Subject: Re: [RFC nf-next-2.6] conntrack: per cpu nf_conntrack_untracked
Date: Fri, 04 Jun 2010 13:40:26 +0200 [thread overview]
Message-ID: <4C08E62A.9020607@trash.net> (raw)
In-Reply-To: <1275409203.2738.227.camel@edumazet-laptop>
Eric Dumazet wrote:
> Le mardi 01 juin 2010 à 12:41 +0200, Patrick McHardy a écrit :
>
>>> BTW, I notice nf_conntrack_untracked is incorrectly annotated
>>> '__read_mostly'.
>>>
>>> It can be written very often :(
>>>
>>> Should'nt we special case it and let be really const ?
>> That would need quite a bit of special-casing to avoid touching
>> the reference counts. So far this is completely hidden, so I'd
>> say it just shouldn't be marked __read_mostly. Alternatively we
>> can make "untracked" a nfctinfo state.
>
> I tried this suggestion, (a new IP_CT_UNTRACKED ctinfo), over a per_cpu
> untracked ct, but its a bit hard.
>
> For example, I cannot find a way to change ctnetlink_conntrack_event() :
>
> if (ct == &nf_conntrack_untracked)
> return 0;
>
> Maybe this piece of code is not necessary, we should not come here
> anyway, or it means several packets could store events for this (shared)
> ct ?
We probably shouldn't be reaching that code since that would mean
that we previously did modifications to the untracked conntrack.
But a quick audit shows that f.i. xt_connmark will do just that.
> Obviously, an IPS_UNTRACKED bit would be much easier to implement.
> Would it be acceptable ?
That also would be fine. However the main idea behind using a nfctinfo
bit was that we wouldn't need the untracked conntrack anymore at all.
But I guess a per-cpu untrack conntrack would already be an improvement
over the current situation.
next prev parent reply other threads:[~2010-06-04 11:40 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-22 12:58 DDoS attack causing bad effect on conntrack searches Jesper Dangaard Brouer
2010-04-22 13:13 ` Changli Gao
2010-04-22 13:17 ` Patrick McHardy
2010-04-22 14:36 ` Eric Dumazet
2010-04-22 14:53 ` Eric Dumazet
2010-04-22 15:51 ` Paul E. McKenney
2010-04-22 16:02 ` Eric Dumazet
2010-04-22 16:34 ` Paul E. McKenney
2010-04-22 20:38 ` Jesper Dangaard Brouer
2010-04-22 21:03 ` Eric Dumazet
2010-04-22 21:14 ` Eric Dumazet
2010-04-22 23:44 ` David Miller
2010-04-23 5:44 ` Eric Dumazet
2010-04-23 8:13 ` David Miller
2010-04-23 8:18 ` David Miller
2010-04-23 8:40 ` Jesper Dangaard Brouer
2010-04-23 10:36 ` Patrick McHardy
2010-04-23 11:06 ` Eric Dumazet
2010-04-22 21:28 ` Jesper Dangaard Brouer
2010-04-23 7:23 ` Jan Engelhardt
2010-04-23 7:46 ` Eric Dumazet
2010-04-23 7:55 ` Jan Engelhardt
2010-04-23 9:23 ` Eric Dumazet
2010-04-23 10:55 ` Patrick McHardy
2010-04-23 11:05 ` Eric Dumazet
2010-04-23 11:06 ` Patrick McHardy
2010-04-23 20:57 ` Eric Dumazet
2010-04-24 11:11 ` Jesper Dangaard Brouer
2010-04-24 20:11 ` Eric Dumazet
2010-04-26 14:36 ` Jesper Dangaard Brouer
2010-05-31 21:21 ` Eric Dumazet
2010-06-01 0:28 ` Changli Gao
2010-06-01 5:05 ` Eric Dumazet
2010-06-01 5:48 ` Changli Gao
2010-06-01 10:18 ` Patrick McHardy
2010-06-01 10:31 ` Eric Dumazet
2010-06-01 10:41 ` Patrick McHardy
2010-06-01 16:20 ` [RFC nf-next-2.6] conntrack: per cpu nf_conntrack_untracked Eric Dumazet
2010-06-04 11:40 ` Patrick McHardy [this message]
2010-06-04 12:10 ` Changli Gao
2010-06-04 12:29 ` Patrick McHardy
2010-06-04 12:36 ` Eric Dumazet
2010-06-04 16:25 ` [PATCH nf-next-2.6] conntrack: IPS_UNTRACKED bit Eric Dumazet
2010-06-04 20:15 ` [PATCH nf-next-2.6 2/2] conntrack: per_cpu untracking Eric Dumazet
2010-06-08 14:29 ` Patrick McHardy
2010-06-08 14:52 ` Eric Dumazet
2010-06-08 15:12 ` Eric Dumazet
2010-06-09 12:45 ` Patrick McHardy
2010-06-08 14:12 ` [PATCH nf-next-2.6] conntrack: IPS_UNTRACKED bit Patrick McHardy
2010-04-23 10:56 ` DDoS attack causing bad effect on conntrack searches Patrick McHardy
2010-04-23 12:45 ` Jesper Dangaard Brouer
2010-04-23 13:57 ` Patrick McHardy
2010-04-22 13:31 ` Jesper Dangaard Brouer
2010-04-23 10:35 ` Patrick McHardy
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