From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: kaber@trash.net, netfilter-devel@vger.kernel.org,
netdev@vger.kernel.org, hawk@diku.dk
Subject: Re: [RFC] netfilter: get rid of atomic ops in fast path
Date: Wed, 16 Mar 2011 13:16:48 -0700 (PDT) [thread overview]
Message-ID: <20110316.131648.15245216.davem@davemloft.net> (raw)
In-Reply-To: <1300302005.3202.23.camel@edumazet-laptop>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 16 Mar 2011 20:00:05 +0100
> We currently use a percpu spinlock to 'protect' rule bytes/packets
> counters, after various attempts to use RCU instead.
>
> Lately we added a seqlock so that get_counters() can run without
> blocking BH or 'writers'. But we really use the seqcount in it.
>
> Spinlock itself is only locked by the current cpu, so we can remove it
> completely.
>
> This cleanups api, using correct 'writer' vs 'reader' semantic.
>
> At replace time, the get_counters() call makes sure all cpus are done
> using the old table.
>
> We could probably avoid blocking BH (we currently block them in xmit
> path), but thats a different topic ;)
>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
FWIW, I think this is a great idea.
next prev parent reply other threads:[~2011-03-16 20:16 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-16 19:00 [RFC] netfilter: get rid of atomic ops in fast path Eric Dumazet
2011-03-16 20:16 ` David Miller [this message]
2011-03-17 10:35 ` [PATCH] netfilter: xtables: fix reentrancy Eric Dumazet
2011-03-17 11:36 ` Jesper Dangaard Brouer
2011-03-17 11:45 ` Eric Dumazet
2011-03-17 13:17 ` Eric Dumazet
2011-03-18 10:27 ` Jesper Dangaard Brouer
2011-03-18 10:50 ` Eric Dumazet
2011-03-17 10:39 ` [RFC] netfilter: get rid of atomic ops in fast path Patrick McHardy
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