netdev - Re: [PATCH 2/2] macvlan: Move broadcasts into a work queue

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Date:	Fri, 11 Apr 2014 10:13:01 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	David Miller <davem@...emloft.net>, greearb@...delatech.com,
	netdev@...r.kernel.org
Subject: Re: [PATCH 2/2] macvlan: Move broadcasts into a work queue

On Thu, Apr 10, 2014 at 07:09:30PM -0700, Eric Dumazet wrote:
> On Fri, 2014-04-11 at 09:59 +0800, Herbert Xu wrote:
> > On Thu, Apr 10, 2014 at 09:40:23PM -0400, David Miller wrote:
> > > From: Herbert Xu <herbert@...dor.apana.org.au>
> > > Date: Wed, 9 Apr 2014 01:23:49 +0800
> > > 
> > > > On Tue, Apr 08, 2014 at 09:48:40AM -0700, Ben Greear wrote:
> > > >> 
> > > >> At least for ARPs, maybe we could inspect the packet and only
> > > >> deliver to interfaces configured with the MAC that is being
> > > >> ARPed for (or ones that are in promisc)?
> > > > 
> > > > Yes this would definitely be a great optimisation.
> > > 
> > > Yes and you can use the direct rather than the workqueue path.
> > 
> > This would be a worthy optimisation for bridge.c too.  In fact,
> > I wonder if it would be possible to share some of the broadcast/
> > multicast logic between macvlan and bridge.
> 
> But many ARP messages are broadcasted, particularly when you restart
> an hypervisor with thousand of macvlan. This is the moment we have
> this horrible quadratic behavior in macvlan.
> 
> I do not understand the idea...
> 
> ARP filter would require to inspect the queried IPv4 address, and
> macvlan do not currently have a list of IPv4 addresses per port.

Indeed.  Thanks for snapping us out of our collective daydream :)
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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