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From: Steffen Klassert <steffen.klassert@secunet•com>
To: "Timo Teräs" <timo.teras@iki•fi>
Cc: David Miller <davem@davemloft•net>, netdev@vger•kernel.org
Subject: Re: linux-3.0.x regression with ipv4 routes having mtu
Date: Mon, 19 Dec 2011 14:52:59 +0100	[thread overview]
Message-ID: <20111219135259.GK6348@secunet.com> (raw)
In-Reply-To: <4EEB5602.2060806@iki.fi>

On Fri, Dec 16, 2011 at 04:30:26PM +0200, Timo Teräs wrote:
> On 12/16/2011 02:21 PM, Steffen Klassert wrote:
> > 
> > "ip route flush cache" does not even flush the routing cache,
> > it just markes the routing cache as invalid by changing the
> > rt_genid which make the old routes invisible. And since we don't
> > have rt_check_expire() anymore, we have to wait until we have
> > collected gc_thresh (1024) useless routes before rt_garbage_collect()
> > starts to remove some of them (btw. is this intentional).
> > 
> > I think we need a trigger in rt_cache_invalidate() that expires
> > all cached pmtu values similar to the routing cache entries.
> > For a moment I thought we could just reset the __rt_peer_genid
> > value back to zero to mark all cached pmtu values as expired,
> > but that's apparently not save to do. So I came to no conclusion
> > how to fix this today. Any ideas?
> 
> Oh, right. This problem is secondary. As long as the mtu value is
> reflected properly, I'll be happy :)
> 

Well, "ip route flush cache" flushed the cached pmtu informations
in 2.6.38 and before, now it does not do it anymore. I guess
some users rely on the old behaviour, so it would be nice if we
could restore it. I think we can fix this by adding a pmtu_genid,
exactly in the same way as we have now the redirect_genid.
I'll give this a try.

  reply	other threads:[~2011-12-19 13:57 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-14 15:54 linux-3.0.x regression with ipv4 routes having mtu Timo Teräs
2011-12-14 17:50 ` David Miller
2011-12-14 17:57   ` Eric Dumazet
2011-12-14 18:22   ` Timo Teräs
2011-12-15 13:49   ` Steffen Klassert
2011-12-16 12:21     ` Steffen Klassert
2011-12-16 14:30       ` Timo Teräs
2011-12-19 13:52         ` Steffen Klassert [this message]
2011-12-19 20:09           ` David Miller
2011-12-20  8:03             ` Steffen Klassert
2011-12-19 21:10       ` David Miller
2011-12-20  6:53         ` Timo Teräs
2011-12-20  7:03           ` David Miller
2011-12-20  7:18             ` Steffen Klassert
2011-12-20 18:35               ` David Miller
2011-12-21  8:56                 ` Steffen Klassert
2011-12-21 20:56                   ` David Miller
2011-12-22 10:25                     ` Steffen Klassert
2011-12-22 18:51                       ` David Miller
2011-12-23  8:47                         ` Steffen Klassert
2011-12-23  9:00                           ` David Miller
2011-12-23  8:58                       ` Steffen Klassert
2012-02-02 10:01                     ` Steffen Klassert

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