Messages in this thread | | | Date | Wed, 10 Sep 2008 16:14:42 -0700 | From | "Ranjit Manomohan" <> | Subject | Re: [PATCH 1/2] Traffic control cgroups subsystem |
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On Wed, Sep 10, 2008 at 4:00 PM, David Miller <davem@davemloft.net> wrote: > From: "Ranjit Manomohan" <ranjitm@google.com> > Date: Wed, 10 Sep 2008 15:56:55 -0700 > >> That is correct for ingress, for egress the sk is already available in >> the skb so should be fine. > > That is not something you can rely upon, even for egress, %100 of the time. > > Some forms of reallocation and mangling might decide to orphan the SKB > and thus drop the skb->sk reference before you see the packet. And they > are absolutely free to do this. > > Just grep for skb_orphan(). > > Therefore, it is absolutely something you should not rely upon for > correct operation.
Thats fine and we do not rely on this. Those packets would just not be classified, the cgroup classid is only a hint and used when available (which is most of the time).
> > Like I said from the beginning, Thomas's approach is the superior one.
It would leave a lot of packets (like acks) unaccounted for and these do take up a significant portion of network packets transmitted on a high speed link). I am ok with Thomas' simpler approach too, just pointing out that it is not as accurate as the proposed alternative.
-Thanks, Ranjit
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