From: Jesper Dangaard Brouer via iovisor-dev <iovisor-dev-9jONkmmOlFHEE9lA1F8Ukti2O/JbrIOy@public.gmane.org>
To: Brenden Blanco <bblanco-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
Cc: Tom Herbert <tom-BjP2VixgY4xUbtYUoyoikg@public.gmane.org>,
"iovisor-dev-9jONkmmOlFHEE9lA1F8Ukti2O/JbrIOy@public.gmane.org"
<iovisor-dev-9jONkmmOlFHEE9lA1F8Ukti2O/JbrIOy@public.gmane.org>,
"netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Daniel Borkmann
<borkmann-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>
Subject: XDP user interface conclusions
Date: Thu, 15 Sep 2016 20:13:47 +0200 [thread overview]
Message-ID: <20160915201347.338061e6@redhat.com> (raw)
Hi Brenden,
I don't quite understand the semantics of the XDP userspace interface.
We allow XDP programs to be (unconditionally) exchanged by another
program, this avoids taking the link down+up and avoids reallocating
RX ring resources (which is great).
We have two XDP samples programs in samples/bpf/ xdp1 and xdp2. Now I
want to first load xdp1 and then to avoid the linkdown I load xdp2,
and then afterwards remove/stop program xdp1.
This does NOT work, because (in samples/bpf/xdp1_user.c) when xdp1
exits it unconditionally removes the running XDP program (loaded by xdp2)
via set_link_xdp_fd(ifindex, -1). The xdp2 user program is still
running, and is unaware of its xdp/bpf program have been unloaded.
I find this userspace interface confusing. What this your intention?
Perhaps you can explain what the intended semantics or specification is?
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
reply other threads:[~2016-09-15 18:13 UTC|newest]
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