xdp: base API for new XDP rx-queue info concept

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This patch only introduce the core data structures and API functions.
All XDP enabled drivers must use the API before this info can used.

There is a need for XDP to know more about the RX-queue a given XDP
frames have arrived on.  For both the XDP bpf-prog and kernel side.

Instead of extending xdp_buff each time new info is needed, the patch
creates a separate read-mostly struct xdp_rxq_info, that contains this
info.  We stress this data/cache-line is for read-only info.  This is
NOT for dynamic per packet info, use the data_meta for such use-cases.

The performance advantage is this info can be setup at RX-ring init
time, instead of updating N-members in xdp_buff.  A possible (driver
level) micro optimization is that xdp_buff->rxq assignment could be
done once per XDP/NAPI loop.  The extra pointer deref only happens for
program needing access to this info (thus, no slowdown to existing
use-cases).

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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This commit is contained in:

Jesper Dangaard Brouer 2018-01-03 11:25:13 +01:00 • committed by Alexei Starovoitov

parent 5f103c5d4d

commit aecd67b607

4 changed files with 117 additions and 1 deletions

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2

include/linux/filter.h

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47

include/net/xdp.h

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