On Tue, Jan 28, 2020 at 7:55 PM Eric Sage [off-list ref] wrote:

At Facebook we use tail calls to jump between our firewall filters and
our L4LB. This is a program I wrote to estimate per program performance
by swapping out the entries in the program array with interceptors that
take measurements and then jump to the original entries.

I found the sample programs to be invaluable in understanding how to use
the libbpf API (as well as the test env from the xdp-tutorial repo for
testing), and want to return the favor. I am currently working on
my next iteration that uses fentry/fexit to be less invasive,
but I thought it was an interesting PoC of what you can do with program
arrays.

Signed-off-by: Eric Sage <redacted>
---

Looks good, thanks!

Acked-by: Andrii Nakryiko <redacted>

Changes in v3:
- Fixed typos in xdp_stat_kern.c
- Switch to using key_size, value_size for prog arrays.

Just for the future: you should keep entire changelog, starting from
v1->v2 changes. Also, netdev patches usually preserve them as part of
commit message (for individual patch) or cover letter (for patch set).
But in this case I think changes are not substantial enough to record
them permanently, so it's fine.


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