I just noticed, there is a difference in the default value of
`/proc/sys/net/core/optmem_max` on armv7l:
On all arches it is 20480, but on armv7l it is 10240.
Is there any specific reason for limiting the maximum ancillary buffer
size allowed per socket on this arch?
No specific reason, I think that would be an upstream kernel default,
I'm not aware we tweak that setting on any of the architectures so it
should be the arch default.