Re: [PATCH net-next 3/4] bpf: add support for persistent maps/progs

From: Daniel Borkmann
Date: Fri Oct 16 2015 - 13:57:29 EST


On 10/16/2015 07:42 PM, Alexei Starovoitov wrote:
On 10/16/15 10:21 AM, Hannes Frederic Sowa wrote:
Another question:
Should multiple mount of the filesystem result in an empty fs (a new
instance) or in one were one can see other ebpf-fs entities? I think
Daniel wanted to already use the mountpoint as some kind of hierarchy
delimiter. I would have used directories for that and multiple mounts
would then have resulted in the same content of the filesystem. IMHO
this would remove some ambiguity but then the question arises how this
is handled in a namespaced environment. Was there some specific reason
to do so?

That's an interesting question!
I think all mounts should be independent.
I can see tracing using one and networking using another one
with different hierarchies suitable for their own use cases.
What's an advantage to have the same content everywhere?
Feels harder to manage, since different users would need to
coordinate.

I initially had it as a mount_single() file system, where I was thinking
to have an entry under /sys/fs/bpf/, so all subsystems would work on top
of that mount point, but for the same reasons above I lifted that restriction.

Cheers,
Daniel
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