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

From: Daniel Borkmann <[email-masked]>
Date: Fri, 16 Oct 2015 19:56:49 +0200

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