Re: [PATCH][RFC] relayfs (1/4) (Documentation)

[Hubertus Franke <frankeh@watson.ibm.com>]

David S. Miller wrote:
> On Tue, 14 Oct 2003 11:32:28 +0000
> Richard J Moore <rasman@uk.ibm.com> wrote:
> 
> 
>>Interesting, that assumes sequential processing, if not semi-synchronous 
>>processing of events on the receiver side, which is far from guaranteed when 
>>considering low-level tracing especially for flight-recorder applications.  
> 
> 
> With netlink you may receive the data asynchronously however you
> wish after you've requested a dump.
> 
> I would like to ask that you go study how netlink works and is used
> by things like routing daemons before we discuss this further as
> it looks to me like half the conversation is going to be showing
> you how netlink works.  And hey there's even an RFC on netlink :)
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Dave, is there a short write-up (2-3 pages) about netlink.
I like to get a quick understanding about it and how it measures
up to relayfs or vice versa. From some of the discussions here I get
the feeling that they simply might address orthogonal issues.

I recently started using relayfs for various projects after hearing
about it at OLS'03. I often need to get information out of the kernel
(either debugging in interrupt/scheduling context thus preempting use
of printk) or other information for data recording (call it trace or 
whatever).
I don't want to use existing "media" (e.g. syslog) as it either clobbers 
up that media or I have to search for the information I have put in or 
the format (typically char) is not appropriate for my use. I simply want 
a dedicated channel to get to the data in the format that I select.

I found relayfs extremely easy to use. Channel setup is a breeze.
User level consumption is through file operations. IMHO it just simply
can not get any simpler that this....
It works in interrupt/scheduling context. Has extremely low overhead
and is stable. I really would like to see relayfs be picked up.
Its a loadable filesystem that at least to this user has provided
some real value, so why would inclusion be so difficult/objectable.

You providing a short document might help me get an appreciation for
your argument.

-- Hubertus