Message-ID: <41F065C0.7070603@bigpond.net.au>
Date: Fri, 21 Jan 2005 13:15:28 +1100
From: Peter Williams <pwil3058@bigpond.net.au>
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To: karim@opersys.com
CC: Greg KH <greg@kroah.com>, linux-kernel <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@osdl.org>, Andi Kleen <ak@muc.de>,
       Roman Zippel <zippel@linux-m68k.org>, Tom Zanussi <zanussi@us.ibm.com>,
       Robert Wisniewski <bob@watson.ibm.com>, Tim Bird <tim.bird@AM.SONY.COM>
Subject: Re: [PATCH] relayfs redux for 2.6.10: lean and mean
References: <41EF4E74.2000304@opersys.com> <20050120145046.GF13036@kroah.com> <41F05D11.5020109@opersys.com>
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Karim Yaghmour wrote:
> Greg KH wrote:
> 
>>Hm, how about this idea for cutting about 500 more lines from the code:
>>
>>Why not drop the "fs" part of relayfs and just make the code a set of
>>struct file_operations.  That way you could have "relayfs-like" files in
>>any ram based file system that is being used.  Then, a user could use
>>these fops and assorted interface to create debugfs or even procfs files
>>using this type of interface.
>>
>>As relayfs really is almost the same (conceptually wise) as debugfs as
>>far as concept of what kinds of files will be in there (nothing anyone
>>would ever rely on for normal operations, but for debugging only) this
>>keeps users and developers from having to spread their debugging and
>>instrumenting files from accross two different file systems.
> 
> 
> However this assumes that the users of relayfs are not going to want
> it during normal system operation. This is an assumption that fails
> with at least LTT as it is targeted at sysadmins, application developers
> and power users who need to be able to trace their systems at any time.
> 
> I don't mind piggy-backing off another fs, if it makes sense, but
> unlike debugfs, relayfs is meant for general use, and all files in there
> are of the same type: relay channels for dumping huge amounts of data
> to user-space. It seems to me the target audience and basic idea (relay
> channels only in the fs) are different, but let me know if there's a
> compeling argument for doing this in another way without making it too
> confusing for users of those special "files" (IOW, when this starts
> being used in distros, it'll be more straightforward for users to
> understand if all files in a mounted fs behave a certain way than if
> they have certain "odd" files in certain directories, even if it's
> /proc.)

Perhaps the logical solution is to implement debugfs in terms of relayfs?

Peter
-- 
Peter Williams                                   pwil3058@bigpond.net.au

"Learning, n. The kind of ignorance distinguishing the studious."
  -- Ambrose Bierce
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