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Message-ID: <33307c790809220929l32427a1as3d6d6bc08ce3173b@mail.gmail.com>
Date: Mon, 22 Sep 2008 09:29:33 -0700
From: "Martin Bligh" <mbligh@google.com>
To: "Peter Zijlstra" <a.p.zijlstra@chello.nl>
Subject: Re: Unified tracing buffer
Cc: prasad@linux.vnet.ibm.com,
       "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
       "Linus Torvalds" <torvalds@linux-foundation.org>,
       "Thomas Gleixner" <tglx@linutronix.de>,
       "Mathieu Desnoyers" <compudj@krystal.dyndns.org>,
       "Steven Rostedt" <rostedt@goodmis.org>, od@novell.com,
       "Frank Ch. Eigler" <fche@redhat.com>,
       "Andrew Morton" <akpm@linux-foundation.org>, hch@lst.de,
       "David Wilder" <dwilder@us.ibm.com>, zanussi@comcast.net
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>> In conjunction with the previous email on this thread
>> (http://lkml.org/lkml/2008/9/22/160), may I suggest
>> the equivalent interfaces in -mm tree (2.6.27-rc5-mm1) to be:
>>
>> relay_printk(<some struct with default filenames/pathnames>, <string>,
>> ....) ;
>> relay_dump(<some struct with default filenames/pathnames>, <binary
>> data>);
>> and
>> relay_cleanup_all(<the struct name>); - Single interface that cleans up
>> all files/directories/output data created under a logical entity.
>
> Dude, relayfs is such a bad performing mess that extending it seems like
> a bad idea. Better to write something new and delete everything relayfs
> related.

There did seem to be pretty universal agreement that we'd rather not
use relayfs.

> Also, it seems prudent to separate the ring-buffer implementation from
> the event encoding/decoding facilities.

Right - in conversation I had with Mathieu later, he suggested cleaning up
relayfs - I fear this will delay us far too long, and get bogged down.
If we can get one clean circular buffer implementation, then both
relayfs and the tracing could share that common solution,