Re: [PATCH RESEND 1/3] printk: convert byte-buffer to variable-length record buffer

From: Joe Perches <joe@perches.com>
To: Kay Sievers <kay@vrfy.org>
Cc: "Ted Ts'o" <tytso@mit.edu>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
	Sasha Levin <levinsasha928@gmail.com>,
	Greg Kroah-Hartmann <greg@kroah.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND 1/3] printk: convert byte-buffer to variable-length record buffer
Date: Thu, 10 May 2012 13:46:12 -0700	[thread overview]
Message-ID: <1336682772.29763.6.camel@joe2Laptop> (raw)
In-Reply-To: <CAPXgP11T7vjBBFaE5jne0hntZ2J-MoVxwJ2C9TNsRzme9DmLuQ@mail.gmail.com>

On Thu, 2012-05-10 at 22:39 +0200, Kay Sievers wrote:
> On Thu, May 10, 2012 at 10:37 PM, Joe Perches <joe@perches.com> wrote:
> > On Thu, 2012-05-10 at 16:14 -0400, Ted Ts'o wrote:
> >> Is there any difference in any of the cases in terms of how printk's
> >> that are prefixed with KERN_CONT versus a printk that does not have
> >> any KERN_* prefix?  If so, is there value in keeping KERN_CONT?
> >
> > As far as I know, no.
> >
> > It is a useful marker to show where prints
> > are actually continued.
> >
> > #define KERN_CONT ""
> >
> > would save a small amount of text.
> 
> Nah, we can't do that. We need it to tell "here is your non-prefix to
> parse, leave the data behind alone".

That's where I think you're still a bit
uncertain how the _current_ printk system
works.  Your _new_ printk system should
have identical behavior.  Though if you
manage to use the call tree and current to
coalesce complete messages more correctly,
that'd be great.