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From: Jason Baron <jbaron@redhat.com>
To: Michael Ellerman <michael@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>, gnb@sgi.com
Subject: Re: [PATCH] Resurrect old pr_debug() semantics as pr_devel()
Date: Mon, 6 Apr 2009 17:24:17 -0400	[thread overview]
Message-ID: <20090406212417.GC3212@redhat.com> (raw)
In-Reply-To: <4a5c6b4cd1b77ebe6d60362bc982f4dc81cba85e.1238992196.git.michael@ellerman.id.au>

On Mon, Apr 06, 2009 at 02:30:03PM +1000, Michael Ellerman wrote:
> pr_debug() used to produce zero code unless DEBUG was #defined. This is
> now no longer the case in practice[1].
> 
> There are places where it's useful to have debugging printks, but we
> don't want them to generate any code in production kernels.
> 
> So add a new macro, pr_devel(), for _devel_opment, to provide the old
> semantics, ie. if the programmer doesn't explicitly enable debugging,
> no code is produced.
> 
> [1]: You can turn CONFIG_DYNAMIC_DEBUG off, but it's enabled in at least
>      one distro kernel, so it's not really a solution.
> 

hmm...its designed to have low overhead when CONFIG_DYNAMIC_DEBUG
is on, but none of the debugging printks are enabled. Is there a
specific benchmark or test case that is unaccpetable?

thanks,

-Jason

  reply	other threads:[~2009-04-06 21:25 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-06  4:30 [PATCH] Resurrect old pr_debug() semantics as pr_devel() Michael Ellerman
2009-04-06 21:24 ` Jason Baron [this message]
2009-04-07  2:08   ` Michael Ellerman

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