linux-kernel - Re: [PATCH 3/6] INIT: Limit the number of per cpu calibration bootup messages

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Date:	Tue, 17 Nov 2009 08:51:31 -0800
From:	Mike Travis <travis@....com>
To:	David Miller <davem@...emloft.net>
CC:	gorcunov@...il.com, hpa@...or.com, mingo@...e.hu,
	tglx@...utronix.de, akpm@...ux-foundation.org,
	heiko.carstens@...ibm.com, rdreier@...co.com, rdunlap@...otime.net,
	tj@...nel.org, andi@...stfloor.org, gregkh@...e.de,
	yhlu.kernel@...il.com, rientjes@...gle.com, rostedt@...dmis.org,
	rusty@...tcorp.com.au, seto.hidetoshi@...fujitsu.com,
	steiner@....com, fweisbec@...il.com, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/6] INIT: Limit the number of per cpu calibration bootup
 messages



David Miller wrote:
> From: Cyrill Gorcunov <gorcunov@...il.com>
> Date: Tue, 17 Nov 2009 00:50:52 +0300
> 
>> On Mon, Nov 16, 2009 at 01:46:07PM -0800, H. Peter Anvin wrote:
>>> On 11/16/2009 01:43 PM, Cyrill Gorcunov wrote:
>>>> It seems we have one
>>>>
>>>> 	arch/x86/kernel/setup.c:125:unsigned int boot_cpu_id __read_mostly;
>>>>
>>>> 	-- Cyrill
>>> We probably should make it an inline function so that if other arches
>>> want to define it to be a constant or some other kind of special thing
>>> they can.
>> IA-64 and SPARC already has this variable. But boot_cpu_id() as an
>> inline function seem to be more natural/portable ineed.
> 
> Only 32-bit SPARC actually has it.  On sparc64 we have no reason to
> remember which processor was the boot cpu, and remembering it merely
> for the sake of only printing out the bogomips message once seems a
> bit excessive?
> 
> How about:
> 
> 	static bool printed;
> 
> 	if (!printed) {
> 		printk(...);
> 		printed = true;
> 	}
> 
> Or, alternatively, use an atomic_t instead of a bool if you think
> races matter this early in the boot process.

Yeah, I was thinking along these same lines.  Thanks for the feedback!

Mike
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