linux-kernel - Re: [PATCH] x86: Drop redundant memory-block sizing code

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Message-ID: <545B4E84.7050707@numascale.com>
Date:	Thu, 06 Nov 2014 18:33:40 +0800
From:	Daniel J Blueman <daniel@...ascale.com>
To:	Borislav Petkov <bp@...en8.de>
CC:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Yinghai Lu <yinghai@...nel.org>, x86@...nel.org,
	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	Steffen Persvold <sp@...ascale.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH] x86: Drop redundant memory-block sizing code

On 11/06/2014 05:40 PM, Borislav Petkov wrote:
> On Thu, Nov 06, 2014 at 12:50:14PM +0800, Daniel J Blueman wrote:
>> Drop the unused code from selecting a fixed memory block size of 2GB
>> on large-memory x86-64 systems.
>>
>> Signed-off-by: Daniel J Blueman <daniel@...ascale.com>
>
> This commit message is seriously lacking an explanation why? Why is it
> unused, why is it ok on systems with mem < 64g, what is the problem it
> solves, ...
>
> Just ask yourself this when you write commit messages: would anyone else
> be able to understand what this commit was improving when anyone reads
> that commit message months, maybe years from now.

Yes, true. I am incorrectly assuming that someone is looking at the 
patch in-context, but perhaps better to write assuming the code isn't 
seen (or at least understood).

How is this?

As the first check for 64GB or larger memory returns a 2GB memory block 
size in that case, the following check for less than 64GB will always 
evaluate true, leading to unreachable code.

Remove the second and unnecessary condition and the code in the 
remainder of the function, as it therefore can't be reached.

Thanks,
   Daniel
-- 
Daniel J Blueman
Principal Software Engineer, Numascale
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