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From: Rob Landley <rob@landley.net>
To: Wen Congyang <wency@cn.fujitsu.com>
Cc: tglx@linutronix.de, Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	bhelgaas@google.com, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 1/2] doc: update mem= option's spec
Date: Thu, 14 Jun 2012 15:22:46 -0500	[thread overview]
Message-ID: <4FDA4816.7000405@landley.net> (raw)
In-Reply-To: <4FD99C88.2010002@cn.fujitsu.com>

On 06/14/2012 03:10 AM, Wen Congyang wrote:
> Current mem= implementation seems buggy because specification and
> implementation doesn't match. Current mem= has been working
> for many years and it's not buggy, it works as expected. So
> we should update the specification.
> 
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> ---
>  Documentation/kernel-parameters.txt |    7 ++++---
>  1 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index a92c5eb..924b1a4 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1471,9 +1471,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>  	mem=nn[KMG]	[KNL,BOOT] Force usage of a specific amount of memory
>  			Amount of memory to be used when the kernel is not able
>  			to see the whole system memory or for test.
> -			[X86-32] Use together with memmap= to avoid physical
> -			address space collisions. Without memmap= PCI devices
> -			could be placed at addresses belonging to unused RAM.
> +			[X86-32] Work as limiting max address. Use together
> +			with memmap= to avoid physical address space collisions.
> +			Without memmap= PCI devices could be placed at addresses
> +			belonging to unused RAM.
>  
>  	mem=nopentium	[BUGS=X86-32] Disable usage of 4MB pages for kernel
>  			memory.

I have no objection to this but can't confirm it's true or not without
an awful lot more digging through the code I don't have time for right
now. (All the x86-32 machines I've used just had the 640k->1m hole and
the rest was contiguous memory, so the behavior would be the same either
way...)

Sort-of-tentatively-acked-by: Rob Landley <rob@landley.net>

Rob
-- 
GNU/Linux isn't: Linux=GPLv2, GNU=GPLv3+, they can't share code.
Either it's "mere aggregation", or a license violation.  Pick one.

      parent reply	other threads:[~2012-06-14 20:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-14  8:10 [PATCH 1/2] doc: update mem= option's spec Wen Congyang
2012-06-14  8:12 ` [PATCH 2/2] x86: reimplement mem boot option Wen Congyang
2012-06-28  1:29   ` Wen Congyang
2012-07-17  5:22     ` Wen Congyang
2012-07-18  9:16       ` Ingo Molnar
2012-08-21  8:11   ` [PATCH v2 " Wen Congyang
2012-09-05  9:28     ` Wen Congyang
2012-06-14 20:22 ` Rob Landley [this message]

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