linux-kernel - Re: [PATCH 1/1] x86: Exclude E820_RESERVED regions and memory holes above 4 GB from direct mapping.

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Date:	Wed, 14 Dec 2011 17:14:25 -0600
From:	Jacob Shin <jacob.shin@....com>
To:	"H. Peter Anvin" <hpa@...or.com>
CC:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Yinghai Lu <yinghai.lu@...cle.com>,
	"Herrmann3, Andreas" <Andreas.Herrmann3@....com>,
	"x86@...nel.org" <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] x86: Exclude E820_RESERVED regions and memory holes
 above 4 GB from direct mapping.

On Wed, Dec 14, 2011 at 02:42:50PM -0800, H. Peter Anvin wrote:
> On 10/20/2011 03:26 PM, Jacob Shin wrote:
> > On Thu, 2011-10-20 at 17:20 -0500, H. Peter Anvin wrote:
> >> On 10/20/2011 02:15 PM, Jacob Shin wrote:
> >>> On systems with very large memory (1 TB in our case), BIOS may report a
> >>> reserved region or a hole in the E820 map, even above the 4 GB range. Exclude
> >>> these from the direct mapping.
> >>
> >>> +			if (ei->type == E820_RESERVED)
> >>> +				continue;
> >>
> >> This should probably be ei->type != E820_RAM or something similar.  I
> >> haven't looked yet, what does the < 4 GiB code do?
> > 
> > Hm, okay, it calls e820_end_of_low_ram_pfn() which effectively is !=
> > E820_RAM.
> > 
> > I'll fix this, test, then resend.
> > 
> 
> I never got any kind of updated patch, did I?

No, I never sent one out, because it would have still only covered > 4GB, and
in later emails, you said that you wanted a general one that covered all x86.

I'll give it another shot at the generic patch, making a special case for the
< 1MB ISA region.

Thanks!

> 
> 	-hpa
> 
> 

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