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Date: Wed, 13 Nov 2013 14:44:45 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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Subject: Re: /proc/vmcore mmap() failure issue
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To: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>, Kexec Mailing List <kexec@lists.infradead.org>, linux kernel mailing list <linux-kernel@vger.kernel.org>, HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>, "Eric W. Biederman" <ebiederm@xmission.com>, Dave Young <dyoung@redhat.com>, WANG Chao <chaowang@redhat.com>

On 11/13/2013 02:41 PM, Vivek Goyal wrote:
> 
> Hi Peter,
> 
> I noticed we seem to be trimming away partial pages in memblock.
> 
> memblock_x86_fill() {
> 	/* throw away partial pages */
>         memblock_trim_memory(PAGE_SIZE);
> }
> 
> But not in e820 hence they show up in /proc/iomem.
> 

Why does /proc/iomem matter?

> How about something along the lines as below patch. This fixes my
> /proc/vmcore mmap() issue.

I'm not sure if what you're seeing is something that is better handled
in userspace.

	-hpa



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