Re: [PATCH 2/2] x86 e820: Introduce memmap=resetusablemap for kdumpusage
From: H. Peter Anvin
Date: Mon Jan 28 2013 - 21:21:32 EST
On 01/28/2013 06:19 PM, Yinghai Lu wrote:
On Mon, Jan 28, 2013 at 6:11 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
On 01/28/2013 06:10 PM, Yinghai Lu wrote:
kexec-tools will change that to E820_KDUMP_RESERVED (or other good name).
We only need to update kernel to get old max_pfn by
checking E820_KDUMP_RESERVED.
OK, I have asked this before, but I still have not gotten any acceptable
answer:
Why do we still have max_*_pfn at all? Shouldn't it all be based on
memblocks by now?
saved_max_pfn is used for kdump:
drivers/char/mem.c::read_oldmem will stop there.
...
while (count) {
pfn = *ppos / PAGE_SIZE;
if (pfn > saved_max_pfn)
return read;
...
That is a non-answer.
Why do we have *any* instances of max_pfn or max_low_pfn in the kernel
anymore?
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
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