Messages in this thread | | | Date | Mon, 28 Jan 2013 18:20:55 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 2/2] x86 e820: Introduce memmap=resetusablemap for kdump usage |
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On 01/28/2013 06:19 PM, Yinghai Lu wrote: > On Mon, Jan 28, 2013 at 6:11 PM, H. Peter Anvin <hpa@zytor.com> 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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