On Mon, Jan 28, 2013 at 6:11 PM, H. Peter Anvin <hpa at 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; ...