Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 1 Feb 2021 16:34:29 +0200 | From | Mike Rapoport <> | Subject | Re: [PATCH v4 1/2] x86/setup: always add the beginning of RAM as memblock.memory |
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On Mon, Feb 01, 2021 at 07:26:05PM +0800, Baoquan He wrote: > On 02/01/21 at 10:32am, David Hildenbrand wrote: > > > > 2) In init_zone_unavailable_mem(), similar to round_up(max_pfn, > > PAGES_PER_SECTION) handling, consider range > > [round_down(min_pfn, PAGES_PER_SECTION), min_pfn - 1] > > which would handle in the x86-64 case [0..0] and, therefore, initialize PFN > > 0. > > Sounds reasonable. Maybe we can change to get the real expected lowest > pfn from find_min_pfn_for_node() by iterating memblock.memory and > memblock.reserved and comparing.
As I've found out the hard way [1], reserved memory is not necessary present.
There could be a system that instead of reserving memory at 0xfe000000 like in Guillaume's report, could have it reserved at 0x0 and populated only from the first gigabyte... [1] https://lore.kernel.org/lkml/127999c4-7d56-0c36-7f88-8e1a5c934cae@collabora.com
-- Sincerely yours, Mike.
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