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@xxxxxxxxxxxxx -- Sincerely yours, Mike.
