> Maybe a stupid question, but I do not see it from the code (this init > code is just to complex to keep it cached in head so I always have to > study the code again and again, sigh). So what exactly prevents > memmap_init_zone to stumble over reserved regions? We do play some ugly > games to find a first !reserved pfn in the node but I do not really see > anything in the init path to properly skip over reserved holes inside > the node. Hi Michal, This is not a stupid question. I figured out how this whole thing became broken: Revert "mm: page_alloc: skip over regions of invalid pfns where possible" caused that. Because, before that was reverted, memmap_init_zone() would use memblock.memory to check that only pages that have physical backing are initialized. But, now after that was reverted zer_resv_unavail() scheme became totally broken. The concept is quite easy: zero all the allocated memmap memory that has not been initialized by memmap_init_zone(). So, I think I will modify memmap_init_zone() to zero the skipped pfns that have memmap backing. But, that requires more thinking. Thank you, Pavel
