Le 01/07/2016 à 16:22, matthew green a écrit :
We use only one L4 slot for the direct map, which means that we cannot map more than 512GB. Panic properly if this limit is reached.thanks for making the failure mode clear. it would be nice to remove this limitation, and support upto at least 16TB of ram. systems with well over 512GB are not entirely uncommon in 2016, and the future is coming ;)
NetBSD cannot support up to 512GB. The page levels used for the direct map are stored below the IOM area in physical memory. If the machine has more than ~160GB, and the CPU does not support superpages, the page levels and the IOM area collide, and the last page levels basically get overwritten.