On Mon, May 11, 2020 at 12:36:19PM -0700, Andy Lutomirski wrote: > I’m guessing the right solution is either your series or your series > plus preallocation on 64-bit. I’m just grumpy about it... Okay, so we can do the pre-allocation when it turns out the pgd_list lock-times become a problem on x86-64. The tracking code in vmalloc.c is needed anyway for 32-bit and there is no reason why 64-bit shouldn't use it as well for now. I don't think that taking the lock _will_ be a problem, as it is only taken when a new PGD/P4D entry is populated. And it is pretty unlikely that a system will populate all 64 of them, with 4-level paging each of these entries will map 512GB of address space. But if I am wrong here pre-allocating is still an option. Joerg
