Hello, On Wed, Jan 02, 2019 at 07:05:38PM +0200, Mike Rapoport wrote: > I agree that currently the bottom-up allocation after the kernel text has > issues with KASLR. But this issues are not necessarily related to the > memory hotplug. Even with a single memory node, a bottom-up allocation will > fail if KASLR would put the kernel near the end of node0. > > What I am trying to understand is whether there is a fundamental reason to > prevent allocations from [0, kernel_start)? > > Maybe Tejun can recall why he suggested to start bottom-up allocations from > kernel_end. That's from 79442ed189ac ("mm/memblock.c: introduce bottom-up allocation mode"). I wasn't involved in that patch, so no idea why the restrictions were added, but FWIW it doesn't seem necessary to me. Thanks. -- tejun