I send out a series [RFC PATCH 0/4] x86_64/mm: remove bottom-up allocation style by pushing forward the parsing of mem hotplug info ( https://lore.kernel.org/lkml/1546849485-27933-1-git-send-email-kernelfans@xxxxxxxxx/T/#t). Please give comment if you are interested. Thanks, Pingfan On Fri, Jan 4, 2019 at 2:47 AM Tejun Heo <tj@xxxxxxxxxx> wrote: > > 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
