On Tue, Dec 8, 2020 at 9:31 AM Joao Martins [off-list ref] wrote:

Replace vmem_altmap with an vmem_context argument. That let us
express how the vmemmap is gonna be initialized e.g. passing
flags and a page size for reusing pages upon initializing the
vmemmap.

Per the comment on the last patch, if compound dev_pagemap never
collides with vmem_altmap then I don't think this patch is needed.