On Tue, Apr 05, 2016 at 04:22:51PM +0800, Chen Feng wrote:

We can reduce the memory allocated at mem-map
by flatmem.

currently, the default memory-model in arm64 is
sparse memory. The mem-map array is not freed in
this scene. If the physical address is too long,
it will reserved too much memory for the mem-map
array.

Can you elaborate a bit more on this, please? We use the vmemmap, so any
spaces between memory banks only burns up virtual space. What exactly is
the problem you're seeing that makes you want to use flatmem (which is
probably unsuitable for the majority of arm64 machines).

Will