答复: [PATCH] arm64: mm: free unused memmap for sparse memory model that define VMEMMAP

[Catalin Marinas]

On Wed, Jul 22, 2020 at 08:41:17AM +0000, liwei (CM) wrote:
> Mike Rapoport wrote:
> > On Tue, Jul 21, 2020 at 03:32:03PM +0800, Wei Li wrote:
> > > For the memory hole, sparse memory model that define SPARSEMEM_VMEMMAP 
> > > do not free the reserved memory for the page map, this patch do it.
> > 
> > Are there numbers showing how much memory is actually freed?
> > 
> > The freeing of empty memmap would become rather complex with these
> > changes, do the memory savings justify it?
> 
> In the sparse memory model, the size of a section is 1 GB
> (SECTION_SIZE_BITS 30) by default.

Can we reduce SECTION_SIZE_BITS instead? Say 26?

-- 
Catalin