Re: [PATCHv7 01/19] mm/sparsemem: Allocate mem_section at runtime for SPARSEMEM_EXTREME

[Kirill A. Shutemov]

On Thu, Sep 28, 2017 at 10:07:11AM +0200, Ingo Molnar wrote:
> 
> * Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
> 
> > Size of mem_section array depends on size of physical address space.
> > 
> > In preparation for boot-time switching between paging modes on x86-64
> > we need to make allocation of mem_section dynamic.
> > 
> > The patch allocates the array on the first call to
> > sparse_memory_present_with_active_regions().
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> 
> What is the size of the allocations here, in bytes, for the two main variants?

For 4-level paging it's 32k. For 5-level paging it's 2M.

-- 
 Kirill A. Shutemov