Re: [PATCH v4 3/4] mm/sparse: Add a new parameter 'data_unit_size' for alloc_usemap_and_memmap

[Dave Hansen]

On 06/08/2018 08:17 AM, Baoquan He wrote:
> 
> Then inside alloc_usemap_and_memmap(), For each node, we get how many
> present sections on this node, call hook alloc_func(). Then we update
> the pointer to point at a new position of usemap_map[] or map_map[].

I think this is the key.

alloc_usemap_and_memmap() is passed in a "void *" that it needs to
update as things get consumed.  But, it knows only the quantity of
objects consumed and not the type.  This effectively tells it enough
about the type to let it update the pointer as objects are consumed.

Right?

Can we get that in the changelog?