On 06/07/18 at 03:48pm, Dave Hansen wrote: > On 05/21/2018 03:15 AM, Baoquan He wrote: > > It's used to pass the size of map data unit into alloc_usemap_and_memmap, > > and is preparation for next patch. > > This is the "what", but not the "why". Could you add another sentence > or two to explain why we need this? Thanks for reviewing, Dave. In alloc_usemap_and_memmap(), it will call sparse_early_usemaps_alloc_node() or sparse_early_mem_maps_alloc_node() to allocate usemap and memmap for each node and install them into usemap_map[] and map_map[]. Here we need pass in the number of present sections on this node so that we can move pointer of usemap_map[] and map_map[] to right position. How do think about above words? Thanks Baoquan
