On Fri, Aug 14, 2020 at 10:31:24AM -0700, Minchan Kim wrote: > There is a need for special HW to require bulk allocation of > high-order pages. For example, 4800 * order-4 pages. ... but you haven't shown that user. > int alloc_pages_bulk(unsigned long start, unsigned long end, > unsigned int migratetype, gfp_t gfp_mask, > unsigned int order, unsigned int nr_elem, > struct page **pages); > > It will investigate the [start, end) and migrate movable pages > out there by best effort(by upcoming patches) to make requested > order's free pages. > > The allocated pages will be returned using pages parameter. > Return value represents how many of requested order pages we got. > It could be less than user requested by nr_elem. I don't understand why a user would need to know the PFNs to allocate between. This seems like something that's usually specified by GFP_DMA32 or similar. Is it useful to return fewer pages than requested?
