> - page = vm_normal_page(vma, addr, pte); > + page = vm_normal_lru_page(vma, addr, pte); Why can't this deal with ZONE_DEVICE pages? It certainly has nothing do with a LRU I think. In fact being able to have stats that count say the number of device pages here would probably be useful at some point. In general I find the vm_normal_lru_page vs vm_normal_page API highly confusing. An explicit check for zone device pages in the dozen or so spots that care has a much better documentation value, especially if accompanied by comments where it isn't entirely obvious. > page = follow_page(vma, addr, > - FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); > + FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE | FOLL_LRU); Overly long line here. > +/* > + * NOTE: Technically this should goto check_pfn label. However, page->_mapcount > + * is never incremented for device pages that are mmap through DAX mechanism > + * using pmem driver mounted into ext4 filesystem. When these pages are unmap, > + * zap_pte_range is called and vm_normal_page return a valid page with > + * page_mapcount() = 0, before page_remove_rmap is called. > + */ Please properly indent comments. > + * zone, as long as the pte's are present and vm_normal_lru_page() succeeds. These > * pages also get pinned. Another overly long line here.
