On 7/28/21 12:23 AM, Dan Williams wrote: > On Thu, Jul 22, 2021 at 3:54 AM Joao Martins <joao.m.martins@xxxxxxxxxx> wrote: > [..] >>> The folio work really touches the page >>> cache for now, and this seems mostly to touch the devmap paths. >>> >> /me nods -- it really is about devmap infra for usage in device-dax for persistent memory. >> >> Perhaps I should do s/pagemaps/devmap/ throughout the series to avoid confusion. > > I also like "devmap" as a more accurate name. It matches the PFN_DEV > and PFN_MAP flags that decorate DAX capable pfn_t instances. It also > happens to match a recommendation I gave to Ira for his support for > supervisor protection keys with devmap pfns. > /me nods Additionally, I think I'll be reordering the patches for more clear/easier bisection i.e. first introducing compound pages for devmap, fixing associated issues wrt to the slow pinning and then introduce vmemmap deduplication for devmap. It should look like below after the reordering from first patch to last. Let me know if you disagree. memory-failure: fetch compound_head after pgmap_pfn_valid() mm/page_alloc: split prep_compound_page into head and tail subparts mm/page_alloc: refactor memmap_init_zone_device() page init mm/memremap: add ZONE_DEVICE support for compound pages device-dax: use ALIGN() for determining pgoff device-dax: compound devmap support mm/gup: grab head page refcount once for group of subpages mm/sparse-vmemmap: add a pgmap argument to section activation mm/sparse-vmemmap: refactor core of vmemmap_populate_basepages() to helper mm/hugetlb_vmemmap: move comment block to Documentation/vm mm/sparse-vmemmap: populate compound devmaps mm/page_alloc: reuse tail struct pages for compound devmaps mm/sparse-vmemmap: improve memory savings for compound pud geometry
