On Thu, May 2, 2019 at 2:07 AM Dan Williams <[email protected]> wrote: > > On Wed, May 1, 2019 at 4:25 PM Pavel Tatashin <[email protected]> > wrote: > > > > On 19-04-17 11:39:00, Dan Williams wrote: > > > Towards enabling memory hotplug to track partial population of a > > > section, introduce 'struct mem_section_usage'. > > > > > > A pointer to a 'struct mem_section_usage' instance replaces the existing > > > pointer to a 'pageblock_flags' bitmap. Effectively it adds one more > > > 'unsigned long' beyond the 'pageblock_flags' (usemap) allocation to > > > house a new 'map_active' bitmap. The new bitmap enables the memory > > > hot{plug,remove} implementation to act on incremental sub-divisions of a > > > section. > > > > > > The primary motivation for this functionality is to support platforms > > > that mix "System RAM" and "Persistent Memory" within a single section, > > > or multiple PMEM ranges with different mapping lifetimes within a single > > > section. The section restriction for hotplug has caused an ongoing saga > > > of hacks and bugs for devm_memremap_pages() users. > > > > > > Beyond the fixups to teach existing paths how to retrieve the 'usemap' > > > from a section, and updates to usemap allocation path, there are no > > > expected behavior changes. > > > > > > Cc: Michal Hocko <[email protected]> > > > Cc: Vlastimil Babka <[email protected]> > > > Cc: Logan Gunthorpe <[email protected]> > > > Signed-off-by: Dan Williams <[email protected]>
Reviewed-by: Pavel Tatashin <[email protected]> _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
