On Fri, 16 Aug 2024 09:44:21 -0500 ira.weiny@xxxxxxxxx wrote: > From: Navneet Singh <navneet.singh@xxxxxxxxx> > > Dynamic Capacity CXL regions must allow memory to be added or removed > dynamically. In addition to the quantity of memory available the > location of the memory within a DC partition is dynamic based on the > extents offered by a device. CXL DAX regions must accommodate the > sparseness of this memory in the management of DAX regions and devices. > > Introduce the concept of a sparse DAX region. Add a create_dc_region() > sysfs entry to create such regions. Special case DC capable regions to > create a 0 sized seed DAX device to maintain compatibility which > requires a default DAX device to hold a region reference. > > Indicate 0 byte available capacity until such time that capacity is > added. > > Sparse regions complicate the range mapping of dax devices. There is no > known use case for range mapping on sparse regions. Avoid the > complication by preventing range mapping of dax devices on sparse > regions. > > Interleaving is deferred for now. Add checks. > > Signed-off-by: Navneet Singh <navneet.singh@xxxxxxxxx> > Co-developed-by: Ira Weiny <ira.weiny@xxxxxxxxx> > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
