Re: [PATCH RFC v2 08/18] cxl/region: Add Dynamic Capacity CXL region support

From: Ira Weiny
Date: Wed Sep 06 2023 - 00:37:08 EST


Dave Jiang wrote:
>
>
> On 8/28/23 22:20, Ira Weiny wrote:
> > CXL devices optionally support dynamic capacity. CXL Regions must be
> > configured correctly to access this capacity. Similar to ram and pmem
> > partitions, DC Regions represent different partitions of the DPA space.
> >
> > Interleaving is deferred due to the complexity of managing extents on
> > multiple devices at the same time. However, there is nothing which
> > directly prevents interleave support at this time. The check allows
> > for early rejection.
> >
> > To maintain backwards compatibility with older software, CXL regions
> > need a default DAX device to hold the reference for the region until it
> > is deleted.
> >
> > Add create_dc_region sysfs entry to create DC regions. Share the logic
> > of devm_cxl_add_dax_region() and region_is_system_ram(). Special case
> > DC capable CXL regions to create a 0 sized seed DAX device until others
> > can be created on dynamic space later.
> >
> > Flag dax_regions to indicate 0 capacity available until dax_region
> > extents are supported by the region.
> >
> > Co-developed-by: Navneet Singh <navneet.singh@xxxxxxxxx>
> > Signed-off-by: Navneet Singh <navneet.singh@xxxxxxxxx>
> > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
>
> You probably should update kernel version to v6.7. Otherwise

Done.

> Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
>