Re: [PATCH v6 0/7] ndctl: Dynamic Capacity additions for cxl-cli

[Anisa Su]

On Wed, Jun 17, 2026 at 12:10:07AM -0700, Alison Schofield wrote:
> On Thu, Jun 04, 2026 at 10:43:10PM -0700, Alison Schofield wrote:
> > On Sat, May 23, 2026 at 02:50:35AM -0700, Anisa Su wrote:
> > > CXL Dynamic Capacity Device (DCD) support has continued to evolve in the
> > > upstream kernel since Ira's v5 posting [1].  The kernel side has settled
> > > on a uuid-driven claim model for sparse DAX devices: dax_resources carry
> > > the tag delivered with each extent, and userspace selects which ones to
> > > claim by writing a UUID to the dax device's sysfs 'uuid' attribute (or
> > > "0" to claim a single untagged resource).  Size on a sparse region is
> > > determined by the claim, not requested up-front.
> > > 
> > > This series brings cxl-cli and daxctl in line with that model and
> > > extends cxl_test to exercise the new paths end-to-end.
> > 
> > Hi Anisa,
> > 
> > I just now picked this up with the kernel side and took it for a quick
> > test drive. Based on what's been touched, first meaningful finding is
> > all the DAX unit tests pass, and then for CXL unit tests, all but these
> > 2 pass: cxl-security.sh and cxl-dcd.sh
> > 
> > Please let me know if there are known problems with either of those
> > before I explore further.
> 
> Hi Anisa,
> 
> Good news, DCD exposed a long hidden bug that made cxl-security.sh
> fail. It is not an issue w DCD patches.
> 
> Found that DCD set changes which mock memdev the test happens to
> land on, and that's enough to uncover a latent hex/decimal bug in
> CXL nvdimm code. We use to always land on id '1', but now this patch:
> 
> tools/testing/cxl: Add DC Regions to mock mem data
> 
> reorders the sorted dimm list, so the test selects a dimm with
> serial 10 (0xa), and there's the hex/decimal mismatch.
> 
> The renumbering is harmless in itself but it just changed the
> serial the test exercises and tripped over the old bug.
> 
> I'll send a separate fixup patch for the hex/dec cleanup.
> 
> (No answer on cxl-dcd.sh yet)
> 
> -- Alison
> 
Thanks for looking into this! I can also look into what might be going
on with cxl-dcd.sh if you let me know the base commit you applied the
dcd patches onto? :)

Thanks,
Anisa

> > 
> > Question below about dependency....
> > 
> > > 
> > > The corresponding kernel patchset is here:
> > > https://lore.kernel.org/linux-cxl/cover.1779528761.git.anisa.su@xxxxxxxxxxx/T/#t
> > > 
> > > Picked up unchanged from v5 (Ira):
> > > 
> > >   libcxl: Add Dynamic RAM A partition mode support
> > >   cxl/region: Add cxl-cli support for dynamic RAM A
> > >   libcxl: Add extent functionality to DC regions
> > >   cxl/region: Add extent output to region query
> > > 
> > > New in v6:
> > > 
> > >   daxctl: Add --uuid option to create-device for DC DAX regions
> > >     - Plumbs writes to the new dax 'uuid' sysfs attribute through a new
> > >       daxctl_dev_set_uuid() helper (LIBDAXCTL_11).
> > >     - --uuid is mutually exclusive with --size; pass "0" to claim a
> > >       single untagged dax_resource.  An unmatched UUID surfaces ENOENT
> > >       from the kernel and leaves the device at size 0.
> > >     - Documents the option in the man page.
> > > 
> > >   cxl/test: Add Dynamic Capacity tests (rewritten on top of Ira's
> > >   original patch to track the post-redesign kernel)
> > >     - Routes untagged claims via --uuid "0" so daxctl exercises the
> > >       kernel uuid_store path; tagged claims use real UUID strings.
> > >     - Asserts that for DC regions, size-grow returns -EOPNOTSUPP (real grow is
> > >       --uuid only) and that tag reuse across More-chains is rejected
> > >       by the cross-More uniqueness gate.
> > >     - Adds coverage for the new validators: test_uuid_no_match,
> > >       test_uuid_no_match_seed_intact, test_uuid_show,
> > >       test_cross_more_uniqueness, test_alignment_rejection.
> > >     - Sharable-partition coverage (test_shared_extent_inject,
> > >       test_seq_integrity_gap) is routed at runtime to a dedicated mock
> > >       memdev that tools/testing/cxl stamps with serial 0xDCDC, so a
> > >       single cxl_test module load exercises both regimes.
> > >     - Localizes positional-arg assignments in every helper so functions
> > >       no longer clobber caller globals (the previous behavior leaked
> > >       the sharable memdev into later tests).
> > >     - test_reject_overlapping arithmetic now lands an actual overlap
> > >       inside the DC region (the prior math landed past the end).
> > > 
> > > Depends on the kernel DCD/sparse-DAX series; without it the new tests
> > > will skip and 'cxl list -r N -Nu' will simply report no extents.
> > 
> > What is this dependency- DCD/sparse-DAX series ?
> > 
> > > 
> > > The branch is also available at:
> > > 
> > >   https://github.com/anisa-su993/anisa-ndctl/tree/dcd-2026-05-21
> > > 
> > > Based on pmem/pending commit:
> > > 
> > >   bbd403a test/cxl-sanitize: avoid sanitize submit/wait race
> > > 
> > > [1] https://lore.kernel.org/nvdimm/20250413-dcd-region2-v5-0-fbd753a2e0e8@xxxxxxxxx/
> > > 
> > > ---
> > > Changes in v6:
> > > - anisa: New patch — daxctl --uuid option + daxctl_dev_set_uuid() helper
> > > - anisa: Rewrite cxl/test DCD tests against the post-redesign kernel
> > >          (uuid sysfs claim, tag-group atomic release, cross-More
> > >          uniqueness, alignment rejection, DC size-grow refusal)
> > > - anisa: Rebase onto bbd403a (pmem/pending)
> > > - Link to v5: https://lore.kernel.org/nvdimm/20250413-dcd-region2-v5-0-fbd753a2e0e8@xxxxxxxxx/
> > > 
> > > Changes in v5:
> > > - iweiny: Adjust all code to view only the dynamic RAM A partition
> > > - Alison: s/tag/uuid/ in region query extent output
> > > - Link to v4: https://patch.msgid.link/20241214-dcd-region2-v4-0-36550a97f8e2@xxxxxxxxx
> > > 
> > > Anisa Su (1):
> > >   daxctl: Add --uuid option to create-device for DC regions
> > > 
> > > Ira Weiny (6):
> > >   ndctl: Dynamic Capacity additions for cxl-cli
> > >   libcxl: Add Dynamic RAM A partition mode support
> > >   cxl/region: Add cxl-cli support for dynamic RAM A
> > >   libcxl: Add extent functionality to DC regions
> > >   cxl/region: Add extent output to region query
> > >   cxl/test: Add Dynamic Capacity tests
> > > 
> > >  Documentation/cxl/cxl-list.txt                |   29 +
> > >  Documentation/cxl/lib/libcxl.txt              |   33 +-
> > >  Documentation/daxctl/daxctl-create-device.txt |   12 +
> > >  cxl/filter.h                                  |    3 +
> > >  cxl/json.c                                    |   67 +
> > >  cxl/json.h                                    |    3 +
> > >  cxl/lib/libcxl.c                              |  181 +++
> > >  cxl/lib/libcxl.sym                            |    9 +
> > >  cxl/lib/private.h                             |   14 +
> > >  cxl/libcxl.h                                  |   21 +-
> > >  cxl/list.c                                    |    3 +
> > >  cxl/memdev.c                                  |    4 +-
> > >  cxl/region.c                                  |   27 +-
> > >  daxctl/device.c                               |   72 +-
> > >  daxctl/lib/libdaxctl.c                        |   44 +
> > >  daxctl/lib/libdaxctl.sym                      |    5 +
> > >  daxctl/libdaxctl.h                            |    1 +
> > >  test/cxl-dcd.sh                               | 1267 +++++++++++++++++
> > >  test/meson.build                              |    2 +
> > >  util/json.h                                   |    1 +
> > >  20 files changed, 1771 insertions(+), 27 deletions(-)
> > >  create mode 100644 test/cxl-dcd.sh
> > > 
> > > 
> > > base-commit: bbd403a03fa2a1551c1a10bbf78f32027c718758
> > > -- 
> > > 2.43.0
> > > 
> >