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. Question below about dependency.... > > The corresponding kernel patchset is here: > https://lore.kernel.org/linux-cxl/[email protected]/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/[email protected]/ > > --- > 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/[email protected]/ > > 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/[email protected] > > 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 >
