Utility library for managing the libnvdimm (non-volatile memory device) sub-system in the Linux kernel
C Shell M4 Makefile
Latest commit 78d5421 Feb 7, 2017 @djbw djbw ndctl: release v56
This release incorporates the capabilities of the 4.10 kernel. Major
highlights include the new 'daxctl' utility and its 'list' command, as
well as several usability tweaks and cleanups to 'ndctl
create-namespace' and 'ndctl list'.

Commands:
    ndctl list: add support for filtering by namespace mode
    daxctl list: generically list device-dax instances in a platform
    ndctl create-namespace: reconcile namespace size against interleave-width

Tests:
    test: sanity check the unit test kernel modules befor running tests
    device-dax: extend it to test 4K and 1G alignments in addition to 2M
    multi-pmem: check namespace deletion cleanup

Apis:
    ndctl_{pfn,dax}_has_align: detect kernels that lack the align attribute
    ndctl_{set,get}_private_data: attach private data to a library context
    daxctl_region_get_size: retrieve the total dax region size
    daxctl_region_get_align: retrieve the physical alignment of the region
    daxctl_region_get_{first,next}: enable listing of device-dax regions

README.md

ndctl

Utility library for managing the libnvdimm (non-volatile memory device) sub-system in the Linux kernel

Build

./autogen.sh
./configure CFLAGS='-g -O0' --prefix=/usr --sysconfdir=/etc --libdir=/usr/lib64
make
make check
sudo make install

Documentation

See the latest documentation for the NVDIMM kernel sub-system here:

https://git.kernel.org/cgit/linux/kernel/git/nvdimm/nvdimm.git/tree/Documentation/nvdimm/nvdimm.txt?h=libnvdimm-for-next

Unit Tests

The unit tests run by make check require the nfit_test.ko module to be loaded. To build and install nfit_test.ko:

  1. Obtain the kernel source. For example,
    git clone -b libnvdimm-for-next git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git

  2. Skip to step 3 if the kernel version is >= v4.8. Otherwise, for kernel versions < v4.8, configure the kernel to make some memory available to CMA (contiguous memory allocator). This will be used to emulate DAX.
    CONFIG_DMA_CMA=y
    CONFIG_CMA_SIZE_MBYTES=200
    or
    cma=200M on the kernel command line.

  3. Compile the libnvdimm sub-system as a module, make sure "zone device" memory is enabled, and enable the btt, pfn, and dax features of the sub-system:
    CONFIG_ZONE_DEVICE=y
    CONFIG_LIBNVDIMM=m
    CONFIG_BLK_DEV_PMEM=m
    CONFIG_ND_BLK=m
    CONFIG_BTT=y
    CONFIG_NVDIMM_PFN=y
    CONFIG_NVDIMM_DAX=y

  4. Build and install the unit test enabled libnvdimm modules in the following order. The unit test modules need to be in place prior to the depmod that runs during the final modules_install
    make M=tools/testing/nvdimm
    sudo make M=tools/testing/nvdimm modules_install
    sudo make modules_install

  5. Now run make check in the ndctl source directory, or ndctl test, if ndctl was built with --enable-test.

Troubleshooting

The unit tests will validate that the environment is set up correctly before they try to run. If the platform is misconfigured, i.e. the unit test modules are not available, or the test versions of the modules are superseded by the "in-tree/production" version of the modules make check will skip tests and report a message like the following in test/test-suite.log:
SKIP: libndctl
==============
test/init: nfit_test_init: nfit.ko: appears to be production version: /lib/modules/4.8.8-200.fc24.x86_64/kernel/drivers/acpi/nfit/nfit.ko.xz
__ndctl_test_skip: explicit skip test_libndctl:2684
nfit_test unavailable skipping tests

If the unit test modules are indeed available in the modules 'extra' directory the default depmod policy can be overridden by adding a file to /etc/depmod.d with the following contents:
override nfit * extra
override dax * extra
override dax_pmem * extra
override libnvdimm * extra
override nd_blk * extra
override nd_btt * extra
override nd_e820 * extra
override nd_pmem * extra