ndctl
Utility library for managing the libnvdimm (non-volatile memory device) sub-system in the Linux kernel
Build
meson setup build;
meson compile -C build;
Optionally, to install:
meson install -C build
There are a number of packages required for the build steps that may not be installed by default. For information about the required packages, see the "BuildRequires:" lines in ndctl.spec.in.
https://github.com/pmem/ndctl/blob/master/ndctl.spec.in
Documentation
See the latest documentation for the NVDIMM kernel sub-system here:
https://www.kernel.org/doc/html/latest/driver-api/nvdimm/index.html
A getting started guide is also available on the kernel.org nvdimm wiki:
https://nvdimm.wiki.kernel.org/start
Unit Tests
The unit tests run by meson test
require the nfit_test.ko module to be
loaded. To build and install nfit_test.ko:
-
Obtain the kernel source. For example,
git clone -b libnvdimm-for-next git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git
-
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. -
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_X86_PMEM_LEGACY=m CONFIG_ZONE_DEVICE=y CONFIG_LIBNVDIMM=m CONFIG_BLK_DEV_PMEM=m CONFIG_BTT=y CONFIG_NVDIMM_PFN=y CONFIG_NVDIMM_DAX=y CONFIG_DEV_DAX_PMEM=m CONFIG_ENCRYPTED_KEYS=y CONFIG_NVDIMM_SECURITY_TEST=y CONFIG_STRICT_DEVMEM=y CONFIG_IO_STRICT_DEVMEM=y
-
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 finalmodules_install
make M=tools/testing/nvdimm sudo make M=tools/testing/nvdimm modules_install sudo make modules_install
-
CXL test
The unit tests will also run CXL tests by default. In order to make these work, we need to install the cxl_test.ko as well.
Obtain the CXL kernel source(optional). For example,
git clone -b pending git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git
Enable CXL-related kernel configuration options.
CONFIG_CXL_BUS=m CONFIG_CXL_PCI=m CONFIG_CXL_ACPI=m CONFIG_CXL_PMEM=m CONFIG_CXL_MEM=m CONFIG_CXL_PORT=m CONFIG_CXL_REGION=y CONFIG_CXL_REGION_INVALIDATION_TEST=y CONFIG_DEV_DAX_CXL=m
-
Install cxl_test and related mock modules.
make M=tools/testing/cxl sudo make M=tools/testing/cxl modules_install sudo make modules_install
-
Now run
meson test -C build
in the ndctl source directory, orndctl test
, if ndctl was built with-Dtest=enabled
as a configuration option to meson. -
To run the 'destructive' set of tests that may clobber existing pmem configurations and data, configure meson with the destructive option after the
meson setup
step:meson configure -Dtest=enabled -Ddestructive=enabled build;
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 meson test
will skip tests and report a message like the following in
build/meson-logs/testlog.txt
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 device_dax * extra
override dax_pmem * extra
override dax_pmem_core * extra
override dax_pmem_compat * extra
override libnvdimm * extra
override nd_btt * extra
override nd_e820 * extra
override nd_pmem * extra
The nfit_test module emulates pmem with memory allocated via vmalloc(). One of the side effects is that this breaks 'physically contiguous' assumptions in the driver. Use the '--align=4K option to 'ndctl create-namespace' to avoid these corner case scenarios.