Re: [PATCH v2 0/3] mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes

[Marc Herbert <marc.herbert@linux.intel.com>]

>>>>> I spent too much time trying to get the ndctl tests mentioned by Dan
>>>>> running (.config tweaks, memmap= setup, ... ), without getting them to
>>>>> pass even without these patches. Some SKIP, some FAIL, some sometimes
>>>>> suddenly SKIP on first invocation, ... instructions unclear or the tests
>>>>> are shaky. This is how far I got:
>>>>
>>>> FWIW I had a similar experience, although I eventually got the FAIL cases below
>>>> to pass. I forget exactly what I needed to tweak for that though :-/
>>>
>>> Add Marc who has been working to clean the documentation up to solve the
>>> reproducibility problem with standing up new environments to run these
>>> tests.
>>
>> I was about to send some doc improvements myself, but I didn't manage to
>> get the tests running in the first place ... even after trying hard :)
>>


>>> http://lore.kernel.org/20250521002640.1700283-1-marc.herbert@linux.intel.com
>>>
>>
>> I think I have CONFIG_XFS_FS=m (instead of y) and CONFIG_DAX=y (instead
>> of =m), and CONFIG_NFIT_SECURITY_DEBUG not set (instead of =y).
>>
>> Let me try with these settings adjusted.
> 
> Yeah, no. Unfortunately doesn't make it work with my debug config. Maybe with the
> defconfig as raised by Marc it would do ... maybe will try that later.

After a lot of trial and error to get them right, these fragments have always
worked for me:

make defconfig ARCH=x86_64
./scripts/kconfig/merge_config.sh .config ../run_qemu/.github/workflows/*.cfg

Warning: there is a CONFIG_DRM=n in there to save a lot of compilation
time.  Nothing against DRM specifically; it's just the best "value" for
a single line change :-)


The run_qemu/.github/workflows/*.cfg fragments are mostly duplicated
from ndctl.git/README.md - but unlike the latter, they're
machine-readable and testable. The CXL fragment is actually tested in 
run_qemu's CI (CI = the only way not to bitrot).
https://github.com/pmem/run_qemu/actions

As I wrote in
https://lore.kernel.org/linux-cxl/aed71134-1029-4b88-ab20-8dfa527a7438@linux.intel.com/
these fragments should ideally live in ndctl.git/, not in run_qemu.git/
(the latter could still add tweaks). Then ndctl.git/README.md could just
refer to the testable fragments instead of inlining them. "Send patches"
they say :-)