Re: [PATCH v6 0/6] selftests/mm: separate GUP microbenchmarking from functional testing

Hi Mike!

On 8/3/26 2:30 PM, Mike Rapoport wrote:
>> gup_test.c currently serves two separate purposes: benchmarking
>> (GUP_FAST_BENCHMARK, PIN_FAST_BENCHMARK and PIN_LONGTERM_BENCHMARK) and
>> functional testing (GUP_BASIC_TEST, PIN_BASIC_TEST and
>> DUMP_USER_PAGES_TEST). Keeping both in one program makes the functional
>> tests harder to run and report individually, while run_vmtests.sh has to
>> invoke the program repeatedly with different options.
>>
>> Separate these roles into tools/mm/gup_bench for benchmarking and
>> tools/testing/selftests/mm/gup for functional testing. Move the shared
>> file and hugepage helpers to tools/lib/mm/ so both programs can use them
>> without duplicating the implementation.
> 
> This sets seems to regress hugetlb tests: 
> 
> https://github.com/linux-mm/linux-mm/actions/runs/30553882784/job/90909219578
> 

Oh, thanks for pointing this out. I found out that the issue is in
thuge-gen.c, where we call test_shmget(getpagesize(), 0), which
internally calls hugetlb_free_pages(size). This attempts to read
/sys/kernel/mm/hugepages/hugepages-4kB, which does not exist.

Earlier, read_file() returned 0 for this case, so there was no issue.
Now that it returns an error for this, the test failed.

Will fix this.