[PATCH v3] tst-{pthread|sched}-affinity-inheritance: Only use in-mask CPUs in affinity mask.

[Stefan Liebler]

On 2/5/26 18:54, Florian Weimer wrote:
> * Stefan Liebler:
> 
>> On s390x, the two tests are failing on a lpar with linux 6.18 booted with nosmt:
>> FAIL:  misc/tst-sched-affinity-inheritance
>> FAIL:  nptl/tst-pthread-affinity-inheritance
>>
>> Both tests were failing because they are claiming that the CPU affinity mask was
>> not correctly inherited in the forked process/thread.
>> The error already happened before forking, as the mask was set up to use
>> CPUs 0-14 in set_cpu_mask().  But according to e.g. lscpu or the line
>> "Cpus_allowed_list" in /proc/self/status, only the following CPUs were in mask at startup:
>> 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30
>> while 1, 3, 5, ... were configured, but not online.
>>
>> Now the test first gets the current CPU mask at startup in do_test() and
>> set_cpu_mask() only selects those available CPUs.  The test is now just
>> counting the available CPUs instead of relying on get_nprocs().  This allows
>> to run the test even if it was already limited via taskset.
>>
>> Therefore both concrete tests now have the get_my_affinity() function.  This
>> also allows to implement verify_my_affinity() in the common skeleton.
>>
>> In order to ensure that the affinity mask is really set as expected,
>> verify_my_affinity() is now also called before forking a new process or
>> creating a new thread.
>>
>> For also printing the list of mismatched CPU IDs in xor_set in
>> verify_my_affinity(), the argument order of CPU_ISSET_S is now fixed.
>> Furthermore we now keep iterating over all configured CPUs to print
>> the list of cpucount IDs instead of iterating over the first nproc CPUs.
>> ---
>>  nptl/tst-pthread-affinity-inheritance.c       | 41 ++--------
>>  nptl/tst-skeleton-affinity-inheritance.c      | 77 +++++++++++++++----
>>  .../linux/tst-sched-affinity-inheritance.c    | 40 ++--------
>>  3 files changed, 76 insertions(+), 82 deletions(-)
> 
> This version looks okay to me.
> 
> Reviewed-by: Florian Weimer <fweimer@redhat.com>
> 
> Thanks,
> Florian
> 
Committed. Thanks a lot