Re: [RESEND PATCH v13 3/3] selftests/rseq: Add test for mm_cid compaction

[Shuah Khan <skhan@linuxfoundation.org>]

On 6/13/25 03:12, Gabriele Monaco wrote:
> A task in the kernel (task_mm_cid_work) runs somewhat periodically to
> compact the mm_cid for each process. Add a test to validate that it runs
> correctly and timely.
> 
> The test spawns 1 thread pinned to each CPU, then each thread, including
> the main one, runs in short bursts for some time. During this period, the
> mm_cids should be spanning all numbers between 0 and nproc.
> 
> At the end of this phase, a thread with high enough mm_cid (>= nproc/2)
> is selected to be the new leader, all other threads terminate.
> 
> After some time, the only running thread should see 0 as mm_cid, if that
> doesn't happen, the compaction mechanism didn't work and the test fails.
> 
> The test never fails if only 1 core is available, in which case, we
> cannot test anything as the only available mm_cid is 0.
> 
> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>

Mathieu,

Let me know if you would like me to take this through my tree.

Acked-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah