Re: [RFC PATCH 3/3] tests/qtest/migration-test: Enable test_ignore_shared

[Fabiano Rosas]

Peter Xu <peterx@redhat.com> writes:

> On Mon, May 27, 2024 at 09:42:28AM -0300, Fabiano Rosas wrote:
>> However, there is an issue here still on all archs - which might very
>> well have been the original issue - which is the fact that the
>> containers on the Gitlab CI have limits on shared memory usage.
>> Unfortunately we cannot enable this test for the CI, so it needs a check
>> on the GITLAB_CI environment variable.
>
> Another option is we teach migration-test to detect whether memory_size of
> shmem is available, skip if not.  It can be a sequence of:
>
>   memfd_create()
>   fallocate()
>   ret = madvise(MADV_POPULATE_WRITE)
>
> To be run at the entry of migration-test, and skip all use_shmem=true tests
> if ret != 0, or any step failed above.

There are actually two issues:

1) Trying to run a test that needs more shmem than available in the
container. This is covered well by your suggestion.

2) Trying to use some shmem while another test has already consumed all
shmem. I'm not sure if this can be done reliably as the tests run in
parallel.