[LTP] [PATCH v4] shell: enable OOM protection by default

[Li Wang]

Hi Andrea, Petr,

After looking into it more, now I slightly think doing OOM protection
in the shell harness isn't worth it: the benefit doesn't justify the
complexity. Forking the whole test body means dealing with cleanup and
timer ownership across the fork, plus passing results back from the
child, and all of that would need revalidating for every shell test
that goes through tst_test.sh.

Given that only a few tests actually produce memory pressure, I'd
rather keep it simple and handle it locally in those tests instead of
touching the common harness. Something like a small helper the test
can wrap the memory hungry workload with:

    tst_oom_run()
    {
        ( echo 0 > /proc/self/oom_score_adj; exec "$@" )
    }

The harness (or the setup) protects itself with oom_score_adj -1000,
and only the workload started via tst_oom_run stays killable.
This keeps the harness alive to report results without forking the
whole test body, and matches the C harness model where the worker is
the unprotected part.

Does this direction make sense to you, or do you see a case that
really needs the protection to be harness-wide?
 
> Suggested-by: Li Wang <liwang@redhat.com>

This email address is no longer in use :).

-- 
Regards,
Li Wang