[LTP] memcg/functional: fix memcg_failcnt intermittent timeout by disabling swap

[linuxtestproject.agent@gmail.com]

Hi Xuewen,

On Fri, Aug 7, 2026, Xuewen Wang wrote:
> memcg/functional: fix memcg_failcnt intermittent timeout by disabling swap

> +do_setup()
> +{
> +	memcg_setup
> +	swapoff -a
> +}

Could this use ROD so a failed swapoff aborts the test? swapoff can fail
when there is not enough memory to page the swap contents back in.
_tst_run_iterations() ignores the setup function's return status, so the
test proceeds with swap enabled and the original intermittent timeout
remains.

> +do_cleanup()
> +{
> +	swapon -a
> +	memcg_cleanup
> +}

Could cleanup restore only swap areas that were active before setup, and
only if swapoff was attempted? TST_DO_CLEANUP is set before do_setup(), so
a TCONF from memcg_setup() reaches this function before swapoff. swapon -a
can then activate previously inactive fstab entries. Conversely, dynamically
managed swap areas absent from fstab are disabled by swapoff -a but are not
restored by swapon -a.

Verdict - Needs revision

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