Re: [PATCH v5 0/8] selftests/cgroup: improve zswap tests robustness and support large page sizes

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 26 Mar 2026 11:26:50 +0800 Li Wang <liwang@redhat.com> wrote:

> This patchset aims to fix various spurious failures and improve the overall
> robustness of the cgroup zswap selftests.
> 
> The primary motivation is to make the tests compatible with architectures
> that use non-4K page sizes (such as 64K on ppc64le and arm64). Currently,
> the tests rely heavily on hardcoded 4K page sizes and fixed memory limits.
> On 64K page size systems, these hardcoded values lead to sub-page granularity
> accesses, incorrect page count calculations, and insufficient memory pressure
> to trigger zswap writeback, ultimately causing the tests to fail.
> 
> Additionally, this series addresses OOM kills occurring in test_swapin_nozswap
> by dynamically scaling memory limits, and prevents spurious test failures
> when zswap is built into the kernel but globally disabled.

Thanks.  AI review flagged a few potential issues.

	https://sashiko.dev/#/patchset/20260326032658.96819-1-liwang%40redhat.com

Please take a look - I'm interested in learning how may of these you
feel are worth addressing.  

The sysconf retval one is real, pretty minor.

I'd be inclined to ignore the unchecked-malloc-return one.  It's
userspace, it's selftests.  If a malloc() fails then gee, fix your
machine and run it again.


Plese understand that I'm serious trying to slow things down now
(https://lkml.kernel.org/r/20260323202941.08ddf2b0411501cae801ab4c@linux-foundation.org).
Maybe we can weasel out of that for selftests but I'd rather not. 
That means post-7.1-r1 for this patchset, so please plan to resend at
that time.

If memcg maintainers decide that this material should target the
upcoming merge window then OK,