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

[Li Wang]

On Thu, Mar 26, 2026 at 11:26:50AM +0800, Li Wang 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.
> 
> Changes in v5:
>   Patch 1/8: Defined PATH_ZSWAP and PATH_ZSWAP_ENABLED macros.
>   Patch 4/8: Merge Waiman's work into this patch (use page_size).
>   Patch 5/8: Change pagesize by the global page_size.
>   Patch 6/8: Swap data patterns: use getrandom() for wb_group and simple
>              memset for zw_group to fix the reversed allocation logic.
>   Patch 7/8: Setting zswap.max to zswap_usage/4 to increase writeback pressure.
>   Patch 8/8: New added. Just add loops for read zswpwb more times.
> 
> Test all passed on:
>   x86_64(4k), aarch64(4K, 64K), ppc64le(64K).

Hi Andrew, All,

I see that Sashiko still points out minor issues in this patchset,
That seems very tiny in selftest programming.

I can correct all that in a new version if you'd like a perfect patchset.

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

-- 
Regards,
Li Wang