Re: [PATCH 4/5] selftest/cgroup: fix zswap test_no_invasive_cgroup_shrink on 64K pagesize system

[Li Wang <liwang@redhat.com>]

On Wed, Mar 11, 2026 at 12:01:24PM -0700, Yosry Ahmed wrote:
> On Wed, Mar 11, 2026 at 4:06 AM Li Wang <liwang@redhat.com> wrote:
> >
> > The test_no_invasive_cgroup_shrink and allocate_bytes use a hardcoded
> > stride of 4095 bytes when touching allocated pages. On systems with 64K
> > page size, this results in writing to the same page multiple times
> > instead of touching all pages, leading to insufficient memory pressure.
> >
> > Additionally, the original memory limits and allocation sizes are too
> > small for 64K page size systems. With only 1M memory.max, there are
> > very few pages available, and a zswap.max of 10K may not provide enough
> > room to store even a single compressed page. This can cause OOM kills
> > or false positives due to insufficient zswap writeback being triggered.
> >
> > Fix these issues by:
> > - Using sysconf(_SC_PAGESIZE) instead of the hardcoded 4095 stride in
> >   both allocate_bytes() and test_no_invasive_cgroup_shrink().
> 
> AFAICT there are other instances of hardcoded 4095 and 4096 values in
> the test, do you mind having a separate patch that updates all of them
> to the runtime value?

Good point, I will achive it in patch V2. Thanks!

-- 
Regards,
Li Wang