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b=UYb54Kxx65LLq0qlCcbXJfPX2Ur0P4LcbnlozgE0qzkgcE1vgcXIHYzjmSdiFd72C b537IQfQ/372i9zPL2tZI3RdE05VqCLNNhSFjzK1VEUE9GnVk9PabkvstDOyRee/8R Tj1gSL8mE+nLLcG3D0whAWOsGKQxGSlBJWP9AU/0= Date: Thu, 26 Mar 2026 16:01:31 -0700 From: Andrew Morton To: Li Wang Cc: yosry@kernel.org, nphamcs@gmail.com, hannes@cmpxchg.org, mhocko@kernel.org, mkoutny@suse.com, muchun.song@linux.dev, tj@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, longman@redhat.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v5 0/8] selftests/cgroup: improve zswap tests robustness and support large page sizes Message-Id: <20260326160131.9f3df79db328ba2095511161@linux-foundation.org> In-Reply-To: <20260326032658.96819-1-liwang@redhat.com> References: <20260326032658.96819-1-liwang@redhat.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: yx687jd8hwkas14boc3rkfhrq7kxwqs6 X-Rspamd-Queue-Id: C93BD40014 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1774566093-207670 X-HE-Meta: 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 H3xj5OVN x/DO6VdqgJHk0yOGSEa+JsTTQ6i96BkoD3RqdWTXEOZ4Nj3YfQktZb/TGbKpo1A/+jtCTqnTA62UEul6ngQjUfTsjAvS3Q9CgKDDrwZZryxkwjQDPigjKkvk3I02h+hgnneCtObN0zIKklvjZGCfcSyK0mjWbAUxaZsHY+7vZt9nXWA+nyuiqUqaRaVppfP8k0IeV29iTPOPIaYWuQncINmbyLpD+/awIJryFlPSZrm/J4weFFU0PFCKEPopq+bhffMeyECIm89mtJUzFy6ZiareTtYV8UEF4gb1Cm5JglMsGC+Py/biT5QGzFj1XF/r41uuxr9exvhMTyNzGmtZWxtdoTVvA6uZNLmOEpe7uo3+GGxqEFkxmjl80olCAZKSR3psrmjjAtXkslgfiNUDvY1jnbAEXYofQXjci Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 26 Mar 2026 11:26:50 +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. 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,