From: Jiayuan Chen <jiayuan.chen@linux.dev>
To: Li Wang <li.wang@linux.dev>,
akpm@linux-foundation.org, tj@kernel.org, longman@redhat.com,
roman.gushchin@linux.dev, hannes@cmpxchg.org, yosry@kernel.org,
nphamcs@gmail.com, chengming.zhou@linux.dev, mkoutny@suse.com,
shuah@kernel.org
Cc: linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
Michal Hocko <mhocko@kernel.org>,
Muchun Song <muchun.song@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>
Subject: Re: [PATCH v7 5/8] selftests/cgroup: replace hardcoded page size values in test_zswap
Date: Fri, 24 Apr 2026 13:20:27 +0800 [thread overview]
Message-ID: <84e67f8e-7cb7-4710-bc46-055a2bb9d0ca@linux.dev> (raw)
In-Reply-To: <20260424040059.12940-6-li.wang@linux.dev>
On 4/24/26 12:00 PM, Li Wang wrote:
> test_zswap uses hardcoded values of 4095 and 4096 throughout as page
> stride and page size, which are only correct on systems with a 4K page
> size. On architectures with larger pages (e.g., 64K on arm64 or ppc64),
> these constants cause memory to be touched at sub-page granularity,
> leading to inefficient access patterns and incorrect page count
> calculations, which can cause test failures.
>
> Replace all hardcoded 4095 and 4096 values with a global pagesize
> variable initialized from sysconf(_SC_PAGESIZE) at startup, and remove
> the redundant local sysconf() calls scattered across individual
> functions. No functional change on 4K page size systems.
>
> Signed-off-by: Li Wang <li.wang@linux.dev>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Michal Koutný <mkoutny@suse.com>
> Cc: Muchun Song <muchun.song@linux.dev>
> Cc: Nhat Pham <nphamcs@gmail.com>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Roman Gushchin <roman.gushchin@linux.dev>
> Cc: Shakeel Butt <shakeel.butt@linux.dev>
> Acked-by: Yosry Ahmed <yosry@kernel.org>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
next prev parent reply other threads:[~2026-04-24 5:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-24 4:00 [PATCH v7 0/8] selftests/cgroup: improve zswap tests robustness and support large page sizes Li Wang
2026-04-24 4:00 ` [PATCH v7 1/8] selftests/cgroup: skip test_zswap if zswap is globally disabled Li Wang
2026-04-24 4:00 ` [PATCH v7 2/8] selftests/cgroup: avoid OOM in test_swapin_nozswap Li Wang
2026-04-24 4:00 ` [PATCH v7 3/8] selftests/cgroup: use runtime page size for zswpin check Li Wang
2026-04-24 4:00 ` [PATCH v7 4/8] selftests/cgroup: rename PAGE_SIZE to BUF_SIZE in cgroup_util Li Wang
[not found] ` <20260424051557.8AA6AC19425@smtp.kernel.org>
2026-04-24 6:04 ` Li Wang
2026-04-24 4:00 ` [PATCH v7 5/8] selftests/cgroup: replace hardcoded page size values in test_zswap Li Wang
2026-04-24 5:20 ` Jiayuan Chen [this message]
2026-04-24 4:00 ` [PATCH v7 6/8] selftest/cgroup: fix zswap test_no_invasive_cgroup_shrink on large pagesize system Li Wang
2026-04-24 4:00 ` [PATCH v7 7/8] selftest/cgroup: fix zswap attempt_writeback() on 64K " Li Wang
2026-04-24 4:00 ` [PATCH v7 8/8] selftests/cgroup: test_zswap: wait for asynchronous writeback Li Wang
2026-04-24 10:06 ` [PATCH v7 0/8] selftests/cgroup: improve zswap tests robustness and support large page sizes Andrew Morton
2026-04-24 11:14 ` Li Wang
2026-04-24 13:31 ` Andrew Morton
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