From: Andrew Morton <akpm@linux-foundation.org>
To: Wilson Felipe Pereira <wfelipe@google.com>
Cc: "Johannes Weiner" <hannes@cmpxchg.org>,
"Yosry Ahmed" <yosry@kernel.org>, "Nhat Pham" <nphamcs@gmail.com>,
"Chengming Zhou" <chengming.zhou@linux.dev>,
"Tejun Heo" <tj@kernel.org>, " Michal Koutný " <mkoutny@suse.com>,
"Shuah Khan" <shuah@kernel.org>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 0/2] selftests/cgroup: fixes for test_zswap on single core VM
Date: Thu, 27 Aug 2026 15:58:27 -0700 [thread overview]
Message-ID: <20260827155827.e40d5d88cee174437a16f432@linux-foundation.org> (raw)
In-Reply-To: <20260827034807.2822234-1-wfelipe@google.com>
On Thu, 27 Aug 2026 03:47:40 +0000 Wilson Felipe Pereira <wfelipe@google.com> wrote:
> This series fixes two test failures in test_zswap observed when running on
> a single-core VM (-smp 1) with 4GB of RAM.
>
> Patch 1 addresses a race condition in test_zswap_writeback() where
> waitpid() returns before the exiting child process is switched away by the
> kernel, causing an immediate write of "+memory" to cgroup.subtree_control
> to fail with -EBUSY. We fix this by waiting for cgroup.events to report
> "populated 0".
>
> Patch 2 fixes an implicit unsigned conversion bug in test_no_kmem_bypass()
> where small negative timing differences between debugfs stored_pages and
> cgroup zswapped bytes caused the comparison to falsely fail due to
> unsigned promotion.
Thanks. Sashiko thinks there remain some
signedness/truncation/overflow issues in there:
https://sashiko.dev/#/patchset/20260827034807.2822234-1-wfelipe@google.com
prev parent reply other threads:[~2026-08-27 22:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-27 3:47 [PATCH v3 0/2] selftests/cgroup: fixes for test_zswap on single core VM Wilson Felipe Pereira
2026-08-27 3:47 ` [PATCH v3 1/2] selftests/cgroup: test_zswap: wait for cgroup to unpopulate in test_zswap_writeback Wilson Felipe Pereira
2026-08-27 3:47 ` [PATCH v3 2/2] selftests/cgroup: test_zswap: fix implicit unsigned promotion bug in test_no_kmem_bypass Wilson Felipe Pereira
2026-08-27 14:28 ` Michal Koutný
2026-08-27 22:58 ` Andrew Morton [this message]
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