Add a selftest to cover the zswapin code path, allocating more memory than the cgroup limit to trigger swapout/zswapout, then reading the pages back in memory several times. This is inspired by a recently encountered kernel crash on the zswapin path in our internal kernel, which went undetected because of a lack of test coverage for this path. Add a selftest to verify that when memory.zswap.max = 0, no pages can go to the zswap pool for the cgroup. [nphamcs@gmail.com: remove redundant comment, add success checks] Link: https://lkml.kernel.org/r/20240222043132.616320-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20240205225608.3083251-4-nphamcs@gmail.com Signed-off-by: Nhat Pham <nphamcs@gmail.com> Suggested-by: Rik van Riel <riel@surriel.com> Suggested-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Yosry Ahmed <yosryahmed@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shuah Khan <shuah@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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