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This adds a special global buffer pool (in the end) for reserved pages. Using a reserved pool for LZ4 decompression significantly reduces the time spent on extra temporary page allocation for the extreme cases in low memory scenarios. The table below shows the reduction in time spent on page allocation for LZ4 decompression when using a reserved pool. The results were obtained from multi-app launch benchmarks on ARM64 Android devices running the 5.15 kernel with an 8-core CPU and 8GB of memory. In the benchmark, we launched 16 frequently-used apps, and the camera app was the last one in each round. The data in the table is the average time of camera app for each round. After using the reserved pool, there was an average improvement of 150ms in the overall launch time of our camera app, which was obtained from the systrace log. +--------------+---------------+--------------+---------+ | | w/o page pool | w/ page pool | diff | +--------------+---------------+--------------+---------+ | Average (ms) | 3434 | 21 | -99.38% | +--------------+---------------+--------------+---------+ Based on the benchmark logs, 64 pages are sufficient for 95% of scenarios. This value can be adjusted with a module parameter `reserved_pages`. The default value is 0. This pool is currently only used for the LZ4 decompressor, but it can be applied to more decompressors if needed. Signed-off-by: Chunhai Guo <guochunhai@vivo.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240402131523.2703948-1-guochunhai@vivo.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> |
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| fs | ||
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| init | ||
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| ipc | ||
| kernel | ||
| lib | ||
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| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
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| Kbuild | ||
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| README | ||
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 reStructuredText 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.