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6fcaebac66
By profiling f2fs compression works, I've found vmap() callings have unexpected hikes in the execution time in our test environment and those are bottlenecks of f2fs decompression path. Changing these with vm_map_ram(), we can enhance f2fs decompression speed pretty much. [Verification] Android Pixel 3(ARM64, 6GB RAM, 128GB UFS) Turned on only 0-3 little cores(at 1.785GHz) dd if=/dev/zero of=dummy bs=1m count=1000 echo 3 > /proc/sys/vm/drop_caches dd if=dummy of=/dev/zero bs=512k - w/o compression - 1048576000 bytes (0.9 G) copied, 2.082554 s, 480 M/s 1048576000 bytes (0.9 G) copied, 2.081634 s, 480 M/s 1048576000 bytes (0.9 G) copied, 2.090861 s, 478 M/s - before patch - 1048576000 bytes (0.9 G) copied, 7.407527 s, 135 M/s 1048576000 bytes (0.9 G) copied, 7.283734 s, 137 M/s 1048576000 bytes (0.9 G) copied, 7.291508 s, 137 M/s - after patch - 1048576000 bytes (0.9 G) copied, 1.998959 s, 500 M/s 1048576000 bytes (0.9 G) copied, 1.987554 s, 503 M/s 1048576000 bytes (0.9 G) copied, 1.986380 s, 503 M/s Signed-off-by: Daeho Jeong <daehojeong@google.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.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.