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af4b6b8edf
check_swap_activate() will lookup block mapping via bmap() one by one, so its performance is very bad, this patch introduces check_swap_activate_fast() to use f2fs_fiemap() to boost this process, since f2fs_fiemap() will lookup block mappings in batch, therefore, it can improve swapon()'s performance significantly. Note that this enhancement only works when page size is equal to f2fs' block size. Testcase: (backend device: zram) - touch file - pin & fallocate file to 8GB - mkswap file - swapon file Before: real 0m2.999s user 0m0.000s sys 0m2.980s After: real 0m0.081s user 0m0.000s sys 0m0.064s Signed-off-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.