f847c699cf
Normally, DIO uses in-pllace-update, but in LFS mode, f2fs doesn't allow triggering any in-place-update writes, so we fallback direct write to buffered write, result in bad performance of large size write. This patch adds to support triggering out-place-update for direct IO to enhance its performance. Note that it needs to exclude direct read IO during direct write, since new data writing to new block address will no be valid until write finished. storage: zram time xfs_io -f -d /mnt/f2fs/file -c "pwrite 0 1073741824" -c "fsync" Before: real 0m13.061s user 0m0.327s sys 0m12.486s After: real 0m6.448s user 0m0.228s sys 0m6.212s 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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.