39d3c0b596
We call xfs_dir_ino_validate() for every dir entry in a directory when doing validity checking of the directory. It calls xfs_verify_dir_ino() then emits a corruption report if bad or does error injection if good. It is extremely costly: 43.27% [kernel] [k] xfs_dir3_leaf_check_int 10.28% [kernel] [k] __xfs_dir3_data_check 6.61% [kernel] [k] xfs_verify_dir_ino 4.16% [kernel] [k] xfs_errortag_test 4.00% [kernel] [k] memcpy 3.48% [kernel] [k] xfs_dir_ino_validate 7% of the cpu usage in this directory traversal workload is xfs_dir_ino_validate() doing absolutely nothing. We don't need error injection to simulate a bad inode numbers in the directory structure because we can do that by fuzzing the structure on disk. And we don't need a corruption report, because the __xfs_dir3_data_check() will emit one if the inode number is bad. So just call xfs_verify_dir_ino() directly here, and get rid of all this unnecessary overhead: 40.30% [kernel] [k] xfs_dir3_leaf_check_int 10.98% [kernel] [k] __xfs_dir3_data_check 8.10% [kernel] [k] xfs_verify_dir_ino 4.42% [kernel] [k] memcpy 2.22% [kernel] [k] xfs_dir2_data_get_ftype 1.52% [kernel] [k] do_raw_spin_lock Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <djwong@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.