84cda1a608
After the conversion to folio interfaces (but without the patch to enable larger folio allocation), there is an LTP report about observable performance drop on metadata heavy operations. https://lore.kernel.org/linux-btrfs/202312221750.571925bd-oliver.sang@intel.com/ This drop is caused by the extra code of calculating the folio_size()/folio_shift(), instead of the old hard coded PAGE_SIZE/PAGE_SHIFT. To slightly reduce the overhead, just cache both folio_size and folio_shift in extent_buffer. The two new members (u32 folio_size and u8 folio_shift) are stored inside the holes of extent_buffer. folio_size is shared with len, which is reduced to u32. The size of eb does not change. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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.