4c469798ee
Currently struct btrfs_delayed_item has a base size of 96 bytes, but its size can be decreased by doing the following 2 tweaks: 1) Change data_len from u32 to u16. Our maximum possible leaf size is 64K, so the data_len can never be larger than that, and in fact it is always much smaller than that. The max length for a dentry's name is ensured at the VFS level (PATH_MAX, 4096 bytes) and in struct btrfs_inode_ref and btrfs_dir_item we use a u16 to store the name's length; 2) Change 'ins_or_del' to a 1 bit enum, which is all we need since it can only have 2 values. After this there's also no longer the need to BUG_ON() before using 'ins_or_del' in several places. Also rename the field from 'ins_or_del' to 'type', which is more clear. These two tweaks decrease the size of struct btrfs_delayed_item from 96 bytes down to 88 bytes. A previous patch already reduced the size of this structure by 16 bytes, but an upcoming change will increase its size by 16 bytes (adding a struct list_head element). Signed-off-by: Filipe Manana <fdmanana@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.