920e69bc3d
This adds a new method of doing btree updates - a straight write buffer, implemented as a flat fixed size array. This is only useful when we don't need to read from the btree in order to do the update, and when reading is infrequent - perfect for the LRU btree. This will make LRU btree updates fast enough that we'll be able to use it for persistently indexing buckets by fragmentation, which will be a massive boost to copygc performance. Changes: - A new btree_insert_type enum, for btree_insert_entries. Specifies btree, btree key cache, or btree write buffer. - bch2_trans_update_buffered(): updates via the btree write buffer don't need a btree path, so we need a new update path. - Transaction commit path changes: The update to the btree write buffer both mutates global, and can fail if there isn't currently room. Therefore we do all write buffer updates in the transaction all at once, and also if it fails we have to revert filesystem usage counter changes. If there isn't room we flush the write buffer in the transaction commit error path and retry. - A new persistent option, for specifying the number of entries in the write buffer. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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.