86f3cd1b58
We always punt async buffered writes to an io-wq helper, as the core kernel does not have IOCB_NOWAIT support for that. Most buffered async writes complete very quickly, as it's just a copy operation. This means that doing multiple locking roundtrips on the shared wqe lock for each buffered write is wasteful. Additionally, buffered writes are hashed work items, which means that any buffered write to a given file is serialized. Keep identicaly hashed work items contiguously in @wqe->work_list, and track a tail for each hash bucket. On dequeue of a hashed item, splice all of the same hash in one go using the tracked tail. Until the batch is done, the caller doesn't have to synchronize with the wqe or worker locks again. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.