1f6b821aef
last_piece is for the last piece in the current data item, not in the
entire data payload of the message. This is harmful for messages with
multiple data items. On top of that, we don't need to signal the end
of a data payload either because it is always followed by a footer.
We used to signal "more" unconditionally, until commit fe38a2b67bc6
("libceph: start defining message data cursor"). Part of a large
series, it introduced cursor->last_piece and also mistakenly inverted
the hint by passing last_piece for "more". This was corrected with
commit c2cfa1940097 ("libceph: Fix ceph_tcp_sendpage()'s more boolean
usage").
As it is, last_piece is not helping at all: because Nagle algorithm is
disabled, for a simple message with two 512-byte data items we end up
emitting three packets: front + first data item, second data item and
footer. Go back to the original pre-fe38a2b67bc6 behavior -- a single
packet in most cases.
Signed-off-by: Ilya Dryomov <idryomov@gmail.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.