e4e6019ce5
[ Upstream commit 76ed0dd96eeb2771b21bf5dcbd88326ef89ee0ed ] During NFSv2 and NFSv3 READDIR/PLUS operations, NFSD advances rq_next_page to the full size of the client-requested buffer, then releases all those pages at the end of the request. The next request to use that nfsd thread has to refill the pages. NFSD does this even when the dirlist in the reply is small. With NFSv3 clients that send READDIR operations with large buffer sizes, that can be 256 put_page/alloc_page pairs per READDIR request, even though those pages often remain unused. We can save some work by not releasing dirlist buffer pages that were not used to form the READDIR Reply. I've left the NFSv2 code alone since there are never more than three pages involved in an NFSv2 READDIR Reply. Eventually we should nail down why these pages need to be released at all in order to avoid allocating and releasing pages unnecessarily. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.