acd2eda2b2
commit f4469f3858352ad1197434557150b1f7086762a0 upstream. Current code uses the specified ring buffer size (either the default of 128 Kbytes or a module parameter specified value) to encompass the one page ring buffer header plus the actual ring itself. When the page size is 4K, carving off one page for the header isn't significant. But when the page size is 64K on ARM64, only half of the default 128 Kbytes is left for the actual ring. While this doesn't break anything, the smaller ring size could be a performance bottleneck. Fix this by applying the VMBUS_RING_SIZE macro to the specified ring buffer size. This macro adds a page for the header, and rounds up the size to a page boundary, using the page size for which the kernel is built. Use this new size for subsequent ring buffer calculations. For example, on ARM64 with 64K page size and the default ring size, this results in the actual ring being 128 Kbytes, which is intended. Cc: stable@vger.kernel.org # 5.15.x Signed-off-by: Michael Kelley <mhklinux@outlook.com> Link: https://lore.kernel.org/r/20240122170956.496436-1-mhklinux@outlook.com Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.