7d04b0b13b
Every mvpp2 unit can use up to 8 buffers mapped by the BM (the HW buffer manager). The HW will place the frames in the buffer pool depending on the frame size: short (< 128 bytes), long (< 1664) or jumbo (up to 9856). As any unit can have up to 4 ports, the driver allocates only 2 pools, one for small and one long frames, and share them between ports. When the first port MTU is set higher than 1664 bytes, a third pool is allocated for jumbo frames. This shared allocation makes impossible to use percpu allocators, and creates contention between HW queues. If possible, i.e. if the number of possible CPU are less than 8 and jumbo frames are not used, switch to a new scheme: allocate 8 per-cpu pools for short and long frames and bind every pool to an RXQ. When the first port MTU is set higher than 1664 bytes, the allocation scheme is reverted to the old behaviour (3 shared pools), and when all ports MTU are lowered, the per-cpu buffers are allocated again. Signed-off-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.