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.
David Arinzon
authored
The device supports a PCIe optimization hint, which indicates on which NUMA the queue is currently processed. This hint is utilized by PCIe in order to reduce its access time by accessing the correct NUMA resources and maintaining cache coherence. The driver calls the register update for the hint (called TPH - TLP Processing Hint) during the NAPI loop. Though the update is expected upon a NUMA change (when a queue is moved from one NUMA to the other), the current logic performs a register update when the queue is moved to a different CPU, but the CPU is not necessarily in a different NUMA. The changes include: 1. Performing the TPH update only when the queue has switched a NUMA node. 2. Moving the TPH update call to be triggered only when NAPI was scheduled from interrupt context, as opposed to a busy-polling loop. This is due to the fact that during busy-polling, the frequency of CPU switches for a particular queue is significantly higher, thus, the likelihood to switch NUMA is much higher. Therefore, providing the frequent updates to the device upon a NUMA update are unlikely to be beneficial. Fixes: 1738cd3e ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)") Signed-off-by:David Arinzon <darinzon@amazon.com> Signed-off-by:
David S. Miller <davem@davemloft.net>