mainlining shenanigans
11f552e217
Linux can run in all sorts of physical machines and VMs where write combining may or may not be supported. Currently there is no way to reliably tell if the system supports WC, or not. The driver uses WC to optimize posting work to the HCA, and getting this wrong in either direction can cause a significant performance loss. Add a test in mlx5_ib initialization process to test whether write-combining is supported on the machine. The test will run as part of the enable_driver callback to ensure that the test runs after the device is setup and can create and modify the QP needed, but runs before the device is exposed to the users. The test opens UD QP and posts NOP WQEs, the WQE written to the BlueFlame is different from the WQE in memory, requesting CQE only on the BlueFlame WQE. By checking whether we received a completion on one of these WQEs we can know if BlueFlame succeeded and this write-combining must be supported. Change reporting of BlueFlame support to be dependent on write-combining support instead of the FW's guess as to what the machine can do. Link: https://lore.kernel.org/r/20191027062234.10993-1-leon@kernel.org Signed-off-by: Michael Guralnik <michaelgur@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.