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Saeed Mahameed says: ==================== mlx5 4K UAR The following series of patches optimizes the usage of the UAR area which is contained within the BAR 0-1. Previous versions of the firmware and the driver assumed each system page contains a single UAR. This patch set will query the firmware for a new capability that if published, means that the firmware can support UARs of fixed 4K regardless of system page size. In the case of powerpc, where page size equals 64KB, this means we can utilize 16 UARs per system page. Since user space processes by default consume eight UARs per context this means that with this change a process will need a single system page to fulfill that requirement and in fact make use of more UARs which is better in terms of performance. In addition to optimizing user-space processes, we introduce an allocator that can be used by kernel consumers to allocate blue flame registers (which are areas within a UAR that are used to write doorbells). This provides further optimization on using the UAR area since the Ethernet driver makes use of a single blue flame register per system page and now it will use two blue flame registers per 4K. The series also makes changes to naming conventions and now the terms used in the driver code match the terms used in the PRM (programmers reference manual). Thus, what used to be called UUAR (micro UAR) is now called BFREG (blue flame register). In order to support compatibility between different versions of library/driver/firmware, the library has now means to notify the kernel driver that it supports the new scheme and the kernel can notify the library if it supports this extension. So mixed versions of libraries can run concurrently without any issues. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.