6598b91b5a
This change gives a dramatic performance improvement in the hot path, since many costly spin_lock_irqsave() calls can be avoided. On an i.MX8MM system with a MCP2518FD CAN controller connected via SPI, the time the driver takes to handle interrupts, or in other words the time the IRQ line of the CAN controller stays low is mainly dominated by the time it takes to do 3 relatively short sync SPI transfers. The effect of this patch is a reduction of this time from 136us down to only 98us. Suggested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David Jander <david@protonic.nl> Link: https://lore.kernel.org/r/20220524091808.2269898-1-david@protonic.nl Signed-off-by: Mark Brown <broonie@kernel.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.