5d272dd1b3
Hardcoding the number of CPUs at compile time does improve code generation, but if you get it wrong the result will be confusion. We already limited this earlier to only "experts" (see commit fe5759d5bfda "cpumask: limit visibility of FORCE_NR_CPUS"), but with distro kernel configs often having EXPERT enabled, that turns out to not be much of a limit. To quote the philosophers at Disney: "Everyone can be an expert. And when everyone's an expert, no one will be". There's a runtime warning if you then set nr_cpus to anything but the forced number, but apparently that can be ignored too [1] and by then it's pretty much too late anyway. If we had some real way to limit this to "embedded only", maybe it would be worth it, but let's see if anybody even notices that the option is gone. We need to simplify kernel configuration anyway. Link: https://lore.kernel.org/all/20240618105036.208a8860@rorschach.local.home/ [1] Reported-by: Steven Rostedt <rostedt@goodmis.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Paul McKenney <paulmck@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Yury Norov <yury.norov@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.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 reStructuredText 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.