+ cpumask-limit-visibility-of-force_nr_cpus.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: cpumask: limit visibility of FORCE_NR_CPUS
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     cpumask-limit-visibility-of-force_nr_cpus.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/cpumask-limit-visibility-of-force_nr_cpus.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Yury Norov <yury.norov@gmail.com>
Subject: cpumask: limit visibility of FORCE_NR_CPUS
Date: Wed, 19 Oct 2022 15:59:39 -0700

In current form, FORCE_NR_CPUS is visible to all users building their
kernels, even not experts.  It is also set in allmodconfig or
allyesconfig, which is not a correct behavior.

The 'choice' and unused config UNFORCE_NR_CPUS are used to ensure that
auto-generated configs that try to enable as much options as possible,
like allmodconfig, don't enable FORCE_NR_CPUS.

Link: https://lkml.kernel.org/r/20221019225939.1646349-1-yury.norov@gmail.com
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sander Vanheule <sander@svanheule.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/Kconfig |   31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

--- a/lib/Kconfig~cpumask-limit-visibility-of-force_nr_cpus
+++ a/lib/Kconfig
@@ -528,14 +528,31 @@ config CPUMASK_OFFSTACK
 	  them on the stack.  This is a bit more expensive, but avoids
 	  stack overflow.
 
+choice
+	prompt "Number of CPUs detection method"
+	default UNFORCE_NR_CPUS
+	depends on SMP && EXPERT
+	help
+	  Select between boot-time and compile-time detection of number
+	  of CPUs. If it's possible to provide exact number of CPUs at
+	  compile-time, kernel code may be optimized better.
+	  For general-purpose kernel, choose "boot time" option.
+
+config UNFORCE_NR_CPUS
+	bool "Set number of CPUs at boot time"
+	help
+	  Choose it if you build general-purpose kernel and want to rely
+	  on kernel to detect actual number of CPUs.
+
 config FORCE_NR_CPUS
-       bool "NR_CPUS is set to an actual number of CPUs"
-       depends on SMP
-       help
-         Say Yes if you have NR_CPUS set to an actual number of possible
-         CPUs in your system, not to a default value. This forces the core
-         code to rely on compile-time value and optimize kernel routines
-         better.
+	bool "Set number of CPUs at compile time"
+	help
+	  Choose it if NR_CPUS corresponds to an actual number of
+	  possible CPUs in your system. This forces the core code
+	  to rely on compile-time value and optimize kernel routines
+	  better.
+
+endchoice
 
 config CPU_RMAP
 	bool
_

Patches currently in -mm which might be from yury.norov@gmail.com are

cpumask-limit-visibility-of-force_nr_cpus.patch